diff --git a/cpp/controllers/abstract_controller.h b/cpp/controllers/abstract_controller.h
index 1ec70aed..ca262abe 100644
--- a/cpp/controllers/abstract_controller.h
+++ b/cpp/controllers/abstract_controller.h
@@ -84,6 +84,10 @@ public:
 	scsi_defs::status GetStatus() const { return ctrl.status; }
 	void SetStatus(scsi_defs::status s) { ctrl.status = s; }
 	uint32_t GetLength() const { return ctrl.length; }
+	void SetLength(uint32_t l) { ctrl.length = l; }
+	uint32_t GetBlocks() const { return ctrl.blocks; }
+	void SetBlocks(uint32_t b) { ctrl.blocks = b; }
+	void DecrementBlocks() { --ctrl.blocks; }
 
 	bool IsByteTransfer() const { return is_byte_transfer; }
 	void SetByteTransfer(bool);
@@ -101,7 +105,6 @@ protected:
 	bool HasValidLength() const { return ctrl.length != 0; }
 	int GetOffset() const { return ctrl.offset; }
 	void ResetOffset() { ctrl.offset = 0; }
-	void SetLength(uint32_t l) { ctrl.length = l; }
 	void UpdateOffsetAndLength() { ctrl.offset += ctrl.length; ctrl.length = 0; }
 
 private:
diff --git a/cpp/controllers/scsi_controller.cpp b/cpp/controllers/scsi_controller.cpp
index 49e34382..116192fa 100644
--- a/cpp/controllers/scsi_controller.cpp
+++ b/cpp/controllers/scsi_controller.cpp
@@ -16,8 +16,9 @@
 #include "hal/gpiobus.h"
 #include "hal/systimer.h"
 #include "rascsi_exceptions.h"
-#include "devices/scsi_host_bridge.h"
-#include "devices/scsi_daynaport.h"
+#include "devices/interfaces/byte_writer.h"
+#include "devices/mode_page_device.h"
+#include "devices/disk.h"
 #include "scsi_controller.h"
 #include <sstream>
 #include <iomanip>
@@ -197,6 +198,7 @@ void ScsiController::Command()
 		bus->SetIO(false);
 
 		const int actual_count = bus->CommandHandShake(GetBuffer().data());
+		// TODO Try to move GetCommandByteCount() to BUS, so that the controller does not need to know GPIOBUS
 		const int command_byte_count = GPIOBUS::GetCommandByteCount(GetBuffer()[0]);
 
 		// If not able to receive all, move to the status phase
@@ -229,7 +231,7 @@ void ScsiController::Execute()
 
 	// Initialization for data transfer
 	ResetOffset();
-	ctrl.blocks = 1;
+	SetBlocks(1);
 	execstart = SysTimer::GetTimerLow();
 
 	// Discard pending sense data from the previous command if the current command is not REQUEST SENSE
@@ -317,7 +319,7 @@ void ScsiController::Status()
 		// Data transfer is 1 byte x 1 block
 		ResetOffset();
 		SetLength(1);
-		ctrl.blocks = 1;
+		SetBlocks(1);
 		GetBuffer()[0] = (BYTE)GetStatus();
 
 		return;
@@ -367,7 +369,7 @@ void ScsiController::MsgOut()
 		// Data transfer is 1 byte x 1 block
 		ResetOffset();
 		SetLength(1);
-		ctrl.blocks = 1;
+		SetBlocks(1);
 
 		return;
 	}
@@ -492,13 +494,13 @@ void ScsiController::Send()
 
 	if (HasValidLength()) {
 		LOGTRACE("%s%s", __PRETTY_FUNCTION__, (" Sending handhake with offset " + to_string(GetOffset()) + ", length "
-				+ to_string(ctrl.length)).c_str())
+				+ to_string(GetLength())).c_str())
 
 		// TODO The delay has to be taken from ctrl.unit[lun], but as there are currently no Daynaport drivers for
 		// LUNs other than 0 this work-around works.
-		if (const int len = bus->SendHandShake(GetBuffer().data() + ctrl.offset, ctrl.length,
+		if (const int len = bus->SendHandShake(GetBuffer().data() + ctrl.offset, GetLength(),
 				HasDeviceForLun(0) ? GetDeviceForLun(0)->GetSendDelay() : 0);
-			len != (int)ctrl.length) {
+			len != (int)GetLength()) {
 			// If you cannot send all, move to status phase
 			Error(sense_key::ABORTED_COMMAND);
 			return;
@@ -510,14 +512,14 @@ void ScsiController::Send()
 	}
 
 	// Block subtraction, result initialization
-	ctrl.blocks--;
+	DecrementBlocks();
 	bool result = true;
 
 	// Processing after data collection (read/data-in only)
-	if (IsDataIn() && ctrl.blocks != 0) {
+	if (IsDataIn() && GetBlocks() != 0) {
 		// set next buffer (set offset, length)
 		result = XferIn(GetBuffer());
-		LOGTRACE("%s%s", __PRETTY_FUNCTION__, (" Processing after data collection. Blocks: " + to_string(ctrl.blocks)).c_str())
+		LOGTRACE("%s%s", __PRETTY_FUNCTION__, (" Processing after data collection. Blocks: " + to_string(GetBlocks())).c_str())
 	}
 
 	// If result FALSE, move to status phase
@@ -527,8 +529,8 @@ void ScsiController::Send()
 	}
 
