DEC-00-TU10M-D TU10 Master

This "TU10 DECmagtape MASTER SYSTEM MANUAL," published in November 1971 by Digital Equipment Corporation, provides comprehensive information on the operation, interface, and internal workings of the TU10 Master DECmagtape unit.

The document details:

1. Introduction and Description:

   • The TU10 Master DECmagtape consists of a TU10 Tape Transport with a master electronics package. It acts as a controller for its host transport and up to seven additional slave transports (including TU10, TU20, TU30, TU40 drives).
   • It supports NRZI recording for both 9-track (800 bpi) and 7-track (200, 556, or 800 bpi) tape formats.
   • Tape Formats for 9-track and 7-track systems are described, including data character counts, interrecord gaps (IRGs), and error checking mechanisms like Cyclic Redundancy Check (CRC) and Longitudinal Redundancy Check (LRC) characters.
   • The concept of Files (groups of records terminated by a file mark) and the "Write with Extended Interrecord Gap" feature for managing bad tape areas are explained.

2. Interface and Control:

   • The master electronics communicates with the host tape control (TM11 or TM8/E) via a Master Interface Bus (48 TTL lines) and with slave transports via a Transport Bus.
   • It covers initialization procedures, unit selection logic for connecting to one of the eight transports, and the various transport status signals (e.g., Beginning/End of Tape, Write Lock, Tape Unit Ready, Rewinding).
   • Detailed descriptions of master command signals from the tape control (e.g., Read, Write, Rewind, Write File Mark, Space Forward/Reverse, parity and density selection) and their functions.
   • Explanation of write data and timing signals (including parity and CRC generation) and read data, format, and timing signals (with comprehensive error detection for vertical parity, CRC, and LRC).

3. Theory of Operation:

   • This section delves into the internal logic and sequencing of operations, including how transports are selected and how commands are initiated.
   • It describes the process of operation sequencing through Acceleration IRG Delay, Reading, and Deceleration IRG Delay phases, controlled by specialized gap timing logic and an IRG Delay Counter. These delays ensure the tape accelerates and decelerates correctly and maintains proper spacing between records. The master can adjust these delays based on the operation and tape position (e.g., Write/Read from BOT, Extended IRG).

In essence, the manual serves as a technical guide for understanding, operating, and maintaining the TU10 Master DECmagtape system, covering everything from fundamental recording principles to complex interface protocols and internal timing logic.