Master Tape Duplicator

This document describes a program for the PDP-7 computer, dated December 11, 1964, designed for handling master tapes. The program, titled "Master Tape Duplicator," serves three primary functions:

1. Making a Master Tape: It creates master tapes by reading an original tape, allowing the user to type in a title via teleprinter, and then punching a new master tape. A halt at address 231 indicates a checksum mismatch during this process.
2. Verifying a Duplicated Tape: It verifies a tape that has been duplicated from a master. The program reads the duplicated tape backward, comparing its character count and checksum against accumulated values. It types "OK" for a correct tape or "ERROR" and halts (with specific AC values) if there's an incorrect character count or checksum.
3. Duplicating a Master Tape or Any Tape: It can also directly duplicate any given tape, including master tapes, by simply placing the tape in the reader and pressing continue with a specific Accumulator (AC) switch set.

A master tape created by this program consists of a typed-in title (in readable ASCII format with the seventh hole punched), a duplicate of the original tape, and a check block containing the complement of the character count and the checksum of all characters. The program is I/O bound and can punch at a rate of 63.3 characters per second. The tape format is FIODEC, ASCII symbolic; FB, and the program's starting address is octal 200.