 	// Continue sending if block !=0
-	if (ctrl.blocks != 0){
-		LOGTRACE("%s%s", __PRETTY_FUNCTION__, (" Continuing to send. Blocks: " + to_string(ctrl.blocks)).c_str())
+	if (GetBlocks() != 0){
+		LOGTRACE("%s%s", __PRETTY_FUNCTION__, (" Continuing to send. Blocks: " + to_string(GetBlocks())).c_str())
 		assert(HasValidLength());
 		assert(ctrl.offset == 0);
 		return;
@@ -562,7 +564,7 @@ void ScsiController::Send()
 		case BUS::phase_t::status:
 			// Message in phase
 			SetLength(1);
-			ctrl.blocks = 1;
+			SetBlocks(1);
 			GetBuffer()[0] = (BYTE)ctrl.message;
 			MsgIn();
 			break;
@@ -588,12 +590,11 @@ void ScsiController::Receive()
 
 	// Length != 0 if received
 	if (HasValidLength()) {
-		LOGTRACE("%s Length is %d bytes", __PRETTY_FUNCTION__, ctrl.length)
+		LOGTRACE("%s Length is %d bytes", __PRETTY_FUNCTION__, GetLength())
 
 		// If not able to receive all, move to status phase
-		if (int len = bus->ReceiveHandShake(GetBuffer().data() + GetOffset(), ctrl.length);
-				len != (int)ctrl.length) {
-			LOGERROR("%s Not able to receive %d bytes of data, only received %d",__PRETTY_FUNCTION__, ctrl.length, len)
+		if (int len = bus->ReceiveHandShake(GetBuffer().data() + GetOffset(), GetLength()); len != (int)GetLength()) {
+			LOGERROR("%s Not able to receive %d bytes of data, only received %d",__PRETTY_FUNCTION__, GetLength(), len)
 			Error(sense_key::ABORTED_COMMAND);
 			return;
 		}
@@ -604,14 +605,14 @@ void ScsiController::Receive()
 	}
 
 	// Block subtraction, result initialization
-	ctrl.blocks--;
+	DecrementBlocks();
 	bool result = true;
 
 	// Processing after receiving data (by phase)
 	LOGTRACE("%s Phase: %s",__PRETTY_FUNCTION__, BUS::GetPhaseStrRaw(GetPhase()))
 	switch (GetPhase()) {
 		case BUS::phase_t::dataout:
-			if (ctrl.blocks == 0) {
+			if (GetBlocks() == 0) {
 				// End with this buffer
 				result = XferOut(false);
 			} else {
@@ -637,14 +638,13 @@ void ScsiController::Receive()
 	}
 
 	// If result FALSE, move to status phase
-	// TODO Check whether we can raise scsi_exception here in order to simplify the error handling
 	if (!result) {
 		Error(sense_key::ABORTED_COMMAND);
 		return;
 	}
 
-	// Continue to receive if block !=0
-	if (ctrl.blocks != 0) {
+	// Continue to receive if block != 0
+	if (GetBlocks() != 0) {
 		assert(HasValidLength());
 		assert(ctrl.offset == 0);
 		return;
@@ -693,18 +693,17 @@ void ScsiController::ReceiveBytes()
 	assert(!bus->GetIO());
 
 	if (HasValidLength()) {
-		LOGTRACE("%s Length is %d bytes", __PRETTY_FUNCTION__, ctrl.length)
+		LOGTRACE("%s Length is %d bytes", __PRETTY_FUNCTION__, GetLength())
 
 		// If not able to receive all, move to status phase
-		if (uint32_t len = bus->ReceiveHandShake(GetBuffer().data() + GetOffset(), ctrl.length);
-				len != ctrl.length) {
+		if (uint32_t len = bus->ReceiveHandShake(GetBuffer().data() + GetOffset(), GetLength()); len != GetLength()) {
 			LOGERROR("%s Not able to receive %d bytes of data, only received %d",
-					__PRETTY_FUNCTION__, ctrl.length, len)
+					__PRETTY_FUNCTION__, GetLength(), len)
 			Error(sense_key::ABORTED_COMMAND);
 			return;
 		}
 
-		bytes_to_transfer = ctrl.length;
+		bytes_to_transfer = GetLength();
 
 		UpdateOffsetAndLength();
 
@@ -795,7 +794,6 @@ void ScsiController::DataOutNonBlockOriented()
 
 		case scsi_command::eCmdModeSelect6:
 		case scsi_command::eCmdModeSelect10: {
-				// TODO Try to get rid of this cast
 				if (auto device = dynamic_pointer_cast<ModePageDevice>(GetDeviceForLun(GetEffectiveLun()));
 					device != nullptr) {
 					device->ModeSelect(GetOpcode(), ctrl.cmd, GetBuffer(), GetOffset());
@@ -867,26 +865,33 @@ bool ScsiController::XferIn(vector<BYTE>& buf)
 //	Data transfer OUT
 //	*If cont=true, reset the offset and length
 //
+// TODO Try to use less casts
+//
 //---------------------------------------------------------------------------
 bool ScsiController::XferOutBlockOriented(bool cont)
 {
-	auto disk = dynamic_pointer_cast<Disk>(GetDeviceForLun(GetEffectiveLun()));
-	if (disk == nullptr) {
-		return false;
-	}
+	auto device = GetDeviceForLun(GetEffectiveLun());
 
