DX20-V100 Magnetic Tape Subsystem Micro-code

This document provides the assembly source code for the DX20-V100 Magnetic Tape Subsystem micro-code, version 4.7. It includes:

• Detailed definitions of Massbus and Channel Bus interface registers.
• Error code definitions and handlers.
• Startup and idle loop routines.
• Command execution routines for various functions, including Read, Write, and Sense operations.
• Diagnostic control routines and test tables used for system checkups.
• Detailed memory maps and data structures for the subsystem.