Read-In-Mode Loader

This document describes the RIM (Read-In-Mode) Loader, a compact routine designed for the PDP-7 computer. Its primary function is to read and store information from read-in mode tapes via the perforated tape reader. The loader requires 13 decimal (15 octal) memory locations.

The document details two methods for loading the RIM Loader itself into memory:

1. Manual Loading: This involves using the console switches (MEMORY ADDRESS and ACCUMULATOR) and control keys (DEPOSIT, DEPOSIT NEXT) to input specific octal contents into designated memory locations (starting at 07763 or 17763).
2. Photo Reader Loading: Alternatively, if a punched paper tape containing the program is available in a specific binary format (where channel 7 is only punched for the first character of the last three-character group), it can be loaded using the photo reader by setting the starting address (7762 or 17762) and pressing the READ IN key.

To use the RIM Loader to load other programs, a RIM format tape is placed in the reader, the ADDRESS switches are set to 17770 (or 7770 for a 4K machine), and the START button is pressed. The RIM Loader cannot be called as a subroutine. The document also provides a program listing and references other related loaders and the PDP-7 Users Handbook.