 	// Limited to write commands
 	switch (GetOpcode()) {
 		case scsi_command::eCmdModeSelect6:
 		case scsi_command::eCmdModeSelect10:
+		{
+			auto mode_page_device = dynamic_pointer_cast<ModePageDevice>(device);
+			if (mode_page_device == nullptr) {
+				return false;
+			}
+
 			try {
-				disk->ModeSelect(GetOpcode(), ctrl.cmd, GetBuffer(), GetOffset());
+				mode_page_device->ModeSelect(GetOpcode(), ctrl.cmd, GetBuffer(), GetOffset());
 			}
 			catch(const scsi_exception& e) {
 				Error(e.get_sense_key(), e.get_asc());
 				return false;
 			}
+
 			break;
+		}
 
 		case scsi_command::eCmdWrite6:
 		case scsi_command::eCmdWrite10:
@@ -895,11 +900,9 @@ bool ScsiController::XferOutBlockOriented(bool cont)
 		case scsi_command::eCmdVerify10:
 		case scsi_command::eCmdVerify16:
 		{
-			// Special case Write function for bridge
-			// TODO This class must not know about SCSIBR
-			if (auto bridge = dynamic_pointer_cast<SCSIBR>(disk); bridge) {
-				if (!bridge->WriteBytes(ctrl.cmd, GetBuffer(), ctrl.length)) {
-					// Write failed
+			// Special case for SCBR and SCDP
+			if (auto byte_writer = dynamic_pointer_cast<ByteWriter>(device); byte_writer) {
+				if (!byte_writer->WriteBytes(ctrl.cmd, GetBuffer(), GetLength())) {
 					return false;
 				}
 
@@ -907,14 +910,9 @@ bool ScsiController::XferOutBlockOriented(bool cont)
 				break;
 			}
 
-			// Special case Write function for DaynaPort
-			// TODO This class must not know about DaynaPort
-			if (auto daynaport = dynamic_pointer_cast<SCSIDaynaPort>(disk); daynaport) {
-				daynaport->WriteBytes(ctrl.cmd, GetBuffer(), 0);
-
-				ResetOffset();
-				ctrl.blocks = 0;
-				break;
+			auto disk = dynamic_pointer_cast<Disk>(device);
+			if (disk == nullptr) {
+				return false;
 			}
 
 			try {
@@ -923,7 +921,6 @@ bool ScsiController::XferOutBlockOriented(bool cont)
 			catch(const scsi_exception& e) {
 				Error(e.get_sense_key(), e.get_asc());
 
-				// Write failed
 				return false;
 			}
 
@@ -938,7 +935,6 @@ bool ScsiController::XferOutBlockOriented(bool cont)
 				SetLength(disk->WriteCheck(ctrl.next - 1));
 			}
 			catch(const scsi_exception&) {
-				// Cannot write
 				return false;
 			}
 
@@ -1006,7 +1002,7 @@ void ScsiController::ParseMessage()
 			// Check only when synchronous transfer is possible
 			if (!scsi.syncenable || scsi.msb[i + 2] != 0x01) {
 				SetLength(1);
-				ctrl.blocks = 1;
+				SetBlocks(1);
 				GetBuffer()[0] = 0x07;
 				MsgIn();
 				return;
@@ -1024,7 +1020,7 @@ void ScsiController::ParseMessage()
 
 			// STDR response message generation
 			SetLength(5);
-			ctrl.blocks = 1;
+			SetBlocks(1);
 			GetBuffer()[0] = 0x01;
 			GetBuffer()[1] = 0x03;
 			GetBuffer()[2] = 0x01;
@@ -1046,7 +1042,7 @@ void ScsiController::ProcessMessage()
 		// Data transfer is 1 byte x 1 block
 		ResetOffset();
 		SetLength(1);
-		ctrl.blocks = 1;
+		SetBlocks(1);
 		return;
 	}
 
diff --git a/cpp/devices/disk.cpp b/cpp/devices/disk.cpp
index c4d40024..74a97c82 100644
--- a/cpp/devices/disk.cpp
+++ b/cpp/devices/disk.cpp
@@ -110,7 +110,7 @@ void Disk::FormatUnit()
 void Disk::Read(access_mode mode)
 {
 	if (uint64_t start; CheckAndGetStartAndCount(start, ctrl->blocks, mode)) {
-		ctrl->length = Read(ctrl->cmd, controller->GetBuffer(), start);
+		controller->SetLength(Read(ctrl->cmd, controller->GetBuffer(), start));
 		LOGTRACE("%s ctrl.length is %d", __PRETTY_FUNCTION__, controller->GetLength())
 
 		// Set next block
@@ -150,7 +150,7 @@ void Disk::ReadWriteLong16()
 void Disk::Write(access_mode mode)
 {
 	if (uint64_t start; CheckAndGetStartAndCount(start, ctrl->blocks, mode)) {
-		ctrl->length = WriteCheck(start);
+		controller->SetLength(WriteCheck(start));
 
 		// Set next block
 		ctrl->next = start + 1;
@@ -172,7 +172,7 @@ void Disk::Verify(access_mode mode)
 		}
 
 		// Test reading
-		ctrl->length = Read(ctrl->cmd, controller->GetBuffer(), start);
+		controller->SetLength(Read(ctrl->cmd, controller->GetBuffer(), start));
 
 		// Set next block
 		ctrl->next = start + 1;
@@ -245,7 +245,7 @@ void Disk::ReadDefectData10()
 
 	// The defect list is empty
 	fill_n(controller->GetBuffer().begin(), allocation_length, 0);
-	ctrl->length = (int)allocation_length;
+	controller->SetLength((uint32_t)allocation_length);
 
 	EnterDataInPhase();
 }
@@ -586,7 +586,7 @@ void Disk::ReadCapacity10()
 	SetInt32(buf, 4, 1 << size_shift_count);
 
 	// the size
-	ctrl->length = 8;
+	controller->SetLength(8);
 
 	EnterDataInPhase();
 }
@@ -613,7 +613,7 @@ void Disk::ReadCapacity16()
 	buf[13] = 0;
 
 	// the size
-	ctrl->length = 14;
+	controller->SetLength(14);
 
