M-1112 BinPunLd Jun61

This document describes the "Binary Punch and Load Package," a utility for PDP computers to save and load memory content to/from binary tapes.

Key Functions:

1. Punching Memory to Tape:

   • Allows users to specify any memory area (start, end, or length) and an optional jump location.
   • The generated tape can include a self-loading "Read-In-Mode" (RIM) binary loader at the beginning, allowing the tape to load itself.
   • Commands:
     • Type 0000b (beginning), 0000f (final), 0000l (length), 0000j (jump location) to define a block (numbers are octal, leading zeros optional).
     • P punches the defined block without a leader or RIM loader.
     • R punches a leader, the RIM loader, then the block, and a trailer if a jump was specified.
     • Multiple blocks can be punched consecutively; the jump location is typically for the last block.
   • Includes a checksum at the end of each punched block for error detection.

2. Loading Tape to Memory:

   • The s command initiates reading a binary tape.
   • After loading, the system jumps to the specified location on the tape, unless Sense Switch #1 (SS#1) is up, in which case it halts.
   • The loader halts if a checksum error is detected during loading.

Modifications and Advanced Features:

• Sense Switch #2 (SS#2): A new feature allows the loader to compare data from the tape with existing memory content during loading. If SS#2 is up, it halts on differences.

• Command Enhancements:

  • The > symbol clears the register used for assembling octal numbers.
  • The b command can now also delete a previously designated jump order.

• Program Control Rider: A subprogram allows the package to be controlled from within a core program using specific jda and jsp instructions, enabling automated punching with or without RIM loaders and jump block designation.

Operational Details:

• The package is available in "High," "Medium," and "Low" memory configurations (e.g., 7520-7777, 4000-4256, 0001-0257).
• It operates using typewriter commands once loaded.
• The binary tape format includes "Initial Location," "Length," "Check Sum" for each block, and an optional "JMP Location."