M-1068 Jan60

This document describes the "Complementing Checkerboard Program," a utility designed to thoroughly test the performance and reliability of magnetic core memory.

The program operates by loading memory with a user-defined "test word" (a configuration of 1s and 0s) and its complement in a fixed order. It then enters a continuous loop: checking the contents of each register, and if correct, complementing and storing the data back. This process is intended to test the memory "in the roughest way possible" and is self-checking to help locate faulty or weak cores.

Key features include:

• Continuous Operation: The program runs indefinitely, cycling through checking, complementing, and storing, until stopped manually or upon error detection.
• Error Detection: If an error is found during checking, the program halts at address 1745, and the Accumulator (AC) displays the address of the faulty memory register.
• Troubleshooting Guidance: Operating instructions are provided for users to set their own test word, initiate the program, and interpret error halts to pinpoint specific faulty cores within the memory.