diff --git a/Components/DiskII/MacintoshDoubleDensityDrive.cpp b/Components/DiskII/MacintoshDoubleDensityDrive.cpp
index 5301bd9e2..54444b0c6 100644
--- a/Components/DiskII/MacintoshDoubleDensityDrive.cpp
+++ b/Components/DiskII/MacintoshDoubleDensityDrive.cpp
@@ -25,10 +25,109 @@ void DoubleDensityDrive::set_enabled(bool) {
 }
 
 void DoubleDensityDrive::set_control_lines(int lines) {
+	const auto old_state = control_state_;
+	control_state_ = lines;
+
+	// Catch low-to-high LSTRB transitions.
+	if((old_state ^ control_state_) & control_state_ & Line::LSTRB) {
+		switch(control_state_ & (Line::CA1 | Line::CA0 | Line::SEL)) {
+			default:
+//				LOG("Unhandled LSTRB");
+			break;
+
+			case 0:
+//				LOG("LSTRB Set stepping direction: " << int(state_ & CA2));
+				step_direction_ = (control_state_ & Line::CA2) ? -1 : 1;
+			break;
+
+			case Line::CA1:
+//				LOG("LSTRB Motor");
+				set_motor_on(!(control_state_ & Line::CA2));
+			break;
+
+			case Line::CA0:
+//				LOG("LSTRB Step");
+				step(Storage::Disk::HeadPosition(step_direction_));
+			break;
+
+			case Line::CA1 | Line::CA0:
+//				LOG("LSTRB Eject disk");
+				set_disk(nullptr);
+			break;
+		}
+	}
 }
 
 bool DoubleDensityDrive::read() {
-	return false;
+	switch(control_state_ & (CA2 | CA1 | CA0 | SEL)) {
+		default:
+//			LOG("unknown)");
+		return false;
+
+		// Possible other meanings:
+		// B = ready			(0 = ready)
+		//
+		// {CA1,CA0,SEL,CA2}
+
+		case 0:					// Head step direction.
+								// (0 = inward)
+//			LOG("head step direction)");
+		return step_direction_ <= 0;
+
+		case SEL:				// Disk in place.
+								// (0 = disk present)
+//			LOG("disk in place)");
+		return !has_disk();
+
+		case CA0:				// Disk head step completed.
+								// (0 = still stepping)
+//			LOG("head stepping)");
+		return true;
+
+		case CA0|SEL:			// Disk locked.
+								// (0 = write protected)
+//			LOG("disk locked)");
+		return !get_is_read_only();
+
+		case CA1:				// Disk motor running.
+								// (0 = motor on)
+//			LOG("disk motor running)");
+		return !get_motor_on();
+
+		case CA1|SEL:			// Head at track 0.
+								// (0 = at track 0)
+//			LOG("head at track 0)");
+		return !get_is_track_zero();
+
+		case CA1|CA0|SEL:		// Tachometer.
+								// (arbitrary)
+		return get_tachometer();
+
+		case CA2:				// Read data, lower head.
+//			LOG("data, lower head)\n");
+			set_head(0);
+		return false;;
+
+		case CA2|SEL:			// Read data, upper head.
+//			LOG("data, upper head)\n");
+			set_head(1);
+		return false;
+
+		case CA2|CA1:			// Single- or double-sided drive.
+								// (0 = single sided)
+//			LOG("single- or double-sided drive)");
+		return get_head_count() != 1;
+
+		case CA2|CA1|CA0:		// "Present/HD" (per the Mac Plus ROM)
+								// (0 = ??HD??)
+//			LOG("present/HD)");
+		return false;
+
+		case CA2|CA1|CA0|SEL:	// Drive installed.
+								// (0 = present, 1 = missing)
+//			LOG("drive installed)");
+		return false;
+	}
 }
 
 void DoubleDensityDrive::write(bool value) {
diff --git a/Components/DiskII/MacintoshDoubleDensityDrive.hpp b/Components/DiskII/MacintoshDoubleDensityDrive.hpp
index cc4f7f1cb..7e070b7db 100644
--- a/Components/DiskII/MacintoshDoubleDensityDrive.hpp
+++ b/Components/DiskII/MacintoshDoubleDensityDrive.hpp
@@ -28,6 +28,8 @@ class DoubleDensityDrive: public IWMDrive {
 		void did_step(Storage::Disk::HeadPosition to_position) override;
 
 		bool is_800k_;
+		int control_state_;
+		int step_direction_;
 };
 
 }