 	EnterDataInPhase();
 }
diff --git a/cpp/devices/interfaces/byte_writer.h b/cpp/devices/interfaces/byte_writer.h
new file mode 100644
index 00000000..a8625264
--- /dev/null
+++ b/cpp/devices/interfaces/byte_writer.h
@@ -0,0 +1,28 @@
+//---------------------------------------------------------------------------
+//
+// SCSI Target Emulator RaSCSI Reloaded
+// for Raspberry Pi
+//
+// Copyright (C) 2022 Uwe Seimet
+//
+// Abstraction for the DaynaPort and the host bridge, which both have methods for writing byte sequences
+//
+//---------------------------------------------------------------------------
+
+#pragma once
+
+#include "os.h"
+#include <vector>
+
+using namespace std;
+
+class ByteWriter
+{
+
+public:
+
+	ByteWriter() = default;
+	virtual ~ByteWriter() = default;
+
+	virtual bool WriteBytes(const vector<int>&, vector<BYTE>&, uint32_t) = 0;
+};
diff --git a/cpp/devices/mode_page_device.cpp b/cpp/devices/mode_page_device.cpp
index 08f58bc6..85c77402 100644
--- a/cpp/devices/mode_page_device.cpp
+++ b/cpp/devices/mode_page_device.cpp
@@ -101,14 +101,14 @@ int ModePageDevice::AddModePages(const vector<int>& cdb, vector<BYTE>& buf, int
 
 void ModePageDevice::ModeSense6()
 {
-	ctrl->length = ModeSense6(ctrl->cmd, controller->GetBuffer());
+	controller->SetLength(ModeSense6(ctrl->cmd, controller->GetBuffer()));
 
 	EnterDataInPhase();
 }
 
 void ModePageDevice::ModeSense10()
 {
-	ctrl->length = ModeSense10(ctrl->cmd, controller->GetBuffer());
+	controller->SetLength(ModeSense10(ctrl->cmd, controller->GetBuffer()));
 
 	EnterDataInPhase();
 }
@@ -120,7 +120,7 @@ void ModePageDevice::ModeSelect(scsi_command, const vector<int>&, const vector<B
 
 void ModePageDevice::ModeSelect6()
 {
-	ctrl->length = SaveParametersCheck(ctrl->cmd[4]);
+	controller->SetLength(SaveParametersCheck(ctrl->cmd[4]));
 
 	EnterDataOutPhase();
 }
@@ -129,7 +129,7 @@ void ModePageDevice::ModeSelect10()
 {
 	const size_t length = min(controller->GetBuffer().size(), (size_t)GetInt16(ctrl->cmd, 7));
 
-	ctrl->length = SaveParametersCheck((int)length);
+	controller->SetLength(SaveParametersCheck((uint32_t)length));
 
 	EnterDataOutPhase();
 }
diff --git a/cpp/devices/primary_device.cpp b/cpp/devices/primary_device.cpp
index d7c03366..c0b69c13 100644
--- a/cpp/devices/primary_device.cpp
+++ b/cpp/devices/primary_device.cpp
@@ -77,7 +77,7 @@ void PrimaryDevice::Inquiry()
 	const size_t allocation_length = min(buf.size(), (size_t)GetInt16(ctrl->cmd, 3));
 
 	memcpy(controller->GetBuffer().data(), buf.data(), allocation_length);
-	ctrl->length = (uint32_t)allocation_length;
+	controller->SetLength((uint32_t)allocation_length);
 
 	// Report if the device does not support the requested LUN
 	if (int lun = controller->GetEffectiveLun(); !controller->HasDeviceForLun(lun)) {
@@ -114,7 +114,7 @@ void PrimaryDevice::ReportLuns()
 
 	size += 8;
 
-	ctrl->length = min(allocation_length, size);
+	controller->SetLength(min(allocation_length, size));
 
 	EnterDataInPhase();
 }
@@ -142,7 +142,7 @@ void PrimaryDevice::RequestSense()
 	const size_t allocation_length = min(buf.size(), (size_t)ctrl->cmd[4]);
 
     memcpy(controller->GetBuffer().data(), buf.data(), allocation_length);
-    ctrl->length = (uint32_t)allocation_length;
+    controller->SetLength((uint32_t)allocation_length);
 
     EnterDataInPhase();
 }
diff --git a/cpp/devices/scsi_command_util.h b/cpp/devices/scsi_command_util.h
index 2d44230f..5a8903c6 100644
--- a/cpp/devices/scsi_command_util.h
+++ b/cpp/devices/scsi_command_util.h
@@ -11,6 +11,7 @@
 
 #pragma once
 
+#include "os.h"
 #include "scsi.h"
 #include <vector>
 #include <map>
diff --git a/cpp/devices/scsi_daynaport.cpp b/cpp/devices/scsi_daynaport.cpp
index 3567f1ae..0967a99a 100644
--- a/cpp/devices/scsi_daynaport.cpp
+++ b/cpp/devices/scsi_daynaport.cpp
@@ -32,8 +32,7 @@
 using namespace scsi_defs;
 using namespace scsi_command_util;
 
-// TODO Disk must not be the superclass
-SCSIDaynaPort::SCSIDaynaPort(int lun) : Disk(SCDP, lun)
+SCSIDaynaPort::SCSIDaynaPort(int lun) : PrimaryDevice(SCDP, lun)
 {
 	dispatcher.Add(scsi_command::eCmdTestUnitReady, "TestUnitReady", &SCSIDaynaPort::TestUnitReady);
 	dispatcher.Add(scsi_command::eCmdRead6, "Read6", &SCSIDaynaPort::Read6);
@@ -48,20 +47,10 @@ SCSIDaynaPort::SCSIDaynaPort(int lun) : Disk(SCDP, lun)
 	SetSendDelay(DAYNAPORT_READ_HEADER_SZ);
 
