Float 1's & 0's Through Memory

This document serves as the technical documentation and diagnostic manual for the "Float 1's & 0's Through Memory" diagnostic program for Digital Equipment Corporation (DEC) computers, including the PDP-5, 8, 8/I, 8/L, 12, and Linc-8.

Summary:

• Purpose: The program is a memory exerciser designed to verify the integrity of computer core memory. It performs two main tests:

  1. Floating bit test: Shifts a single bit (1 or 0) through every memory location to ensure each bit can be stored and retrieved correctly without interference.
  2. Accumulator test: Sets the accumulator to a specific state (all ones or all zeros) and rotates it through memory locations to confirm data stability.

• Operations: The document provides detailed loading procedures, including the use of a RIM (Readin Mode) loader for the 33 ASR teletype.

• Configuration: Users can configure the diagnostic test using console switches to select memory banks, control error reporting (type-out or halt), and enable looping on errors.
• Technical Details: The document includes an appendix detailing the RIM loader instructions and provides the full assembly code for the diagnostic program.