PDP-12 Checkerboard

This document describes the PDP-12 Checkerboard diagnostic program, created on October 20, 1969. The program is designed to test the operation of PDP-12 memory (ranging from 4K to 32K) by verifying data integrity using specific L-mode instructions (LAM, ADM, SAE). The test iterates through available memory, setting memory cells to 5252, performing calculations in the accumulator (AC), and verifying the results. If a comparison fails, the diagnostic logs an error report containing the field, memory location, expected contents, and actual contents. The manual covers loading procedures using a binary loader, starting instructions, and detailed error handling and analysis configurations.