Merge pull request #950 from TomHarte/Enterprise

Adds emulation of the Enterprise
2025-04-06 10:38:16 +00:00 · 2021-06-29 21:37:38 -04:00 · 2021-06-29 21:37:38 -04:00 · c04a395499
commit c04a395499
parent 1f686c4e6b 1c424833a9
47 changed files with 3286 additions and 313 deletions
--- a/Analyser/Machines.hpp
+++ b/Analyser/Machines.hpp
@ -19,6 +19,7 @@ enum class Machine {
 	AtariST,
 	ColecoVision,
 	Electron,
+	Enterprise,
 	Macintosh,
 	MasterSystem,
 	MSX,
--- a/Analyser/Static/Enterprise/StaticAnalyser.cpp
+++ b/Analyser/Static/Enterprise/StaticAnalyser.cpp
@ -0,0 +1,34 @@
+//
+//  StaticAnalyser.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 24/06/2021.
+//  Copyright 2021 Thomas Harte. All rights reserved.
+//
+
+#include "StaticAnalyser.hpp"
+#include "Target.hpp"
+
+Analyser::Static::TargetList Analyser::Static::Enterprise::GetTargets(const Media &media, const std::string &, TargetPlatform::IntType) {
+	// This analyser can comprehend disks only.
+	if(media.disks.empty()) return {};
+
+	// Otherwise, for now: wave it through.
+	Analyser::Static::TargetList targets;
+
+	using Target = Analyser::Static::Enterprise::Target;
+	auto *const target = new Target;
+	target->media = media;
+
+	// Always require a BASIC.
+	target->basic_version = Target::BASICVersion::Any;
+
+	// If this is a single-sided floppy disk, guess the Macintosh 512kb.
+	if(!media.disks.empty()) {
+		target->dos = Target::DOS::EXDOS;
+	}
+
+	targets.push_back(std::unique_ptr<Analyser::Static::Target>(target));
+
+	return targets;
+}
--- a/Analyser/Static/Enterprise/StaticAnalyser.hpp
+++ b/Analyser/Static/Enterprise/StaticAnalyser.hpp
@ -0,0 +1,27 @@
+//
+//  StaticAnalyser.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 24/06/2021.
+//  Copyright 2018 Thomas Harte. All rights reserved.
+//
+
+#ifndef Analyser_Static_Enterprise_StaticAnalyser_hpp
+#define Analyser_Static_Enterprise_StaticAnalyser_hpp
+
+#include "../StaticAnalyser.hpp"
+#include "../../../Storage/TargetPlatforms.hpp"
+#include <string>
+
+namespace Analyser {
+namespace Static {
+namespace Enterprise {
+
+TargetList GetTargets(const Media &media, const std::string &file_name, TargetPlatform::IntType potential_platforms);
+
+}
+}
+}
+
+
+#endif /* Analyser_Static_Enterprise_StaticAnalyser_hpp */
--- a/Analyser/Static/Enterprise/Target.hpp
+++ b/Analyser/Static/Enterprise/Target.hpp
@ -0,0 +1,50 @@
+//
+//  Target.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 14/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#ifndef Analyser_Static_Enterprise_Target_h
+#define Analyser_Static_Enterprise_Target_h
+
+#include "../../../Reflection/Enum.hpp"
+#include "../../../Reflection/Struct.hpp"
+#include "../StaticAnalyser.hpp"
+
+namespace Analyser {
+namespace Static {
+namespace Enterprise {
+
+struct Target: public Analyser::Static::Target, public Reflection::StructImpl<Target> {
+	ReflectableEnum(Model, Enterprise64, Enterprise128, Enterprise256);
+	ReflectableEnum(EXOSVersion, v10, v20, v21, v23, Any);
+	ReflectableEnum(BASICVersion, v10, v11, v21, Any, None);
+	ReflectableEnum(DOS, EXDOS, None);
+
+	Model model = Model::Enterprise128;
+	EXOSVersion exos_version = EXOSVersion::Any;
+	BASICVersion basic_version = BASICVersion::None;
+	DOS dos = DOS::None;
+
+	Target() : Analyser::Static::Target(Machine::Enterprise) {
+		if(needs_declare()) {
+			AnnounceEnum(Model);
+			AnnounceEnum(EXOSVersion);
+			AnnounceEnum(BASICVersion);
+			AnnounceEnum(DOS);
+
+			DeclareField(model);
+			DeclareField(exos_version);
+			DeclareField(basic_version);
+			DeclareField(dos);
+		}
+	}
+};
+
+}
+}
+}
+
+#endif /* Analyser_Static_Enterprise_Target_h */
--- a/Analyser/Static/StaticAnalyser.cpp
+++ b/Analyser/Static/StaticAnalyser.cpp
@ -23,6 +23,7 @@
 #include "Coleco/StaticAnalyser.hpp"
 #include "Commodore/StaticAnalyser.hpp"
 #include "DiskII/StaticAnalyser.hpp"
+#include "Enterprise/StaticAnalyser.hpp"
 #include "Macintosh/StaticAnalyser.hpp"
 #include "MSX/StaticAnalyser.hpp"
 #include "Oric/StaticAnalyser.hpp"
@ -43,9 +44,9 @@
 #include "../../Storage/Disk/DiskImage/Formats/MacintoshIMG.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/G64.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/DMK.hpp"
+#include "../../Storage/Disk/DiskImage/Formats/FAT12.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/HFE.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/MSA.hpp"
-#include "../../Storage/Disk/DiskImage/Formats/MSXDSK.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/NIB.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/OricMFMDSK.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/SSD.hpp"
@ -147,7 +148,7 @@ static Media GetMediaAndPlatforms(const std::string &file_name, TargetPlatform::
 	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::MacintoshIMG>, TargetPlatform::Macintosh)	// DSK (Macintosh, floppy disk)
 	Format("dsk", result.mass_storage_devices, MassStorage::HFV, TargetPlatform::Macintosh)						// DSK (Macintosh, hard disk, single volume image)
 	Format("dsk", result.mass_storage_devices, MassStorage::DSK, TargetPlatform::Macintosh)						// DSK (Macintosh, hard disk, full device image)
-	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::MSXDSK>, TargetPlatform::MSX)				// DSK (MSX)
+	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::FAT12>, TargetPlatform::MSX)				// DSK (MSX)
 	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::OricMFMDSK>, TargetPlatform::Oric)			// DSK (Oric)
 	Format("g64", result.disks, Disk::DiskImageHolder<Storage::Disk::G64>, TargetPlatform::Commodore)			// G64
 	Format(	"hfe",
@ -157,6 +158,7 @@ static Media GetMediaAndPlatforms(const std::string &file_name, TargetPlatform::
 			// HFE (TODO: switch to AllDisk once the MSX stops being so greedy)
 	Format("img", result.disks, Disk::DiskImageHolder<Storage::Disk::MacintoshIMG>, TargetPlatform::Macintosh)		// IMG (DiskCopy 4.2)
 	Format("image", result.disks, Disk::DiskImageHolder<Storage::Disk::MacintoshIMG>, TargetPlatform::Macintosh)	// IMG (DiskCopy 4.2)
+	Format("img", result.disks, Disk::DiskImageHolder<Storage::Disk::FAT12>, TargetPlatform::Enterprise)		// IMG (Enterprise/MS-DOS style)
 	Format("msa", result.disks, Disk::DiskImageHolder<Storage::Disk::MSA>, TargetPlatform::AtariST)				// MSA
 	Format("nib", result.disks, Disk::DiskImageHolder<Storage::Disk::NIB>, TargetPlatform::DiskII)				// NIB
 	Format("o", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)											// O
@ -256,6 +258,7 @@ TargetList Analyser::Static::GetTargets(const std::string &file_name) {
 	Append(Coleco);
 	Append(Commodore);
 	Append(DiskII);
+	Append(Enterprise);
 	Append(Macintosh);
 	Append(MSX);
 	Append(Oric);
--- a/ClockReceiver/ClockReceiver.hpp
+++ b/ClockReceiver/ClockReceiver.hpp
@ -213,7 +213,7 @@ class HalfCycles: public WrappedInt<HalfCycles> {

 		/*!
 			Severs from @c this the effect of dividing by @c divisor; @c this will end up with
-			the value of @c this modulo @c divisor and @c divided by @c divisor is returned.
+			the value of @c this modulo @c divisor . @c this divided by @c divisor is returned.
 		*/
 		forceinline Cycles divide_cycles(const Cycles &divisor) {
 			const HalfCycles half_divisor = HalfCycles(divisor);
--- a/ClockReceiver/JustInTime.hpp
+++ b/ClockReceiver/JustInTime.hpp
@ -103,9 +103,9 @@ template <class T, class LocalTimeScale = HalfCycles, int multiplier = 1, int di
 			}

 			if constexpr (has_sequence_points<T>::value) {
-				time_until_event_ -= rhs;
+				time_until_event_ -= rhs * multiplier;
 				if(time_until_event_ <= LocalTimeScale(0)) {
-					time_overrun_ = time_until_event_;
+					time_overrun_ = time_until_event_ / divider;
 					flush();
 					update_sequence_point();
 					return true;
@ -145,13 +145,21 @@ template <class T, class LocalTimeScale = HalfCycles, int multiplier = 1, int di

 		/// @returns the amount of time since the object was last flushed, in the target time scale.
 		[[nodiscard]] forceinline TargetTimeScale time_since_flush() const {
-			// TODO: does this handle conversions properly where TargetTimeScale != LocalTimeScale?
 			if constexpr (divider == 1) {
 				return time_since_update_;
 			}
 			return TargetTimeScale(time_since_update_.as_integral() / divider);
 		}

+		/// @returns the amount of time since the object was last flushed, plus the local time scale @c offset,
+		/// converted to the target time scale.
+		[[nodiscard]] forceinline TargetTimeScale time_since_flush(LocalTimeScale offset) const {
+			if constexpr (divider == 1) {
+				return time_since_update_ + offset;
+			}
+			return TargetTimeScale((time_since_update_ + offset).as_integral() / divider);
+		}
+
 		/// Flushes all accumulated time.
 		///
 		/// This does not affect this actor's record of when the next sequence point will occur.
@ -185,7 +193,7 @@ template <class T, class LocalTimeScale = HalfCycles, int multiplier = 1, int di
 		/// @returns the number of cycles until the next sequence-point-based flush, if the embedded object
 		/// supports sequence points; @c LocalTimeScale() otherwise.
 		[[nodiscard]] LocalTimeScale cycles_until_implicit_flush() const {
-			return time_until_event_;
+			return time_until_event_ / divider;
 		}

 		/// Indicates whether a sequence-point-caused flush will occur if the specified period is added.
@ -196,10 +204,43 @@ template <class T, class LocalTimeScale = HalfCycles, int multiplier = 1, int di
 			return rhs >= time_until_event_;
 		}

+		/// Indicates the amount of time, in the local time scale, until the first local slot that falls wholly
+		/// after @c duration, if that delay were to occur in @c offset units of time from now.
+		[[nodiscard]] forceinline LocalTimeScale back_map(TargetTimeScale duration, TargetTimeScale offset) const {
+			// A 1:1 mapping is easy.
+			if constexpr (multiplier == 1 && divider == 1) {
+				return duration;
+			}
+
+			// Work out when this query is placed, and the time to which it relates
+			const auto base = time_since_update_ + offset * divider;
+			const auto target = base + duration * divider;
+
+			// Figure out the number of whole input steps that is required to get
+			// past target, and subtract the number of whole input steps necessary
+			// to get to base.
+			const auto steps_to_base = base.as_integral() / multiplier;
+			const auto steps_to_target = (target.as_integral() + divider - 1) / multiplier;
+
+			return LocalTimeScale(steps_to_target - steps_to_base);
+		}
+
 		/// Updates this template's record of the next sequence point.
 		void update_sequence_point() {
 			if constexpr (has_sequence_points<T>::value) {
-				time_until_event_ = object_.get_next_sequence_point();
+				// Keep a fast path where no conversions will be applied; if conversions are
+				// going to be applied then do a direct max -> max translation rather than
+				// allowing the arithmetic to overflow.
+				if constexpr (divider == 1 && std::is_same_v<LocalTimeScale, TargetTimeScale>) {
+					time_until_event_ = object_.get_next_sequence_point();
+				} else {
+					const auto time = object_.get_next_sequence_point();
+					if(time == TargetTimeScale::max()) {
+						time_until_event_ = LocalTimeScale::max();
+					} else {
+						time_until_event_ = time * divider;
+					}
+				}
 				assert(time_until_event_ > LocalTimeScale(0));
 			}
 		}
--- a/Components/1770/1770.cpp
+++ b/Components/1770/1770.cpp
@ -276,7 +276,10 @@ void WD1770::posit_event(int new_event_type) {
 		goto test_type1_type;

 	begin_type1_spin_up:
-		if((command_&0x08) || get_drive().get_motor_on()) goto test_type1_type;
+		if((command_&0x08) || get_drive().get_motor_on()) {
+			set_motor_on(true);
+			goto test_type1_type;
+		}
 		SPIN_UP();

 	test_type1_type:
@ -387,7 +390,10 @@ void WD1770::posit_event(int new_event_type) {
 		distance_into_section_ = 0;

 		if((command_&0x08) && has_motor_on_line()) goto test_type2_delay;
-		if(!has_motor_on_line() && !has_head_load_line()) goto test_type2_delay;
+		if(!has_motor_on_line() && !has_head_load_line()) {
+			if(has_motor_on_line()) set_motor_on(true);
+			goto test_type2_delay;
+		}

 		if(has_motor_on_line()) goto begin_type2_spin_up;
 		goto begin_type2_load_head;
--- a/InstructionSets/CachingExecutor.hpp
+++ b/InstructionSets/CachingExecutor.hpp
@ -9,7 +9,7 @@
 #ifndef CachingExecutor_hpp
 #define CachingExecutor_hpp

-#include "Sizes.hpp"
+#include "../Numeric/Sizes.hpp"

 #include <array>
 #include <cstdint>
--- a/InstructionSets/Disassembler.hpp
+++ b/InstructionSets/Disassembler.hpp
@ -9,7 +9,7 @@
 #ifndef Disassembler_hpp
 #define Disassembler_hpp

-#include "Sizes.hpp"
+#include "../Numeric/Sizes.hpp"

 #include <list>
 #include <map>
--- a/Machines/Apple/Macintosh/Keyboard.hpp
+++ b/Machines/Apple/Macintosh/Keyboard.hpp
@ -271,7 +271,7 @@ class Keyboard {
 		/// so this may not be valid prior to Mode::PerformingCommand.
 		int command_ = 0;
 		/// Populated during PerformingCommand as the response to the most-recently-received command, this
-		/// is then shifted out to teh host computer. So it is guaranteed valid at the beginning of Mode::SendingResponse,
+		/// is then shifted out to the host computer. So it is guaranteed valid at the beginning of Mode::SendingResponse,
 		/// but not afterwards.
 		int response_ = 0;