 	SupportsParams(true);
-	// TODO Remove as soon as SCDP is not a subclass of Disk anymore
-	SetStoppable(false);
-	// TODO Remove as soon as SCDP is not a subclass of Disk anymore
-	SupportsFile(false);
 }
 
 bool SCSIDaynaPort::Dispatch(scsi_command cmd)
 {
-	// TODO As long as DaynaPort suffers from being a subclass of Disk at least reject MODE SENSE and MODE SELECT
-	if (cmd == scsi_command::eCmdModeSense6 || cmd == scsi_command::eCmdModeSelect6 ||
-			cmd == scsi_command::eCmdModeSense10 || cmd == scsi_command::eCmdModeSelect10) {
-		return false;
-	}
-
 	// The superclass class handles the less specific commands
 	return dispatcher.Dispatch(this, cmd) ? true : super::Dispatch(cmd);
 }
@@ -89,11 +78,6 @@ bool SCSIDaynaPort::Init(const unordered_map<string, string>& params)
 	return true;
 }
 
-void SCSIDaynaPort::Open()
-{
-	m_tap.OpenDump(GetFilename().c_str());
-}
-
 vector<byte> SCSIDaynaPort::InquiryInternal() const
 {
 	vector<byte> buf = HandleInquiry(device_type::PROCESSOR, scsi_level::SCSI_2, false);
@@ -145,8 +129,8 @@ int SCSIDaynaPort::Read(const vector<int>& cdb, vector<BYTE>& buf, uint64_t)
 	const int requested_length = cdb[4];
 	LOGTRACE("%s Read maximum length %d, (%04X)", __PRETTY_FUNCTION__, requested_length, requested_length)
 
-	// At host startup, it will send a READ(6) command with a length of 1. We should
-	// respond by going into the status mode with a code of 0x02
+	// At startup the host may send a READ(6) command with a sector count of 1 to read the root sector.
+	// We should respond by going into the status mode with a code of 0x02.
 	if (requested_length == 1) {
 		return 0;
 	}
@@ -253,17 +237,6 @@ int SCSIDaynaPort::Read(const vector<int>& cdb, vector<BYTE>& buf, uint64_t)
 	return DAYNAPORT_READ_HEADER_SZ;
 }
 
-int SCSIDaynaPort::WriteCheck(uint64_t)
-{
-	CheckReady();
-
-	if (!m_bTapEnable) {
-		throw scsi_exception(sense_key::UNIT_ATTENTION, asc::MEDIUM_NOT_PRESENT);
-	}
-
-	return 1;
-}
-
 //---------------------------------------------------------------------------
 //
 //  Write
@@ -282,7 +255,7 @@ int SCSIDaynaPort::WriteCheck(uint64_t)
 //               XX XX ... is the actual packet
 //
 //---------------------------------------------------------------------------
-bool SCSIDaynaPort::WriteBytes(const vector<int>& cdb, const vector<BYTE>& buf, uint64_t)
+bool SCSIDaynaPort::WriteBytes(const vector<int>& cdb, vector<BYTE>& buf, uint32_t)
 {
 	const int data_format = cdb[5];
 	int data_length = GetInt16(cdb, 3);
@@ -301,6 +274,8 @@ bool SCSIDaynaPort::WriteBytes(const vector<int>& cdb, const vector<BYTE>& buf,
 		LOGWARN("%s Unknown data format %02X", __PRETTY_FUNCTION__, data_format)
 	}
 
+	controller->SetBlocks(0);
+
 	return true;
 }
 
@@ -337,7 +312,7 @@ void SCSIDaynaPort::Read6()
 {
 	// Get record number and block number
     const uint32_t record = GetInt24(ctrl->cmd, 1) & 0x1fffff;
-	ctrl->blocks=1;
+	controller->SetBlocks(1);
 
 	// If any commands have a bogus control value, they were probably not
 	// generated by the DaynaPort driver so ignore them
@@ -346,10 +321,10 @@ void SCSIDaynaPort::Read6()
 		throw scsi_exception(sense_key::ILLEGAL_REQUEST, asc::INVALID_FIELD_IN_CDB);
 	}
 
-	LOGTRACE("%s READ(6) command record=%d blocks=%d", __PRETTY_FUNCTION__, record, ctrl->blocks)
+	LOGTRACE("%s READ(6) command record=%d blocks=%d", __PRETTY_FUNCTION__, record, controller->GetBlocks())
 
-	ctrl->length = Read(ctrl->cmd, controller->GetBuffer(), record);
-	LOGTRACE("%s ctrl.length is %d", __PRETTY_FUNCTION__, ctrl->length)
+	controller->SetLength(Read(ctrl->cmd, controller->GetBuffer(), record));
+	LOGTRACE("%s ctrl.length is %d", __PRETTY_FUNCTION__, controller->GetLength())
 
 	// Set next block
 	ctrl->next = record + 1;
@@ -365,22 +340,23 @@ void SCSIDaynaPort::Write6()
 	const int data_format = ctrl->cmd[5];
 
 	if (data_format == 0x00) {
-		ctrl->length = GetInt16(ctrl->cmd, 3);
+		controller->SetLength(GetInt16(ctrl->cmd, 3));
 	}
 	else if (data_format == 0x80) {
-		ctrl->length = GetInt16(ctrl->cmd, 3) + 8;
+		controller->SetLength(GetInt16(ctrl->cmd, 3) + 8);
 	}
 	else {
 		LOGWARN("%s Unknown data format $%02X", __PRETTY_FUNCTION__, data_format)
 	}
-	LOGTRACE("%s length: $%04X (%d) format: $%02X", __PRETTY_FUNCTION__, ctrl->length, ctrl->length, data_format)
+	LOGTRACE("%s length: $%04X (%d) format: $%02X", __PRETTY_FUNCTION__, controller->GetLength(),
+			controller->GetLength(), data_format)
 
