TC59 Drive Function Timer

This document describes the TC59 Drive Function Timer (DFT) program, a diagnostic tool designed for debugging and maintaining the TC59 Magnetic Tape Control (MTC) and its associated magnetic tape drives. The program is compatible with PDP-9 or PDP-9L systems and can operate with 1 to 8, 45 or 75 inch per second, 7 or 9 track TU20 or similar magnetic tape transports.

The DFT program initiates and precisely times various tape drive operations, outputting the measured times in decimal microseconds. It's crucial to note that the program does not include internal error detection or validation of these times; the operator is responsible for assessing the validity of the results.

The document details the program's requirements, memory usage, and step-by-step loading and starting procedures. It then comprehensively describes numerous functions that the program times, including:

• Write Operations: Write Load Point Delay, Write Shut Down, Write Start, Write to Erase Head, Write Non-stop Gap, Write EOF Time, and Write with Extended Interrecord Gap.
• Read Operations: Read Shut Down, Read From BOT Delays, Last Character Input to MTF, One Inch Data Time, and EOR to EOF Space Time.
• Tape Motion & Consistency: Settle Down Delay, Backspace Shut Down, Gap Consistency (including various interrecord gap relationships), Forward Acceleration, Forward Deceleration, and Backward Deceleration.

For each timed function, the document outlines its purpose, the program's timing procedure, potential control and drive failures that could affect the accuracy of the measurements, and an assessment of the timing loop's accuracy, including any cycles lost during operation. It also provides typical function times for a 45 IPS TU20 drive as examples.