--- a/Machines/Enterprise/Dave.cpp
+++ b/Machines/Enterprise/Dave.cpp
@ -0,0 +1,313 @@
+//
+//  Dave.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 22/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#include "Dave.hpp"
+
+using namespace Enterprise::Dave;
+
+// MARK: - Audio generator
+
+Audio::Audio(Concurrency::DeferringAsyncTaskQueue &audio_queue) :
+	audio_queue_(audio_queue) {}
+
+void Audio::write(uint16_t address, uint8_t value) {
+	address &= 0xf;
+	audio_queue_.defer([address, value, this] {
+		switch(address) {
+			case 0:	case 2:	case 4:
+				channels_[address >> 1].reload = (channels_[address >> 1].reload & 0xff00) | value;
+			break;
+			case 1:	case 3:	case 5:
+				channels_[address >> 1].reload = uint16_t((channels_[address >> 1].reload & 0x00ff) | ((value & 0xf) << 8));
+				channels_[address >> 1].distortion = Channel::Distortion((value >> 4)&3);
+				channels_[address >> 1].high_pass = value & 0x40;
+				channels_[address >> 1].ring_modulate = value & 0x80;
+			break;
+			case 6:
+				noise_.frequency = Noise::Frequency(value&3);
+				noise_.polynomial = Noise::Polynomial((value >> 2)&3);
+				noise_.swap_polynomial = value & 0x10;
+				noise_.low_pass = value & 0x20;
+				noise_.high_pass = value & 0x40;
+				noise_.ring_modulate = value & 0x80;
+			break;
+
+			case 7:
+				channels_[0].sync = value & 0x01;
+				channels_[1].sync = value & 0x02;
+				channels_[2].sync = value & 0x04;
+				use_direct_output_[0] = value & 0x08;
+				use_direct_output_[1] = value & 0x10;
+				// Interrupt bits are handled separately.
+			break;
+
+			case 8: case 9: case 10:
+				channels_[address - 8].amplitude[0] = value & 0x3f;
+			break;
+			case 12: case 13: case 14:
+				channels_[address - 12].amplitude[1] = value & 0x3f;
+			break;
+			case 11:	noise_.amplitude[0] = value & 0x3f;		break;
+			case 15:	noise_.amplitude[1] = value & 0x3f;		break;
+		}
+	});
+}
+
+void Audio::set_sample_volume_range(int16_t range) {
+	audio_queue_.defer([range, this] {
+		volume_ = range / (63*4);
+	});
+}
+
+void Audio::update_channel(int c) {
+	if(channels_[c].sync) {
+		channels_[c].count = channels_[c].reload;
+		channels_[c].output <<= 1;
+		return;
+	}
+
+	auto output = channels_[c].output & 1;
+	channels_[c].output <<= 1;
+	if(!channels_[c].count) {
+		channels_[c].count = channels_[c].reload;
+
+		if(channels_[c].distortion == Channel::Distortion::None)
+			output ^= 1;
+		else
+			output = poly_state_[int(channels_[c].distortion)];
+
+		if(channels_[c].high_pass && (channels_[(c+1)%3].output&3) == 2) {
+			output = 0;
+		}
+		if(channels_[c].ring_modulate) {
+			output = ~(output ^ channels_[(c+2)%3].output) & 1;
+		}
+	} else {
+		--channels_[c].count;
+	}
+
+	channels_[c].output |= output;
+}
+
+void Audio::get_samples(std::size_t number_of_samples, int16_t *target) {
+	for(size_t c = 0; c < number_of_samples; c++) {
+		poly_state_[int(Channel::Distortion::FourBit)] = poly4_.next();
+		poly_state_[int(Channel::Distortion::FiveBit)] = poly5_.next();
+		poly_state_[int(Channel::Distortion::SevenBit)] = poly7_.next();
+		if(noise_.swap_polynomial) {
+			poly_state_[int(Channel::Distortion::SevenBit)] = poly_state_[int(Channel::Distortion::None)];
+		}
+
+		// Update tone channels.
+		update_channel(0);
+		update_channel(1);
+		update_channel(2);
+
+		// Update noise channel.
+
+		// Step 1: decide whether there is a tick to apply.
+		bool noise_tick = false;
+		if(noise_.frequency == Noise::Frequency::DivideByFour) {
+			if(!noise_.count) {
+				noise_tick = true;
+				noise_.count = 3;
+			} else {
+				--noise_.count;
+			}
+		} else {
+			noise_tick = (channels_[int(noise_.frequency) - 1].output&3) == 2;
+		}
+
+		// Step 2: tick if necessary.
+		if(noise_tick) {
+			switch(noise_.polynomial) {
+				case Noise::Polynomial::SeventeenBit:
+					poly_state_[int(Channel::Distortion::None)] = uint8_t(poly17_.next());
+				break;
+				case Noise::Polynomial::FifteenBit:
+					poly_state_[int(Channel::Distortion::None)] = uint8_t(poly15_.next());
+				break;
+				case Noise::Polynomial::ElevenBit:
+					poly_state_[int(Channel::Distortion::None)] = uint8_t(poly11_.next());
+				break;
+				case Noise::Polynomial::NineBit:
+					poly_state_[int(Channel::Distortion::None)] = uint8_t(poly9_.next());
+				break;
+			}
+
+			noise_.output <<= 1;
+			noise_.output |= poly_state_[int(Channel::Distortion::None)];
+
+			// Low pass: sample channel 2 on downward transitions of the prima facie output.
+			if(noise_.low_pass) {
+				if((noise_.output & 3) == 2) {
+					noise_.output = (noise_.output & ~1) | (channels_[2].output & 1);
+				} else {
+					noise_.output = (noise_.output & ~1) | (noise_.output & 1);
+				}
+			}
+		}
+
+		// Apply noise high-pass at the rate of the tone channels.
+		if(noise_.high_pass && (channels_[0].output & 3) == 2) {
+			noise_.output &= ~1;
+		}
+
+		// Update noise ring modulation, if any.
+		if(noise_.ring_modulate) {
+			noise_.final_output = !((noise_.output ^ channels_[1].output) & 1);
+		} else {
+			noise_.final_output = noise_.output & 1;
+		}
+
+		// I'm unclear on the details of the time division multiplexing so,
+		// for now, just sum the outputs.
+		target[(c << 1) + 0] =
+			volume_ *
+				(use_direct_output_[0] ?
+					channels_[0].amplitude[0]
+					: (
+						channels_[0].amplitude[0] * (channels_[0].output & 1) +
+						channels_[1].amplitude[0] * (channels_[1].output & 1) +
+						channels_[2].amplitude[0] * (channels_[2].output & 1) +
+						noise_.amplitude[0] * noise_.final_output
+				));
+
+		target[(c << 1) + 1] =
+			volume_ *
+				(use_direct_output_[1] ?
+					channels_[0].amplitude[1]
+					: (
+						channels_[0].amplitude[1] * (channels_[0].output & 1) +
+						channels_[1].amplitude[1] * (channels_[1].output & 1) +
+						channels_[2].amplitude[1] * (channels_[2].output & 1) +
+						noise_.amplitude[1] * noise_.final_output
+				));
+	}
+}
+
+// MARK: - Interrupt source
+
+uint8_t TimedInterruptSource::get_new_interrupts() {
+	const uint8_t result = interrupts_;
+	interrupts_ = 0;
+	return result;
+}
+
+void TimedInterruptSource::write(uint16_t address, uint8_t value) {
+	address &= 15;
+	switch(address) {
+		default: break;
+
+		case 0: case 2:
+			channels_[address >> 1].reload = (channels_[address >> 1].reload & 0xff00) | value;
+		break;
+		case 1:	case 3:
+			channels_[address >> 1].reload = uint16_t((channels_[address >> 1].reload & 0x00ff) | ((value & 0xf) << 8));
+		break;
+
+		case 7: {
+			channels_[0].sync = value & 0x01;
+			channels_[1].sync = value & 0x02;
+
+			const InterruptRate rate = InterruptRate((value >> 5) & 3);
+			if(rate != rate_) {
+				rate_ = InterruptRate((value >> 5) & 3);
+
+				if(rate_ >= InterruptRate::ToneGenerator0) {
+					programmable_level_ = channels_[int(rate_) - int(InterruptRate::ToneGenerator0)].level;
+				} else {
+					programmable_offset_ = programmble_reload(rate_);
+				}
+			}
+		} break;
+	}
+}
+
+void TimedInterruptSource::update_channel(int c, bool is_linked, int decrement) {
+	if(channels_[c].sync) {
+		channels_[c].value = channels_[c].reload;
+	} else {
+		if(decrement <= channels_[c].value) {
+			channels_[c].value -= decrement;
+		} else {
+			const int num_flips = (decrement - channels_[c].value) / (channels_[c].reload + 1);
+			if(is_linked && num_flips + channels_[c].level >= 2) {
+				interrupts_ |= uint8_t(Interrupt::VariableFrequency);
+			}
+			channels_[c].level ^= (num_flips & 1);
+			channels_[c].value = (decrement - channels_[c].value) % (channels_[c].reload + 1);
+		}
+	}
+}
+
+void TimedInterruptSource::run_for(Cycles cycles) {
+	// Update the 1Hz interrupt.
+	one_hz_offset_ -= cycles;
+	if(one_hz_offset_ <= Cycles(0)) {
+		interrupts_ |= uint8_t(Interrupt::OneHz);
+		one_hz_offset_ += clock_rate;
+	}
+
+	// Update the two tone channels.
+	update_channel(0, rate_ == InterruptRate::ToneGenerator0, cycles.as<int>());
+	update_channel(1, rate_ == InterruptRate::ToneGenerator1, cycles.as<int>());
+
+	// Update the programmable-frequency interrupt.
+	if(rate_ < InterruptRate::ToneGenerator0) {
+		programmable_offset_ -= cycles.as<int>();
+		if(programmable_offset_ <= 0) {
+			if(programmable_level_) {
+				interrupts_ |= uint8_t(Interrupt::VariableFrequency);
+			}
+			programmable_level_ ^= true;
+			programmable_offset_ = programmble_reload(rate_);
+		}
+	}
+}
+
+Cycles TimedInterruptSource::get_next_sequence_point() const {
+	int result = one_hz_offset_.as<int>();
+
+	switch(rate_) {
+		case InterruptRate::OnekHz:
+		case InterruptRate::FiftyHz:
+			result = std::min(result, programmable_offset_);
+		break;
+		case InterruptRate::ToneGenerator0:
+		case InterruptRate::ToneGenerator1: {
+			const auto& channel = channels_[int(rate_) - int(InterruptRate::ToneGenerator0)];
+			const int cycles_until_interrupt = (channel.value + 1) + (channel.level ? 0 : channel.reload + 1);
+			result = std::min(result, cycles_until_interrupt);
+		} break;
+	}
+
+	return Cycles(result);
+}
+
+uint8_t TimedInterruptSource::get_divider_state() {
+	bool programmable_flag = false;
+	switch(rate_) {
+		case InterruptRate::OnekHz:
+		case InterruptRate::FiftyHz:
+			programmable_flag = programmable_level_;
+		break;
+		case InterruptRate::ToneGenerator0:
+			programmable_flag = channels_[0].level;
+		break;
+		case InterruptRate::ToneGenerator1:
+			programmable_flag = channels_[1].level;
+		break;
+	}
+
+	// one_hz_offset_ counts downwards, so when it crosses the halfway mark
+	// it enters the high part of its wave.
+	return
+		(one_hz_offset_ < half_clock_rate ? 0x4 : 0x0) |
+		(programmable_flag ? 0x1 : 0x0);
+}
--- a/Machines/Enterprise/Dave.hpp
+++ b/Machines/Enterprise/Dave.hpp
@ -0,0 +1,166 @@
+//
+//  Dave.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 22/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#ifndef Dave_hpp
+#define Dave_hpp
+
+#include <cstdint>
+
+#include "../../ClockReceiver/ClockReceiver.hpp"
+#include "../../Concurrency/AsyncTaskQueue.hpp"
+#include "../../Numeric/LFSR.hpp"
+#include "../../Outputs/Speaker/Implementation/SampleSource.hpp"
+
+namespace Enterprise {
+namespace Dave {
+
+enum class Interrupt: uint8_t {
+	VariableFrequency = 0x02,
+	OneHz = 0x08,
+	Nick = 0x20,
+};
+
+/*!
+	Models the audio-production subset of Dave's behaviour.
+*/
+class Audio: public Outputs::Speaker::SampleSource {
+	public:
+		Audio(Concurrency::DeferringAsyncTaskQueue &audio_queue);
+
+		void write(uint16_t address, uint8_t value);
+
+		// MARK: - SampleSource.
+		void set_sample_volume_range(int16_t range);
+		static constexpr bool get_is_stereo() { return true; }	// Dave produces stereo sound.
+		void get_samples(std::size_t number_of_samples, int16_t *target);
+
+	private:
+		Concurrency::DeferringAsyncTaskQueue &audio_queue_;
+
+		// Tone channels.
+		struct Channel {
+			// User-set values.
+			uint16_t reload = 0;
+			bool high_pass = false;
+			bool ring_modulate = false;
+			enum class Distortion {
+				None = 0,
+				FourBit = 1,
+				FiveBit = 2,
+				SevenBit = 3,
+			} distortion = Distortion::None;
+			uint8_t amplitude[2]{};
+			bool sync = false;
+
+			// Current state.
+			uint16_t count = 0;
+			int output = 0;
+		} channels_[3];
+		void update_channel(int);
+
+		// Noise channel.
+		struct Noise {
+			// User-set values.
+			uint8_t amplitude[2]{};
+			enum class Frequency {
+				DivideByFour,
+				ToneChannel0,
+				ToneChannel1,
+				ToneChannel2,
+			} frequency = Frequency::DivideByFour;
+			enum class Polynomial {
+				SeventeenBit,
+				FifteenBit,
+				ElevenBit,
+				NineBit
+			} polynomial = Polynomial::SeventeenBit;
+			bool swap_polynomial = false;
+			bool low_pass = false;
+			bool high_pass = false;
+			bool ring_modulate = false;
+
+			// Current state.
+			int count = 0;
+			int output = false;
+			bool final_output = false;
+		} noise_;
+		void update_noise();
+
+		bool use_direct_output_[2]{};
+
+		// Global volume, per SampleSource obligations.
+		int16_t volume_ = 0;
+
+		// Polynomials that are always running.
+		Numeric::LFSRv<0xc> poly4_;
+		Numeric::LFSRv<0x14> poly5_;
+		Numeric::LFSRv<0x60> poly7_;
+
+		// The selectable, noise-related polynomial.
+		Numeric::LFSRv<0x110> poly9_;
+		Numeric::LFSRv<0x500> poly11_;
+		Numeric::LFSRv<0x6000> poly15_;
+		Numeric::LFSRv<0x12000> poly17_;
+
+		// Current state of the active polynomials.
+		uint8_t poly_state_[4];
+};
+
+/*!
+	Provides Dave's timed interrupts — those that are provided at 1 kHz,
+	50 Hz or according to the rate of tone generators 0 or 1, plus the fixed
+	1 Hz interrupt.
+
+*/
+class TimedInterruptSource {
+	public:
+		void write(uint16_t address, uint8_t value);
+
+		uint8_t get_new_interrupts();
+		uint8_t get_divider_state();
+
+		void run_for(Cycles);
+
+		Cycles get_next_sequence_point() const;
+
+	private:
+		uint8_t interrupts_ = 0;
+
+		static constexpr Cycles clock_rate{250000};
+		static constexpr Cycles half_clock_rate{125000};
+
+		Cycles one_hz_offset_ = clock_rate;
+
+		enum class InterruptRate {
+			OnekHz,
+			FiftyHz,
+			ToneGenerator0,
+			ToneGenerator1,
+		} rate_ = InterruptRate::OnekHz;
+		int programmable_offset_ = programmble_reload(InterruptRate::OnekHz);
+		bool programmable_level_ = false;
+
+		struct Channel {
+			int value = 100, reload = 100;
+			bool sync = false;
+			bool level = false;
+		} channels_[2];
+		void update_channel(int c, bool is_linked, int decrement);
+		static constexpr int programmble_reload(InterruptRate rate) {
+			switch(rate) {
+				default: return 0;
+				case InterruptRate::OnekHz:		return 125;
+				case InterruptRate::FiftyHz:	return 2500;
+			}
+		}
+};
+
+}
+}
+
+#endif /* Dave_hpp */
--- a/Machines/Enterprise/EXDos.cpp
+++ b/Machines/Enterprise/EXDos.cpp
@ -0,0 +1,83 @@
+//
+//  EXDos.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 20/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#include "EXDos.hpp"
+
+using namespace Enterprise;
+
+EXDos::EXDos() : WD1770(P1770) {
+	emplace_drives(4, 8000000, 300, 2);
+	set_control_register(0x00);
+}
+
+void EXDos::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, size_t drive) {
+	get_drive(drive).set_disk(disk);
+	disk_did_change_ = true;
+}
+
+// Documentation for the control register:
+//
+//	Write:
+//		b7	in use				(???)
+//		b6	disk change reset
+//		b5	0 = double density, 1 = single density
+//		b4	side 1 select
+//		b3, b3, b1, b0	select drive 3, 2, 1, 0
+//
+//	Read:
+//		b7 data request from WD1770
+//		b6 disk change
+//		b5, b4, b3, b2: not used
+//		b1 interrupt request from WD1770
+//		b0 drive ready
+
+void EXDos::set_control_register(uint8_t control) {
+//	printf("Set control: %02x\n", control);
+
+	if(control & 0x40) disk_did_change_ = false;
+	set_is_double_density(!(control & 0x20));
+
+	// Set side.
+	const int head = (control >> 4) & 1;
+	for(size_t c = 0; c < 4; c++) {
+		get_drive(c).set_head(head);
+	}
+
+	// Select drive, ensuring handover of the motor-on state.
+	const bool motor_state = get_drive().get_motor_on();
+	for_all_drives([] (Storage::Disk::Drive &drive, size_t) {
+		drive.set_motor_on(false);
+	});
+	set_drive(control & 0xf);
+	get_drive().set_motor_on(motor_state);
+}
+
+uint8_t EXDos::get_control_register() {
+	// TODO: how does disk_did_change_ really work? Presumably
+	// it latches RDY?
+	const uint8_t status =
+		(get_data_request_line() ? 0x80 : 0x00) |
+		(disk_did_change_ ? 0x40 : 0x00) |
+		(get_interrupt_request_line() ? 0x02 : 0x00) |
+		(get_drive().get_is_ready() ? 0x01 : 0x00);
+
+//	printf("Get status: %02x\n", status);
+	return status;
+}
+
+void EXDos::set_motor_on(bool on) {
+	// TODO: this status should transfer if the selected drive changes. But the same goes for
+	// writing state, so plenty of work to do in general here.
+	get_drive().set_motor_on(on);
+}
+
+void EXDos::set_activity_observer(Activity::Observer *observer) {
+	for_all_drives([observer] (Storage::Disk::Drive &drive, size_t index) {
+		drive.set_activity_observer(observer, "Drive " + std::to_string(index+1), true);
+	});
+}
--- a/Machines/Enterprise/EXDos.hpp
+++ b/Machines/Enterprise/EXDos.hpp
@ -0,0 +1,36 @@
+//
+//  EXDos.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 20/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#ifndef EXDos_hpp
+#define EXDos_hpp
+
+#include "../../Components/1770/1770.hpp"
+#include "../../Activity/Observer.hpp"
+
+namespace Enterprise {
+
+class EXDos final : public WD::WD1770 {
+	public:
+		EXDos();
+
+		void set_disk(std::shared_ptr<Storage::Disk::Disk> disk, size_t drive);
+
+		void set_control_register(uint8_t control);
+		uint8_t get_control_register();
+
+		void set_activity_observer(Activity::Observer *observer);
+
+	private:
+		bool disk_did_change_ = false;
+
+		void set_motor_on(bool on) override;
+};
+
+}
+
+#endif /* EXDos_hpp */
--- a/Machines/Enterprise/Enterprise.cpp
+++ b/Machines/Enterprise/Enterprise.cpp
@ -0,0 +1,647 @@
+//
+//  Enterprise.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 10/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#include "Enterprise.hpp"
+
+#include "Dave.hpp"
+#include "EXDos.hpp"
+#include "Keyboard.hpp"
+#include "Nick.hpp"
+
+#include "../MachineTypes.hpp"
+
+#include "../../Analyser/Static/Enterprise/Target.hpp"
+#include "../../ClockReceiver/JustInTime.hpp"
+#include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
+#include "../../Processors/Z80/Z80.hpp"
+
+namespace Enterprise {
+
+/*
+	Notes to self on timing:
+
+	Nick divides each line into 57 windows; each window lasts 16 cycles and dedicates the
+	first 10 of those to VRAM accesses, leaving the final six for a Z80 video RAM access
+	if one has been requested.
+
+	The Z80 has a separate, asynchronous 4Mhz clock. That's that.
+
+	The documentation is also very forward in emphasising that Nick generates phaselocked
+	(i.e. in-phase) PAL video.
+
+	So: 57*16 = 912 cycles/line.
+
+	A standard PAL line lasts 64µs and during that time outputs 283.7516 colour cycles.
+
+	I shall _guess_ that the Enterprise stretches each line to 284 colour cycles rather than
+	reducing it to 283.
+
+	Therefore 912 cycles occurs in 284/283.7516 * 64 µs.
+
+	So one line = 181760000 / 2837516 µs = 45440000 / 709379 µs
+	=> one cycle = 45440000 / 709379*912 = 45440000 / 646953648 = 2840000 / 40434603 µs
+	=> clock rate of 40434603 / 2840000 Mhz
+
+	And, therefore, the ratio to a 4Mhz Z80 clock is:
+
+		40434603 / (2840000 * 4)
+		= 40434603 / 11360000
+		i.e. roughly 3.55 Nick cycles per Z80 cycle.
+
+	If that's true then the 6-cycle window is around 1.69 Z80 cycles long. Given that the Z80
+	clock in an Enterprise can be stopped in half-cycle increments only, the Z80 can only be
+	guaranteed to have around a 1.19 cycle minimum for its actual access. I'm therefore further
+	postulating that the clock stoppage takes place so as to align the final cycle of a relevant
+	access over the available window.
+
+*/
+
+template <bool has_disk_controller> class ConcreteMachine:
+	public Activity::Source,
+	public CPU::Z80::BusHandler,
+	public Machine,
+	public MachineTypes::AudioProducer,
+	public MachineTypes::MappedKeyboardMachine,
+	public MachineTypes::MediaTarget,
+	public MachineTypes::ScanProducer,
+	public MachineTypes::TimedMachine {
+	private:
+		constexpr uint8_t min_ram_slot(const Analyser::Static::Enterprise::Target &target) {
+			size_t ram_size = 128*1024;
+			switch(target.model) {
+				case Analyser::Static::Enterprise::Target::Model::Enterprise64:		ram_size = 64*1024;		break;
+				case Analyser::Static::Enterprise::Target::Model::Enterprise128:	ram_size = 128*1024;	break;
+				case Analyser::Static::Enterprise::Target::Model::Enterprise256:	ram_size = 256*1024;	break;
+			}
+
+			return uint8_t(0x100 - ram_size / 0x4000);
+		}
+
+	public:
+		ConcreteMachine([[maybe_unused]] const Analyser::Static::Enterprise::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
+			min_ram_slot_(min_ram_slot(target)),
+			z80_(*this),
+			nick_(ram_.end() - 65536),
+			dave_audio_(audio_queue_),
+			speaker_(dave_audio_) {
+			// Request a clock of 4Mhz; this'll be mapped upwards for Nick and Dave elsewhere.
+			set_clock_rate(4'000'000);
+
+			ROM::Request request;
+			using Target = Analyser::Static::Enterprise::Target;
+
+			// Pick one or more EXOS ROMs.
+			switch(target.exos_version) {
+				case Target::EXOSVersion::v10:	request = request && ROM::Request(ROM::Name::EnterpriseEXOS10);	break;
+				case Target::EXOSVersion::v20:	request = request && ROM::Request(ROM::Name::EnterpriseEXOS20);	break;
+				case Target::EXOSVersion::v21:	request = request && ROM::Request(ROM::Name::EnterpriseEXOS21);	break;
+				case Target::EXOSVersion::v23:	request = request && ROM::Request(ROM::Name::EnterpriseEXOS23);	break;
+				case Target::EXOSVersion::Any:
+					request =
+						request && (
+							ROM::Request(ROM::Name::EnterpriseEXOS10) || ROM::Request(ROM::Name::EnterpriseEXOS20) ||
+							ROM::Request(ROM::Name::EnterpriseEXOS21) || ROM::Request(ROM::Name::EnterpriseEXOS23)
+						);
+				break;
+
+				default: break;
+			}
+
+			// Similarly pick one or more BASIC ROMs.
+			switch(target.basic_version) {
+				case Target::BASICVersion::v10:
+					request = request && (
+						ROM::Request(ROM::Name::EnterpriseBASIC10) ||
+						(ROM::Request(ROM::Name::EnterpriseBASIC10Part1) && ROM::Request(ROM::Name::EnterpriseBASIC10Part2))
+					);
+				break;
+				case Target::BASICVersion::v11:
+					request = request && (
+						ROM::Request(ROM::Name::EnterpriseBASIC11) ||
+						ROM::Request(ROM::Name::EnterpriseBASIC11Suffixed)
+					);
+				case Target::BASICVersion::v21:
+					request = request && ROM::Request(ROM::Name::EnterpriseBASIC21);
+				break;
+				case Target::BASICVersion::Any:
+					request =
+						request && (
+							ROM::Request(ROM::Name::EnterpriseBASIC10) ||
+							(ROM::Request(ROM::Name::EnterpriseBASIC10Part1) && ROM::Request(ROM::Name::EnterpriseBASIC10Part2)) ||
+							ROM::Request(ROM::Name::EnterpriseBASIC11) ||
+							ROM::Request(ROM::Name::EnterpriseBASIC21)
+						);
+				break;
+
+				default: break;
+			}
+
+			// Possibly add in a DOS.
+			switch(target.dos) {
+				case Target::DOS::EXDOS:			request = request && ROM::Request(ROM::Name::EnterpriseEXDOS);	break;
+				default: break;
+			}
+
+			// Get and validate ROMs.
+			auto roms = rom_fetcher(request);
+			if(!request.validate(roms)) {
+				throw ROMMachine::Error::MissingROMs;
+			}
+
+			// Extract the appropriate EXOS ROM.
+			exos_.fill(0xff);
+			for(const auto rom_name: { ROM::Name::EnterpriseEXOS10, ROM::Name::EnterpriseEXOS20, ROM::Name::EnterpriseEXOS21, ROM::Name::EnterpriseEXOS23 }) {
+				const auto exos = roms.find(rom_name);
+				if(exos != roms.end()) {
+					memcpy(exos_.data(), exos->second.data(), std::min(exos_.size(), exos->second.size()));
+					break;
+				}
+			}
+
+			// Extract the appropriate BASIC ROM[s] (if any).
+			basic_.fill(0xff);
+			bool has_basic = false;
+			for(const auto rom_name: { ROM::Name::EnterpriseBASIC10, ROM::Name::EnterpriseBASIC11, ROM::Name::EnterpriseBASIC11Suffixed, ROM::Name::EnterpriseBASIC21 }) {
+				const auto basic = roms.find(rom_name);
+				if(basic != roms.end()) {
+					memcpy(basic_.data(), basic->second.data(), std::min(basic_.size(), basic->second.size()));
+					has_basic = true;
+					break;
+				}
+			}
+			if(!has_basic) {
+				const auto basic1 = roms.find(ROM::Name::EnterpriseBASIC10Part1);
+				const auto basic2 = roms.find(ROM::Name::EnterpriseBASIC10Part2);
+				if(basic1 != roms.end() && basic2 != roms.end()) {
+					memcpy(&basic_[0x0000], basic1->second.data(), std::min(size_t(8192), basic1->second.size()));
+					memcpy(&basic_[0x2000], basic2->second.data(), std::min(size_t(8192), basic2->second.size()));
+				}
+			}
+
+			// Extract the appropriate DOS ROMs.
+			epdos_rom_.fill(0xff);
+			const auto epdos = roms.find(ROM::Name::EnterpriseEPDOS);
+			if(epdos != roms.end()) {
+				memcpy(epdos_rom_.data(), epdos->second.data(), std::min(epdos_rom_.size(), epdos->second.size()));
+			}
+			exdos_rom_.fill(0xff);
+			const auto exdos = roms.find(ROM::Name::EnterpriseEXDOS);
+			if(exdos != roms.end()) {
+				memcpy(exdos_rom_.data(), exdos->second.data(), std::min(exdos_rom_.size(), exdos->second.size()));
+			}
+
+			// Seed key state.
+			clear_all_keys();
+
+			// Take a reasonable guess at the initial memory configuration:
+			// put EXOS into the first bank since this is a Z80 and therefore
+			// starts from address 0; the third instruction in EXOS is a jump
+			// to $c02e so it's reasonable to assume EXOS is in the highest bank
+			// too, and it appears to act correctly if it's the first 16kb that's
+			// in the highest bank. From there I guess: all banks are initialised
+			// to 0.
+			page<0>(0x00);
+			page<1>(0x00);
+			page<2>(0x00);
+			page<3>(0x00);
+
+			// Set up audio.
+			speaker_.set_input_rate(250000.0f);	// TODO: a bigger number, and respect the programmable divider.
+
+			// Pass on any media.
+			insert_media(target.media);
+		}
+
+		~ConcreteMachine() {
+			audio_queue_.flush();
+		}
+
+		// MARK: - Z80::BusHandler.
+		forceinline void advance_nick(HalfCycles duration) {
+			if(nick_ += duration) {
+				const auto nick = nick_.last_valid();
+				const bool nick_interrupt_line = nick->get_interrupt_line();
+				if(nick_interrupt_line && !previous_nick_interrupt_line_) {
+					set_interrupts(uint8_t(Dave::Interrupt::Nick), nick_.last_sequence_point_overrun());
+				}
+				previous_nick_interrupt_line_ = nick_interrupt_line;
+			}
+		}
+
+		forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
+			using PartialMachineCycle = CPU::Z80::PartialMachineCycle;
+			const uint16_t address = cycle.address ? *cycle.address : 0x0000;
+
+			// Calculate an access penalty, if applicable.
+			//
+			// Rule applied here, which is slightly inferred:
+			//
+			//	Non-video reads and writes are delayed by exactly a cycle or not delayed at all,
+			//	depending on the programmer's configuration of Dave.
+			//
+			//	Video reads and writes, and Nick port accesses, are delayed so that the last
+			//	clock cycle of the machine cycle falls wholly inside the designated Z80 access
+			//	window, per Nick.
+			//
+			// The switch statement below just attempts to implement that logic.
+			//
+			HalfCycles penalty;
+			switch(cycle.operation) {
+				default: break;
+
+				// For non-video pauses, insert during the initial part of the bus cycle.
+				case CPU::Z80::PartialMachineCycle::ReadStart:
+				case CPU::Z80::PartialMachineCycle::WriteStart:
+					if(!is_video_[address >> 14] && wait_mode_ == WaitMode::OnAllAccesses) {
+						penalty = HalfCycles(2);
+					}
+				break;
+				case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
+					if(!is_video_[address >> 14] && wait_mode_ != WaitMode::None) {
+						penalty = HalfCycles(2);
+					} else {
+						// Query Nick for the amount of delay that would occur with one cycle left
+						// in this read opcode.
+						const auto delay_time = nick_.time_since_flush(HalfCycles(2));
+						const auto delay = nick_.last_valid()->get_time_until_z80_slot(delay_time);
+						penalty = nick_.back_map(delay, delay_time);
+					}
+				break;
+
+				// Video pauses: insert right at the end of the bus cycle.
+				case CPU::Z80::PartialMachineCycle::Write:
+					// Ensure all video that should have been collected prior to
+					// this write has been.
+					if(is_video_[address >> 14]) {
+						nick_.flush();
+					}
+					[[fallthrough]];
+
+				case CPU::Z80::PartialMachineCycle::Read:
+					if(is_video_[address >> 14]) {
+						// Get delay, in Nick cycles, for a Z80 access that occurs in 0.5
+						// cycles from now (i.e. with one cycle left to run).
+						const auto delay_time = nick_.time_since_flush(HalfCycles(1));
+						const auto delay = nick_.last_valid()->get_time_until_z80_slot(delay_time);
+						penalty = nick_.back_map(delay, delay_time);
+					}
+				break;
+
+				case CPU::Z80::PartialMachineCycle::Input:
+				case CPU::Z80::PartialMachineCycle::Output: {
+					if((address & 0xf0) == 0x80) {
+						// Get delay, in Nick cycles, for a Z80 access that occurs in 0.5
+						// cycles from now (i.e. with one cycle left to run).
+						const auto delay_time = nick_.time_since_flush(HalfCycles(1));
+						const auto delay = nick_.last_valid()->get_time_until_z80_slot(delay_time);
+						penalty = nick_.back_map(delay, delay_time);
+					}
+				}
+			}
+
+			const HalfCycles full_length = cycle.length + penalty;
+			time_since_audio_update_ += full_length;
+			advance_nick(full_length);
+			if(dave_timer_ += full_length) {
+				set_interrupts(dave_timer_.last_valid()->get_new_interrupts(), dave_timer_.last_sequence_point_overrun());
+			}
+
+			// The WD/etc runs at a nominal 8Mhz.
+			if constexpr (has_disk_controller) {
+				exdos_.run_for(Cycles(full_length.as_integral()));
+			}
+
+			switch(cycle.operation) {
+				default: break;
+
+				case CPU::Z80::PartialMachineCycle::Input:
+					switch(address & 0xff) {
+						default:
+							printf("Unhandled input: %04x\n", address);
+//							assert(false);
+							*cycle.value = 0xff;
+						break;
+
+						case 0x10:	case 0x11:	case 0x12:	case 0x13:
+						case 0x14:	case 0x15:	case 0x16:	case 0x17:
+							if constexpr (has_disk_controller) {
+								*cycle.value = exdos_.read(address);
+							} else {
+								*cycle.value = 0xff;
+							}
+						break;
+						case 0x18:	case 0x19:	case 0x1a:	case 0x1b:
+						case 0x1c:	case 0x1d:	case 0x1e:	case 0x1f:
+							if constexpr (has_disk_controller) {
+								*cycle.value = exdos_.get_control_register();
+							} else {
+								*cycle.value = 0xff;
+							}
+						break;
+
+						case 0xb0:	*cycle.value = pages_[0];	break;
+						case 0xb1:	*cycle.value = pages_[1];	break;
+						case 0xb2:	*cycle.value = pages_[2];	break;
+						case 0xb3:	*cycle.value = pages_[3];	break;
+
+						case 0xb4:
+							*cycle.value =
+								(nick_->get_interrupt_line() ? 0x00 : 0x10) |
+								dave_timer_->get_divider_state() |
+								interrupt_state_;
+						break;
+						case 0xb5:
+							if(active_key_line_ < key_lines_.size()) {
+								*cycle.value = key_lines_[active_key_line_];
+							} else {
+								*cycle.value = 0xff;
+							}
+						break;
+						case 0xb6: {
+							// TODO: selected keyboard row, 0 to 9, should return one bit of joystick
+							// input. That being the case:
+							//
+							//	b0:		joystick input
+							//	b1, b2:	unused (in theory read from control port, but not used by any hardware)
+							//	b3:		0 = printer ready; 1 = not ready
+							//	b4:		serial, data in
+							//	b5:		serial, status in
+							//	b6:		tape input volume level, 0 = high, 1 = low
+							//	b7:		tape data input
+							*cycle.value = 0xff;
+						} break;
+					}
+				break;
+
+				case CPU::Z80::PartialMachineCycle::Output:
+					switch(address & 0xff) {
+						default:
+							printf("Unhandled output: %04x\n", address);
+//							assert(false);
+						break;
+
+						case 0x10:	case 0x11:	case 0x12:	case 0x13:
+						case 0x14:	case 0x15:	case 0x16:	case 0x17:
+							if constexpr(has_disk_controller) {
+								exdos_.write(address, *cycle.value);
+							}
+						break;
+						case 0x18:	case 0x19:	case 0x1a:	case 0x1b:
+						case 0x1c:	case 0x1d:	case 0x1e:	case 0x1f:
+							if constexpr(has_disk_controller) {
+								exdos_.set_control_register(*cycle.value);
+							}
+						break;
+
+						case 0x80:	case 0x81:	case 0x82:	case 0x83:
+						case 0x84:	case 0x85:	case 0x86:	case 0x87:
+						case 0x88:	case 0x89:	case 0x8a:	case 0x8b:
+						case 0x8c:	case 0x8d:	case 0x8e:	case 0x8f:
+							nick_->write(address, *cycle.value);
+						break;
+
+						case 0xb0:	page<0>(*cycle.value);	break;
+						case 0xb1:	page<1>(*cycle.value);	break;
+						case 0xb2:	page<2>(*cycle.value);	break;
+						case 0xb3:	page<3>(*cycle.value);	break;
+
+						case 0xa0:	case 0xa1:	case 0xa2:	case 0xa3:
+						case 0xa4:	case 0xa5:	case 0xa6:	case 0xa7:
+						case 0xa8:	case 0xa9:	case 0xaa:	case 0xab:
+						case 0xac:	case 0xad:	case 0xae:	case 0xaf:
+							update_audio();
+							dave_audio_.write(address, *cycle.value);
+							dave_timer_->write(address, *cycle.value);
+						break;
+
+						case 0xb4:
+							interrupt_mask_ = *cycle.value & 0x55;
+							interrupt_state_ &= ~*cycle.value;
+							update_interrupts();
+						break;
+						case 0xb5:
+							active_key_line_ = *cycle.value & 0xf;
+							// TODO:
+							//
+							//	b4:	strobe output for printer
+							//	b5:	tape sound control (?)
+							//	b6:	tape motor control 1, 1 = on
+							//	b7: tape motor control 2, 1 = on
+						break;
+						case 0xb6:
+							// Just 8 bits of printer data.
+							printf("TODO: printer output %02x\n", *cycle.value);
+						break;
+						case 0xb7:
+							// b0 = serial data out
+							// b1 = serial status out
+							printf("TODO: serial output %02x\n", *cycle.value);
+						break;
+						case 0xbf:
+							// TODO: onboard RAM, Dave 8/12Mhz select.
+							switch((*cycle.value >> 2)&3) {
+								default:	wait_mode_ = WaitMode::None;			break;
+								case 0:		wait_mode_ = WaitMode::OnAllAccesses;	break;
+								case 1:		wait_mode_ = WaitMode::OnM1;			break;
+							}
+						break;
+					}
+				break;
+
+				case CPU::Z80::PartialMachineCycle::Read:
+				case CPU::Z80::PartialMachineCycle::ReadOpcode:
+					if(read_pointers_[address >> 14]) {
+						*cycle.value = read_pointers_[address >> 14][address];
+					} else {
+						*cycle.value = 0xff;
+					}
+				break;
+
+				case CPU::Z80::PartialMachineCycle::Write:
+					if(write_pointers_[address >> 14]) {
+						write_pointers_[address >> 14][address] = *cycle.value;
+					}
+				break;
+			}
+
+			return penalty;
+		}
+
