Focal Readable Punch

This document serves as the library write-up for "Focal Readable Punch," a program developed by Thomas J. Ford in 1970 for the FOCAL 5/69 operating system.

Key features and instructions:

• Purpose: The program utilizes groups 1 and 2 to punch "tape-high" readable characters using a low-speed punch. Groups 3, 4, and 5 are utility tools for building or modifying the character definitions in group 2.
• Requirements: The program requires FOCAL 5/69 and operates on a 4K system (provided extended functions are deleted).
• Operation: Users can run the existing group 2 by typing "GO." To build a new set of characters, users must load groups 3, 4, and 5, and input the octal values corresponding to the desired hole patterns. The program converts these octal inputs to decimal.

• Limitations & Warnings:

  • Entering undefined key combinations will result in an error and program halt.
  • Because keyboard echo is suppressed during setup, users must be cautious to ensure the program has finished processing before entering subsequent codes to prevent buffer overflow.

• Addendum: The document includes a letter from Edward A. Taft III, who identifies a bug in FOCAL 5/69 regarding carriage returns in character mode. He suggests two workarounds: choosing specific octal codes that circumvent the carriage return trigger, or modifying the FOCAL system's memory at a specific location to disable the automatic insertion of line feeds.