-	if (ctrl->length <= 0) {
+	if (controller->GetLength() <= 0) {
 		throw scsi_exception(sense_key::ILLEGAL_REQUEST, asc::INVALID_FIELD_IN_CDB);
 	}
 
 	// Set next block
-	ctrl->blocks = 1;
+	controller->SetBlocks(1);
 	ctrl->next = 1;
 
 	EnterDataOutPhase();
@@ -388,10 +364,10 @@ void SCSIDaynaPort::Write6()
 
 void SCSIDaynaPort::RetrieveStatistics()
 {
-	ctrl->length = RetrieveStats(ctrl->cmd, controller->GetBuffer());
+	controller->SetLength(RetrieveStats(ctrl->cmd, controller->GetBuffer()));
 
 	// Set next block
-	ctrl->blocks = 1;
+	controller->SetBlocks(1);
 	ctrl->next = 1;
 
 	EnterDataInPhase();
@@ -427,7 +403,7 @@ void SCSIDaynaPort::SetInterfaceMode()
 {
 	// Check whether this command is telling us to "Set Interface Mode" or "Set MAC Address"
 
-	ctrl->length = RetrieveStats(ctrl->cmd, controller->GetBuffer());
+	controller->SetLength(RetrieveStats(ctrl->cmd, controller->GetBuffer()));
 	switch(ctrl->cmd[5]){
 		case CMD_SCSILINK_SETMODE:
 			// TODO Not implemented, do nothing
@@ -435,7 +411,7 @@ void SCSIDaynaPort::SetInterfaceMode()
 			break;
 
 		case CMD_SCSILINK_SETMAC:
-			ctrl->length = 6;
+			controller->SetLength(6);
 			EnterDataOutPhase();
 			break;
 
@@ -455,8 +431,8 @@ void SCSIDaynaPort::SetInterfaceMode()
 
 void SCSIDaynaPort::SetMcastAddr()
 {
-	ctrl->length = ctrl->cmd[4];
-	if (ctrl->length == 0) {
+	controller->SetLength(ctrl->cmd[4]);
+	if (controller->GetLength() == 0) {
 		LOGWARN("%s Not supported SetMcastAddr Command %02X", __PRETTY_FUNCTION__, ctrl->cmd[2])
 
 		throw scsi_exception(sense_key::ILLEGAL_REQUEST, asc::INVALID_FIELD_IN_CDB);
@@ -502,3 +478,4 @@ void SCSIDaynaPort::EnableInterface()
 
 	EnterStatusPhase();
 }
+
diff --git a/cpp/devices/scsi_daynaport.h b/cpp/devices/scsi_daynaport.h
index 11157a42..b6a24f05 100644
--- a/cpp/devices/scsi_daynaport.h
+++ b/cpp/devices/scsi_daynaport.h
@@ -29,8 +29,8 @@
 
 #pragma once
 
-#include "os.h"
-#include "disk.h"
+#include "interfaces/byte_writer.h"
+#include "primary_device.h"
 #include "ctapdriver.h"
 #include <string>
 #include <unordered_map>
@@ -41,7 +41,7 @@
 //	DaynaPort SCSI Link
 //
 //===========================================================================
-class SCSIDaynaPort : public Disk
+class SCSIDaynaPort : public PrimaryDevice, public ByteWriter
 {
 public:
 
@@ -49,19 +49,17 @@ public:
 	~SCSIDaynaPort() override = default;
 
 	bool Init(const unordered_map<string, string>&) override;
-	void Open() override;
 
 	// Commands
 	vector<byte> InquiryInternal() const override;
-	int Read(const vector<int>&, vector<BYTE>&, uint64_t) override;
-	bool WriteBytes(const vector<int>&, const vector<BYTE>&, uint64_t);
-	int WriteCheck(uint64_t block) override;
+	int Read(const vector<int>&, vector<BYTE>&, uint64_t);
+	bool WriteBytes(const vector<int>&, vector<BYTE>&, uint32_t) override;
 
 	int RetrieveStats(const vector<int>&, vector<BYTE>&) const;
 
 	void TestUnitReady() override;
-	void Read6() override;
-	void Write6() override;
+	void Read6();
+	void Write6();
 	void RetrieveStatistics();
 	void SetInterfaceMode();
 	void SetMcastAddr();
@@ -90,7 +88,7 @@ public:
 
 private:
 
-	using super = Disk;
+	using super = PrimaryDevice;
 
 	Dispatcher<SCSIDaynaPort> dispatcher;
 
diff --git a/cpp/devices/scsi_host_bridge.cpp b/cpp/devices/scsi_host_bridge.cpp
index 3a1e7e88..cffced02 100644
--- a/cpp/devices/scsi_host_bridge.cpp
+++ b/cpp/devices/scsi_host_bridge.cpp
@@ -27,7 +27,7 @@ using namespace std;
 using namespace scsi_defs;
 using namespace scsi_command_util;
 
-SCSIBR::SCSIBR(int lun) : Disk(SCBR, lun)
+SCSIBR::SCSIBR(int lun) : PrimaryDevice(SCBR, lun)
 {
 	// Create host file system
 	fs.Reset();
@@ -37,10 +37,6 @@ SCSIBR::SCSIBR(int lun) : Disk(SCBR, lun)
 	dispatcher.Add(scsi_command::eCmdWrite6, "SendMessage10", &SCSIBR::SendMessage10);
 
 	SupportsParams(true);
-	// TODO Remove as soon as SCBR is not a subclass of Disk anymore
-	SetStoppable(false);
-	// TODO Remove as soon as SCBR is not a subclass of Disk anymore
-	SupportsFile(false);
 }
 
 bool SCSIBR::Init(const unordered_map<string, string>& params)
@@ -198,7 +194,7 @@ int SCSIBR::GetMessage10(const vector<int>& cdb, vector<BYTE>& buf)
 	return 0;
 }
 