+		void flush() {
+			nick_.flush();
+			update_audio();
+			audio_queue_.perform();
+		}
+
+	private:
+		// MARK: - Memory layout
+		std::array<uint8_t, 256 * 1024> ram_{};
+		std::array<uint8_t, 64 * 1024> exos_;
+		std::array<uint8_t, 16 * 1024> basic_;
+		std::array<uint8_t, 16 * 1024> exdos_rom_;
+		std::array<uint8_t, 32 * 1024> epdos_rom_;
+		const uint8_t min_ram_slot_;
+
+		const uint8_t *read_pointers_[4] = {nullptr, nullptr, nullptr, nullptr};
+		uint8_t *write_pointers_[4] = {nullptr, nullptr, nullptr, nullptr};
+		uint8_t pages_[4] = {0x80, 0x80, 0x80, 0x80};
+
+		template <size_t slot> void page(uint8_t offset) {
+			pages_[slot] = offset;
+
+#define Map(location, source)												\
+	if(offset >= location && offset < location + source.size() / 0x4000) {	\
+		page<slot>(&source[(offset - location) * 0x4000], nullptr);			\
+		is_video_[slot] = false;											\
+		return;																\
+	}
+
+			Map(0, exos_);
+			Map(16, basic_);
+			Map(32, exdos_rom_);
+			Map(48, epdos_rom_);
+
+#undef Map
+
+			// Of whatever size of RAM I've declared above, use only the final portion.
+			// This correlated with Nick always having been handed the final 64kb and,
+			// at least while the RAM is the first thing declared above, does a little
+			// to benefit data locality. Albeit not in a useful sense.
+			if(offset >= min_ram_slot_) {
+				const auto ram_floor = 4194304 - ram_.size();
+				const size_t address = offset * 0x4000 - ram_floor;
+				is_video_[slot] = offset >= 0xfc;	// TODO: this hard-codes a 64kb video assumption.
+				page<slot>(&ram_[address], &ram_[address]);
+				return;
+			}
+
+			page<slot>(nullptr, nullptr);
+		}
+
+		template <size_t slot> void page(const uint8_t *read, uint8_t *write) {
+			read_pointers_[slot] = read ? read - (slot * 0x4000) : nullptr;
+			write_pointers_[slot] = write ? write - (slot * 0x4000) : nullptr;
+		}
+
+		// MARK: - Memory Timing
+
+		// The wait mode affects all memory accesses _outside of the video area_.
+		enum class WaitMode {
+			None,
+			OnM1,
+			OnAllAccesses
+		} wait_mode_ = WaitMode::None;
+		bool is_video_[4]{};
+
+		// MARK: - ScanProducer
+		void set_scan_target(Outputs::Display::ScanTarget *scan_target) override {
+			nick_.last_valid()->set_scan_target(scan_target);
+		}
+
+		Outputs::Display::ScanStatus get_scaled_scan_status() const override {
+			return nick_.last_valid()->get_scaled_scan_status();
+		}
+
+		// MARK: - AudioProducer
+
+		Outputs::Speaker::Speaker *get_speaker() final {
+			return &speaker_;
+		}
+
+		// MARK: - TimedMachine
+		void run_for(const Cycles cycles) override {
+			z80_.run_for(cycles);
+		}
+
+		// MARK: - KeyboardMachine
+		Enterprise::KeyboardMapper keyboard_mapper_;
+		KeyboardMapper *get_keyboard_mapper() final {
+			return &keyboard_mapper_;
+		}
+
+		uint8_t active_key_line_ = 0;
+		std::array<uint8_t, 10> key_lines_;
+		void set_key_state(uint16_t key, bool is_pressed) final {
+			if(is_pressed) {
+				key_lines_[key >> 8] &= ~uint8_t(key);
+			} else {
+				key_lines_[key >> 8] |= uint8_t(key);
+			}
+		}
+
+		void clear_all_keys() final {
+			key_lines_.fill(0xff);
+		}
+
+		// MARK: - MediaTarget
+		bool insert_media(const Analyser::Static::Media &media) final {
+			if constexpr (has_disk_controller) {
+				if(!media.disks.empty()) {
+					exdos_.set_disk(media.disks.front(), 0);
+				}
+			}
+
+			return true;
+		}
+
+		// MARK: - Interrupts
+
+		uint8_t interrupt_mask_ = 0x00, interrupt_state_ = 0x00;
+		void set_interrupts(uint8_t mask, HalfCycles offset = HalfCycles(0)) {
+			interrupt_state_ |= uint8_t(mask);
+			update_interrupts(offset);
+		}
+		void update_interrupts(HalfCycles offset = HalfCycles(0)) {
+			z80_.set_interrupt_line((interrupt_state_ >> 1) & interrupt_mask_, offset);
+		}
+
+		// MARK: - Chips.
+		CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
+		JustInTimeActor<Nick, HalfCycles, 40434603, 11360000> nick_;
+		bool previous_nick_interrupt_line_ = false;
+		// Cf. timing guesses above.
+
+		Concurrency::DeferringAsyncTaskQueue audio_queue_;
+		Dave::Audio dave_audio_;
+		Outputs::Speaker::LowpassSpeaker<Dave::Audio> speaker_;
+		HalfCycles time_since_audio_update_;
+
+		// The following two should both use the same divider.
+		JustInTimeActor<Dave::TimedInterruptSource, HalfCycles, 1, 16> dave_timer_;
+		inline void update_audio() {
+			// TODO: divide by only 8, letting Dave divide itself by a further 2 or 3
+			// as per its own register.
+			speaker_.run_for(audio_queue_, time_since_audio_update_.divide_cycles(Cycles(16)));
+		}
+
+		// MARK: - EXDos card.
+		EXDos exdos_;
+
+		// MARK: - Activity Source
+		void set_activity_observer(Activity::Observer *observer) final {
+			if constexpr (has_disk_controller) {
+				exdos_.set_activity_observer(observer);
+			}
+		}
+};
+
+}
+
+using namespace Enterprise;
+
+Machine *Machine::Enterprise(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
+	using Target = Analyser::Static::Enterprise::Target;
+	const Target *const enterprise_target = dynamic_cast<const Target *>(target);
+
+	if(enterprise_target->dos == Target::DOS::None)
+		return new Enterprise::ConcreteMachine<false>(*enterprise_target, rom_fetcher);
+	else
+		return new Enterprise::ConcreteMachine<true>(*enterprise_target, rom_fetcher);
+}
+
+Machine::~Machine() {}
--- a/Machines/Enterprise/Enterprise.hpp
+++ b/Machines/Enterprise/Enterprise.hpp
@ -0,0 +1,27 @@
+//
+//  Enterprise.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 10/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#ifndef Enterprise_hpp
+#define Enterprise_hpp
+
+#include "../../Analyser/Static/StaticAnalyser.hpp"
+#include "../ROMMachine.hpp"
+
+namespace Enterprise {
+
+class Machine {
+	public:
+		virtual ~Machine();
+
+		static Machine *Enterprise(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher);
+
+};
+
+};
+
+#endif /* Enterprise_hpp */
--- a/Machines/Enterprise/Keyboard.cpp
+++ b/Machines/Enterprise/Keyboard.cpp
@ -0,0 +1,74 @@
+//
+//  Keyboard.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 17/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#include "Keyboard.hpp"
+
+using namespace Enterprise;
+
+uint16_t KeyboardMapper::mapped_key_for_key(Inputs::Keyboard::Key key) const {
+#define BIND(source, dest)	case Inputs::Keyboard::Key::source:	return uint16_t(Key::dest)
+	switch(key) {
+		default: break;
+
+		BIND(Backslash, Backslash);
+		BIND(CapsLock, Lock);
+		BIND(Tab, Tab);
+		BIND(Escape, Escape);
+		BIND(Hyphen, Hyphen);
+		BIND(Equals, Tilde);
+		BIND(Backspace, Erase);
+		BIND(Delete, Delete);
+		BIND(Semicolon, Semicolon);
+		BIND(Quote, Colon);
+		BIND(OpenSquareBracket, OpenSquareBracket);
+		BIND(CloseSquareBracket, CloseSquareBracket);
+
+		BIND(End, Stop);
+		BIND(Insert, Insert);
+		BIND(BackTick, At);
+
+		BIND(k1, k1);	BIND(k2, k2);	BIND(k3, k3);	BIND(k4, k4);	BIND(k5, k5);
+		BIND(k6, k6);	BIND(k7, k7);	BIND(k8, k8);	BIND(k9, k9);	BIND(k0, k0);
+
+		BIND(F1, F1);	BIND(F2, F2);	BIND(F3, F3);	BIND(F4, F4);
+		BIND(F5, F5);	BIND(F6, F6);	BIND(F7, F7);	BIND(F8, F8);
+
+		BIND(Keypad1, F1);	BIND(Keypad2, F2);	BIND(Keypad3, F3);	BIND(Keypad4, F4);
+		BIND(Keypad5, F5);	BIND(Keypad6, F6);	BIND(Keypad7, F7);	BIND(Keypad8, F8);
+
+		BIND(Q, Q);	BIND(W, W);	BIND(E, E);	BIND(R, R);	BIND(T, T);
+		BIND(Y, Y);	BIND(U, U);	BIND(I, I);	BIND(O, O);	BIND(P, P);
+
+		BIND(A, A);	BIND(S, S);	BIND(D, D);	BIND(F, F);	BIND(G, G);
+		BIND(H, H);	BIND(J, J);	BIND(K, K);	BIND(L, L);
+
+		BIND(Z, Z);	BIND(X, X);	BIND(C, C);	BIND(V, V);
+		BIND(B, B);	BIND(N, N);	BIND(M, M);
+
+		BIND(FullStop, FullStop);
+		BIND(Comma, Comma);
+		BIND(ForwardSlash, ForwardSlash);
+
+		BIND(Space, Space);	BIND(Enter, Enter);
+
+		BIND(LeftShift, LeftShift);
+		BIND(RightShift, RightShift);
+		BIND(LeftOption, Alt);
+		BIND(RightOption, Alt);
+		BIND(LeftControl, Control);
+		BIND(RightControl, Control);
+
+		BIND(Left, Left);
+		BIND(Right, Right);
+		BIND(Up, Up);
+		BIND(Down, Down);
+	}
+#undef BIND
+
+	return MachineTypes::MappedKeyboardMachine::KeyNotMapped;
+}
--- a/Machines/Enterprise/Keyboard.hpp
+++ b/Machines/Enterprise/Keyboard.hpp
@ -0,0 +1,61 @@
+//
+//  Keyboard.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 17/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#ifndef Machines_Enterprise_Keyboard_hpp
+#define Machines_Enterprise_Keyboard_hpp
+
+#include "../KeyboardMachine.hpp"
+
+namespace Enterprise {
+
+#define KeyCode(line, mask)	(line << 8) | mask
+
+enum class Key: uint16_t {
+	N		= 0x0000 | 0x01,	Backslash	= 0x0000 | 0x02,	B		= 0x0000 | 0x04,	C			= 0x0000 | 0x08,
+	V		= 0x0000 | 0x10,	X 			= 0x0000 | 0x20,	Z		= 0x0000 | 0x40,	LeftShift	= 0x0000 | 0x80,
+
+	H		= 0x0100 | 0x01,	Lock		= 0x0100 | 0x02,	G		= 0x0100 | 0x04,	D			= 0x0100 | 0x08,
+	F		= 0x0100 | 0x10,	S			= 0x0100 | 0x20,	A		= 0x0100 | 0x40,	Control		= 0x0100 | 0x80,
+
+	U		= 0x0200 | 0x01,	Q			= 0x0200 | 0x02,	Y		= 0x0200 | 0x04,	R			= 0x0200 | 0x08,
+	T		= 0x0200 | 0x10,	E			= 0x0200 | 0x20,	W		= 0x0200 | 0x40,	Tab			= 0x0200 | 0x80,
+
+	k7		= 0x0300 | 0x01,	k1			= 0x0300 | 0x02,	k6		= 0x0300 | 0x04,	k4			= 0x0300 | 0x08,
+	k5		= 0x0300 | 0x10,	k3			= 0x0300 | 0x20,	k2		= 0x0300 | 0x40,	Escape		= 0x0300 | 0x80,
+
+	F4		= 0x0400 | 0x01,	F8			= 0x0400 | 0x02,	F3		= 0x0400 | 0x04,	F6			= 0x0400 | 0x08,
+	F5		= 0x0400 | 0x10,	F7			= 0x0400 | 0x20,	F2		= 0x0400 | 0x40,	F1			= 0x0400 | 0x80,
+
+	k8		= 0x0500 | 0x01,									k9		= 0x0500 | 0x04,	Hyphen		= 0x0500 | 0x08,
+	k0		= 0x0500 | 0x10,	Tilde		= 0x0500 | 0x20,	Erase	= 0x0500 | 0x40,
+
+	J		= 0x0600 | 0x01,									K		= 0x0600 | 0x04,	Semicolon	= 0x0600 | 0x08,
+	L		= 0x0600 | 0x10,	Colon		= 0x0600 | 0x20,	CloseSquareBracket		= 0x0600 | 0x40,
+
+	Stop	= 0x0700 | 0x01,	Down		= 0x0700 | 0x02,	Right	= 0x0700 | 0x04,	Up			= 0x0700 | 0x08,
+	Hold	= 0x0700 | 0x10,	Left		= 0x0700 | 0x20,	Enter	= 0x0700 | 0x40,	Alt			= 0x0700 | 0x80,
+
+	M		= 0x0800 | 0x01,	Delete		= 0x0800 | 0x02,	Comma	= 0x0800 | 0x04,
+	ForwardSlash	= 0x0800 | 0x08,
+	FullStop		= 0x0800 | 0x10,
+								RightShift	= 0x0800 | 0x20,	Space	= 0x0800 | 0x40,	Insert		= 0x0800 | 0x80,
+
+	I		= 0x0900 | 0x01,									O		= 0x0900 | 0x04,	At			= 0x0900 | 0x08,
+	P		= 0x0900 | 0x10,
+	OpenSquareBracket		= 0x0900 | 0x20
+};
+
+#undef KeyCode
+
+struct KeyboardMapper: public MachineTypes::MappedKeyboardMachine::KeyboardMapper {
+	uint16_t mapped_key_for_key(Inputs::Keyboard::Key key) const final;
+};
+
+}
+
+#endif /* Keyboard_hpp */
--- a/Machines/Enterprise/Nick.cpp
+++ b/Machines/Enterprise/Nick.cpp
@ -0,0 +1,610 @@
+//
+//  Nick.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 14/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#include "Nick.hpp"
+
+#include <cstdio>
+
+namespace  {
+
+uint16_t mapped_colour(uint8_t source) {
+	// On the Enterprise, red and green are 3-bit quantities; blue is a 2-bit quantity.
+	int red		= ((source&0x01) << 2) | ((source&0x08) >> 2) | ((source&0x40) >> 6);
+	int green	= ((source&0x02) << 1) | ((source&0x10) >> 3) | ((source&0x80) >> 7);
+	int blue	= ((source&0x04) >> 1) | ((source&0x20) >> 5);
+
+	assert(red <= 7);
+	assert(green <= 7);
+	assert(blue <= 3);
+
+	red = (red << 1) + (red >> 3);
+	green = (green << 1) + (green >> 3);
+	blue = (blue << 2) + blue;
+
+	assert(red <= 15);
+	assert(green <= 15);
+	assert(blue <= 15);
+
+	// Duplicate bits where necessary to map to a full 4-bit range per channel.
+	const uint8_t parts[2] = {
+		uint8_t(
+			red
+		),
+		uint8_t(
+			(green << 4) + blue
+		)
+	};
+	return *reinterpret_cast<const uint16_t *>(parts);
+}
+
+}
+
+using namespace Enterprise;
+
+Nick::Nick(const uint8_t *ram) :
+	crt_(57*16, 16, Outputs::Display::Type::PAL50, Outputs::Display::InputDataType::Red4Green4Blue4),
+	ram_(ram) {
+
+	// Just use RGB for now.
+	crt_.set_display_type(Outputs::Display::DisplayType::RGB);
+
+	// Crop to the centre 90% of the display.
+	crt_.set_visible_area(Outputs::Display::Rect(0.05f, 0.05f, 0.9f, 0.9f));
+}
+
+void Nick::write(uint16_t address, uint8_t value) {
+	switch(address & 3) {
+		case 0:
+			// Ignored: everything to do with external colour.
+			for(int c = 0; c < 8; c++) {
+				palette_[c + 8] = mapped_colour(uint8_t(((value & 0x1f) << 3) + c));
+			}
+		break;
+		case 1:
+			if(output_type_ == OutputType::Border) {
+				set_output_type(OutputType::Border, true);
+			}
+			border_colour_ = mapped_colour(value);
+		break;
+		case 2:
+			line_parameter_base_ = uint16_t((line_parameter_base_ & 0xf000) | (value << 4));
+		break;
+		case 3:
+			line_parameter_base_ = uint16_t((line_parameter_base_ & 0x0ff0) | (value << 12));
+
+			// Still a mystery to me: the exact meaning of the top two bits here. For now
+			// just treat a 0 -> 1 transition of the MSB as a forced frame restart.
+			if((value^line_parameter_control_) & value & 0x80) {
+				// For now: just force this to be the final line of this mode block.
+				// I'm unclear whether I should also reset the horizontal counter
+				// (i.e. completely abandon current video phase).
+				lines_remaining_ = 0xff;
+				should_reload_line_parameters_ = true;
+			}
+			line_parameter_control_ = value & 0xc0;
+		break;
+	}
+}
+
+uint8_t Nick::read([[maybe_unused]] uint16_t address) {
+	return 0xff;
+}
+
+Cycles Nick::get_time_until_z80_slot(Cycles after_period) const {
+	// Place Z80 accesses as the first six cycles in each sixteen-cycle window.
+	// That models video accesses as being the final ten. Which has the net effect
+	// of responding to the line parameter table interrupt flag as soon as it's
+	// loaded.
+
+	// i.e. 0 -> 0, 1 -> 15 ... 15 -> 1.
+	return Cycles(
+		15 ^ ((horizontal_counter_ + 15 + after_period.as<int>()) & 15)
+	);
+}
+
+void Nick::run_for(Cycles duration) {
+	constexpr int line_length = 912;
+
+	// TODO: test here for window < 57? Or maybe just nudge up left_/right_margin_ if they
+	// exactly equal 57?
+#define add_window(x)											\
+	line_data_pointer_[0] += is_sync_or_pixels_ * line_data_per_column_increments_[0] * (x);	\
+	line_data_pointer_[1] += is_sync_or_pixels_ * line_data_per_column_increments_[1] * (x);	\
+	window += x;												\
+	if(window == left_margin_) is_sync_or_pixels_ = true;		\
+	if(window == right_margin_) is_sync_or_pixels_ = false;
+
+	int clocks_remaining = duration.as<int>();
+	while(clocks_remaining) {
+		// Determine how many cycles are left this line.
+		const int clocks_this_line = std::min(clocks_remaining, line_length - horizontal_counter_);
+
+		// Convert that into a [start/current] and end window.
+		int window = horizontal_counter_ >> 4;
+		const int end_window = (horizontal_counter_ + clocks_this_line) >> 4;
+
+		// Advance the line counters.
+		clocks_remaining -= clocks_this_line;
+		horizontal_counter_ = (horizontal_counter_ + clocks_this_line) % line_length;
+
+		// Do nothing if a window boundary isn't crossed.
+		if(window == end_window) continue;
+
+		// HSYNC is signalled for four windows at the start of the line.
+		// I currently believe this happens regardless of Vsync mode.
+		//
+		// This is also when the non-palette line parameters
+		// are loaded, if appropriate.
+		if(!window) {
+			set_output_type(OutputType::Sync);
+
+			// There's no increment to get to 0, it happens when the horizontal_counter_
+			// is reset. So test for active bit effect manually.
+			if(!left_margin_) is_sync_or_pixels_ = true;
+			if(!right_margin_) is_sync_or_pixels_ = false;
+		}
+
+		while(window < 4 && window < end_window) {
+			if(should_reload_line_parameters_) {
+				switch(window) {
+					// First slot: line count, mode and interrupt flag.
+					case 0:
+						// Byte 0: lines remaining.
+						lines_remaining_ = ram_[line_parameter_pointer_];
+
+						// Set the new interrupt line output.
+						interrupt_line_ = ram_[line_parameter_pointer_ + 1] & 0x80;
+
+						// Determine the mode and depth, and hence the column size.
+						mode_ = Mode((ram_[line_parameter_pointer_ + 1] >> 1)&7);
+						bpp_ = 1 << ((ram_[line_parameter_pointer_ + 1] >> 5)&3);
+						switch(mode_) {
+							default:
+							case Mode::Pixel:
+								column_size_ = 16 / bpp_;
+								line_data_per_column_increments_[0] = 2;
+								line_data_per_column_increments_[1] = 0;
+							break;
+
+							case Mode::LPixel:
+							case Mode::CH64:
+							case Mode::CH128:
+							case Mode::CH256:
+								column_size_ = 8 / bpp_;
+								line_data_per_column_increments_[0] = 1;
+								line_data_per_column_increments_[1] = 0;
+							break;
+
+							case Mode::Attr:
+								column_size_ = 8;
+								line_data_per_column_increments_[0] = 1;
+								line_data_per_column_increments_[1] = 1;
+							break;
+						}
+
+						vres_ = ram_[line_parameter_pointer_ + 1] & 0x10;
+						reload_line_parameter_pointer_ = ram_[line_parameter_pointer_ + 1] & 0x01;
+					break;
+
+					// Second slot: margins and ALT/IND bits.
+					case 1:
+						// Determine the margins.
+						left_margin_ = ram_[line_parameter_pointer_ + 2] & 0x3f;
+						right_margin_ = ram_[line_parameter_pointer_ + 3] & 0x3f;
+
+						// Set up the alternative palettes,
+						switch(mode_) {
+							default:
+							break;
+
+							// NB: LSBALT/MSBALT and ALTIND0/ALTIND1 appear to have opposite effects on palette selection.
+
+							case Mode::Pixel:
+							case Mode::LPixel: {
+								const uint8_t flags = ram_[line_parameter_pointer_ + 2];
+
+								// Use MSBALT and LSBALT to pick the alt_ind_palettes.
+								//
+								// LSBALT = b6 of params[2], if set => character codes with bit 6 set should use palette indices 4... instead of 0... .
+								// MSBALT = b7 of params[2], if set => character codes with bit 7 set should use palette indices 2 and 3.
+								two_colour_mask_ = 0xff &~ (((flags&0x80) >> 7) | ((flags&0x40) << 1));
+
+								alt_ind_palettes[0] = palette_;
+								alt_ind_palettes[2] = alt_ind_palettes[0] + ((flags & 0x80) ? 2 : 0);
+
+								alt_ind_palettes[1] = alt_ind_palettes[0] + ((flags & 0x40) ? 4 : 0);
+								alt_ind_palettes[3] = alt_ind_palettes[2] + ((flags & 0x40) ? 4 : 0);
+							} break;
+
+							case Mode::CH64:
+							case Mode::CH128:
+							case Mode::CH256: {
+								const uint8_t flags = ram_[line_parameter_pointer_ + 3];
+
+								// Use ALTIND0 and ALTIND1 to pick the alt_ind_palettes.
+								//
+								// ALTIND1 = b6 of params[3], if set => character codes with bit 7 set should use palette indices 2 and 3.
+								// ALTIND0 = b7 of params[3], if set => character codes with bit 6 set should use palette indices 4... instead of 0... .
+								alt_ind_palettes[0] = palette_;
+								alt_ind_palettes[2] = alt_ind_palettes[0] + ((flags & 0x40) ? 2 : 0);
+
+								alt_ind_palettes[1] = alt_ind_palettes[0] + ((flags & 0x80) ? 4 : 0);
+								alt_ind_palettes[3] = alt_ind_palettes[2] + ((flags & 0x80) ? 4 : 0);
+							} break;
+						}
+					break;
+
+					// Third slot: Line data pointer 1.
+					case 2:
+						start_line_data_pointer_[0] = ram_[line_parameter_pointer_ + 4];
+						start_line_data_pointer_[0] |= ram_[line_parameter_pointer_ + 5] << 8;
+
+						line_data_pointer_[0] = start_line_data_pointer_[0];
+					break;
+
+					// Fourth slot: Line data pointer 2.
+					case 3:
+						start_line_data_pointer_[1] = ram_[line_parameter_pointer_ + 6];
+						start_line_data_pointer_[1] |= ram_[line_parameter_pointer_ + 7] << 8;
+
+						line_data_pointer_[1] = start_line_data_pointer_[1];
+					break;
+				}
+			}
+
+			++output_duration_;
+			add_window(1);
+		}
+		if(window == 4) {
+			if(mode_ == Mode::Vsync) {
+				set_output_type(is_sync_or_pixels_ ? OutputType::Sync : OutputType::Blank);
+			} else {
+				set_output_type(OutputType::Blank);
+			}
+		}
+
+		// Deal with vsync mode out here.
+		if(mode_ == Mode::Vsync) {
+			if(window >= 4) {
+				while(window < end_window) {
+					// Skip straight to the next event.
+					int next_event = end_window;
+					if(window < left_margin_) next_event = std::min(next_event, left_margin_);
+					if(window < right_margin_) next_event = std::min(next_event, right_margin_);
+
+					output_duration_ += next_event - window;
+					add_window(next_event - window);
+					set_output_type(is_sync_or_pixels_ ? OutputType::Sync : OutputType::Blank);
+				}
+			}
+		} else {
+			// If present then the colour burst is output for the period from
+			// the start of window 6 to the end of window 10.
+			//
+			// The first 8 palette entries also need to be fetched here.
+			while(window < 10 && window < end_window) {
+				if(window == 6) {
+					set_output_type(OutputType::ColourBurst);
+				}
+
+				if(should_reload_line_parameters_ && window < 8) {
+					const int base = (window - 4) << 1;
+					assert(base < 7);
+					palette_[base] = mapped_colour(ram_[line_parameter_pointer_ + base + 8]);
+					palette_[base + 1] = mapped_colour(ram_[line_parameter_pointer_ + base + 9]);
+				}
+
+				++output_duration_;
+				add_window(1);
+			}
+
+			if(window >= 10) {
+				if(window == 10) {
+					set_output_type(is_sync_or_pixels_ ? OutputType::Pixels : OutputType::Border);
+				}
+
+				while(window < end_window) {
+					int next_event = end_window;
+					if(window < left_margin_) next_event = std::min(next_event, left_margin_);
+					if(window < right_margin_) next_event = std::min(next_event, right_margin_);
+
+					if(is_sync_or_pixels_) {
+
+#define DispatchBpp(func) \
+	switch(bpp_) {	\
+		default:	\
+		case 1: func(1)(pixel_pointer_, output_duration);	break;	\
+		case 2: func(2)(pixel_pointer_, output_duration);	break;	\
+		case 4: func(4)(pixel_pointer_, output_duration);	break;	\
+		case 8: func(8)(pixel_pointer_, output_duration);	break;	\
+	}
+
+#define pixel(x) output_pixel<x, false>
+#define lpixel(x) output_pixel<x, true>
+#define ch256(x) output_character<x, 8>
+#define ch128(x) output_character<x, 7>
+#define ch64(x) output_character<x, 6>
+#define attr(x) output_attributed<x>
+
+						int columns_remaining = next_event - window;
+						while(columns_remaining) {
+							if(!pixel_pointer_) {
+								if(output_duration_) {
+									set_output_type(OutputType::Pixels, true);
+								}
+								pixel_pointer_ = allocated_pointer_ = reinterpret_cast<uint16_t *>(crt_.begin_data(allocation_size));
+							}
+
+							if(allocated_pointer_) {
+								const int output_duration = std::min(columns_remaining, int(allocated_pointer_ + allocation_size - pixel_pointer_) / column_size_);
+
+								switch(mode_) {
+									default:
+									case Mode::Pixel:	DispatchBpp(pixel);		break;
+									case Mode::LPixel:	DispatchBpp(lpixel);	break;
+									case Mode::CH256:	DispatchBpp(ch256);		break;
+									case Mode::CH128:	DispatchBpp(ch128);		break;
+									case Mode::CH64:	DispatchBpp(ch64);		break;
+									case Mode::Attr:	DispatchBpp(attr);		break;
+								}
+
+								pixel_pointer_ += output_duration * column_size_;
+								output_duration_ += output_duration;
+								if(pixel_pointer_ - allocated_pointer_ == allocation_size) {
+									set_output_type(OutputType::Pixels, true);
+								}
+								columns_remaining -= output_duration;
+								add_window(output_duration);
+							} else {
+								output_duration_ += columns_remaining;
+								add_window(columns_remaining);
+								columns_remaining = 0;
+							}
+						}
+
+#undef attr
+#undef ch64
+#undef ch128
+#undef ch256
+#undef pixel
+#undef lpixel
+#undef DispatchBpp
+					} else {
+						output_duration_ += next_event - window;
+						add_window(next_event - window);
+					}
+
+					set_output_type(is_sync_or_pixels_ ? OutputType::Pixels : OutputType::Border);
+				}
+			}
+		}
+
+		// Check for end of line.
+		if(!horizontal_counter_) {
+			assert(window == 57);
+
+			++lines_remaining_;
+			if(!lines_remaining_) {
+				should_reload_line_parameters_ = true;
+
+				// Check for end-of-frame.
+				if(reload_line_parameter_pointer_) {
+					line_parameter_pointer_ = line_parameter_base_;
+				} else {
+					line_parameter_pointer_ += 16;
+				}
+			} else {
+				should_reload_line_parameters_ = false;
+			}
+
+			// Deal with VRES and other address reloading, dependant upon mode.
+			switch(mode_) {
+				default: break;
+				case Mode::CH64:
+				case Mode::CH128:
+				case Mode::CH256:
+					line_data_pointer_[0] = start_line_data_pointer_[0];
+					++line_data_pointer_[1];
+				break;
+
+				case Mode::Pixel:
+				case Mode::LPixel:
+				case Mode::Attr:
+					// Reload the pixel or attribute address if VRES is clear.
+					if(!vres_) {
+						line_data_pointer_[0] = start_line_data_pointer_[0];
+					}
+				break;
+			}
+		}
+	}
+
+#undef add_window
+
+}
+
+void Nick::set_output_type(OutputType type, bool force_flush) {
+	if(type == output_type_ && !force_flush) {
+		return;
+	}
+	if(output_duration_) {
+		switch(output_type_) {
+			case OutputType::Border: {
+				uint16_t *const colour_pointer = reinterpret_cast<uint16_t *>(crt_.begin_data(1));
+				if(colour_pointer) *colour_pointer = border_colour_;
+				crt_.output_level(output_duration_*16);
+			} break;
+
+			case OutputType::Pixels: {
+				crt_.output_data(output_duration_*16, size_t(output_duration_*column_size_));
+				pixel_pointer_ = nullptr;
+				allocated_pointer_ = nullptr;
+			} break;
+
+			case OutputType::Sync:			crt_.output_sync(output_duration_*16);				break;
+			case OutputType::Blank:			crt_.output_blank(output_duration_*16);				break;
+			case OutputType::ColourBurst:	crt_.output_colour_burst(output_duration_*16, 0);	break;
+		}
+	}
+
+	output_duration_ = 0;
+	output_type_ = type;
+}
+
+// MARK: - Sequence points.
+
+Cycles Nick::get_next_sequence_point() const {
+	// TODO: the below is incorrect; unit test and correct.
+	// Changing to e.g. Cycles(1) reveals the relevant discrepancy.
+//	return Cycles(1);
+
+	constexpr int load_point = 2*16;
+
+	// Any mode line may cause a change in the interrupt output, so as a first blush
+	// just always report the time until the end of the mode line.
+	if(lines_remaining_ || horizontal_counter_ >= load_point) {
+		return Cycles(load_point + (912 - horizontal_counter_) + (0xff - lines_remaining_) * 912);
+	} else {
+		return Cycles(load_point - horizontal_counter_);
+	}
+}
+
+// MARK: - CRT passthroughs.
+
+void Nick::set_scan_target(Outputs::Display::ScanTarget *scan_target) {
+	crt_.set_scan_target(scan_target);
+}
+
+Outputs::Display::ScanStatus Nick::get_scaled_scan_status() const {
+	return crt_.get_scaled_scan_status();
+}
+
+// MARK: - Specific pixel outputters.
+
+#define output1bpp(x)	\
+	target[0] = palette[(x & 0x80) >> 7];	\
+	target[1] = palette[(x & 0x40) >> 6];	\
+	target[2] = palette[(x & 0x20) >> 5];	\
+	target[3] = palette[(x & 0x10) >> 4];	\
+	target[4] = palette[(x & 0x08) >> 3];	\
+	target[5] = palette[(x & 0x04) >> 2];	\
+	target[6] = palette[(x & 0x02) >> 1];	\
+	target[7] = palette[(x & 0x01) >> 0];	\
+	target += 8
+
+#define output2bpp(x)	\
+	target[0] = palette_[((x & 0x80) >> 7) | ((x & 0x08) >> 2)];	\
+	target[1] = palette_[((x & 0x40) >> 6) | ((x & 0x04) >> 1)];	\
+	target[2] = palette_[((x & 0x20) >> 5) | ((x & 0x02) >> 0)];	\
+	target[3] = palette_[((x & 0x10) >> 4) | ((x & 0x01) << 1)];	\
+	target += 4
+
+#define output4bpp(x)	\
+	target[0] = palette_[((x & 0x02) << 2) | ((x & 0x20) >> 3) | ((x & 0x08) >> 2) | ((x & 0x80) >> 7)];	\
+	target[1] = palette_[((x & 0x01) << 3) | ((x & 0x10) >> 2) | ((x & 0x04) >> 1) | ((x & 0x40) >> 6)];	\
+	target += 2
+
+#define output8bpp(x)	\
+	target[0] = mapped_colour(x);	\
+	++target
+
+template <int bpp, bool is_lpixel> void Nick::output_pixel(uint16_t *target, int columns) const {
+	static_assert(bpp == 1 || bpp == 2 || bpp == 4 || bpp == 8);
+
+	int index = 0;
+	for(int c = 0; c < columns; c++) {
+		uint8_t pixels[2] = {
+			ram_[(line_data_pointer_[0] + index) & 0xffff],
+			ram_[(line_data_pointer_[0] + index + 1) & 0xffff]
+		};
+		index += is_lpixel ? 1 : 2;
+
+		switch(bpp) {
+			default:
+			case 1: {
+				const uint16_t *palette = alt_ind_palettes[((pixels[0] >> 6) & 0x02) | (pixels[0]&1)];
+				pixels[0] &= two_colour_mask_;
+				output1bpp(pixels[0]);
+
+				if constexpr (!is_lpixel) {
+					palette = alt_ind_palettes[((pixels[1] >> 6) & 0x02) | (pixels[1]&1)];
+					pixels[1] &= two_colour_mask_;
+					output1bpp(pixels[1]);
+				}
+			} break;
+
+			case 2:
+				output2bpp(pixels[0]);
+				if constexpr (!is_lpixel) {
+					output2bpp(pixels[1]);
+				}
+			break;
+
+			case 4:
+				output4bpp(pixels[0]);
+				if constexpr (!is_lpixel) {
+					output4bpp(pixels[1]);
+				}
+			break;
+
+			case 8:
+				output8bpp(pixels[0]);
+				if constexpr (!is_lpixel) {
+					output8bpp(pixels[1]);
+				}
+			break;
+		}
+	}
+}
+
+template <int bpp, int index_bits> void Nick::output_character(uint16_t *target, int columns) const {
+	static_assert(bpp == 1 || bpp == 2 || bpp == 4 || bpp == 8);
+
+	for(int c = 0; c < columns; c++) {
+		const uint8_t character = ram_[(line_data_pointer_[0] + c) & 0xffff];
+		const uint8_t pixels = ram_[(
+			(line_data_pointer_[1] << index_bits) +
+			(character & ((1 << index_bits) - 1))
+		) & 0xffff];
+
+		switch(bpp) {
+			default:
+				assert(false);
+			break;
+
+			case 1: {
+				// This applies ALTIND0 and ALTIND1.
+				const uint16_t *palette = alt_ind_palettes[character >> 6];
+				output1bpp(pixels);
+			} break;
+
+			case 2:		output2bpp(pixels);		break;
+			case 4:		output4bpp(pixels);		break;
+			case 8:		output8bpp(pixels);		break;
+		}
+	}
+}
+
+template <int bpp> void Nick::output_attributed(uint16_t *target, int columns) const {
+	static_assert(bpp == 1 || bpp == 2 || bpp == 4 || bpp == 8);
+
+	for(int c = 0; c < columns; c++) {
+		const uint8_t pixels = ram_[(line_data_pointer_[1] + c) & 0xffff];
+		const uint8_t attributes = ram_[(line_data_pointer_[0] + c) & 0xffff];
+
+		const uint16_t palette[2] = {
+			palette_[attributes >> 4], palette_[attributes & 0x0f]
+		};
+		output1bpp(pixels);
+	}
+}
+
+#undef output1bpp
+#undef output2bpp
+#undef output4bpp
+#undef output8bpp
--- a/Machines/Enterprise/Nick.hpp
+++ b/Machines/Enterprise/Nick.hpp
@ -0,0 +1,108 @@
+//
+//  Nick.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 14/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#ifndef Nick_hpp
+#define Nick_hpp
+
+#include <cstdint>
+#include "../../ClockReceiver/ClockReceiver.hpp"
+#include "../../Outputs/CRT/CRT.hpp"
+
+namespace Enterprise {
+
+class Nick {
+	public:
+		Nick(const uint8_t *ram);
+
+		void write(uint16_t address, uint8_t value);
+		uint8_t read(uint16_t address);
+
+		void run_for(Cycles);
+		Cycles get_time_until_z80_slot(Cycles after_period) const;
+
+		void set_scan_target(Outputs::Display::ScanTarget *scan_target);
+		Outputs::Display::ScanStatus get_scaled_scan_status() const;
+
+		Cycles get_next_sequence_point() const;
+
+		/*!
+			@returns The current state of the interrupt line — @c true for active;
+				@c false for inactive.
+		*/
+		inline bool get_interrupt_line() const {
+			return interrupt_line_;
+		}
+
+	private:
+		Outputs::CRT::CRT crt_;
+		const uint8_t *const ram_;
+
+		// CPU-provided state.
+		uint8_t line_parameter_control_ = 0xc0;
+		uint16_t line_parameter_base_ = 0x0000;
+		uint16_t border_colour_ = 0;
+
+		// Ephemerals, related to current video position.
+		int horizontal_counter_ = 0;
+		uint16_t line_parameter_pointer_ = 0x0000;
+		bool should_reload_line_parameters_ = true;
+		uint16_t line_data_pointer_[2];
+		uint16_t start_line_data_pointer_[2];
+
+		// Current mode line parameters.
+		uint8_t lines_remaining_ = 0x00;
+		uint8_t two_colour_mask_ = 0xff;
+		int left_margin_ = 0, right_margin_ = 0;
+		const uint16_t *alt_ind_palettes[4];
+		enum class Mode {
+			Vsync,
+			Pixel,
+			Attr,
+			CH256,
+			CH128,
+			CH64,
+			Unused,
+			LPixel,
+		} mode_ = Mode::Vsync;
+		bool is_sync_or_pixels_ = false;
+		int bpp_ = 0;
+		int column_size_ = 0;
+		bool interrupt_line_ = true;
+		int line_data_per_column_increments_[2] = {0, 0};
+		bool vres_ = false;
+		bool reload_line_parameter_pointer_ = false;
+
+		// An accumulator for border output regions.
+		int border_duration_ = 0;
+
+		// The destination for new pixels.
+		static constexpr int allocation_size = 336;
+		static_assert((allocation_size % 16) == 0, "Allocation size must be a multiple of 16");
+		uint16_t *pixel_pointer_ = nullptr, *allocated_pointer_ = nullptr;
+
+		// Output transitions.
+		enum class OutputType {
+			Sync, Blank, Pixels, Border, ColourBurst
+		};
+		void set_output_type(OutputType, bool force_flush = false);
+		int output_duration_ = 0;
+		OutputType output_type_ = OutputType::Sync;
+
+		// Current palette.
+		uint16_t palette_[16]{};
+
+		// Specific outputters.
+		template <int bpp, bool is_lpixel> void output_pixel(uint16_t *target, int columns) const;
+		template <int bpp, int index_bits> void output_character(uint16_t *target, int columns) const;
+		template <int bpp> void output_attributed(uint16_t *target, int columns) const;
+};
+
+
+}
+
+#endif /* Nick_hpp */
--- a/Machines/Utility/MachineForTarget.cpp
+++ b/Machines/Utility/MachineForTarget.cpp
@ -20,6 +20,7 @@
 #include "../ColecoVision/ColecoVision.hpp"
 #include "../Commodore/Vic-20/Vic20.hpp"
 #include "../Electron/Electron.hpp"
+#include "../Enterprise/Enterprise.hpp"
 #include "../MasterSystem/MasterSystem.hpp"
 #include "../MSX/MSX.hpp"
 #include "../Oric/Oric.hpp"
@ -34,6 +35,7 @@
 #include "../../Analyser/Static/Atari2600/Target.hpp"
 #include "../../Analyser/Static/AtariST/Target.hpp"
 #include "../../Analyser/Static/Commodore/Target.hpp"
+#include "../../Analyser/Static/Enterprise/Target.hpp"
 #include "../../Analyser/Static/Macintosh/Target.hpp"
 #include "../../Analyser/Static/MSX/Target.hpp"
 #include "../../Analyser/Static/Oric/Target.hpp"
@ -49,7 +51,7 @@ Machine::DynamicMachine *Machine::MachineForTarget(const Analyser::Static::Targe

