RIM Puncher

This document describes the "RIM Puncher," a program from the PDF-4 Program Library, authored by J. M. Graetz of DEC and dated September 28, 1962. Its purpose is to create a "readin-mode" tape by punching data from any specified area of core memory.

The output tape has a specific format: it begins with approximately 30 inches (or 3 1/2 fanfold units) of leader, followed by data blocks in readin-mode format, then a start block (comprising a jump instruction and a blank dummy word to stop the tape reader), and finally a few inches of trailer.

The program's usage involves the following steps:

1. Loading the desired version of the RIM Puncher (high or low).
2. Setting AC Switch 0 (ACS0) to the down position, entering the first memory address to be punched into the AC Switches, and pressing "continue."
3. When the program halts, the final memory address of the block is entered into the AC Switches, and "continue" is pressed (the program will not proceed if ACS0 is up at this point).
4. If ACS0 is down when the program stops punching, pressing "continue" again will punch a new block of data starting from the address currently in the AC Switches.
5. If ACS0 is up, the address in the AC Switches will be used as a starting location to punch the start block and trailer, completing the tape.
6. To create a new tape after a start block has been punched, ACS0 must be put down, and the punching process repeated from step 2.

The program does not have specific error stops; all halts are part of its controlled operation.