TC59 (7 Track) Data Reliability Test

This document outlines the TC59 (7 Track) Data Reliability Test, a program developed for the PDP-9 computer system to evaluate the data reliability of magnetic tape drives used with the TC59 Magnetic Tape Control. Its primary purposes are to collect statistical information on tape drive performance, aid in hardware debugging and maintenance, and function as an acceptance test for tape drives.

The program requires a PDP-9 with a TC59 Magnetic Tape Control and 1 to 8 TU20 or similar 7-track magnetic tape transports. It occupies a specific memory allocation within the lower 4K. Loading involves placing an ABS binary tape in the reader and initiating it via a specific address (17720).

Operation of the test is flexible, allowing operators to input parameters through a teletype or AC switches. It offers extensive control over test execution, including selection of specific drives, write routine exit modes, read stop modes, record length sequences, data densities, parity types (even and odd with multiple patterns), and data patterns. The program features nine distinct test sequences, ranging from basic write-only operations to complex write-read-backspace sequences and read-only compatibility tests. These tests can incorporate varying parameters per record or drive to thoroughly assess reliability.

Error handling is a critical component, with provisions for altering error recovery procedures, displaying error information, and re-running tests with adjusted parameters. The program accumulates write and read errors, which can be output to a teletype. Error recovery mechanisms include automatic backspacing and rewriting for write errors, and backspacing and rereading for read errors. The document also details the program's internal structure, utilizing main write and read subroutines, alongside smaller routines for managing drive selection, error handling, and data logging.