 	Machine::DynamicMachine *machine = nullptr;
 	try {
-#define BindD(name, m)	case Analyser::Machine::m: machine = new Machine::TypedDynamicMachine<name::Machine>(name::Machine::m(target, rom_fetcher));	break;
+#define BindD(name, m)	case Analyser::Machine::m: machine = new Machine::TypedDynamicMachine<::name::Machine>(name::Machine::m(target, rom_fetcher));	break;
 #define Bind(m)	BindD(m, m)
 		switch(target->machine) {
 			Bind(AmstradCPC)
@ -61,6 +63,7 @@ Machine::DynamicMachine *Machine::MachineForTarget(const Analyser::Static::Targe
 			BindD(Coleco::Vision, ColecoVision)
 			BindD(Commodore::Vic20, Vic20)
 			Bind(Electron)
+			Bind(Enterprise)
 			Bind(MSX)
 			Bind(Oric)
 			BindD(Sega::MasterSystem, MasterSystem)
@ -127,6 +130,7 @@ std::string Machine::ShortNameForTargetMachine(const Analyser::Machine machine)
 		case Analyser::Machine::AtariST:		return "AtariST";
 		case Analyser::Machine::ColecoVision:	return "ColecoVision";
 		case Analyser::Machine::Electron:		return "Electron";
+		case Analyser::Machine::Enterprise:		return "Enterprise";
 		case Analyser::Machine::Macintosh:		return "Macintosh";
 		case Analyser::Machine::MasterSystem:	return "MasterSystem";
 		case Analyser::Machine::MSX:			return "MSX";
@ -148,6 +152,7 @@ std::string Machine::LongNameForTargetMachine(Analyser::Machine machine) {
 		case Analyser::Machine::AtariST:		return "Atari ST";
 		case Analyser::Machine::ColecoVision:	return "ColecoVision";
 		case Analyser::Machine::Electron:		return "Acorn Electron";
+		case Analyser::Machine::Enterprise:		return "Enterprise";
 		case Analyser::Machine::Macintosh:		return "Apple Macintosh";
 		case Analyser::Machine::MasterSystem:	return "Sega Master System";
 		case Analyser::Machine::MSX:			return "MSX";
@ -177,6 +182,7 @@ std::vector<std::string> Machine::AllMachines(Type type, bool long_names) {
 		AddName(AppleIIgs);
 		AddName(AtariST);
 		AddName(Electron);
+		AddName(Enterprise);
 		AddName(Macintosh);
 		AddName(MSX);
 		AddName(Oric);
@ -226,6 +232,7 @@ std::map<std::string, std::unique_ptr<Analyser::Static::Target>> Machine::Target
 	Add(AppleIIgs);
 	Add(AtariST);
 	AddMapped(Electron, Acorn);
+	Add(Enterprise);
 	Add(Macintosh);
 	Add(MSX);
 	Add(Oric);
--- a/Machines/Utility/ROMCatalogue.cpp
+++ b/Machines/Utility/ROMCatalogue.cpp
@ -27,8 +27,15 @@ Request::Request(Name name, bool optional) {
 }

