Mark 12 A Formatting And Verification Program For Uncertified Tapes (Version 0)

This document describes MARK12, a program designed to format and verify uncertified LINC tapes for use with the PDP-12 computer. It offers two formatting options: "STANDARD" LINCtape format (256 words per block) or a special 129-word format.

The program performs several verification steps, including formatting the tape, writing a data pattern to each block, checking checksums, verifying backward block numbers, and finally checking all data from the last block. It requires a PDP-12B or PDP-12A with at least one TL35 tape transport and occupies memory between 06000₈ and 07000₈, using 00000₈ and 02000₈ for data.

Users load the program via a Dial system tape and interact through the console teletype to select the desired tape format. The process involves three complete passes: formatting, writing, and checking. Upon completion, the program displays either "GOOD TAPE" or "TAPE CHECK FAILED." The document also provides mechanical considerations for reliable tape operation, such as cleaning heads and guides, proper reel mounting, and pre-running tapes. Detailed specifications for both LINC formats, including block and word counts and zone structures, are provided.