Df32 Discless Logic Test, Minidisc

Summary

This document is a technical manual for the "DF32 Discless" diagnostic program, created on April 4, 1968, for the PDP-8/I computer. The program is designed to test the DF32 disc logic and its computer interface. It explicitly does not test the physical disc drive or its analog interface circuits; if a disc is connected, the motor should be turned off during testing.

Key operational details include:

• Requirements: Requires a standard PDP-8/I computer, the DF32 disc logic, and an optional light card for testing the track selector.
• Loading & Starting: The program is loaded using standard binary tape procedures. The primary starting address is 100, with various other addresses available for specific tests (such as register tests, shift/interrupt tests, and scope loops).
• Operation: Operators must turn off the disc motor, set the operation mode to "Maintain," and use the Switch Register (SR) to manage the program flow. Operational switches (SW0–SW4) allow the user to delete printouts, halt after errors, or perform sub-tests.
• Diagnostics: The program includes a comprehensive table of "Error Halts and Descriptions" (pages 4 and 5). This table maps specific memory address tags to the functions being tested and provides the expected "Good" vs. "Bad" Accumulator (AC) results, along with the specific hardware components (Corrective Action) to inspect if a test fails.