 Request Request::append(Node::Type type, const Request &rhs) {
-	// Start with the easiest case: this is already an appropriate
-	// request, and so is the new thing.
+	// If either side is empty, act appropriately.
+	if(node.empty() && !rhs.node.empty()) {
+		return rhs;
+	}
+	if(rhs.node.empty()) {
+		return *this;
+	}
+
+	// Just copy in the RHS child nodes if types match.
 	if(node.type == type && rhs.node.type == type) {
 		Request new_request = *this;
 		new_request.node.children.insert(new_request.node.children.end(), rhs.node.children.begin(), rhs.node.children.end());
@ -404,6 +411,62 @@ Description::Description(Name name) {
 			*this = Description(name, "DiskII", "the Disk II 13-sector state machine ROM", "state-machine-13.rom", 256, 0x62e22620u);
 		break;

+		case Name::EnterpriseEXOS10: {
+			const std::initializer_list<std::string> filenames = {"exos10.bin", "Exos (198x)(Enterprise).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise EXOS ROM v1.0", filenames, 32 * 1024, 0x30b26387u);
+		} break;
+		case Name::EnterpriseEXOS20: {
+			const std::initializer_list<std::string> filenames = {"exos20.bin", "Expandible OS v2.0 (1984)(Intelligent Software).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise EXOS ROM v2.0", filenames, 32 * 1024, 0xd421795fu);
+		} break;
+		case Name::EnterpriseEXOS21: {
+			const std::initializer_list<std::string> filenames = {"exos21.bin", "Expandible OS v2.1 (1985)(Intelligent Software).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise EXOS ROM v2.1", filenames, 32 * 1024, 0x982a3b44u);
+		} break;
+		case Name::EnterpriseEXOS23: {
+			const std::initializer_list<std::string> filenames = {"exos23.bin", "Expandible OS v2.3 (1987)(Intelligent Software).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise EXOS ROM v2.1", filenames, 64 * 1024, 0x24838410u);
+		} break;
+
+		case Name::EnterpriseBASIC10: {
+			const std::initializer_list<std::string> filenames = {"basic10.bin"};
+			*this = Description(name, "Enterprise", "the Enterprise BASIC ROM v1.0", filenames, 16 * 1024, 0xd62e4fb7u);
+		} break;
+		case Name::EnterpriseBASIC10Part1: {
+			const std::initializer_list<std::string> filenames = {"BASIC 1.0 - EPROM 1-2 (198x)(Enterprise).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise BASIC ROM v1.0, Part 1", filenames, 8193, 0x37bf48e1u);
+		} break;
+		case Name::EnterpriseBASIC10Part2: {
+			const std::initializer_list<std::string> filenames = {"BASIC 1.0 - EPROM 2-2 (198x)(Enterprise).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise BASIC ROM v1.0, Part 2", filenames, 8193, 0xc5298c79u);
+		} break;
+		case Name::EnterpriseBASIC11: {
+			const std::initializer_list<std::string> filenames = {"basic11.bin"};
+			*this = Description(name, "Enterprise", "the Enterprise BASIC ROM v1.1", filenames, 16 * 1024, 0x683cf455u);
+		} break;
+		case Name::EnterpriseBASIC11Suffixed: {
+			const std::initializer_list<std::string> filenames = {"BASIC 1.1 - EPROM 1.1 (198x)(Enterprise).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise BASIC ROM v1.1, with trailing byte", filenames, 16385, 0xc96b7602u);
+		} break;
+		case Name::EnterpriseBASIC21: {
+			const std::initializer_list<std::string> filenames = {
+				"basic21.bin",
+				"BASIC Interpreter v2.1 (1985)(Intelligent Software).bin",
+				"BASIC Interpreter v2.1 (1985)(Intelligent Software)[a].bin"
+			};
+			const std::initializer_list<uint32_t> crcs = { 0x55f96251, 0x683cf455 };
+			*this = Description(name, "Enterprise", "the Enterprise BASIC ROM v2.1", filenames, 16 * 1024, crcs);
+		} break;
+
+		case Name::EnterpriseEPDOS: {
+			const std::initializer_list<std::string> filenames = {"epdos.bin", "EPDOS v1.7 (19xx)(Haluska, Laszlo).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise EPDOS ROM", filenames, 32 * 1024, 0x201319ebu);
+		} break;
+		case Name::EnterpriseEXDOS: {
+			const std::initializer_list<std::string> filenames = {"exdos.bin", "EX-DOS EPROM (198x)(Enterprise).bin"};
+			*this = Description(name, "Enterprise", "the Enterprise EXDOS ROM", filenames, 16 * 1024, 0xe6daa0e9u);
+		} break;
+
 		case Name::Macintosh128k:	*this = Description(name, "Macintosh", "the Macintosh 128k ROM", "mac128k.rom", 64*1024, 0x6d0c8a28u);	break;
 		case Name::Macintosh512k:	*this = Description(name, "Macintosh", "the Macintosh 512k ROM", "mac512k.rom", 64*1024, 0xcf759e0d);	break;
 		case Name::MacintoshPlus: {
--- a/Machines/Utility/ROMCatalogue.hpp
+++ b/Machines/Utility/ROMCatalogue.hpp
@ -71,6 +71,22 @@ enum Name {
 	DiskIIStateMachine13Sector,
 	DiskIIBoot13Sector,

+	// Enterprise.
+	EnterpriseEXOS10,
+	EnterpriseEXOS20,
+	EnterpriseEXOS21,
+	EnterpriseEXOS23,
+
+	EnterpriseBASIC10,
+	EnterpriseBASIC10Part1,
+	EnterpriseBASIC10Part2,
+	EnterpriseBASIC11,
+	EnterpriseBASIC11Suffixed,
+	EnterpriseBASIC21,
+
+	EnterpriseEPDOS,
+	EnterpriseEXDOS,
+
 	// Macintosh.
 	Macintosh128k,
 	Macintosh512k,
@ -237,6 +253,10 @@ struct Request {
 			bool is_optional = false;
 			std::vector<Node> children;

+			bool empty() const {
+				return type == Type::One && name == Name::None;
+			}
+
 			void add_descriptions(std::vector<Description> &) const;
 			bool validate(Map &) const;
 			void visit(
--- a/Numeric/LFSR.hpp
+++ b/Numeric/LFSR.hpp
@ -12,6 +12,8 @@
 #include <cstdint>
 #include <cstdlib>

+#include "Sizes.hpp"
+
 namespace Numeric {

 template <typename IntType> struct LSFRPolynomial {};
@ -67,8 +69,8 @@ template <typename IntType = uint64_t, IntType polynomial = LSFRPolynomial<IntTy
 			determining the bit that was just shifted out.
 		*/
 		IntType next() {
-			const auto result = value_ & 1;
-			value_ = (value_ >> 1) ^ (result * polynomial);
+			const auto result = IntType(value_ & 1);
+			value_ = IntType((value_ >> 1) ^ (result * polynomial));
 			return result;
 		}

@ -76,6 +78,8 @@ template <typename IntType = uint64_t, IntType polynomial = LSFRPolynomial<IntTy
 		IntType value_ = 0;
 };

+template <uint64_t polynomial> class LFSRv: public LFSR<typename MinIntTypeValue<polynomial>::type, polynomial> {};
+
 }

 #endif /* LFSR_h */
--- a/InstructionSets/Sizes.hpp
+++ b/InstructionSets/Sizes.hpp
@ -10,6 +10,7 @@
 #define Sizes_h

 #include <limits>
+#include <type_traits>

 /*!
 	Maps to the smallest integral type that can contain max_value, from the following options:
--- a/Signal.xcodeproj/project.pbxproj
+++ b/Signal.xcodeproj/project.pbxproj
@ -17,6 +17,17 @@
 		4B051C93266D9D6900CA44E8 /* ROMImages in Resources */ = {isa = PBXBuildFile; fileRef = 4BC9DF441D044FCA00F44158 /* ROMImages */; };
 		4B051C95266EF50200CA44E8 /* AppleIIOptionsPanel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B051C94266EF50200CA44E8 /* AppleIIOptionsPanel.swift */; };
 		4B051C97266EF5F600CA44E8 /* CSAppleII.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B051C96266EF5F600CA44E8 /* CSAppleII.mm */; };
+		4B051CA22676F52200CA44E8 /* Enterprise.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CA12676F52200CA44E8 /* Enterprise.cpp */; };
+		4B051CA32676F52200CA44E8 /* Enterprise.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CA12676F52200CA44E8 /* Enterprise.cpp */; };
+		4B051CA826781D6500CA44E8 /* StaticAnalyser.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CA726781D6500CA44E8 /* StaticAnalyser.cpp */; };
+		4B051CA926781D6500CA44E8 /* StaticAnalyser.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CA726781D6500CA44E8 /* StaticAnalyser.cpp */; };
+		4B051CAC26783E2000CA44E8 /* Nick.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CAA26783E2000CA44E8 /* Nick.cpp */; };
+		4B051CAD26783E2000CA44E8 /* Nick.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CAA26783E2000CA44E8 /* Nick.cpp */; };
+		4B051CB0267C1CA200CA44E8 /* Keyboard.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CAE267C1CA200CA44E8 /* Keyboard.cpp */; };
+		4B051CB1267C1CA200CA44E8 /* Keyboard.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CAE267C1CA200CA44E8 /* Keyboard.cpp */; };
+		4B051CB3267D3FF800CA44E8 /* EnterpriseNickTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CB2267D3FF800CA44E8 /* EnterpriseNickTests.mm */; };
+		4B051CB62680158600CA44E8 /* EXDos.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CB42680158600CA44E8 /* EXDos.cpp */; };
+		4B051CB72680158600CA44E8 /* EXDos.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B051CB42680158600CA44E8 /* EXDos.cpp */; };
 		4B05401E219D1618001BF69C /* ScanTarget.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B05401D219D1618001BF69C /* ScanTarget.cpp */; };
 		4B05401F219D1618001BF69C /* ScanTarget.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B05401D219D1618001BF69C /* ScanTarget.cpp */; };
 		4B055A7A1FAE78A00060FFFF /* SDL2.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 4B055A771FAE78210060FFFF /* SDL2.framework */; };
@ -312,7 +323,7 @@
 		4B778F0023A5EB990000D260 /* G64.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B4518931F75FD1B00926311 /* G64.cpp */; };
 		4B778F0123A5EBA00000D260 /* MacintoshIMG.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BB4BFAE22A42F290069048D /* MacintoshIMG.cpp */; };
 		4B778F0223A5EBA40000D260 /* MFMSectorDump.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B58601C1F806AB200AEE2E3 /* MFMSectorDump.cpp */; };
-		4B778F0323A5EBB00000D260 /* MSXDSK.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEBFB4B2002C4BF000708CC /* MSXDSK.cpp */; };
+		4B778F0323A5EBB00000D260 /* FAT12.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEBFB4B2002C4BF000708CC /* FAT12.cpp */; };
 		4B778F0423A5EBB00000D260 /* OricMFMDSK.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B4518971F75FD1B00926311 /* OricMFMDSK.cpp */; };
 		4B778F0523A5EBB00000D260 /* ST.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BE0A3EC237BB170002AB46F /* ST.cpp */; };
 		4B778F0623A5EC150000D260 /* CAS.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B0E04E81FC9E5DA00F43484 /* CAS.cpp */; };
@ -950,8 +961,8 @@
 		4BE9A6B11EDE293000CBCB47 /* zexdoc.com in Resources */ = {isa = PBXBuildFile; fileRef = 4BE9A6B01EDE293000CBCB47 /* zexdoc.com */; };
 		4BEA525E1DF33323007E74F2 /* Tape.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEA525D1DF33323007E74F2 /* Tape.cpp */; };
 		4BEA52631DF339D7007E74F2 /* SoundGenerator.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEA52611DF339D7007E74F2 /* SoundGenerator.cpp */; };
-		4BEBFB4D2002C4BF000708CC /* MSXDSK.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEBFB4B2002C4BF000708CC /* MSXDSK.cpp */; };
-		4BEBFB4E2002C4BF000708CC /* MSXDSK.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEBFB4B2002C4BF000708CC /* MSXDSK.cpp */; };
+		4BEBFB4D2002C4BF000708CC /* FAT12.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEBFB4B2002C4BF000708CC /* FAT12.cpp */; };
+		4BEBFB4E2002C4BF000708CC /* FAT12.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEBFB4B2002C4BF000708CC /* FAT12.cpp */; };
 		4BEBFB512002DB30000708CC /* DiskROM.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEBFB4F2002DB30000708CC /* DiskROM.cpp */; };
 		4BEBFB522002DB30000708CC /* DiskROM.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEBFB4F2002DB30000708CC /* DiskROM.cpp */; };
 		4BEDA3BA25B25563000C2DBD /* Decoder.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BEDA3B425B25563000C2DBD /* Decoder.cpp */; };
@ -987,6 +998,8 @@
 		4BFCA1291ECBE7A700AC40C1 /* zexall.com in Resources */ = {isa = PBXBuildFile; fileRef = 4BFCA1281ECBE7A700AC40C1 /* zexall.com */; };
 		4BFCA12B1ECBE7C400AC40C1 /* ZexallTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4BFCA12A1ECBE7C400AC40C1 /* ZexallTests.swift */; };
 		4BFDD78C1F7F2DB4008579B9 /* ImplicitSectors.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BFDD78B1F7F2DB4008579B9 /* ImplicitSectors.cpp */; };
+		4BFEA2EF2682A7B900EBF94C /* Dave.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BFEA2ED2682A7B900EBF94C /* Dave.cpp */; };
+		4BFEA2F02682A7B900EBF94C /* Dave.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BFEA2ED2682A7B900EBF94C /* Dave.cpp */; };
 		4BFF1D3922337B0300838EA1 /* 68000Storage.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BFF1D3822337B0300838EA1 /* 68000Storage.cpp */; };
 		4BFF1D3A22337B0300838EA1 /* 68000Storage.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BFF1D3822337B0300838EA1 /* 68000Storage.cpp */; };
 		4BFF1D3D2235C3C100838EA1 /* EmuTOSTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4BFF1D3C2235C3C100838EA1 /* EmuTOSTests.mm */; };
@ -1028,6 +1041,18 @@
 		4B051C94266EF50200CA44E8 /* AppleIIOptionsPanel.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AppleIIOptionsPanel.swift; sourceTree = "<group>"; };
 		4B051C96266EF5F600CA44E8 /* CSAppleII.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = CSAppleII.mm; sourceTree = "<group>"; };
 		4B051C98266EF60500CA44E8 /* CSAppleII.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = CSAppleII.h; sourceTree = "<group>"; };
+		4B051CA02676F52200CA44E8 /* Enterprise.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Enterprise.hpp; sourceTree = "<group>"; };
+		4B051CA12676F52200CA44E8 /* Enterprise.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Enterprise.cpp; sourceTree = "<group>"; };
+		4B051CA526781D6500CA44E8 /* StaticAnalyser.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = StaticAnalyser.hpp; sourceTree = "<group>"; };
+		4B051CA626781D6500CA44E8 /* Target.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Target.hpp; sourceTree = "<group>"; };
+		4B051CA726781D6500CA44E8 /* StaticAnalyser.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = StaticAnalyser.cpp; sourceTree = "<group>"; };
+		4B051CAA26783E2000CA44E8 /* Nick.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = Nick.cpp; sourceTree = "<group>"; };
+		4B051CAB26783E2000CA44E8 /* Nick.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Nick.hpp; sourceTree = "<group>"; };
+		4B051CAE267C1CA200CA44E8 /* Keyboard.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = Keyboard.cpp; sourceTree = "<group>"; };
+		4B051CAF267C1CA200CA44E8 /* Keyboard.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Keyboard.hpp; sourceTree = "<group>"; };
+		4B051CB2267D3FF800CA44E8 /* EnterpriseNickTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = EnterpriseNickTests.mm; sourceTree = "<group>"; };
+		4B051CB42680158600CA44E8 /* EXDos.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = EXDos.cpp; sourceTree = "<group>"; };
+		4B051CB52680158600CA44E8 /* EXDos.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = EXDos.hpp; sourceTree = "<group>"; };
 		4B05401D219D1618001BF69C /* ScanTarget.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = ScanTarget.cpp; sourceTree = "<group>"; };
 		4B055A6A1FAE763F0060FFFF /* Clock Signal Kiosk */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = "Clock Signal Kiosk"; sourceTree = BUILT_PRODUCTS_DIR; };
 		4B055A771FAE78210060FFFF /* SDL2.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = SDL2.framework; path = ../../../../Library/Frameworks/SDL2.framework; sourceTree = SOURCE_ROOT; };
@ -1998,8 +2023,8 @@
 		4BEA52601DF3343A007E74F2 /* Interrupts.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Interrupts.hpp; sourceTree = "<group>"; };
 		4BEA52611DF339D7007E74F2 /* SoundGenerator.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = SoundGenerator.cpp; sourceTree = "<group>"; };
 		4BEA52621DF339D7007E74F2 /* SoundGenerator.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = SoundGenerator.hpp; sourceTree = "<group>"; };
-		4BEBFB4B2002C4BF000708CC /* MSXDSK.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = MSXDSK.cpp; sourceTree = "<group>"; };
-		4BEBFB4C2002C4BF000708CC /* MSXDSK.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = MSXDSK.hpp; sourceTree = "<group>"; };
+		4BEBFB4B2002C4BF000708CC /* FAT12.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = FAT12.cpp; sourceTree = "<group>"; };
+		4BEBFB4C2002C4BF000708CC /* FAT12.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = FAT12.hpp; sourceTree = "<group>"; };
 		4BEBFB4F2002DB30000708CC /* DiskROM.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = DiskROM.cpp; sourceTree = "<group>"; };
 		4BEBFB502002DB30000708CC /* DiskROM.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = DiskROM.hpp; sourceTree = "<group>"; };
 		4BEDA3B425B25563000C2DBD /* Decoder.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Decoder.cpp; sourceTree = "<group>"; };
@ -2049,6 +2074,9 @@
 		4BFDD78A1F7F2DB4008579B9 /* ImplicitSectors.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = ImplicitSectors.hpp; sourceTree = "<group>"; };
 		4BFDD78B1F7F2DB4008579B9 /* ImplicitSectors.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = ImplicitSectors.cpp; sourceTree = "<group>"; };
 		4BFE7B861FC39BF100160B38 /* StandardOptions.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = StandardOptions.hpp; sourceTree = "<group>"; };
+		4BFEA2ED2682A7B900EBF94C /* Dave.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = Dave.cpp; sourceTree = "<group>"; };
+		4BFEA2EE2682A7B900EBF94C /* Dave.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Dave.hpp; sourceTree = "<group>"; };
+		4BFEA2F12682A90200EBF94C /* Sizes.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Sizes.hpp; sourceTree = "<group>"; };
 		4BFF1D342233778C00838EA1 /* 68000.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = 68000.hpp; sourceTree = "<group>"; };
 		4BFF1D37223379D500838EA1 /* 68000Storage.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = 68000Storage.hpp; sourceTree = "<group>"; };
 		4BFF1D3822337B0300838EA1 /* 68000Storage.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = 68000Storage.cpp; sourceTree = "<group>"; };
@ -2090,6 +2118,33 @@
 /* End PBXFrameworksBuildPhase section */

