PDP-9 Punch Test

This document describes the PDP-9 Punch Test, a diagnostic program designed to verify the operational status of the PDP-9 computer's punch control logic and its mechanical functions. The program requires a standard PDP-9 computer with 3403 (octal) words of core memory and no preliminary programs.

The test suite consists of two main parts:

1. Control Logic Tests (6 tests): These tests check the punch's internal logic, including handling illegal instructions, setting and clearing the punch flag (using PSA, PSB, and PCF IOTs), punch interrupt behavior, "no tape" indicator functionality, and a 1-second timing check. Specific starting addresses are provided for individual tests, enabling focused troubleshooting.
2. Data Check Tests (9 tests): These tests involve punching various data patterns and then reading them back, checking for mechanical failures such as tape skew, feed-hole registration problems, and the ability to punch all channel combinations. The program monitors both the punch and reader "no tape" indicators during these operations. Punching speed can be controlled via console switches for most data tests.

The program includes provisions for continuous looping on specific tests ('scope mode) to aid in power supply margin testing or mechanical adjustments. Errors encountered trigger halts with specific program counter values and descriptive tags, along with error printouts. Recovery from an error typically involves pressing CONTINUE to re-execute the current control logic test or proceed to the next data check test in sequence. Before running the data check portion, the high-speed reader must be confirmed as error-free using a separate diagnostic. The document also details procedures for loading, starting, and operating the program, including console switch settings and restarting addresses.