-bool SCSIBR::WriteBytes(const vector<int>& cdb, vector<BYTE>& buf, uint64_t)
+bool SCSIBR::WriteBytes(const vector<int>& cdb, vector<BYTE>& buf, uint32_t)
 {
 	// Type
 	const int type = cdb[2];
@@ -261,13 +257,13 @@ void SCSIBR::GetMessage10()
 	// Ensure a sufficient buffer size (because it is not a transfer for each block)
 	controller->AllocateBuffer(0x1000000);
 
-	ctrl->length = GetMessage10(ctrl->cmd, controller->GetBuffer());
-	if (ctrl->length <= 0) {
+	controller->SetLength(GetMessage10(ctrl->cmd, controller->GetBuffer()));
+	if (controller->GetLength() <= 0) {
 		throw scsi_exception(sense_key::ILLEGAL_REQUEST, asc::INVALID_FIELD_IN_CDB);
 	}
 
 	// Set next block
-	ctrl->blocks = 1;
+	controller->SetBlocks(1);
 	ctrl->next = 1;
 
 	EnterDataInPhase();
@@ -282,8 +278,8 @@ void SCSIBR::GetMessage10()
 //---------------------------------------------------------------------------
 void SCSIBR::SendMessage10()
 {
-	ctrl->length = GetInt24(ctrl->cmd, 6);
-	if (ctrl->length <= 0) {
+	controller->SetLength(GetInt24(ctrl->cmd, 6));
+	if (controller->GetLength() <= 0) {
 		throw scsi_exception(sense_key::ILLEGAL_REQUEST, asc::INVALID_FIELD_IN_CDB);
 	}
 
@@ -291,7 +287,7 @@ void SCSIBR::SendMessage10()
 	controller->AllocateBuffer(0x1000000);
 
 	// Set next block
-	ctrl->blocks = 1;
+	controller->SetBlocks(1);
 	ctrl->next = 1;
 
 	EnterDataOutPhase();
diff --git a/cpp/devices/scsi_host_bridge.h b/cpp/devices/scsi_host_bridge.h
index 89d16396..08417ff8 100644
--- a/cpp/devices/scsi_host_bridge.h
+++ b/cpp/devices/scsi_host_bridge.h
@@ -17,8 +17,8 @@
 //---------------------------------------------------------------------------
 #pragma once
 
-#include "os.h"
-#include "disk.h"
+#include "interfaces/byte_writer.h"
+#include "primary_device.h"
 #include "ctapdriver.h"
 #include "cfilesystem.h"
 #include <string>
@@ -26,7 +26,7 @@
 
 using namespace std;
 
-class SCSIBR : public Disk
+class SCSIBR : public PrimaryDevice, public ByteWriter
 {
 	static constexpr const array<BYTE, 6> bcast_addr = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 
@@ -38,20 +38,17 @@ public:
 	bool Init(const unordered_map<string, string>&) override;
 	bool Dispatch(scsi_command) override;
 
-	// TODO Remove as soon as SCSIBR is not a subclass of Disk anymore
-	void Open() override { super::ValidateFile(); }
-
 	// Commands
 	vector<byte> InquiryInternal() const override;
 	int GetMessage10(const vector<int>&, vector<BYTE>&);
-	bool WriteBytes(const vector<int>&, vector<BYTE>&, uint64_t);
+	bool WriteBytes(const vector<int>&, vector<BYTE>&, uint32_t) override;
 	void TestUnitReady() override;
 	void GetMessage10();
 	void SendMessage10();
 
 private:
 
-	using super = Disk;
+	using super = PrimaryDevice;
 
 	Dispatcher<SCSIBR> dispatcher;
 
diff --git a/cpp/devices/scsi_printer.cpp b/cpp/devices/scsi_printer.cpp
index 921206bb..e3612beb 100644
--- a/cpp/devices/scsi_printer.cpp
+++ b/cpp/devices/scsi_printer.cpp
@@ -109,7 +109,7 @@ void SCSIPrinter::Print()
 		throw scsi_exception(sense_key::ILLEGAL_REQUEST, asc::INVALID_FIELD_IN_CDB);
 	}
 
-	ctrl->length = length;
+	controller->SetLength(length);
 	controller->SetByteTransfer(true);
 
 	EnterDataOutPhase();
diff --git a/cpp/devices/scsicd.cpp b/cpp/devices/scsicd.cpp
index 10188cc7..3e019044 100644
--- a/cpp/devices/scsicd.cpp
+++ b/cpp/devices/scsicd.cpp
@@ -162,7 +162,7 @@ void SCSICD::CreateDataTrack()
 
 void SCSICD::ReadToc()
 {
-	ctrl->length = ReadTocInternal(ctrl->cmd, controller->GetBuffer());
+	controller->SetLength(ReadTocInternal(ctrl->cmd, controller->GetBuffer()));
 
 	EnterDataInPhase();
 }
diff --git a/cpp/hal/gpiobus.cpp b/cpp/hal/gpiobus.cpp
index 9d02e36a..0f6868f3 100644
--- a/cpp/hal/gpiobus.cpp
+++ b/cpp/hal/gpiobus.cpp
@@ -981,7 +981,7 @@ int GPIOBUS::GetCommandByteCount(BYTE opcode)
         return 16;
     } else if (opcode == 0xA0) {
         return 12;
-    } else if (opcode == 0x05 || (opcode >= 0x20 && opcode <= 0x7D)) {
+    } else if (opcode >= 0x20 && opcode <= 0x7D) {
         return 10;
     } else {
         return 6;
diff --git a/cpp/hal/gpiobus.h b/cpp/hal/gpiobus.h
index 39afc819..e3e81bba 100644
--- a/cpp/hal/gpiobus.h
+++ b/cpp/hal/gpiobus.h
@@ -13,6 +13,7 @@
 