 /* Begin PBXGroup section */
+		4B051C9F2676F52200CA44E8 /* Enterprise */ = {
+			isa = PBXGroup;
+			children = (
+				4BFEA2ED2682A7B900EBF94C /* Dave.cpp */,
+				4B051CA12676F52200CA44E8 /* Enterprise.cpp */,
+				4B051CB42680158600CA44E8 /* EXDos.cpp */,
+				4B051CAE267C1CA200CA44E8 /* Keyboard.cpp */,
+				4B051CAA26783E2000CA44E8 /* Nick.cpp */,
+				4BFEA2EE2682A7B900EBF94C /* Dave.hpp */,
+				4B051CA02676F52200CA44E8 /* Enterprise.hpp */,
+				4B051CB52680158600CA44E8 /* EXDos.hpp */,
+				4B051CAF267C1CA200CA44E8 /* Keyboard.hpp */,
+				4B051CAB26783E2000CA44E8 /* Nick.hpp */,
+			);
+			path = Enterprise;
+			sourceTree = "<group>";
+		};
+		4B051CA426781D6500CA44E8 /* Enterprise */ = {
+			isa = PBXGroup;
+			children = (
+				4B051CA726781D6500CA44E8 /* StaticAnalyser.cpp */,
+				4B051CA526781D6500CA44E8 /* StaticAnalyser.hpp */,
+				4B051CA626781D6500CA44E8 /* Target.hpp */,
+			);
+			path = Enterprise;
+			sourceTree = "<group>";
+		};
 		4B055A761FAE78210060FFFF /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
@ -2655,34 +2710,36 @@
 		4B45188C1F75FD1B00926311 /* Formats */ = {
 			isa = PBXGroup;
 			children = (
+				4B80CD74256CA15E00176FCC /* 2MG.cpp */,
 				4B45188D1F75FD1B00926311 /* AcornADF.cpp */,
 				4B0333AD2094081A0050B93D /* AppleDSK.cpp */,
 				4B45188F1F75FD1B00926311 /* CPCDSK.cpp */,
 				4B4518911F75FD1B00926311 /* D64.cpp */,
 				4BAF2B4C2004580C00480230 /* DMK.cpp */,
+				4BEBFB4B2002C4BF000708CC /* FAT12.cpp */,
 				4B4518931F75FD1B00926311 /* G64.cpp */,
 				4B4518951F75FD1B00926311 /* HFE.cpp */,
 				4BB4BFAE22A42F290069048D /* MacintoshIMG.cpp */,
 				4B58601C1F806AB200AEE2E3 /* MFMSectorDump.cpp */,
 				4BC131782346DF2B00E4FF3D /* MSA.cpp */,
-				4BEBFB4B2002C4BF000708CC /* MSXDSK.cpp */,
 				4B0F94FC208C1A1600FE41D9 /* NIB.cpp */,
 				4B4518971F75FD1B00926311 /* OricMFMDSK.cpp */,
 				4B4518991F75FD1B00926311 /* SSD.cpp */,
 				4BE0A3EC237BB170002AB46F /* ST.cpp */,
 				4B7BA03323C58B1E00B98D9E /* STX.cpp */,
 				4B6ED2EE208E2F8A0047B343 /* WOZ.cpp */,
+				4B80CD75256CA15E00176FCC /* 2MG.hpp */,
 				4B45188E1F75FD1B00926311 /* AcornADF.hpp */,
 				4B0333AE2094081A0050B93D /* AppleDSK.hpp */,
 				4B4518901F75FD1B00926311 /* CPCDSK.hpp */,
 				4B4518921F75FD1B00926311 /* D64.hpp */,
 				4BAF2B4D2004580C00480230 /* DMK.hpp */,
+				4BEBFB4C2002C4BF000708CC /* FAT12.hpp */,
 				4B4518941F75FD1B00926311 /* G64.hpp */,
 				4B4518961F75FD1B00926311 /* HFE.hpp */,
 				4BB4BFAF22A42F290069048D /* MacintoshIMG.hpp */,
 				4B58601D1F806AB200AEE2E3 /* MFMSectorDump.hpp */,
 				4BC131792346DF2B00E4FF3D /* MSA.hpp */,
-				4BEBFB4C2002C4BF000708CC /* MSXDSK.hpp */,
 				4B0F94FD208C1A1600FE41D9 /* NIB.hpp */,
 				4B4518981F75FD1B00926311 /* OricMFMDSK.hpp */,
 				4B45189A1F75FD1B00926311 /* SSD.hpp */,
@ -2690,8 +2747,6 @@
 				4B7BA03223C58B1E00B98D9E /* STX.hpp */,
 				4B6ED2EF208E2F8A0047B343 /* WOZ.hpp */,
 				4BFDD7891F7F2DB4008579B9 /* Utility */,
-				4B80CD74256CA15E00176FCC /* 2MG.cpp */,
-				4B80CD75256CA15E00176FCC /* 2MG.hpp */,
 			);
 			path = Formats;
 			sourceTree = "<group>";
@ -3048,6 +3103,7 @@
 			children = (
 				4B7BA03E23D55E7900B98D9E /* CRC.hpp */,
 				4B7BA03F23D55E7900B98D9E /* LFSR.hpp */,
+				4BFEA2F12682A90200EBF94C /* Sizes.hpp */,
 			);
 			name = Numeric;
 			path = ../../Numeric;
@ -3185,6 +3241,7 @@
 				4B8944FB201967B4007DE474 /* Commodore */,
 				4B894507201967B4007DE474 /* Disassembler */,
 				4BD67DC8209BE4D600AB2146 /* DiskII */,
+				4B051CA426781D6500CA44E8 /* Enterprise */,
 				4BB4BFB622A4372E0069048D /* Macintosh */,
 				4B89450F201967B4007DE474 /* MSX */,
 				4B8944F6201967B4007DE474 /* Oric */,
@ -3990,12 +4047,8 @@
 		4BB73EB51B587A5100552FC2 /* Clock SignalTests */ = {
 			isa = PBXGroup;
 			children = (
-				4BC9E1ED1D23449A003FCEE4 /* 6502InterruptTests.swift */,
-				4B92EAC91B7C112B00246143 /* 6502TimingTests.swift */,
-				4BC751B11D157E61006C31D9 /* 6522Tests.swift */,
-				4B1E85801D176468001EF87D /* 6532Tests.swift */,
-				4B4F478925367EDC004245B8 /* 65816AddressingTests.swift */,
-				4B8DF5132550D62900F3433C /* 65816kromTests.swift */,
+				4B85322922778E4200F26553 /* Comparative68000.hpp */,
+				4B90467222C6FA31000E2074 /* TestRunner68000.hpp */,
 				4B90467522C6FD6E000E2074 /* 68000ArithmeticTests.mm */,
 				4B9D0C4A22C7D70900DE1AD3 /* 68000BCDTests.mm */,
 				4B90467322C6FADD000E2074 /* 68000BitwiseTests.mm */,
@ -4004,43 +4057,48 @@
 				4BC5C3DF22C994CC00795658 /* 68000MoveTests.mm */,
 				4B9D0C4E22C7E0CF00DE1AD3 /* 68000RollShiftTests.mm */,
 				4BD388872239E198002D14B5 /* 68000Tests.mm */,
-				4BB73EB61B587A5100552FC2 /* AllSuiteATests.swift */,
 				4B924E981E74D22700B76AF1 /* AtariStaticAnalyserTests.mm */,
 				4BE34437238389E10058E78F /* AtariSTVideoTests.mm */,
-				4B049CDC1DA3C82F00322067 /* BCDTest.swift */,
-				4B3BA0C41D318B44005DD7A7 /* Bridges */,
-				4B3BA0C21D318AEB005DD7A7 /* C1540Tests.swift */,
-				4B85322922778E4200F26553 /* Comparative68000.hpp */,
 				4BB2A9AE1E13367E001A5C23 /* CRCTests.mm */,
-				4BEF6AAB1D35D1C400E73575 /* DPLLTests.swift */,
 				4BFF1D3C2235C3C100838EA1 /* EmuTOSTests.mm */,
-				4BBF49AE1ED2880200AB3669 /* FUSETests.swift */,
+				4B051CB2267D3FF800CA44E8 /* EnterpriseNickTests.mm */,
 				4B8DF4D725465B7500F3433C /* IIgsMemoryMapTests.mm */,
-				4BB73EB81B587A5100552FC2 /* Info.plist */,
-				4B4F477B253530B7004245B8 /* Jeek816Tests.swift */,
-				4B1414611B58888700E04248 /* KlausDormannTests.swift */,
 				4BEE1EBF22B5E236000A26A6 /* MacGCRTests.mm */,
 				4BE90FFC22D5864800FB464D /* MacintoshVideoTests.mm */,
 				4BA91E1C216D85BA00F79557 /* MasterSystemVDPTests.mm */,
 				4B98A0601FFADCDE00ADF63B /* MSXStaticAnalyserTests.mm */,
 				4BC0CB272446BC7B00A79DBB /* OPLTests.mm */,
-				4BD91D762401C2B8007BDC91 /* PatrikRakTests.swift */,
 				4B121F9A1E06293F00BFDA12 /* PCMSegmentEventSourceTests.mm */,
 				4BD4A8CF1E077FD20020D856 /* PCMTrackTests.mm */,
 				4B3F76B825A1635300178AEC /* PowerPCDecoderTests.mm */,
 				4BE76CF822641ED300ACD6FA /* QLTests.mm */,
 				4B8DD3672633B2D400B3C866 /* SpectrumVideoContentionTests.mm */,
-				4B1414631B588A1100E04248 /* Test Binaries */,
-				4B90467222C6FA31000E2074 /* TestRunner68000.hpp */,
 				4B2AF8681E513FC20027EE29 /* TIATests.mm */,
 				4B1D08051E0F7A1100763741 /* TimeTests.mm */,
-				4B14145F1B58885000E04248 /* WolfgangLorenzTests.swift */,
 				4BEE4BD325A26E2B00011BD2 /* x86DecoderTests.mm */,
 				4BDA8234261E8E000021AA19 /* Z80ContentionTests.mm */,
+				4BB73EB81B587A5100552FC2 /* Info.plist */,
+				4BC9E1ED1D23449A003FCEE4 /* 6502InterruptTests.swift */,
+				4B92EAC91B7C112B00246143 /* 6502TimingTests.swift */,
+				4BC751B11D157E61006C31D9 /* 6522Tests.swift */,
+				4B1E85801D176468001EF87D /* 6532Tests.swift */,
+				4B4F478925367EDC004245B8 /* 65816AddressingTests.swift */,
+				4B8DF5132550D62900F3433C /* 65816kromTests.swift */,
+				4BB73EB61B587A5100552FC2 /* AllSuiteATests.swift */,
+				4B049CDC1DA3C82F00322067 /* BCDTest.swift */,
+				4B3BA0C21D318AEB005DD7A7 /* C1540Tests.swift */,
+				4BEF6AAB1D35D1C400E73575 /* DPLLTests.swift */,
+				4BBF49AE1ED2880200AB3669 /* FUSETests.swift */,
+				4B4F477B253530B7004245B8 /* Jeek816Tests.swift */,
+				4B1414611B58888700E04248 /* KlausDormannTests.swift */,
+				4BD91D762401C2B8007BDC91 /* PatrikRakTests.swift */,
+				4B14145F1B58885000E04248 /* WolfgangLorenzTests.swift */,
 				4B08A2741EE35D56008B7065 /* Z80InterruptTests.swift */,
 				4BDDBA981EF3451200347E61 /* Z80MachineCycleTests.swift */,
 				4B01A6871F22F0DB001FD6E3 /* Z80MemptrTests.swift */,
 				4BFCA12A1ECBE7C400AC40C1 /* ZexallTests.swift */,
+				4B3BA0C41D318B44005DD7A7 /* Bridges */,
+				4B1414631B588A1100E04248 /* Test Binaries */,
 			);
 			path = "Clock SignalTests";
 			sourceTree = "<group>";
@ -4075,6 +4133,7 @@
 				4B7A90E22041097C008514A2 /* ColecoVision */,
 				4B4DC81D1D2C2425003C5BF8 /* Commodore */,
 				4B2E2D9E1C3A070900138695 /* Electron */,
+				4B051C9F2676F52200CA44E8 /* Enterprise */,
 				4B7F188B2154825D00388727 /* MasterSystem */,
 				4B79A4FC1FC8FF9800EEDAD5 /* MSX */,
 				4BCF1FA51DADC3E10039D2E7 /* Oric */,
@ -5177,6 +5236,7 @@
 				4B055AB41FAE860F0060FFFF /* OricTAP.cpp in Sources */,
 				4B055AB71FAE860F0060FFFF /* TZX.cpp in Sources */,
 				4B2BF19123DCC6A200C3AD60 /* BD500.cpp in Sources */,
+				4B051CA926781D6500CA44E8 /* StaticAnalyser.cpp in Sources */,
 				4B055ADA1FAE9B460060FFFF /* 1770.cpp in Sources */,
 				4B80CD77256CA16600176FCC /* 2MG.cpp in Sources */,
 				4B0F1BE62602FF9D00B85C66 /* ZX8081.cpp in Sources */,
@ -5186,6 +5246,7 @@
 				4B055AB61FAE860F0060FFFF /* TapeUEF.cpp in Sources */,
 				4B055A9D1FAE85DA0060FFFF /* D64.cpp in Sources */,
 				4B0ACC2B23775819008902D0 /* Video.cpp in Sources */,
+				4B051CA32676F52200CA44E8 /* Enterprise.cpp in Sources */,
 				4B055ABB1FAE86170060FFFF /* Oric.cpp in Sources */,
 				4B12C0EE1FCFAD1A005BFD93 /* Keyboard.cpp in Sources */,
 				4BCD634A22D6756400F567F1 /* MacintoshDoubleDensityDrive.cpp in Sources */,
@ -5214,6 +5275,7 @@
 				4BB307BC235001C300457D33 /* 6850.cpp in Sources */,
 				4B055AB31FAE860F0060FFFF /* CSW.cpp in Sources */,
 				4B89451D201967B4007DE474 /* Disk.cpp in Sources */,
+				4BFEA2F02682A7B900EBF94C /* Dave.cpp in Sources */,
 				4BDACBED22FFA5D20045EF7E /* ncr5380.cpp in Sources */,
 				4BC131772346DE9100E4FF3D /* StaticAnalyser.cpp in Sources */,
 				4B055ACF1FAE9B030060FFFF /* SoundGenerator.cpp in Sources */,
@ -5230,7 +5292,7 @@
 				4BB4BFBA22A4372F0069048D /* StaticAnalyser.cpp in Sources */,
 				4B055AA21FAE85DA0060FFFF /* SSD.cpp in Sources */,
 				4B2E86E325DC95150024F1E9 /* Joystick.cpp in Sources */,
-				4BEBFB4E2002C4BF000708CC /* MSXDSK.cpp in Sources */,
+				4BEBFB4E2002C4BF000708CC /* FAT12.cpp in Sources */,
 				4B055ADD1FAE9B460060FFFF /* i8272.cpp in Sources */,
 				4B055A9C1FAE85DA0060FFFF /* CPCDSK.cpp in Sources */,
 				4B2BF19223DCC6A800C3AD60 /* STX.cpp in Sources */,
@ -5248,6 +5310,7 @@
 				4BC131712346DE5000E4FF3D /* StaticAnalyser.cpp in Sources */,
 				4B055ACA1FAE9AFB0060FFFF /* Vic20.cpp in Sources */,
 				4BE21200253FC80900435408 /* StaticAnalyser.cpp in Sources */,
+				4B051CB72680158600CA44E8 /* EXDos.cpp in Sources */,
 				4B8318B222D3E53C006DB630 /* Video.cpp in Sources */,
 				4B055ABC1FAE86170060FFFF /* ZX8081.cpp in Sources */,
 				4B055AC91FAE9AFB0060FFFF /* Keyboard.cpp in Sources */,
@ -5292,6 +5355,7 @@
 				4B055AAD1FAE85FD0060FFFF /* PCMTrack.cpp in Sources */,
 				4BD67DD1209BF27B00AB2146 /* Encoder.cpp in Sources */,
 				4BE2121A253FCE9C00435408 /* AppleIIgs.cpp in Sources */,
+				4B051CAD26783E2000CA44E8 /* Nick.cpp in Sources */,
 				4B89451F201967B4007DE474 /* Tape.cpp in Sources */,
 				4B055AA81FAE85EF0060FFFF /* Shifter.cpp in Sources */,
 				4BEDA3BC25B25563000C2DBD /* Decoder.cpp in Sources */,
@ -5338,6 +5402,7 @@
 				4B051C912669C90B00CA44E8 /* ROMCatalogue.cpp in Sources */,
 				4B055AB91FAE86170060FFFF /* Acorn.cpp in Sources */,
 				4B302185208A550100773308 /* DiskII.cpp in Sources */,
+				4B051CB1267C1CA200CA44E8 /* Keyboard.cpp in Sources */,
 				4B0F1BB32602645900B85C66 /* StaticAnalyser.cpp in Sources */,
 				4B055A931FAE85B50060FFFF /* BinaryDump.cpp in Sources */,
 				4B89452D201967B4007DE474 /* Tape.cpp in Sources */,
@ -5461,6 +5526,7 @@
 				4B7BA03023C2B19C00B98D9E /* Jasmin.cpp in Sources */,
 				4B7136911F789C93008B8ED9 /* SegmentParser.cpp in Sources */,
 				4BEDA3BA25B25563000C2DBD /* Decoder.cpp in Sources */,
+				4BFEA2EF2682A7B900EBF94C /* Dave.cpp in Sources */,
 				4B4518A21F75FD1C00926311 /* G64.cpp in Sources */,
 				4B89452C201967B4007DE474 /* Tape.cpp in Sources */,
 				4B448E811F1C45A00009ABD6 /* TZX.cpp in Sources */,
@ -5492,11 +5558,13 @@
 				4B12C0ED1FCFA98D005BFD93 /* Keyboard.cpp in Sources */,
 				4BA0F68E1EEA0E8400E9489E /* ZX8081.cpp in Sources */,
 				4BD468F71D8DF41D0084958B /* 1770.cpp in Sources */,
+				4B051CA22676F52200CA44E8 /* Enterprise.cpp in Sources */,
 				4B7F1897215486A200388727 /* StaticAnalyser.cpp in Sources */,
 				4B47F6C5241C87A100ED06F7 /* Struct.cpp in Sources */,
 				4B5FADBA1DE3151600AEC565 /* FileHolder.cpp in Sources */,
 				4B643F3A1D77AD1900D431D6 /* CSStaticAnalyser.mm in Sources */,
 				4B622AE5222E0AD5008B59F2 /* DisplayMetrics.cpp in Sources */,
+				4B051CB0267C1CA200CA44E8 /* Keyboard.cpp in Sources */,
 				4B1497881EE4A1DA00CE2596 /* ZX80O81P.cpp in Sources */,
 				4B894520201967B4007DE474 /* StaticAnalyser.cpp in Sources */,
 				4BB4BFAD22A33DE50069048D /* DriveSpeedAccumulator.cpp in Sources */,
@ -5505,6 +5573,7 @@
 				4B74CF812312FA9C00500CE8 /* HFV.cpp in Sources */,
 				4B17B58B20A8A9D9007CCA8F /* StringSerialiser.cpp in Sources */,
 				4B2E2D9D1C3A070400138695 /* Electron.cpp in Sources */,
+				4B051CA826781D6500CA44E8 /* StaticAnalyser.cpp in Sources */,
 				4B3940E71DA83C8300427841 /* AsyncTaskQueue.cpp in Sources */,
 				4B0E04FA1FC9FA3100F43484 /* 9918.cpp in Sources */,
 				4B69FB3D1C4D908A00B5F0AA /* Tape.cpp in Sources */,
@ -5538,7 +5607,7 @@
 				4B894536201967B4007DE474 /* Z80.cpp in Sources */,
 				4BCA6CC81D9DD9F000C2D7B2 /* CommodoreROM.cpp in Sources */,
 				4BC1317A2346DF2B00E4FF3D /* MSA.cpp in Sources */,
-				4BEBFB4D2002C4BF000708CC /* MSXDSK.cpp in Sources */,
+				4BEBFB4D2002C4BF000708CC /* FAT12.cpp in Sources */,
 				4BBFBB6C1EE8401E00C01E7A /* ZX8081.cpp in Sources */,
 				4B83348A1F5DB94B0097E338 /* IRQDelegatePortHandler.cpp in Sources */,
 				4B8DD3862634D37E00B3C866 /* SNA.cpp in Sources */,
@ -5549,9 +5618,11 @@
 				4BFDD78C1F7F2DB4008579B9 /* ImplicitSectors.cpp in Sources */,
 				4B894526201967B4007DE474 /* StaticAnalyser.cpp in Sources */,
 				4BEE0A6F1D72496600532C7B /* Cartridge.cpp in Sources */,
+				4B051CB62680158600CA44E8 /* EXDos.cpp in Sources */,
 				4B8805FB1DCFF807003085B1 /* Oric.cpp in Sources */,
 				4B6ED2F0208E2F8A0047B343 /* WOZ.cpp in Sources */,
 				4B15A9FC208249BB005E6C8D /* StaticAnalyser.cpp in Sources */,
+				4B051CAC26783E2000CA44E8 /* Nick.cpp in Sources */,
 				4B5FADC01DE3BF2B00AEC565 /* Microdisc.cpp in Sources */,
 				4B0F1BDA2602FF9800B85C66 /* Video.cpp in Sources */,
 				4B051C922669C90B00CA44E8 /* ROMCatalogue.cpp in Sources */,
@ -5684,7 +5755,7 @@
 				4B3BA0CF1D318B44005DD7A7 /* MOS6522Bridge.mm in Sources */,
 				4B778F6023A5F3460000D260 /* Disk.cpp in Sources */,
 				4B778F5C23A5F3070000D260 /* MSX.cpp in Sources */,
-				4B778F0323A5EBB00000D260 /* MSXDSK.cpp in Sources */,
+				4B778F0323A5EBB00000D260 /* FAT12.cpp in Sources */,
 				4B778F4023A5F1910000D260 /* z8530.cpp in Sources */,
 				4B778EFD23A5EB8E0000D260 /* AppleDSK.cpp in Sources */,
 				4B778EFB23A5EB7E0000D260 /* HFE.cpp in Sources */,
@ -5692,6 +5763,7 @@
 				4BFCA12B1ECBE7C400AC40C1 /* ZexallTests.swift in Sources */,
 				4B778F2223A5EDDD0000D260 /* PulseQueuedTape.cpp in Sources */,
 				4B778EF123A5D6B50000D260 /* 9918.cpp in Sources */,
+				4B051CB3267D3FF800CA44E8 /* EnterpriseNickTests.mm in Sources */,
 				4B9D0C4D22C7DA1A00DE1AD3 /* 68000ControlFlowTests.mm in Sources */,
 				4BB2A9AF1E13367E001A5C23 /* CRCTests.mm in Sources */,
 				4B778F5623A5F2AF0000D260 /* CPM.cpp in Sources */,
@ -6055,7 +6127,7 @@
 				CODE_SIGN_IDENTITY = "-";
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = DV3346VVUN;
-				ENABLE_HARDENED_RUNTIME = YES;
+				ENABLE_HARDENED_RUNTIME = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(inherited)",
 					"$(USER_LIBRARY_DIR)/Frameworks",
@ -6105,7 +6177,7 @@
 				CODE_SIGN_IDENTITY = "-";
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = DV3346VVUN;
-				ENABLE_HARDENED_RUNTIME = YES;
+				ENABLE_HARDENED_RUNTIME = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(inherited)",
 					"$(USER_LIBRARY_DIR)/Frameworks",
--- a/Signal.xcodeproj/xcshareddata/xcschemes/Clock
+++ b/Signal.xcodeproj/xcshareddata/xcschemes/Clock
@ -85,8 +85,12 @@
            isEnabled = "YES">
         </CommandLineArgument>
         <CommandLineArgument
-            argument = "--new=amstradcpc"
-            isEnabled = "NO">
+            argument = "--new=enterprise"
+            isEnabled = "YES">
+         </CommandLineArgument>
+         <CommandLineArgument
+            argument = "--basic-version=any"
+            isEnabled = "YES">
         </CommandLineArgument>
         <CommandLineArgument
            argument = "&quot;/Users/thomasharte/Library/Mobile Documents/com~apple~CloudDocs/Desktop/Soft/ColecoVision/Galaxian (1983)(Atari).col&quot;"
@ -126,15 +130,15 @@
         </CommandLineArgument>
         <CommandLineArgument
            argument = "--model=mac512k"
-            isEnabled = "YES">
+            isEnabled = "NO">
         </CommandLineArgument>
         <CommandLineArgument
            argument = "--new=macintosh"
-            isEnabled = "YES">
+            isEnabled = "NO">
         </CommandLineArgument>
         <CommandLineArgument
            argument = "--use-square-pixels"
-            isEnabled = "YES">
+            isEnabled = "NO">
         </CommandLineArgument>
      </CommandLineArguments>
   </LaunchAction>
--- a/Signal.xcodeproj/xcshareddata/xcschemes/Clock
+++ b/Signal.xcodeproj/xcshareddata/xcschemes/Clock
@ -73,6 +73,7 @@
      debugDocumentVersioning = "YES"
      migratedStopOnEveryIssue = "YES"
      debugServiceExtension = "internal"
+      enableGPUShaderValidationMode = "2"
      allowLocationSimulation = "NO">
      <BuildableProductRunnable
         runnableDebuggingMode = "0">
--- a/Signal/Machine/StaticAnalyser/CSStaticAnalyser.h
+++ b/Signal/Machine/StaticAnalyser/CSStaticAnalyser.h
@ -41,6 +41,30 @@ typedef NS_ENUM(NSInteger, CSMachineCPCModel) {
 	CSMachineCPCModel6128
 };

