Pdp-8, 8/I Extended Memory Checkerboard

Summary

The PDP-8, 8/I Extended Memory Checkerboard is a diagnostic program designed to test the integrity of core memory on PDP-8 or 8/I computer systems equipped with 8K to 32K words of memory.

Key functions include:

• Stress Testing: The program performs four distinct "checkerboard" data patterns and their complements to simulate worst-case half-select noise conditions, which helps identify potential memory failures.
• Automated Relocation: The program can automatically relocate itself across different 4K memory stacks, ensuring that all available memory can be tested without manually moving the diagnostic software.
• Error Reporting: If a memory error is detected, the program provides a detailed Teletype print-out indicating the memory field, the specific address, the expected data, and the test pattern that failed.
• Operator Control: Using the Switch Register (SR) and Teletype keyboard, operators can specify the memory limits to be tested, select specific test patterns, inhibit error print-outs, or loop on a specific address range for troubleshooting.

The diagnostic requires a system with at least 8K of core memory and must be run after all basic 4K PDP-8 diagnostics have been successfully completed.