 #include "config.h"
 #include "scsi.h"
+#include "bus.h"
 #include <array>
 
 #ifdef __linux__
@@ -47,7 +48,7 @@
 #define GPIO_FUNCTION_TRACE
 #endif
 
-using namespace std; // NOSONAR Not relevant for rascsi
+using namespace std;
 
 //---------------------------------------------------------------------------
 //
diff --git a/cpp/rascsi/rascsi_executor.cpp b/cpp/rascsi/rascsi_executor.cpp
index b0da6570..1fb83ebb 100644
--- a/cpp/rascsi/rascsi_executor.cpp
+++ b/cpp/rascsi/rascsi_executor.cpp
@@ -319,12 +319,11 @@ bool RascsiExecutor::Attach(const CommandContext& context, const PbDeviceDefinit
 	}
 
 	if (device->SupportsParams() && !device->Init(params)) {
-		return context.ReturnLocalizedError(LocalizationKey::ERROR_INITIALIZATION, PbDeviceType_Name(type),
+		return context.ReturnLocalizedError(LocalizationKey::ERROR_INITIALIZATION, PbDeviceType_Name(device->GetType()),
 				to_string(id), to_string(lun));
 	}
 
-	// Remove SupportsFile as soon as Daynaport and bridge do not inherit from Disk anymore
-	if (storage_device != nullptr && storage_device->SupportsFile()) {
+	if (storage_device != nullptr) {
 		storage_device->ReserveFile(full_path, id, lun);
 	}
 
@@ -397,7 +396,6 @@ bool RascsiExecutor::Insert(const CommandContext& context, const PbDeviceDefinit
 
 bool RascsiExecutor::Detach(const CommandContext& context, shared_ptr<PrimaryDevice> device, bool dryRun) const
 {
-	cerr << "AAA  " << device->GetId() << endl;
 	auto controller = controller_manager.FindController(device->GetId());
 	if (controller == nullptr) {
 		return context.ReturnLocalizedError(LocalizationKey::ERROR_DETACH);
diff --git a/cpp/scsi.h b/cpp/scsi.h
index a6e18717..749b9956 100644
--- a/cpp/scsi.h
+++ b/cpp/scsi.h
@@ -9,9 +9,6 @@
 
 #pragma once
 
-// TODO Remove this include as soon as gpiobus.cpp/h is open for editing (adding the include there) again
-#include "bus.h"
-
 namespace scsi_defs {
 	enum class scsi_level : int {
 		SCSI_1_CCS = 1,
diff --git a/cpp/test/gpiobus_test.cpp b/cpp/test/gpiobus_test.cpp
index 7a48c9c0..faaf920e 100644
--- a/cpp/test/gpiobus_test.cpp
+++ b/cpp/test/gpiobus_test.cpp
@@ -31,10 +31,6 @@ TEST(GpioBusTest, GetCommandByteCount)
 	EXPECT_EQ(12, GPIOBUS::GetCommandByteCount(0xa0));
 	opcodes.insert(0xa0);
 
-	// TODO Opcode 0x05 must be removed from gpiobus.cpp
-	EXPECT_EQ(10, GPIOBUS::GetCommandByteCount(0x05));
-	opcodes.insert(0x05);
-
 	for (int i = 0x20; i <= 0x7d; i++) {
 		EXPECT_EQ(10, GPIOBUS::GetCommandByteCount(i));
 		opcodes.insert(i);
diff --git a/cpp/test/rascsi_executor_test.cpp b/cpp/test/rascsi_executor_test.cpp
index 18c55a71..7d2cd5fe 100644
--- a/cpp/test/rascsi_executor_test.cpp
+++ b/cpp/test/rascsi_executor_test.cpp
@@ -39,10 +39,10 @@ TEST_F(RascsiExecutorTest, ProcessDeviceCmd)
 	const int ID = 3;
 	const int LUN = 0;
 
-	shared_ptr<MockBus> bus_ptr = make_shared<MockBus>();
+	auto bus = make_shared<MockBus>();
 	DeviceFactory device_factory;
-	MockAbstractController controller(bus_ptr, ID);
-	ControllerManager controller_manager(bus_ptr);
+	MockAbstractController controller(bus, ID);
+	ControllerManager controller_manager(bus);
 	RascsiImage rascsi_image;
 	RascsiResponse rascsi_response(device_factory, controller_manager, 32);
 	auto executor = make_shared<MockRascsiExecutor>(rascsi_response, rascsi_image, device_factory, controller_manager);
diff --git a/cpp/test/scsi_daynaport_test.cpp b/cpp/test/scsi_daynaport_test.cpp
index c7d7c291..586691b6 100644
--- a/cpp/test/scsi_daynaport_test.cpp
+++ b/cpp/test/scsi_daynaport_test.cpp
@@ -57,15 +57,6 @@ TEST(ScsiDaynaportTest, Read)
 	EXPECT_EQ(0, daynaport->Read(cmd, buf, 0)) << "Trying to read the root sector must fail";
 }
 
-TEST(ScsiDaynaportTest, WriteCheck)
-{
-	vector<BYTE> buf(0);
-	NiceMock<MockAbstractController> controller(make_shared<MockBus>(), 0);
-	auto daynaport = dynamic_pointer_cast<SCSIDaynaPort>(CreateDevice(SCDP, controller));
-
-	EXPECT_THROW(daynaport->WriteCheck(0), scsi_exception);
-}
-
 TEST(ScsiDaynaportTest, WriteBytes)
 {
 	vector<BYTE> buf(0);