Pdp-8e Extended Memory Data & Checkerboard Test

Summary

This document is a technical manual for the "PDP-8E Extended Memory Data & Checkerboard Test" (MAINDEC-08-DHKMA-C-0), a diagnostic program released in February 1976 by Digital Equipment Corporation.

Purpose: The primary function of this diagnostic program is to detect memory failures in PDP-8E computer systems equipped with at least 8K of core memory. It exercises memory using various worst-case data and noise patterns to identify hardware faults, including memory relocation errors.

Key Features:

• Testing Capability: Tests memory from 8K up to 32K by employing alternating worst-case checkerboard patterns and noise-inducing bit sequences.
• Switch Register Control: Operators can control the testing process (e.g., setting field limits, halting on errors, or enabling/disabling relocation) via the computer's Switch Register (SR).
• Console Package: Includes an addendum for systems without a hardware console, allowing the test to be run and controlled via a terminal using specific control characters (e.g., Control-C to restart, Control-S to stop).
• Error Reporting: Provides detailed printouts upon detecting errors, identifying the failing location, the data written, the data read, and the test pattern being executed at the time of failure.
• Program Relocation: Features an automatic program relocation capability to ensure all memory fields are thoroughly tested even if specific fields contain errors.

The document concludes with the complete source code listing of the diagnostic program.