+typedef NS_ENUM(NSInteger, CSMachineEnterpriseModel) {
+	CSMachineEnterpriseModel64,
+	CSMachineEnterpriseModel128,
+	CSMachineEnterpriseModel256,
+};
+
+typedef NS_ENUM(NSInteger, CSMachineEnterpriseEXOS) {
+	CSMachineEnterpriseEXOSVersion21,
+	CSMachineEnterpriseEXOSVersion20,
+	CSMachineEnterpriseEXOSVersion10,
+};
+
+typedef NS_ENUM(NSInteger, CSMachineEnterpriseBASIC) {
+	CSMachineEnterpriseBASICVersion21,
+	CSMachineEnterpriseBASICVersion11,
+	CSMachineEnterpriseBASICVersion10,
+	CSMachineEnterpriseBASICNone,
+};
+
+typedef NS_ENUM(NSInteger, CSMachineEnterpriseDOS) {
+	CSMachineEnterpriseDOSEXDOS,
+	CSMachineEnterpriseDOSNone,
+};
+
 typedef NS_ENUM(NSInteger, CSMachineMacintoshModel) {
 	CSMachineMacintoshModel128k,
 	CSMachineMacintoshModel512k,
@ -96,6 +120,7 @@ typedef int Kilobytes;
 - (instancetype)initWithAppleIIgsModel:(CSMachineAppleIIgsModel)model memorySize:(Kilobytes)memorySize;
 - (instancetype)initWithAtariSTModel:(CSMachineAtariSTModel)model;
 - (instancetype)initWithElectronDFS:(BOOL)dfs adfs:(BOOL)adfs ap6:(BOOL)ap6 sidewaysRAM:(BOOL)sidewaysRAM;
+- (instancetype)initWithEnterpriseModel:(CSMachineEnterpriseModel)model exosVersion:(CSMachineEnterpriseEXOS)exosVersion basicVersion:(CSMachineEnterpriseBASIC)basicVersion dos:(CSMachineEnterpriseDOS)dos;
 - (instancetype)initWithMacintoshModel:(CSMachineMacintoshModel)model;
 - (instancetype)initWithMSXRegion:(CSMachineMSXRegion)region hasDiskDrive:(BOOL)hasDiskDrive;
 - (instancetype)initWithOricModel:(CSMachineOricModel)model diskInterface:(CSMachineOricDiskInterface)diskInterface;
--- a/Signal/Machine/StaticAnalyser/CSStaticAnalyser.mm
+++ b/Signal/Machine/StaticAnalyser/CSStaticAnalyser.mm
@ -19,6 +19,7 @@
 #include "../../../../../Analyser/Static/AppleIIgs/Target.hpp"
 #include "../../../../../Analyser/Static/AtariST/Target.hpp"
 #include "../../../../../Analyser/Static/Commodore/Target.hpp"
+#include "../../../../../Analyser/Static/Enterprise/Target.hpp"
 #include "../../../../../Analyser/Static/Macintosh/Target.hpp"
 #include "../../../../../Analyser/Static/MSX/Target.hpp"
 #include "../../../../../Analyser/Static/Oric/Target.hpp"
@ -130,6 +131,45 @@
 	return self;
 }

+- (instancetype)initWithEnterpriseModel:(CSMachineEnterpriseModel)model exosVersion:(CSMachineEnterpriseEXOS)exosVersion basicVersion:(CSMachineEnterpriseBASIC)basicVersion dos:(CSMachineEnterpriseDOS)dos {
+	self = [super init];
+	if(self) {
+		using Target = Analyser::Static::Enterprise::Target;
+		auto target = std::make_unique<Target>();
+
+		switch(model) {
+			case CSMachineEnterpriseModel64:		target->model = Target::Model::Enterprise64;		break;
+			default:
+			case CSMachineEnterpriseModel128:		target->model = Target::Model::Enterprise128;		break;
+			case CSMachineEnterpriseModel256:		target->model = Target::Model::Enterprise256;		break;
+		}
+
+		switch(exosVersion) {
+			case CSMachineEnterpriseEXOSVersion21:	target->exos_version = Target::EXOSVersion::v21;	break;
+			default:
+			case CSMachineEnterpriseEXOSVersion20:	target->exos_version = Target::EXOSVersion::v20;	break;
+			case CSMachineEnterpriseEXOSVersion10:	target->exos_version = Target::EXOSVersion::v10;	break;
+		}
+
+		switch(basicVersion) {
+			case CSMachineEnterpriseBASICNone:		target->basic_version = Target::BASICVersion::None;	break;
+			default:
+			case CSMachineEnterpriseBASICVersion21:	target->basic_version = Target::BASICVersion::v21;	break;
+			case CSMachineEnterpriseBASICVersion11:	target->basic_version = Target::BASICVersion::v11;	break;
+			case CSMachineEnterpriseBASICVersion10:	target->basic_version = Target::BASICVersion::v10;	break;
+		}
+
+		switch(dos) {
+			case CSMachineEnterpriseDOSEXDOS:		target->dos = Target::DOS::EXDOS;					break;
+			default:
+			case CSMachineEnterpriseDOSNone:		target->dos = Target::DOS::None;					break;
+		}
+
+		_targets.push_back(std::move(target));
+	}
+	return self;
+}
+
 - (instancetype)initWithMacintoshModel:(CSMachineMacintoshModel)model {
 	self = [super init];
 	if(self) {
--- a/Signal/MachinePicker/Base.lproj/MachinePicker.xib
+++ b/Signal/MachinePicker/Base.lproj/MachinePicker.xib
@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="17701" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="18122" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
    <dependencies>
        <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="17701"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="18122"/>
        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
    </dependencies>
    <objects>
@ -17,10 +17,10 @@
        <window title="Window" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" titleVisibility="hidden" id="QvC-M9-y7g">
            <windowStyleMask key="styleMask" titled="YES" documentModal="YES"/>
            <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
-            <rect key="contentRect" x="196" y="240" width="590" height="316"/>
+            <rect key="contentRect" x="196" y="240" width="590" height="353"/>
            <rect key="screenRect" x="0.0" y="0.0" width="2560" height="1440"/>
            <view key="contentView" wantsLayer="YES" id="EiT-Mj-1SZ">
-                <rect key="frame" x="0.0" y="0.0" width="590" height="316"/>
+                <rect key="frame" x="0.0" y="0.0" width="590" height="353"/>
                <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                <subviews>
                    <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="hKn-1l-OSN">
@ -59,16 +59,16 @@ Gw
                        </textFieldCell>
                    </textField>
                    <tabView type="noTabsBezelBorder" translatesAutoresizingMaskIntoConstraints="NO" id="VUb-QG-x7c">
-                        <rect key="frame" x="154" y="56" width="420" height="206"/>
+                        <rect key="frame" x="154" y="56" width="420" height="243"/>
                        <font key="font" metaFont="system"/>
                        <tabViewItems>
                            <tabViewItem label="Apple II" identifier="appleii" id="P59-QG-LOa">
                                <view key="view" id="dHz-Yv-GNq">
-                                    <rect key="frame" x="10" y="7" width="400" height="186"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="V5Z-dX-Ns4">
-                                            <rect key="frame" x="18" y="163" width="46" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="46" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="qV3-2P-3JW">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -76,7 +76,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="WnO-ef-IC6">
-                                            <rect key="frame" x="18" y="133" width="96" height="16"/>
+                                            <rect key="frame" x="18" y="155" width="96" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Disk controller:" id="kbf-rc-Y4M">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -84,7 +84,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="jli-ac-Sij">
-                                            <rect key="frame" x="67" y="157" width="117" height="25"/>
+                                            <rect key="frame" x="67" y="179" width="117" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="Apple II" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="VBQ-JG-AeM" id="U6V-us-O2F">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -99,7 +99,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="LSB-WP-FMi">
-                                            <rect key="frame" x="117" y="127" width="134" height="25"/>
+                                            <rect key="frame" x="117" y="149" width="134" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="Sixteen Sector" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="16" imageScaling="axesIndependently" inset="2" selectedItem="QaV-Yr-k9o" id="8BT-RV-2Nm">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -115,11 +115,11 @@ Gw
                                    </subviews>
                                    <constraints>
                                        <constraint firstItem="WnO-ef-IC6" firstAttribute="leading" secondItem="dHz-Yv-GNq" secondAttribute="leading" constant="20" symbolic="YES" id="5RF-1w-9HW"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="LSB-WP-FMi" secondAttribute="bottom" constant="5" id="865-cv-qVk"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="LSB-WP-FMi" secondAttribute="bottom" constant="20" symbolic="YES" id="865-cv-qVk"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="LSB-WP-FMi" secondAttribute="trailing" constant="20" symbolic="YES" id="9GL-al-1qi"/>
                                        <constraint firstItem="WnO-ef-IC6" firstAttribute="centerY" secondItem="LSB-WP-FMi" secondAttribute="centerY" id="Fuj-zT-MIm"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="jli-ac-Sij" secondAttribute="trailing" constant="20" symbolic="YES" id="I8d-OR-ICN"/>
-                                        <constraint firstItem="jli-ac-Sij" firstAttribute="top" secondItem="dHz-Yv-GNq" secondAttribute="top" constant="5" id="Qi1-CV-A0c"/>
+                                        <constraint firstItem="jli-ac-Sij" firstAttribute="top" secondItem="dHz-Yv-GNq" secondAttribute="top" constant="20" symbolic="YES" id="Qi1-CV-A0c"/>
                                        <constraint firstItem="V5Z-dX-Ns4" firstAttribute="leading" secondItem="dHz-Yv-GNq" secondAttribute="leading" constant="20" symbolic="YES" id="SWc-iX-1We"/>
                                        <constraint firstItem="LSB-WP-FMi" firstAttribute="leading" secondItem="WnO-ef-IC6" secondAttribute="trailing" constant="8" symbolic="YES" id="bte-XA-xNQ"/>
                                        <constraint firstItem="LSB-WP-FMi" firstAttribute="top" secondItem="jli-ac-Sij" secondAttribute="bottom" constant="10" symbolic="YES" id="ki5-JR-vRe"/>
@ -129,12 +129,12 @@ Gw
                                </view>
                            </tabViewItem>
                            <tabViewItem label="Apple IIgs" identifier="appleiigs" id="u5E-8n-ghF">
-                                <view key="view" ambiguous="YES" id="jOM-9f-vkk">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                <view key="view" id="jOM-9f-vkk">
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="0d9-IG-gKU">
-                                            <rect key="frame" x="18" y="53" width="46" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="46" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="kiv-1P-FWc">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -142,7 +142,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="LES-76-Ovz">
-                                            <rect key="frame" x="18" y="23" width="85" height="16"/>
+                                            <rect key="frame" x="18" y="155" width="85" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory size:" id="OLJ-nC-yyj">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -150,7 +150,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="gcS-uy-mzl">
-                                            <rect key="frame" x="67" y="47" width="89" height="25"/>
+                                            <rect key="frame" x="67" y="179" width="89" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="ROM 03" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="2" imageScaling="axesIndependently" inset="2" selectedItem="0TS-DO-O9h" id="hjw-g8-e2f">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -164,7 +164,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="nQa-YS-utT">
-                                            <rect key="frame" x="106" y="17" width="82" height="25"/>
+                                            <rect key="frame" x="106" y="149" width="82" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="8 mb" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="8192" imageScaling="axesIndependently" inset="2" selectedItem="UHg-gU-Xnn" id="dl3-cq-uWO">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -182,24 +182,24 @@ Gw
                                        <constraint firstItem="LES-76-Ovz" firstAttribute="leading" secondItem="jOM-9f-vkk" secondAttribute="leading" constant="20" symbolic="YES" id="2D3-Ve-6CN"/>
                                        <constraint firstItem="0d9-IG-gKU" firstAttribute="leading" secondItem="jOM-9f-vkk" secondAttribute="leading" constant="20" symbolic="YES" id="8Xz-86-tDf"/>
                                        <constraint firstItem="0d9-IG-gKU" firstAttribute="centerY" secondItem="gcS-uy-mzl" secondAttribute="centerY" id="Eww-Qq-eBT"/>
-                                        <constraint firstItem="gcS-uy-mzl" firstAttribute="top" secondItem="jOM-9f-vkk" secondAttribute="top" constant="5" id="F6i-cP-7AR"/>
+                                        <constraint firstItem="gcS-uy-mzl" firstAttribute="top" secondItem="jOM-9f-vkk" secondAttribute="top" constant="20" symbolic="YES" id="F6i-cP-7AR"/>
                                        <constraint firstItem="gcS-uy-mzl" firstAttribute="leading" secondItem="0d9-IG-gKU" secondAttribute="trailing" constant="8" symbolic="YES" id="LUm-rI-LYP"/>
                                        <constraint firstItem="LES-76-Ovz" firstAttribute="centerY" secondItem="nQa-YS-utT" secondAttribute="centerY" id="UdP-U6-OFE"/>
                                        <constraint firstItem="nQa-YS-utT" firstAttribute="leading" secondItem="LES-76-Ovz" secondAttribute="trailing" constant="8" symbolic="YES" id="Xm1-iG-Dgj"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="gcS-uy-mzl" secondAttribute="trailing" constant="20" symbolic="YES" id="a38-Cx-CEh"/>
                                        <constraint firstItem="nQa-YS-utT" firstAttribute="top" secondItem="gcS-uy-mzl" secondAttribute="bottom" constant="10" symbolic="YES" id="aM9-m8-s7z"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="nQa-YS-utT" secondAttribute="trailing" constant="20" symbolic="YES" id="cqx-Jc-rUb"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="nQa-YS-utT" secondAttribute="bottom" constant="5" id="sbT-If-NTU"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="nQa-YS-utT" secondAttribute="bottom" constant="20" symbolic="YES" id="sbT-If-NTU"/>
                                    </constraints>
                                </view>
                            </tabViewItem>
                            <tabViewItem label="Amstrad CPC" identifier="cpc" id="JmB-OF-xcM">
                                <view key="view" id="5zS-Nj-Ynx">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="00d-sg-Krh">
-                                            <rect key="frame" x="67" y="47" width="96" height="25"/>
+                                            <rect key="frame" x="67" y="179" width="96" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="CPC6128" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="6128" imageScaling="axesIndependently" inset="2" selectedItem="klh-ZE-Agp" id="hVJ-h6-iea">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -213,7 +213,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="q9q-sl-J0q">
-                                            <rect key="frame" x="18" y="53" width="46" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="46" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="Cw3-q5-1bC">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -224,8 +224,8 @@ Gw
                                    <constraints>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="00d-sg-Krh" secondAttribute="trailing" constant="20" symbolic="YES" id="4AF-5C-2IF"/>
                                        <constraint firstItem="q9q-sl-J0q" firstAttribute="leading" secondItem="5zS-Nj-Ynx" secondAttribute="leading" constant="20" symbolic="YES" id="Wof-5h-gfD"/>
-                                        <constraint firstItem="00d-sg-Krh" firstAttribute="top" secondItem="5zS-Nj-Ynx" secondAttribute="top" constant="5" id="c92-uU-NRr"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="00d-sg-Krh" secondAttribute="bottom" constant="5" id="enU-LN-Nep"/>
+                                        <constraint firstItem="00d-sg-Krh" firstAttribute="top" secondItem="5zS-Nj-Ynx" secondAttribute="top" constant="20" symbolic="YES" id="c92-uU-NRr"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="00d-sg-Krh" secondAttribute="bottom" constant="20" symbolic="YES" id="enU-LN-Nep"/>
                                        <constraint firstItem="00d-sg-Krh" firstAttribute="leading" secondItem="q9q-sl-J0q" secondAttribute="trailing" constant="8" symbolic="YES" id="mA8-US-ndo"/>
                                        <constraint firstItem="q9q-sl-J0q" firstAttribute="centerY" secondItem="00d-sg-Krh" secondAttribute="centerY" id="vA8-IA-Uwf"/>
                                    </constraints>
@ -233,11 +233,11 @@ Gw
                            </tabViewItem>
                            <tabViewItem label="Atari ST" identifier="atarist" id="a6Y-mx-yFn">
                                <view key="view" id="nnv-Wi-7hc">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="nLf-LI-nWO">
-                                            <rect key="frame" x="18" y="57" width="728" height="16"/>
+                                            <rect key="frame" x="18" y="204" width="364" height="16"/>
                                            <textFieldCell key="cell" lineBreakMode="clipping" title="At present only a 512k Atari ST is supported." id="gBA-ke-mur">
                                                <font key="font" usesAppearanceFont="YES"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -254,32 +254,32 @@ Gw
                            </tabViewItem>
                            <tabViewItem label="Electron" identifier="electron" id="muc-z9-Vqc">
                                <view key="view" id="SRc-2D-95G">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="JqM-IK-FMP">
-                                            <rect key="frame" x="18" y="56" width="168" height="18"/>
+                                            <rect key="frame" x="18" y="186" width="168" height="18"/>
                                            <buttonCell key="cell" type="check" title="With Disk Filing System" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="tpW-5C-xKp">
                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                <font key="font" metaFont="system"/>
                                            </buttonCell>
                                        </button>
                                        <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="945-wU-JOH">
-                                            <rect key="frame" x="18" y="34" width="232" height="18"/>
+                                            <rect key="frame" x="18" y="164" width="232" height="18"/>
                                            <buttonCell key="cell" type="check" title="With Advanced Disk Filing System" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="S0c-Jg-7Pu">
                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                <font key="font" metaFont="system"/>
                                            </buttonCell>
                                        </button>
                                        <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="cG2-Ph-S3Z">
-                                            <rect key="frame" x="18" y="12" width="231" height="18"/>
+                                            <rect key="frame" x="18" y="142" width="231" height="18"/>
                                            <buttonCell key="cell" type="check" title="With Advanced Plus 6 Utility ROM" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="yjF-XS-zx6">
                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                <font key="font" metaFont="system"/>
                                            </buttonCell>
                                        </button>
                                        <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="lzo-8g-o4S">
-                                            <rect key="frame" x="18" y="-10" width="284" height="18"/>
+                                            <rect key="frame" x="18" y="120" width="284" height="18"/>
                                            <buttonCell key="cell" type="check" title="Fill unused ROM banks with sideways RAM" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="JEz-eK-uWp">
                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                <font key="font" metaFont="system"/>
@ -289,13 +289,13 @@ Gw
                                    <constraints>
                                        <constraint firstItem="945-wU-JOH" firstAttribute="leading" secondItem="SRc-2D-95G" secondAttribute="leading" constant="20" symbolic="YES" id="1iM-70-oZq"/>
                                        <constraint firstItem="cG2-Ph-S3Z" firstAttribute="top" secondItem="945-wU-JOH" secondAttribute="bottom" constant="6" symbolic="YES" id="E9b-RP-9vj"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="lzo-8g-o4S" secondAttribute="bottom" constant="5" id="FM6-AA-Vhf"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="lzo-8g-o4S" secondAttribute="bottom" constant="20" symbolic="YES" id="FM6-AA-Vhf"/>
                                        <constraint firstItem="JqM-IK-FMP" firstAttribute="leading" secondItem="SRc-2D-95G" secondAttribute="leading" constant="20" symbolic="YES" id="NfY-dE-aJw"/>
                                        <constraint firstItem="lzo-8g-o4S" firstAttribute="top" secondItem="cG2-Ph-S3Z" secondAttribute="bottom" constant="6" symbolic="YES" id="S45-42-Gtv"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="lzo-8g-o4S" secondAttribute="trailing" constant="20" symbolic="YES" id="X3p-qJ-ENH"/>
                                        <constraint firstItem="lzo-8g-o4S" firstAttribute="leading" secondItem="SRc-2D-95G" secondAttribute="leading" constant="20" symbolic="YES" id="b5a-SX-2ty"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="945-wU-JOH" secondAttribute="trailing" constant="20" symbolic="YES" id="dmY-PV-ap4"/>
-                                        <constraint firstItem="JqM-IK-FMP" firstAttribute="top" secondItem="SRc-2D-95G" secondAttribute="top" constant="3" id="ggl-QH-mV4"/>
+                                        <constraint firstItem="JqM-IK-FMP" firstAttribute="top" secondItem="SRc-2D-95G" secondAttribute="top" constant="20" symbolic="YES" id="ggl-QH-mV4"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="cG2-Ph-S3Z" secondAttribute="trailing" constant="20" symbolic="YES" id="m6t-dP-71d"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="JqM-IK-FMP" secondAttribute="trailing" constant="20" symbolic="YES" id="mvO-UZ-BtT"/>
                                        <constraint firstItem="cG2-Ph-S3Z" firstAttribute="leading" secondItem="SRc-2D-95G" secondAttribute="leading" constant="20" symbolic="YES" id="npw-IZ-6xU"/>
@ -303,13 +303,133 @@ Gw
                                    </constraints>
                                </view>
                            </tabViewItem>
+                            <tabViewItem label="Enterprise" identifier="enterprise" id="zhO-EO-wUe">
+                                <view key="view" id="1cs-PX-RAH">
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
+                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                                    <subviews>
+                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="PhH-bu-pb5">
+                                            <rect key="frame" x="80" y="179" width="129" height="25"/>
+                                            <popUpButtonCell key="cell" type="push" title="Enterprise 128" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="128" imageScaling="axesIndependently" inset="2" selectedItem="roH-nL-f8o" id="z9O-XC-XBv">
+                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
+                                                <font key="font" metaFont="menu"/>
+                                                <menu key="menu" id="ojI-Vb-iHz">
+                                                    <items>
+                                                        <menuItem title="Enterprise 256" tag="256" id="Al3-A0-tvw"/>
+                                                        <menuItem title="Enterprise 128" state="on" tag="128" id="roH-nL-f8o"/>
+                                                        <menuItem title="Enterprise 64" tag="64" id="vNG-Tv-bDI"/>
+                                                    </items>
+                                                </menu>
+                                            </popUpButtonCell>
+                                        </popUpButton>
+                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="nen-Za-7zH">
+                                            <rect key="frame" x="64" y="149" width="107" height="25"/>
+                                            <popUpButtonCell key="cell" type="push" title="Version 2.1" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="21" imageScaling="axesIndependently" inset="2" selectedItem="Qja-xZ-wVM" id="xGG-ri-8Sb">
+                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
+                                                <font key="font" metaFont="menu"/>
+                                                <menu key="menu" id="uNC-hA-d5z">
+                                                    <items>
+                                                        <menuItem title="Version 2.1" state="on" tag="21" id="Qja-xZ-wVM"/>
+                                                        <menuItem title="Version 2.0" tag="20" id="XTj-l7-KX3"/>
+                                                        <menuItem title="Version 1.0" tag="10" id="Ky2-2D-wcY"/>
+                                                    </items>
+                                                </menu>
+                                            </popUpButtonCell>
+                                        </popUpButton>
+                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="hIr-GH-7xi">
+                                            <rect key="frame" x="67" y="119" width="105" height="25"/>
+                                            <popUpButtonCell key="cell" type="push" title="Version 2.1" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="21" imageScaling="axesIndependently" inset="2" selectedItem="TME-cv-Jh1" id="9mQ-GW-lq9">
+                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
+                                                <font key="font" metaFont="menu"/>
+                                                <menu key="menu" id="VcH-Xm-1hY">
+                                                    <items>
+                                                        <menuItem title="Version 2.1" state="on" tag="21" id="TME-cv-Jh1"/>
+                                                        <menuItem title="Version 1.1" tag="11" id="7P2-aF-6fp"/>
+                                                        <menuItem title="Version 1.0" tag="10" id="j8p-uY-BhG"/>
+                                                        <menuItem title="None" id="eGk-Bj-IVT"/>
+                                                    </items>
+                                                </menu>
+                                            </popUpButtonCell>
+                                        </popUpButton>
+                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="syE-e7-TjU">
+                                            <rect key="frame" x="57" y="89" width="83" height="25"/>
+                                            <popUpButtonCell key="cell" type="push" title="EXDOS" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" borderStyle="borderAndBezel" tag="1" imageScaling="axesIndependently" inset="2" selectedItem="8rP-2w-PdU" id="NvO-Zm-2Rq">
+                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
+                                                <font key="font" metaFont="menu"/>
+                                                <menu key="menu" title="DOS" id="sdr-al-7mi">
+                                                    <items>
+                                                        <menuItem title="EXDOS" tag="1" id="8rP-2w-PdU"/>
+                                                        <menuItem title="None" state="on" id="qoS-KO-iEZ"/>
+                                                    </items>
+                                                </menu>
+                                            </popUpButtonCell>
+                                        </popUpButton>
+                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ykc-W1-YaS">
+                                            <rect key="frame" x="18" y="155" width="43" height="16"/>
+                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="EXOS:" id="gUC-PN-zVL">
+                                                <font key="font" metaFont="system"/>
+                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                                                <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                                            </textFieldCell>
+                                        </textField>
+                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="frx-nk-c3P">
+                                            <rect key="frame" x="18" y="185" width="59" height="16"/>
+                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Machine:" id="uTv-hH-mIC">
+                                                <font key="font" metaFont="system"/>
+                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                                                <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                                            </textFieldCell>
+                                        </textField>
+                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="dzd-tH-BjX">
+                                            <rect key="frame" x="18" y="125" width="46" height="16"/>
+                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="BASIC:" id="ai1-oR-X6Y">
+                                                <font key="font" metaFont="system"/>
+                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                                                <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                                            </textFieldCell>
+                                        </textField>
+                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="pxr-Bq-yh0">
+                                            <rect key="frame" x="18" y="95" width="36" height="16"/>
+                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="DOS:" id="NFk-cp-DfS">
+                                                <font key="font" metaFont="system"/>
+                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                                                <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                                            </textFieldCell>
+                                        </textField>
+                                    </subviews>
+                                    <constraints>
+                                        <constraint firstItem="dzd-tH-BjX" firstAttribute="centerY" secondItem="hIr-GH-7xi" secondAttribute="centerY" id="3TV-RU-Kgh"/>
+                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="hIr-GH-7xi" secondAttribute="trailing" constant="20" symbolic="YES" id="44v-9O-y7L"/>
+                                        <constraint firstItem="frx-nk-c3P" firstAttribute="centerY" secondItem="PhH-bu-pb5" secondAttribute="centerY" id="6Wc-aR-wuL"/>
+                                        <constraint firstItem="dzd-tH-BjX" firstAttribute="leading" secondItem="1cs-PX-RAH" secondAttribute="leading" constant="20" symbolic="YES" id="7RZ-Om-TAa"/>
+                                        <constraint firstItem="ykc-W1-YaS" firstAttribute="centerY" secondItem="nen-Za-7zH" secondAttribute="centerY" id="CLa-6E-8BB"/>
+                                        <constraint firstItem="PhH-bu-pb5" firstAttribute="leading" secondItem="frx-nk-c3P" secondAttribute="trailing" constant="8" symbolic="YES" id="ENF-TY-TQ7"/>
+                                        <constraint firstItem="nen-Za-7zH" firstAttribute="leading" secondItem="ykc-W1-YaS" secondAttribute="trailing" constant="8" symbolic="YES" id="GWR-VI-9PG"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="syE-e7-TjU" secondAttribute="bottom" constant="20" symbolic="YES" id="K3s-FA-zMB"/>
+                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="PhH-bu-pb5" secondAttribute="trailing" constant="20" symbolic="YES" id="LwB-ef-uF4"/>
+                                        <constraint firstItem="PhH-bu-pb5" firstAttribute="top" secondItem="1cs-PX-RAH" secondAttribute="top" constant="20" symbolic="YES" id="Myt-i4-jVq"/>
+                                        <constraint firstItem="pxr-Bq-yh0" firstAttribute="leading" secondItem="1cs-PX-RAH" secondAttribute="leading" constant="20" symbolic="YES" id="Qzp-IY-Pa0"/>
+                                        <constraint firstItem="PhH-bu-pb5" firstAttribute="leading" secondItem="frx-nk-c3P" secondAttribute="trailing" constant="8" symbolic="YES" id="T3e-u7-fiQ"/>
+                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="syE-e7-TjU" secondAttribute="trailing" constant="20" symbolic="YES" id="TEX-Nw-y2K"/>
+                                        <constraint firstItem="frx-nk-c3P" firstAttribute="leading" secondItem="1cs-PX-RAH" secondAttribute="leading" constant="20" symbolic="YES" id="TgR-RR-eA1"/>
+                                        <constraint firstItem="pxr-Bq-yh0" firstAttribute="centerY" secondItem="syE-e7-TjU" secondAttribute="centerY" id="UYw-uz-Am0"/>
+                                        <constraint firstItem="hIr-GH-7xi" firstAttribute="top" secondItem="nen-Za-7zH" secondAttribute="bottom" constant="10" symbolic="YES" id="VOc-2v-s3u"/>
+                                        <constraint firstItem="syE-e7-TjU" firstAttribute="top" secondItem="hIr-GH-7xi" secondAttribute="bottom" constant="10" symbolic="YES" id="W9S-on-Heq"/>
+                                        <constraint firstItem="nen-Za-7zH" firstAttribute="top" secondItem="PhH-bu-pb5" secondAttribute="bottom" constant="10" symbolic="YES" id="Yes-o3-V0m"/>
+                                        <constraint firstItem="ykc-W1-YaS" firstAttribute="leading" secondItem="1cs-PX-RAH" secondAttribute="leading" constant="20" symbolic="YES" id="bAP-lx-pdi"/>
+                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="nen-Za-7zH" secondAttribute="trailing" constant="20" symbolic="YES" id="eEI-5Q-TnO"/>
+                                        <constraint firstItem="syE-e7-TjU" firstAttribute="leading" secondItem="pxr-Bq-yh0" secondAttribute="trailing" constant="8" symbolic="YES" id="fmM-Ma-Jyu"/>
+                                        <constraint firstItem="hIr-GH-7xi" firstAttribute="leading" secondItem="dzd-tH-BjX" secondAttribute="trailing" constant="8" symbolic="YES" id="jDQ-TF-Ogf"/>
+                                    </constraints>
+                                </view>
+                            </tabViewItem>
                            <tabViewItem label="Macintosh" identifier="mac" id="lmR-z3-xSm">
                                <view key="view" id="7Yf-vi-Q0W">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ZOY-4E-Cfl">
-                                            <rect key="frame" x="18" y="53" width="46" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="46" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="h9r-i6-66j">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -317,7 +437,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="xa6-NA-JY5">
-                                            <rect key="frame" x="67" y="47" width="75" height="25"/>
+                                            <rect key="frame" x="67" y="179" width="75" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="Plus" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="3" imageScaling="axesIndependently" inset="2" selectedItem="R6T-hg-rOF" id="1Kb-Q2-BGM">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -333,9 +453,9 @@ Gw
                                        </popUpButton>
                                    </subviews>
                                    <constraints>
-                                        <constraint firstItem="xa6-NA-JY5" firstAttribute="top" secondItem="7Yf-vi-Q0W" secondAttribute="top" constant="5" id="3hY-Ca-mnR"/>
+                                        <constraint firstItem="xa6-NA-JY5" firstAttribute="top" secondItem="7Yf-vi-Q0W" secondAttribute="top" constant="20" symbolic="YES" id="3hY-Ca-mnR"/>
                                        <constraint firstItem="ZOY-4E-Cfl" firstAttribute="leading" secondItem="7Yf-vi-Q0W" secondAttribute="leading" constant="20" symbolic="YES" id="5s6-87-VT6"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="xa6-NA-JY5" secondAttribute="bottom" constant="5" id="KYf-GJ-Y7k"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="xa6-NA-JY5" secondAttribute="bottom" constant="20" symbolic="YES" id="KYf-GJ-Y7k"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="xa6-NA-JY5" secondAttribute="trailing" constant="20" symbolic="YES" id="LZ5-xH-fU0"/>
                                        <constraint firstItem="ZOY-4E-Cfl" firstAttribute="centerY" secondItem="xa6-NA-JY5" secondAttribute="centerY" id="Wa5-KX-3Me"/>
                                        <constraint firstItem="xa6-NA-JY5" firstAttribute="leading" secondItem="ZOY-4E-Cfl" secondAttribute="trailing" constant="8" symbolic="YES" id="ktS-sr-F8L"/>
@ -344,18 +464,18 @@ Gw
                            </tabViewItem>
                            <tabViewItem label="MSX" identifier="msx" id="6SR-DY-zdI">
                                <view key="view" id="mWD-An-tR7">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="8xT-Pr-8SE">
-                                            <rect key="frame" x="18" y="26" width="128" height="18"/>
+                                            <rect key="frame" x="18" y="158" width="128" height="18"/>
                                            <buttonCell key="cell" type="check" title="Attach disk drive" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="CB3-nA-VTM">
                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                <font key="font" metaFont="system"/>
                                            </buttonCell>
                                        </button>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="LG6-mP-SeG">
-                                            <rect key="frame" x="71" y="47" width="146" height="25"/>
+                                            <rect key="frame" x="71" y="179" width="146" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="European (PAL)" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="xAh-Ch-tby" id="yR4-yv-Lvu">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -369,7 +489,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ZaD-7v-rMS">
-                                            <rect key="frame" x="18" y="53" width="50" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="50" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Region:" id="x4m-eh-Nif">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -380,9 +500,9 @@ Gw
                                    <constraints>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="LG6-mP-SeG" secondAttribute="trailing" constant="20" symbolic="YES" id="0Oc-n7-gaM"/>
                                        <constraint firstItem="8xT-Pr-8SE" firstAttribute="top" secondItem="LG6-mP-SeG" secondAttribute="bottom" constant="8" symbolic="YES" id="LBt-4m-GDc"/>
-                                        <constraint firstItem="LG6-mP-SeG" firstAttribute="top" secondItem="mWD-An-tR7" secondAttribute="top" constant="5" id="bcb-ZZ-VpQ"/>
+                                        <constraint firstItem="LG6-mP-SeG" firstAttribute="top" secondItem="mWD-An-tR7" secondAttribute="top" constant="20" symbolic="YES" id="bcb-ZZ-VpQ"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="8xT-Pr-8SE" secondAttribute="trailing" constant="20" symbolic="YES" id="l8P-UW-8ig"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="8xT-Pr-8SE" secondAttribute="bottom" constant="3" id="mga-YX-Bek"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="8xT-Pr-8SE" secondAttribute="bottom" constant="20" symbolic="YES" id="mga-YX-Bek"/>
                                        <constraint firstItem="8xT-Pr-8SE" firstAttribute="leading" secondItem="mWD-An-tR7" secondAttribute="leading" constant="20" symbolic="YES" id="q8Q-kh-Opj"/>
                                        <constraint firstItem="LG6-mP-SeG" firstAttribute="leading" secondItem="ZaD-7v-rMS" secondAttribute="trailing" constant="8" symbolic="YES" id="svb-nH-GlP"/>
                                        <constraint firstItem="ZaD-7v-rMS" firstAttribute="leading" secondItem="mWD-An-tR7" secondAttribute="leading" constant="20" symbolic="YES" id="zgh-a5-FNF"/>
@ -392,11 +512,11 @@ Gw
                            </tabViewItem>
                            <tabViewItem label="Oric" identifier="oric" id="NSx-DC-p4M">
                                <view key="view" id="sOR-e0-8iZ">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="0ct-tf-uRH">
-                                            <rect key="frame" x="18" y="53" width="46" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="46" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="Xm1-7x-YVl">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -404,7 +524,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ENP-hI-BVZ">
-                                            <rect key="frame" x="67" y="47" width="107" height="25"/>
+                                            <rect key="frame" x="67" y="179" width="107" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="Oric-1" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="jGN-1a-biF" id="Jll-EJ-cMr">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -418,7 +538,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="fYL-p6-wyn">
-                                            <rect key="frame" x="113" y="17" width="130" height="25"/>
+                                            <rect key="frame" x="113" y="149" width="130" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="None" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="XhK-Jh-oTW" id="aYb-m1-H9X">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -434,7 +554,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="okM-ZI-NbF">
-                                            <rect key="frame" x="18" y="23" width="92" height="16"/>
+                                            <rect key="frame" x="18" y="155" width="92" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Disk interface:" id="SFK-hS-tFC">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -443,7 +563,7 @@ Gw
                                        </textField>
                                    </subviews>
                                    <constraints>
-                                        <constraint firstItem="ENP-hI-BVZ" firstAttribute="top" secondItem="sOR-e0-8iZ" secondAttribute="top" constant="5" id="Bgq-8R-8I4"/>
+                                        <constraint firstItem="ENP-hI-BVZ" firstAttribute="top" secondItem="sOR-e0-8iZ" secondAttribute="top" constant="20" symbolic="YES" id="Bgq-8R-8I4"/>
                                        <constraint firstItem="fYL-p6-wyn" firstAttribute="leading" secondItem="okM-ZI-NbF" secondAttribute="trailing" constant="8" symbolic="YES" id="Pra-lC-JPB"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="ENP-hI-BVZ" secondAttribute="trailing" constant="20" symbolic="YES" id="Sr5-QZ-xU3"/>
                                        <constraint firstItem="ENP-hI-BVZ" firstAttribute="leading" secondItem="0ct-tf-uRH" secondAttribute="trailing" constant="8" symbolic="YES" id="Wcg-1P-z6l"/>
@ -453,17 +573,17 @@ Gw
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="fYL-p6-wyn" secondAttribute="trailing" constant="20" symbolic="YES" id="ewV-Dw-zj2"/>
                                        <constraint firstItem="0ct-tf-uRH" firstAttribute="leading" secondItem="sOR-e0-8iZ" secondAttribute="leading" constant="20" symbolic="YES" id="huH-9L-97Y"/>
                                        <constraint firstItem="fYL-p6-wyn" firstAttribute="top" secondItem="ENP-hI-BVZ" secondAttribute="bottom" constant="10" symbolic="YES" id="l3T-Ve-0Jw"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="fYL-p6-wyn" secondAttribute="bottom" constant="5" id="mN9-AZ-wSn"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="fYL-p6-wyn" secondAttribute="bottom" constant="20" symbolic="YES" id="mN9-AZ-wSn"/>
                                    </constraints>
                                </view>
                            </tabViewItem>
                            <tabViewItem label="Vic-20" identifier="vic20" id="cyO-PU-hSU">
                                <view key="view" id="fLI-XB-QCr">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ueK-gq-gaF">
-                                            <rect key="frame" x="71" y="47" width="146" height="25"/>
+                                            <rect key="frame" x="71" y="179" width="146" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="European (PAL)" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="45i-0n-gau" id="yi7-eo-I0q">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -479,7 +599,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="2eV-Us-eEv">
-                                            <rect key="frame" x="108" y="17" width="116" height="25"/>
+                                            <rect key="frame" x="108" y="149" width="116" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="Unexpanded" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="fOl-8Q-fsA" id="rH0-7T-pJE">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -493,7 +613,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="MTh-9p-FqC">
-                                            <rect key="frame" x="18" y="53" width="50" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="50" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Region:" id="F3g-Ya-ypU">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -501,7 +621,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="gRS-DK-rIy">
-                                            <rect key="frame" x="18" y="23" width="87" height="16"/>
+                                            <rect key="frame" x="18" y="155" width="87" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="a4I-vG-yCp">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -509,7 +629,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="Lrf-gL-6EI">
-                                            <rect key="frame" x="18" y="-4" width="177" height="18"/>
+                                            <rect key="frame" x="18" y="128" width="177" height="18"/>
                                            <buttonCell key="cell" type="check" title="Attach C-1540 disk drive" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="tsq-YD-xw8">
                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                <font key="font" metaFont="system"/>
@ -521,7 +641,7 @@ Gw
                                        <constraint firstItem="MTh-9p-FqC" firstAttribute="centerY" secondItem="ueK-gq-gaF" secondAttribute="centerY" id="8KD-Bm-KRA"/>
                                        <constraint firstItem="ueK-gq-gaF" firstAttribute="leading" secondItem="MTh-9p-FqC" secondAttribute="trailing" constant="8" symbolic="YES" id="9m6-6j-8j2"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="Lrf-gL-6EI" secondAttribute="trailing" constant="20" symbolic="YES" id="M08-mP-Plz"/>
-                                        <constraint firstItem="ueK-gq-gaF" firstAttribute="top" secondItem="fLI-XB-QCr" secondAttribute="top" constant="5" id="XN3-GK-BX9"/>
+                                        <constraint firstItem="ueK-gq-gaF" firstAttribute="top" secondItem="fLI-XB-QCr" secondAttribute="top" constant="20" symbolic="YES" id="XN3-GK-BX9"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="ueK-gq-gaF" secondAttribute="trailing" constant="20" symbolic="YES" id="YZ9-7N-ssA"/>
                                        <constraint firstItem="MTh-9p-FqC" firstAttribute="leading" secondItem="fLI-XB-QCr" secondAttribute="leading" constant="20" symbolic="YES" id="bgZ-k9-IQC"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="2eV-Us-eEv" secondAttribute="trailing" constant="20" symbolic="YES" id="eiB-vH-17d"/>
@ -529,18 +649,18 @@ Gw
                                        <constraint firstItem="2eV-Us-eEv" firstAttribute="leading" secondItem="gRS-DK-rIy" secondAttribute="trailing" constant="8" symbolic="YES" id="hQ9-uy-KHg"/>
                                        <constraint firstItem="gRS-DK-rIy" firstAttribute="leading" secondItem="fLI-XB-QCr" secondAttribute="leading" constant="20" symbolic="YES" id="iyp-1K-rdC"/>
                                        <constraint firstItem="gRS-DK-rIy" firstAttribute="centerY" secondItem="2eV-Us-eEv" secondAttribute="centerY" id="qWf-Nb-PfJ"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="Lrf-gL-6EI" secondAttribute="bottom" constant="3" id="vNb-Sw-Mxw"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="Lrf-gL-6EI" secondAttribute="bottom" constant="20" symbolic="YES" id="vNb-Sw-Mxw"/>
                                        <constraint firstItem="Lrf-gL-6EI" firstAttribute="top" secondItem="2eV-Us-eEv" secondAttribute="bottom" constant="8" symbolic="YES" id="zBX-Qq-j5f"/>
                                    </constraints>
                                </view>
                            </tabViewItem>
                            <tabViewItem label="ZX80" identifier="zx80" id="tMH-kF-GUz">
                                <view key="view" id="8hL-Vn-Hg0">
-                                    <rect key="frame" x="10" y="7" width="400" height="76"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="I1a-Eu-5UB">
-                                            <rect key="frame" x="108" y="47" width="116" height="25"/>
+                                            <rect key="frame" x="108" y="179" width="116" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="Unexpanded" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="4Sa-jR-xOd" id="B8M-do-Yod">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -554,7 +674,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="NCX-4e-lSu">
-                                            <rect key="frame" x="18" y="53" width="87" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="87" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="e6x-TE-OC5">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -562,7 +682,7 @@ Gw
                                            </textFieldCell>
                                        </textField>
                                        <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ReP-bV-Thu">
-                                            <rect key="frame" x="18" y="26" width="118" height="18"/>
+                                            <rect key="frame" x="18" y="158" width="118" height="18"/>
                                            <buttonCell key="cell" type="check" title="Use ZX81 ROM" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="VQH-nv-Pfm">
                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                <font key="font" metaFont="system"/>
@ -574,8 +694,8 @@ Gw
                                        <constraint firstItem="NCX-4e-lSu" firstAttribute="centerY" secondItem="I1a-Eu-5UB" secondAttribute="centerY" id="1ve-sc-QwI"/>
                                        <constraint firstItem="I1a-Eu-5UB" firstAttribute="leading" secondItem="NCX-4e-lSu" secondAttribute="trailing" constant="8" symbolic="YES" id="Bu6-60-74x"/>
                                        <constraint firstItem="NCX-4e-lSu" firstAttribute="leading" secondItem="8hL-Vn-Hg0" secondAttribute="leading" constant="20" symbolic="YES" id="W09-iG-ARI"/>
-                                        <constraint firstItem="I1a-Eu-5UB" firstAttribute="top" secondItem="8hL-Vn-Hg0" secondAttribute="top" constant="5" id="fkf-wO-Q8i"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="ReP-bV-Thu" secondAttribute="bottom" constant="3" id="fmT-7E-hUT"/>
+                                        <constraint firstItem="I1a-Eu-5UB" firstAttribute="top" secondItem="8hL-Vn-Hg0" secondAttribute="top" constant="20" symbolic="YES" id="fkf-wO-Q8i"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="ReP-bV-Thu" secondAttribute="bottom" constant="20" symbolic="YES" id="fmT-7E-hUT"/>
                                        <constraint firstItem="ReP-bV-Thu" firstAttribute="top" secondItem="I1a-Eu-5UB" secondAttribute="bottom" constant="8" symbolic="YES" id="hYk-xC-63o"/>
                                        <constraint firstItem="ReP-bV-Thu" firstAttribute="leading" secondItem="8hL-Vn-Hg0" secondAttribute="leading" constant="20" symbolic="YES" id="qen-KS-rWi"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="ReP-bV-Thu" secondAttribute="trailing" constant="20" symbolic="YES" id="r7F-DT-oRc"/>
@ -584,11 +704,11 @@ Gw
                            </tabViewItem>
                            <tabViewItem label="ZX81" identifier="zx81" id="Wnn-nQ-gZ6">
                                <view key="view" id="bmd-gL-gzT">
-                                    <rect key="frame" x="10" y="7" width="400" height="186"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="5aO-UX-HnX">
-                                            <rect key="frame" x="108" y="157" width="116" height="25"/>
+                                            <rect key="frame" x="108" y="179" width="116" height="25"/>
                                            <popUpButtonCell key="cell" type="push" title="Unexpanded" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="7QC-Ij-hES" id="d3W-Gl-3Mf">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
@ -602,7 +722,7 @@ Gw
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="8tU-73-XEE">
-                                            <rect key="frame" x="18" y="163" width="87" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="87" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="z4b-oR-Yl2">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -613,37 +733,37 @@ Gw
                                    <constraints>
                                        <constraint firstItem="8tU-73-XEE" firstAttribute="centerY" secondItem="5aO-UX-HnX" secondAttribute="centerY" id="1Jm-YL-OKU"/>
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="5aO-UX-HnX" secondAttribute="trailing" constant="20" symbolic="YES" id="ALj-0x-bFb"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="5aO-UX-HnX" secondAttribute="bottom" constant="5" id="LJ2-W9-fOf"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="5aO-UX-HnX" secondAttribute="bottom" constant="20" symbolic="YES" id="LJ2-W9-fOf"/>
                                        <constraint firstItem="8tU-73-XEE" firstAttribute="leading" secondItem="bmd-gL-gzT" secondAttribute="leading" constant="20" symbolic="YES" id="M6Y-jN-LAf"/>
-                                        <constraint firstItem="5aO-UX-HnX" firstAttribute="top" secondItem="bmd-gL-gzT" secondAttribute="top" constant="5" id="PPD-Jz-qCL"/>
+                                        <constraint firstItem="5aO-UX-HnX" firstAttribute="top" secondItem="bmd-gL-gzT" secondAttribute="top" constant="20" symbolic="YES" id="PPD-Jz-qCL"/>
                                        <constraint firstItem="5aO-UX-HnX" firstAttribute="leading" secondItem="8tU-73-XEE" secondAttribute="trailing" constant="8" symbolic="YES" id="j1u-n4-2IK"/>
                                    </constraints>
                                </view>
                            </tabViewItem>
                            <tabViewItem label="ZX Spectrum" identifier="spectrum" id="HQv-oF-k8b">
                                <view key="view" id="bMx-F6-JUb">
-                                    <rect key="frame" x="10" y="7" width="400" height="186"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="223"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <subviews>
                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="gFZ-d4-WFv">
-                                            <rect key="frame" x="67" y="157" width="76" height="25"/>
-                                            <popUpButtonCell key="cell" type="push" title="16kb" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" borderStyle="borderAndBezel" tag="16" imageScaling="axesIndependently" inset="2" selectedItem="Fo7-NL-Kv5" id="tYs-sA-oek">
+                                            <rect key="frame" x="67" y="179" width="76" height="25"/>
+                                            <popUpButtonCell key="cell" type="push" title="16kb" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="16" imageScaling="axesIndependently" inset="2" selectedItem="Fo7-NL-Kv5" id="tYs-sA-oek">
                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                <font key="font" metaFont="menu"/>
                                                <menu key="menu" id="8lt-dk-zPr">
                                                    <items>
-                                                        <menuItem title="16kb" tag="16" id="Fo7-NL-Kv5"/>
+                                                        <menuItem title="16kb" state="on" tag="16" id="Fo7-NL-Kv5"/>
                                                        <menuItem title="48kb" tag="48" id="xks-Rv-Umd"/>
                                                        <menuItem title="128kb" tag="128" id="w8h-lY-JLX"/>
                                                        <menuItem title="+2" tag="2" id="Vvu-ua-pjg"/>
-                                                        <menuItem title="+2a" state="on" tag="21" id="bFk-nC-Txe"/>
+                                                        <menuItem title="+2a" tag="21" id="bFk-nC-Txe"/>
                                                        <menuItem title="+3" tag="3" id="jwx-fZ-vXp"/>
                                                    </items>
                                                </menu>
                                            </popUpButtonCell>
                                        </popUpButton>
                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="fJ3-ma-Byy">
-                                            <rect key="frame" x="18" y="163" width="46" height="16"/>
+                                            <rect key="frame" x="18" y="185" width="46" height="16"/>
                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="JId-Tp-LrE">
                                                <font key="font" metaFont="system"/>
                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -655,23 +775,23 @@ Gw
                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="gFZ-d4-WFv" secondAttribute="trailing" constant="20" symbolic="YES" id="90E-uI-MQg"/>
                                        <constraint firstItem="fJ3-ma-Byy" firstAttribute="leading" secondItem="bMx-F6-JUb" secondAttribute="leading" constant="20" symbolic="YES" id="9kE-iQ-dxd"/>
                                        <constraint firstItem="fJ3-ma-Byy" firstAttribute="centerY" secondItem="gFZ-d4-WFv" secondAttribute="centerY" id="LxG-5E-Q5Y"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="gFZ-d4-WFv" secondAttribute="bottom" constant="5" id="d8S-vX-B5e"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="gFZ-d4-WFv" secondAttribute="bottom" constant="20" symbolic="YES" id="d8S-vX-B5e"/>
                                        <constraint firstItem="gFZ-d4-WFv" firstAttribute="leading" secondItem="fJ3-ma-Byy" secondAttribute="trailing" constant="8" symbolic="YES" id="hKS-47-R2y"/>
-                                        <constraint firstItem="gFZ-d4-WFv" firstAttribute="top" secondItem="bMx-F6-JUb" secondAttribute="top" constant="5" id="wsX-Wq-iPt"/>
+                                        <constraint firstItem="gFZ-d4-WFv" firstAttribute="top" secondItem="bMx-F6-JUb" secondAttribute="top" constant="20" symbolic="YES" id="wsX-Wq-iPt"/>
                                    </constraints>
                                </view>
                            </tabViewItem>
                        </tabViewItems>
                    </tabView>
                    <scrollView borderType="line" autohidesScrollers="YES" horizontalLineScroll="24" horizontalPageScroll="10" verticalLineScroll="24" verticalPageScroll="10" hasHorizontalScroller="NO" usesPredominantAxisScrolling="NO" id="z5Q-Bs-hJj">
-                        <rect key="frame" x="20" y="60" width="130" height="201"/>
+                        <rect key="frame" x="20" y="60" width="130" height="238"/>
                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" heightSizable="YES"/>
                        <clipView key="contentView" id="O8s-Vw-9yQ">
-                            <rect key="frame" x="1" y="1" width="128" height="199"/>
+                            <rect key="frame" x="1" y="1" width="128" height="236"/>
                            <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                            <subviews>
                                <tableView verticalHuggingPriority="750" allowsExpansionToolTips="YES" columnAutoresizingStyle="none" columnReordering="NO" columnResizing="NO" multipleSelection="NO" emptySelection="NO" autosaveColumns="NO" typeSelect="NO" rowHeight="24" id="3go-Eb-GOy">
-                                    <rect key="frame" x="0.0" y="0.0" width="128" height="199"/>
+                                    <rect key="frame" x="0.0" y="0.0" width="128" height="236"/>
                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                    <size key="intercellSpacing" width="17" height="0.0"/>
                                    <color key="backgroundColor" name="controlBackgroundColor" catalog="System" colorSpace="catalog"/>
@ -708,7 +828,7 @@ Gw
                        </scroller>
                    </scrollView>
                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="VAc-6N-O7q">
-                        <rect key="frame" x="18" y="269" width="554" height="27"/>
+                        <rect key="frame" x="18" y="306" width="554" height="27"/>
                        <textFieldCell key="cell" lineBreakMode="clipping" title="Choose a machine" id="32m-Vs-dPO">
                            <font key="font" textStyle="title2" name=".SFNS-Regular"/>
                            <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -737,7 +857,7 @@ Gw
                    <constraint firstItem="9YM-5x-pc0" firstAttribute="top" secondItem="z5Q-Bs-hJj" secondAttribute="bottom" constant="14" id="suf-rn-Bmy"/>
                </constraints>
            </view>
-            <point key="canvasLocation" x="-1" y="88"/>
+            <point key="canvasLocation" x="-1" y="106.5"/>
        </window>
        <customObject id="192-Eb-Rpg" customClass="MachinePicker" customModule="Clock_Signal" customModuleProvider="target">
            <connections>
@ -750,6 +870,10 @@ Gw
                <outlet property="electronAP6Button" destination="cG2-Ph-S3Z" id="vkq-1J-KBG"/>
                <outlet property="electronDFSButton" destination="JqM-IK-FMP" id="C80-1k-TdQ"/>
                <outlet property="electronSidewaysRAMButton" destination="lzo-8g-o4S" id="LtS-wv-tMf"/>
+                <outlet property="enterpriseBASICButton" destination="hIr-GH-7xi" id="fM6-It-9UO"/>
+                <outlet property="enterpriseDOSButton" destination="syE-e7-TjU" id="sCW-Bj-ZTW"/>
+                <outlet property="enterpriseEXOSButton" destination="nen-Za-7zH" id="NwS-ua-FdA"/>
+                <outlet property="enterpriseModelButton" destination="PhH-bu-pb5" id="8wD-sW-aBw"/>
                <outlet property="machineNameTable" destination="3go-Eb-GOy" id="Ppf-S0-IP1"/>
                <outlet property="machineSelector" destination="VUb-QG-x7c" id="crR-hB-jGd"/>
                <outlet property="macintoshModelTypeButton" destination="xa6-NA-JY5" id="2jX-PY-v2z"/>
--- a/Signal/MachinePicker/MachinePicker.swift
+++ b/Signal/MachinePicker/MachinePicker.swift
@ -27,14 +27,20 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 	@IBOutlet var appleIIgsModelButton: NSPopUpButton!
 	@IBOutlet var appleIIgsMemorySizeButton: NSPopUpButton!

+	// MARK: - CPC properties
+	@IBOutlet var cpcModelTypeButton: NSPopUpButton!
+
 	// MARK: - Electron properties
 	@IBOutlet var electronDFSButton: NSButton!
 	@IBOutlet var electronADFSButton: NSButton!
 	@IBOutlet var electronAP6Button: NSButton!
 	@IBOutlet var electronSidewaysRAMButton: NSButton!

-	// MARK: - CPC properties
-	@IBOutlet var cpcModelTypeButton: NSPopUpButton!
+	// MARK: - Enterprise properties
+	@IBOutlet var enterpriseModelButton: NSPopUpButton!
+	@IBOutlet var enterpriseEXOSButton: NSPopUpButton!
+	@IBOutlet var enterpriseBASICButton: NSPopUpButton!
+	@IBOutlet var enterpriseDOSButton: NSPopUpButton!

 	// MARK: - Macintosh properties
 	@IBOutlet var macintoshModelTypeButton: NSPopUpButton!
@ -93,14 +99,20 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 		appleIIgsModelButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.appleIIgsModel"))
 		appleIIgsMemorySizeButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.appleIIgsMemorySize"))

+		// CPC settings
+		cpcModelTypeButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.cpcModel"))
+
 		// Electron settings
 		electronDFSButton.state = standardUserDefaults.bool(forKey: "new.electronDFS") ? .on : .off
 		electronADFSButton.state = standardUserDefaults.bool(forKey: "new.electronADFS") ? .on : .off
 		electronAP6Button.state = standardUserDefaults.bool(forKey: "new.electronAP6") ? .on : .off
 		electronSidewaysRAMButton.state = standardUserDefaults.bool(forKey: "new.electronSidewaysRAM") ? .on : .off

-		// CPC settings
-		cpcModelTypeButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.cpcModel"))
+		// Enterprise settings
+		enterpriseModelButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseModel"))
+		enterpriseEXOSButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseEXOSVersion"))
+		enterpriseBASICButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseBASICVersion"))
+		enterpriseDOSButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseDOS"))

 		// Macintosh settings
 		macintoshModelTypeButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.macintoshModel"))
@ -143,14 +155,20 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 		standardUserDefaults.set(appleIIgsModelButton.selectedTag(), forKey: "new.appleIIgsModel")
 		standardUserDefaults.set(appleIIgsMemorySizeButton.selectedTag(), forKey: "new.appleIIgsMemorySize")

+		// CPC settings
+		standardUserDefaults.set(cpcModelTypeButton.selectedTag(), forKey: "new.cpcModel")
+
 		// Electron settings
 		standardUserDefaults.set(electronDFSButton.state == .on, forKey: "new.electronDFS")
 		standardUserDefaults.set(electronADFSButton.state == .on, forKey: "new.electronADFS")
 		standardUserDefaults.set(electronAP6Button.state == .on, forKey: "new.electronAP6")
 		standardUserDefaults.set(electronSidewaysRAMButton.state == .on, forKey: "new.electronSidewaysRAM")

-		// CPC settings
-		standardUserDefaults.set(cpcModelTypeButton.selectedTag(), forKey: "new.cpcModel")
+		// Enterprise settings
+		standardUserDefaults.set(enterpriseModelButton.selectedTag(), forKey: "new.enterpriseModel")
+		standardUserDefaults.set(enterpriseEXOSButton.selectedTag(), forKey: "new.enterpriseEXOSVersion")
+		standardUserDefaults.set(enterpriseBASICButton.selectedTag(), forKey: "new.enterpriseBASICVersion")
+		standardUserDefaults.set(enterpriseDOSButton.selectedTag(), forKey: "new.enterpriseDOS")

 		// Macintosh settings
 		standardUserDefaults.set(macintoshModelTypeButton.selectedTag(), forKey: "new.macintoshModel")
@ -205,12 +223,6 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 		storeOptions()

 		switch machineSelector.selectedTabViewItem!.identifier as! String {
-			case "electron":
-				return CSStaticAnalyser(
-					electronDFS: electronDFSButton.state == .on,
-					adfs: electronADFSButton.state == .on,
-					ap6: electronAP6Button.state == .on,
-					sidewaysRAM: electronSidewaysRAMButton.state == .on)

 			case "appleii":
 				var model: CSMachineAppleIIModel = .appleII
@ -255,6 +267,48 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 					default:	return CSStaticAnalyser(amstradCPCModel: .model6128)
 				}

+			case "electron":
+				return CSStaticAnalyser(
+					electronDFS: electronDFSButton.state == .on,
+					adfs: electronADFSButton.state == .on,
+					ap6: electronAP6Button.state == .on,
+					sidewaysRAM: electronSidewaysRAMButton.state == .on)
+
+			case "enterprise":
+				var model: CSMachineEnterpriseModel = .model128
+				switch enterpriseModelButton.selectedItem!.tag {
+					case 64:	model = .model64
+					case 256:	model = .model256
+					case 128:	fallthrough
+					default:	model = .model128
+				}
+
+				var exos: CSMachineEnterpriseEXOS = .version21
+				switch enterpriseEXOSButton.selectedItem!.tag {
+					case 10:	exos = .version10
+					case 20:	exos = .version20
+					case 21:	fallthrough
+					default:	exos = .version21
+				}
+
+				var basic: CSMachineEnterpriseBASIC = .version21
+				switch enterpriseBASICButton.selectedTag() {
+					case 0:		basic = .none
+					case 10:	basic = .version10
+					case 11:	basic = .version11
+					case 21:	fallthrough
+					default:	basic = .version21
+				}
+
+				var dos: CSMachineEnterpriseDOS = .dosNone
+				switch enterpriseDOSButton.selectedTag() {
+					case 1:		dos = .DOSEXDOS
+					case 0:		fallthrough
+					default:	dos = .dosNone
+				}
+
+				return CSStaticAnalyser(enterpriseModel: model, exosVersion: exos, basicVersion: basic, dos: dos)
+
 			case "mac":
 				switch macintoshModelTypeButton.selectedItem!.tag {
 					case 0:		return CSStaticAnalyser(macintoshModel: .model128k)
--- a/SignalTests/EnterpriseNickTests.mm
+++ b/SignalTests/EnterpriseNickTests.mm
@ -0,0 +1,72 @@
+//
+//  EnterpriseNickTests.m
+//  Clock SignalTests
+//
+//  Created by Thomas Harte on 18/06/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#import <XCTest/XCTest.h>
+
+#include "../../../Machines/Enterprise/Nick.hpp"
+#include <memory>
+
+@interface EnterpriseNickTests : XCTestCase
+@end
+
+@implementation EnterpriseNickTests {
+	std::unique_ptr<Enterprise::Nick> _nick;
+	uint8_t _ram[64*1024];
+	int _totalLines;
+}
+
+- (void)setUp {
+	[super setUp];
+
+	// Create a Nick.
+	_nick = std::make_unique<Enterprise::Nick>(_ram);
+
+	// Add a basic line table of blocks proceeding in length: 1, 2, 3, 4, etc and toggling the interrupt bit.
+	_totalLines = 0;
+	int nextLength = 0;
+	int pointer = 0;
+	uint8_t interruptFlag = 0x80;
+	while(nextLength < 256) {
+		_ram[pointer] = 0x100 - nextLength;
+		_ram[pointer+1] = interruptFlag;
+
+		pointer += 16;
+		++nextLength;
+		interruptFlag ^= 0x80;
+		_totalLines += nextLength;
+	}
+
+	// For now: assume Nick starts at address 0 from creation.
+}
+
+- (void)testInterruptPrediction {
+	// Run for the number of cycles implied by the number of lines.
+	int next_sequence_point = _nick->get_next_sequence_point().as<int>();
+	bool last_interrupt_line = _nick->get_interrupt_line();
+
+	for(int c = 0; c < _totalLines*912; c++) {
+		// Check that interrupt line transitions happen only on declared sequence points.
+		_nick->run_for(Cycles(1));
+		--next_sequence_point;
+		const bool interrupt_line = _nick->get_interrupt_line();
+
+		if(interrupt_line != last_interrupt_line) {
+			XCTAssertEqual(next_sequence_point, 0);
+		}
+		last_interrupt_line = interrupt_line;
+
+		if(!next_sequence_point) {
+			next_sequence_point = _nick->get_next_sequence_point().as<int>();
+		} else {
+			const int expected_next_sequence_point = _nick->get_next_sequence_point().as<int>();
+			XCTAssertEqual(next_sequence_point, expected_next_sequence_point);
+		}
+	}
+}
+
+@end
--- a/OSBindings/Qt/ClockSignal.pro
+++ b/OSBindings/Qt/ClockSignal.pro
@ -47,6 +47,7 @@ SOURCES += \
 	$$SRC/Analyser/Static/Commodore/*.cpp \
 	$$SRC/Analyser/Static/Disassembler/*.cpp \
 	$$SRC/Analyser/Static/DiskII/*.cpp \
+	$$SRC/Analyser/Static/Enterprise/*.cpp \
 	$$SRC/Analyser/Static/Macintosh/*.cpp \
 	$$SRC/Analyser/Static/MSX/*.cpp \
 	$$SRC/Analyser/Static/Oric/*.cpp \
@ -92,6 +93,7 @@ SOURCES += \
 	$$SRC/Machines/Commodore/1540/Implementation/*.cpp \
 	$$SRC/Machines/Commodore/Vic-20/*.cpp \
 	$$SRC/Machines/Electron/*.cpp \
+	$$SRC/Machines/Enterprise/*.cpp \
 	$$SRC/Machines/MasterSystem/*.cpp \
 	$$SRC/Machines/MSX/*.cpp \
 	$$SRC/Machines/Oric/*.cpp \
@ -166,6 +168,7 @@ HEADERS += \
 	$$SRC/Analyser/Static/Commodore/*.hpp \
 	$$SRC/Analyser/Static/Disassembler/*.hpp \
 	$$SRC/Analyser/Static/DiskII/*.hpp \
+	$$SRC/Analyser/Static/Enterprise/*.hpp \
 	$$SRC/Analyser/Static/Macintosh/*.hpp \
 	$$SRC/Analyser/Static/MSX/*.hpp \
 	$$SRC/Analyser/Static/Oric/*.hpp \
@ -221,6 +224,7 @@ HEADERS += \
 	$$SRC/Machines/Commodore/1540/Implementation/*.hpp \
 	$$SRC/Machines/Commodore/Vic-20/*.hpp \
 	$$SRC/Machines/Electron/*.hpp \
+	$$SRC/Machines/Enterprise/*.hpp \
 	$$SRC/Machines/MasterSystem/*.hpp \
 	$$SRC/Machines/MSX/*.hpp \
 	$$SRC/Machines/Oric/*.hpp \
--- a/OSBindings/Qt/mainwindow.cpp
+++ b/OSBindings/Qt/mainwindow.cpp
@ -953,6 +953,7 @@ void MainWindow::setButtonPressed(int index, bool isPressed) {
 #include "../../Analyser/Static/AppleIIgs/Target.hpp"
 #include "../../Analyser/Static/AtariST/Target.hpp"
 #include "../../Analyser/Static/Commodore/Target.hpp"
+#include "../../Analyser/Static/Enterprise/Target.hpp"
 #include "../../Analyser/Static/Macintosh/Target.hpp"
 #include "../../Analyser/Static/MSX/Target.hpp"
 #include "../../Analyser/Static/Oric/Target.hpp"
@ -973,6 +974,7 @@ void MainWindow::startMachine() {
 	TEST(amstradCPC);
 	TEST(atariST);
 	TEST(electron);
+	TEST(enterprise);
 	TEST(macintosh);
 	TEST(msx);
 	TEST(oric);
@ -1057,6 +1059,38 @@ void MainWindow::start_electron() {
 	launchTarget(std::move(target));
 }

+void MainWindow::start_enterprise() {
+	using Target = Analyser::Static::Enterprise::Target;
+	auto target = std::make_unique<Target>();
+
+	switch(ui->enterpriseModelComboBox->currentIndex()) {
+		default:	target->model = Target::Model::Enterprise64;	break;
+		case 1:		target->model = Target::Model::Enterprise128;	break;
+		case 2:		target->model = Target::Model::Enterprise256;	break;
+	}
+
+	switch(ui->enterpriseEXOSComboBox->currentIndex()) {
+		default:	target->exos_version = Target::EXOSVersion::v10;	break;
+		case 1:		target->exos_version = Target::EXOSVersion::v20;	break;
+		case 2:		target->exos_version = Target::EXOSVersion::v21;	break;
+		case 3:		target->exos_version = Target::EXOSVersion::v23;	break;
+	}
+
+	switch(ui->enterpriseBASICComboBox->currentIndex()) {
+		default:	target->basic_version = Target::BASICVersion::None;	break;
+		case 1:		target->basic_version = Target::BASICVersion::v10;	break;
+		case 2:		target->basic_version = Target::BASICVersion::v11;	break;
+		case 3:		target->basic_version = Target::BASICVersion::v21;	break;
+	}
+
+	switch(ui->enterpriseDOSComboBox->currentIndex()) {
+		default:	target->dos = Target::DOS::None;	break;
+		case 1:		target->dos = Target::DOS::EXDOS;	break;
+	}
+
+	launchTarget(std::move(target));
+}
+
 void MainWindow::start_macintosh() {
 	using Target = Analyser::Static::Macintosh::Target;
 	auto target = std::make_unique<Target>();
@ -1212,6 +1246,12 @@ void MainWindow::launchTarget(std::unique_ptr<Analyser::Static::Target> &&target
 	CheckBox(electronAP6CheckBox, "electron.hasAP6");					\
 	CheckBox(electronSidewaysRAMCheckBox, "electron.fillSidewaysRAM");	\
 																		\
+	/* Enterprise. */													\
+	ComboBox(enterpriseModelComboBox, "enterprise.model");				\
+	ComboBox(enterpriseEXOSComboBox, "enterprise.exos");				\
+	ComboBox(enterpriseBASICComboBox, "enterprise.basic");				\
+	ComboBox(enterpriseDOSComboBox, "enterprise.dos");					\
+																		\
 	/* Macintosh. */													\
 	ComboBox(macintoshModelComboBox, "macintosh.model");				\
 																		\
--- a/OSBindings/Qt/mainwindow.h
+++ b/OSBindings/Qt/mainwindow.h
@ -91,6 +91,7 @@ class MainWindow : public QMainWindow, public Outputs::Speaker::Speaker::Delegat
 		void start_amstradCPC();
 		void start_atariST();
 		void start_electron();
+		void start_enterprise();
 		void start_macintosh();
 		void start_msx();
 		void start_oric();
--- a/OSBindings/Qt/mainwindow.ui
+++ b/OSBindings/Qt/mainwindow.ui
@ -310,6 +310,138 @@
        </item>
       </layout>
      </widget>
+      <widget class="QWidget" name="enterpriseTab">
+       <attribute name="title">
+        <string>Enterprise</string>
+       </attribute>
+       <layout class="QVBoxLayout" name="enterpriseLayout">
+        <item>
+         <layout class="QHBoxLayout" name="enterpriseHorizontalLayout">
+          <item>
+           <layout class="QFormLayout" name="enterpriseFormLayout">
+            <item row="0" column="0">
+             <widget class="QLabel" name="enterpriseModelLabel">
+              <property name="text">
+               <string>Model:</string>
+              </property>
+             </widget>
+            </item>
+            <item row="0" column="1">
+             <widget class="QComboBox" name="enterpriseModelComboBox">
+              <item>
+               <property name="text">
+                <string>Enterprise 64</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>Enterprise 128</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>Enterprise 256</string>
+               </property>
+              </item>
+             </widget>
+            </item>
+            <item row="1" column="0">
+             <widget class="QLabel" name="enterpriseEXOSLabel">
+              <property name="text">
+               <string>EXOS:</string>
+              </property>
+             </widget>
+            </item>
+            <item row="1" column="1">
+             <widget class="QComboBox" name="enterpriseEXOSComboBox">
+              <item>
+               <property name="text">
+                <string>Version 1.0</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>Version 2.0</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>Version 2.1</string>
+               </property>
+              </item>
+             </widget>
+            </item>
+            <item row="2" column="0">
+             <widget class="QLabel" name="enterpriseBASICLabel">
+              <property name="text">
+               <string>BASIC:</string>
+              </property>
+             </widget>
+            </item>
+            <item row="2" column="1">
+             <widget class="QComboBox" name="enterpriseBASICComboBox">
+              <item>
+               <property name="text">
+                <string>None</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>Version 1.0</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>Version 1.1</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>Version 2.1</string>
+               </property>
+              </item>
+             </widget>
+            </item>
+            <item row="3" column="0">
+             <widget class="QLabel" name="enterpriseDOSLabel">
+              <property name="text">
+               <string>DOS:</string>
+              </property>
+             </widget>
+            </item>
+            <item row="3" column="1">
+             <widget class="QComboBox" name="enterpriseDOSComboBox">
+              <item>
+               <property name="text">
+                <string>None</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>EXDOS</string>
+               </property>
+              </item>
+             </widget>
+            </item>
+           </layout>
+          </item>
+          <item>
+           <spacer name="enterpriseHSpacer">
+            <property name="orientation">
+             <enum>Qt::Horizontal</enum>
+            </property>
+            <property name="sizeHint" stdset="0">
+             <size>
+              <width>40</width>
+              <height>20</height>
+             </size>
+            </property>
+           </spacer>
+          </item>
+         </layout>
+        </item>
+       </layout>
+      </widget>
      <widget class="QWidget" name="macintoshTab">
       <attribute name="title">
        <string>Macintosh</string>
@ -533,75 +665,6 @@
        </item>
       </layout>
      </widget>
-      <widget class="QWidget" name="spectrumTab">
-       <attribute name="title">
-        <string>Spectrum</string>
-       </attribute>
-       <layout class="QVBoxLayout" name="spectrumLayout">
-        <item>
-         <layout class="QHBoxLayout" name="spectrumHorizontalLayout">
-          <item>
-           <layout class="QFormLayout" name="spectrumFormLayout">
-            <item row="0" column="0">
-             <widget class="QLabel" name="spectrumModelLabel">
-              <property name="text">
-               <string>Model:</string>
-              </property>
-             </widget>
-            </item>
-            <item row="0" column="1">
-             <widget class="QComboBox" name="spectrumModelComboBox">
-              <item>
-               <property name="text">
-                <string>16kb</string>
-               </property>
-              </item>
-              <item>
-               <property name="text">
-                <string>48kb</string>
-               </property>
-              </item>
-              <item>
-               <property name="text">
-                <string>128kb</string>
-               </property>
-              </item>
-              <item>
-               <property name="text">
-                <string>+2</string>
-               </property>
-              </item>
-              <item>
-               <property name="text">
-                <string>+2a</string>
-               </property>
-              </item>
-              <item>
-               <property name="text">
-                <string>+3</string>
-               </property>
-              </item>
-             </widget>
-            </item>
-           </layout>
-          </item>
-          <item>
-           <spacer name="spectrumHSpacer">
-            <property name="orientation">
-             <enum>Qt::Horizontal</enum>
-            </property>
-            <property name="sizeHint" stdset="0">
-             <size>
-              <width>40</width>
-              <height>20</height>
-             </size>
-            </property>
-           </spacer>
-          </item>
-         </layout>
-        </item>
-       </layout>
-      </widget>
      <widget class="QWidget" name="vic20Tab">
       <attribute name="title">
        <string>Vic-20</string>
@ -830,6 +893,75 @@
        </item>
       </layout>
      </widget>
+      <widget class="QWidget" name="spectrumTab">
+       <attribute name="title">
+        <string>ZX Spectrum</string>
+       </attribute>
+       <layout class="QVBoxLayout" name="spectrumLayout">
+        <item>
+         <layout class="QHBoxLayout" name="spectrumHorizontalLayout">
+          <item>
+           <layout class="QFormLayout" name="spectrumFormLayout">
+            <item row="0" column="0">
+             <widget class="QLabel" name="spectrumModelLabel">
+              <property name="text">
+               <string>Model:</string>
+              </property>
+             </widget>
+            </item>
+            <item row="0" column="1">
+             <widget class="QComboBox" name="spectrumModelComboBox">
+              <item>
+               <property name="text">
+                <string>16kb</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>48kb</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>128kb</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>+2</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>+2a</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>+3</string>
+               </property>
+              </item>
+             </widget>
+            </item>
+           </layout>
+          </item>
+          <item>
+           <spacer name="spectrumHSpacer">
+            <property name="orientation">
+             <enum>Qt::Horizontal</enum>
+            </property>
+            <property name="sizeHint" stdset="0">
+             <size>
+              <width>40</width>
+              <height>20</height>
+             </size>
+            </property>
+           </spacer>
+          </item>
+         </layout>
+        </item>
+       </layout>
+      </widget>
     </widget>
    </item>
    <item alignment="Qt::AlignBottom">
--- a/OSBindings/SDL/SConstruct
+++ b/OSBindings/SDL/SConstruct
@ -31,6 +31,7 @@ SOURCES += glob.glob('../../Analyser/Static/Coleco/*.cpp')
 SOURCES += glob.glob('../../Analyser/Static/Commodore/*.cpp')
 SOURCES += glob.glob('../../Analyser/Static/Disassembler/*.cpp')
 SOURCES += glob.glob('../../Analyser/Static/DiskII/*.cpp')
+SOURCES += glob.glob('../../Analyser/Static/Enterprise/*.cpp')
 SOURCES += glob.glob('../../Analyser/Static/Macintosh/*.cpp')
 SOURCES += glob.glob('../../Analyser/Static/MSX/*.cpp')
 SOURCES += glob.glob('../../Analyser/Static/Oric/*.cpp')
@ -79,6 +80,7 @@ SOURCES += glob.glob('../../Machines/Commodore/*.cpp')
 SOURCES += glob.glob('../../Machines/Commodore/1540/Implementation/*.cpp')
 SOURCES += glob.glob('../../Machines/Commodore/Vic-20/*.cpp')
 SOURCES += glob.glob('../../Machines/Electron/*.cpp')
+SOURCES += glob.glob('../../Machines/Enterprise/*.cpp')
 SOURCES += glob.glob('../../Machines/MasterSystem/*.cpp')
 SOURCES += glob.glob('../../Machines/MSX/*.cpp')
 SOURCES += glob.glob('../../Machines/Oric/*.cpp')
--- a/OSBindings/SDL/main.cpp
+++ b/OSBindings/SDL/main.cpp
@ -832,8 +832,11 @@ int main(int argc, char *argv[]) {
 			} else if(volume < 0.0 || volume > 1.0) {
 				std::cerr << "Cannot run with volume " << volume_string << "; volumes must be between 0.0 and 1.0." << std::endl;
 			} else {
-				const auto speaker = machine->audio_producer()->get_speaker();
-				if(speaker) speaker->set_output_volume(volume);
+				const auto audio_producer = machine->audio_producer();
+				if(audio_producer) {
+					const auto speaker = machine->audio_producer()->get_speaker();
+					if(speaker) speaker->set_output_volume(volume);
+				}
 			}
 		}
 	}
@ -907,26 +910,29 @@ int main(int argc, char *argv[]) {
 		machine->scan_producer()->set_scan_target(&scan_target);

 		// For now, lie about audio output intentions.
-		auto speaker = machine->audio_producer()->get_speaker();
-		if(speaker) {
-			// Create an audio pipe.
-			SDL_AudioSpec desired_audio_spec;
-			SDL_AudioSpec obtained_audio_spec;
+		const auto audio_producer = machine->audio_producer();
+		if(audio_producer) {
+			auto speaker = audio_producer->get_speaker();
+			if(speaker) {
+				// Create an audio pipe.
+				SDL_AudioSpec desired_audio_spec;
+				SDL_AudioSpec obtained_audio_spec;

-			SDL_zero(desired_audio_spec);
-			desired_audio_spec.freq = 48000;	// TODO: how can I get SDL to reveal the output rate of this machine?
-			desired_audio_spec.format = AUDIO_S16;
-			desired_audio_spec.channels = 1 + int(speaker->get_is_stereo());
-			desired_audio_spec.samples = Uint16(SpeakerDelegate::buffered_samples);
-			desired_audio_spec.callback = SpeakerDelegate::SDL_audio_callback;
-			desired_audio_spec.userdata = &speaker_delegate;
+				SDL_zero(desired_audio_spec);
+				desired_audio_spec.freq = 48000;	// TODO: how can I get SDL to reveal the output rate of this machine?
+				desired_audio_spec.format = AUDIO_S16;
+				desired_audio_spec.channels = 1 + int(speaker->get_is_stereo());
+				desired_audio_spec.samples = Uint16(SpeakerDelegate::buffered_samples);
+				desired_audio_spec.callback = SpeakerDelegate::SDL_audio_callback;
+				desired_audio_spec.userdata = &speaker_delegate;

-			speaker_delegate.audio_device = SDL_OpenAudioDevice(nullptr, 0, &desired_audio_spec, &obtained_audio_spec, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE);
+				speaker_delegate.audio_device = SDL_OpenAudioDevice(nullptr, 0, &desired_audio_spec, &obtained_audio_spec, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE);

-			speaker->set_output_rate(obtained_audio_spec.freq, desired_audio_spec.samples, obtained_audio_spec.channels == 2);
-			speaker_delegate.is_stereo = obtained_audio_spec.channels == 2;
-			speaker->set_delegate(&speaker_delegate);
-			SDL_PauseAudioDevice(speaker_delegate.audio_device, 0);
+				speaker->set_output_rate(obtained_audio_spec.freq, desired_audio_spec.samples, obtained_audio_spec.channels == 2);
+				speaker_delegate.is_stereo = obtained_audio_spec.channels == 2;
+				speaker->set_delegate(&speaker_delegate);
+				SDL_PauseAudioDevice(speaker_delegate.audio_device, 0);
+			}
 		}

 		/*
--- a/Processors/Z80/Z80.hpp
+++ b/Processors/Z80/Z80.hpp
@ -145,6 +145,12 @@ struct PartialMachineCycle {
 	forceinline bool is_wait() const {
 		return operation >= Operation::ReadOpcodeWait && operation <= Operation::InterruptWait;
 	}
+	/*!
+		@returns @c true if this partial machine cycle is a memory access; @c false otherwise.
+	*/
+	forceinline bool is_memory_access() const {
+		return operation <= Operation::Write;
+	}

 	enum Line {
 		CLK = 1 << 0,
--- a/ROMImages/Enterprise/readme.txt
+++ b/ROMImages/Enterprise/readme.txt
@ -0,0 +1,5 @@
+ROM files would ordinarily go here; the copyright status of these is uncertain so they have not been included in this repository.
+
+Expected files:
+
+exos.rom
--- a/Storage/Disk/Controller/DiskController.hpp
+++ b/Storage/Disk/Controller/DiskController.hpp
@ -49,8 +49,10 @@ class Controller:
 		void run_for(const Cycles cycles);

 		/*!
-			Sets the current drive(s). Normally this will be exactly one, but some machines allow
-			zero or multiple drives to be attached, with useless results.
+			Sets the current drive(s), by bit mask. Normally this will be exactly one, but some
+			machines allow zero or multiple drives to be attached, with useless results.
+
+			E.g. supply 1 to select drive 0, 2 to select drive 1, 4 to select drive 2, etc.
 		*/
 		void set_drive(int index_mask);

--- a/Storage/Disk/DiskImage/Formats/FAT12.cpp
+++ b/Storage/Disk/DiskImage/Formats/FAT12.cpp
@ -0,0 +1,57 @@
+//
+//  FAT12.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/01/2018.
+//  Copyright 2018 Thomas Harte. All rights reserved.
+//
+
+#include "FAT12.hpp"
+
+#include "Utility/ImplicitSectors.hpp"
+
+using namespace Storage::Disk;
+
+FAT12::FAT12(const std::string &file_name) :
+	MFMSectorDump(file_name) {
+	// The only sanity check here is whether a sensible
+	// geometry is encoded in the first sector, or can be guessed.
+	off_t file_size = file_.stats().st_size;
+
+	if(file_size < 512) throw Error::InvalidFormat;
+
+	// Inspect the FAT.
+	file_.seek(11, SEEK_SET);
+	sector_size_ = file_.get16le();
+	file_.seek(19, SEEK_SET);
+	const uint16_t total_sectors = file_.get16le();
+	file_.seek(24, SEEK_SET);
+	sector_count_ = file_.get16le();
+	head_count_ = file_.get16le();
+
+	// Throw if there would seemingly be an incomplete track.
+	if(file_size != total_sectors*sector_size_) throw Error::InvalidFormat;
+	if(total_sectors % (head_count_ * sector_count_)) throw Error::InvalidFormat;
+	track_count_ = int(total_sectors / (head_count_ * sector_count_));
+
+	// Check that there is a valid power-of-two sector size.
+	uint8_t log_sector_size = 2;
+	while(log_sector_size < 5 && (1 << (7+log_sector_size)) != sector_size_) {
+		++log_sector_size;
+	}
+	if(log_sector_size >= 5) throw Error::InvalidFormat;
+
+	set_geometry(sector_count_, log_sector_size, 1, true);
+}
+
+HeadPosition FAT12::get_maximum_head_position() {
+	return HeadPosition(track_count_);
+}
+
+int FAT12::get_head_count() {
+	return head_count_;
+}
+
+long FAT12::get_file_offset_for_position(Track::Address address) {
+	return (address.position.as_int()*head_count_ + address.head) * sector_size_ * sector_count_;
+}
--- a/Storage/Disk/DiskImage/Formats/MSXDSK.hpp
+++ b/Storage/Disk/DiskImage/Formats/MSXDSK.hpp
@ -1,5 +1,5 @@
 //
-//  MSXDSK.hpp
+//  FAT12.hpp
 //  Clock Signal
 //
 //  Created by Thomas Harte on 07/01/2018.
@ -17,12 +17,12 @@ namespace Storage {
 namespace Disk {

 /*!
-	Provides a @c DiskImage descriging an MSX-style disk image:
+	Provides a @c DiskImage holding an MSDOS-style FAT12 disk image:
 	a sector dump of appropriate proportions.
 */
-class MSXDSK: public MFMSectorDump {
+class FAT12: public MFMSectorDump {
 	public:
-		MSXDSK(const std::string &file_name);
+		FAT12(const std::string &file_name);
 		HeadPosition get_maximum_head_position() final;
 		int get_head_count() final;

@ -31,6 +31,8 @@ class MSXDSK: public MFMSectorDump {

 		int head_count_;
 		int track_count_;
+		int sector_count_;
+		int sector_size_;
 };

 }
--- a/Storage/Disk/DiskImage/Formats/MSXDSK.cpp
+++ b/Storage/Disk/DiskImage/Formats/MSXDSK.cpp
@ -1,59 +0,0 @@
-//
-//  MSXDSK.cpp
-//  Clock Signal
-//
-//  Created by Thomas Harte on 07/01/2018.
-//  Copyright 2018 Thomas Harte. All rights reserved.
-//
-
-#include "MSXDSK.hpp"
-
-#include "Utility/ImplicitSectors.hpp"
-
-namespace {
-	constexpr int sectors_per_track = 9;
-	constexpr int sector_size = 2;
-	constexpr off_t track_size = (128 << sector_size)*sectors_per_track;
-}
-
-using namespace Storage::Disk;
-
-MSXDSK::MSXDSK(const std::string &file_name) :
-	MFMSectorDump(file_name) {
-	// The only sanity check here is whether a sensible
-	// geometry can be guessed.
-	off_t file_size = file_.stats().st_size;
-
-	// Throw if there would seemingly be an incomplete track.
-	if(file_size % track_size) throw Error::InvalidFormat;
-
-	track_count_ = int(file_size / track_size);
-	head_count_ = 1;
-
-	// Throw if too large or too small or too large for single sided and
-	// clearly not double sided.
-	if(track_count_ < 40) throw Error::InvalidFormat;
-	if(track_count_ > 82*2) throw Error::InvalidFormat;
-	if(track_count_ > 82 && track_count_&1) throw Error::InvalidFormat;
-
-	// The below effectively prefers the idea of a single-sided 80-track disk
-	// to a double-sided 40-track disk. Emulators have to guess.
-	if(track_count_ > 82) {
-		track_count_ /= 2;
-		head_count_ = 2;
-	}
-
-	set_geometry(sectors_per_track, sector_size, 1, true);
-}
-
-HeadPosition MSXDSK::get_maximum_head_position() {
-	return HeadPosition(track_count_);
-}
-
-int MSXDSK::get_head_count() {
-	return head_count_;
-}
-
-long MSXDSK::get_file_offset_for_position(Track::Address address) {
-	return (address.position.as_int()*head_count_ + address.head) * 512 * 9;
-}
--- a/Storage/TargetPlatforms.hpp
+++ b/Storage/TargetPlatforms.hpp
@ -29,13 +29,14 @@ enum Type: IntType {
 	Coleco			=	1 << 10,
 	Commodore		=	1 << 11,
 	DiskII			=	1 << 12,
-	Sega			=	1 << 13,
-	Macintosh		=	1 << 14,
-	MSX				=	1 << 15,
-	Oric			=	1 << 16,
-	ZX80			=	1 << 17,
-	ZX81			=	1 << 18,
-	ZXSpectrum		=	1 << 19,
+	Enterprise		=	1 << 13,
+	Sega			=	1 << 14,
+	Macintosh		=	1 << 15,
+	MSX				=	1 << 16,
+	Oric			=	1 << 17,
+	ZX80			=	1 << 18,
+	ZX81			=	1 << 19,
+	ZXSpectrum		=	1 << 20,

 	Acorn			=	AcornAtom | AcornElectron | BBCMaster | BBCModelA | BBCModelB,
 	ZX8081			=	ZX80 | ZX81,