50 51 52 MagtapeCtl 1963

This document is an instruction manual for personnel involved in the installation, operation, and maintenance of two magnetic tape systems (Types 50, 51, and 52) used with the DEC Programmed Data Processor-1 (PDP-1).

It describes two primary systems:

1. Type 52 Automatic Tape System: An automatic system designed for high-speed block transfers of characters between computer memory and tape. It uses high-speed channels, allowing simultaneous computation, and includes features like scatter/gather read/write, automatic bit-by-bit read-compare, parity error detection, and rapid record searching. A single Type 52 control unit can manage up to eight Type 50 Tape Transport Units.
2. Type 51 Programmed Tape System: A programmed system that transfers information character-by-character. Error checking and character assembly into computer words are handled by software subroutines. A Type 51 control unit can manage up to three Type 50 Tape Transport Units.

Both systems utilize Type 50 Tape Transport Units, which integrate DEC-designed local tape control (read-write electronics) and Potter Instrument Company transport components.

Key characteristics and covered topics include:

• Tape Format & Performance: Employs 7-bit characters (6 data, 1 parity), supporting standard IBM format with selectable odd or even parity. It operates at a transfer rate of 15,000 characters/second, a density of 200 characters/inch, and a tape speed of 75 inches/second using 7-channel read-write heads on 1/2" wide, 2400' long polyester tape.
• Hardware: Components are housed in standard DEC steel equipment frames, utilizing solid-state logic (transistors and crystal diodes) and running on 117-volt, 60-cycle single-phase current.
• Manual Contents: The document details general descriptions, installation procedures, system functions (including tape format, signal flow, and instruction sets for each type), operating procedures (controls, indicators, and checklists), a complete breakdown of tape system logic (with flow charts), circuit descriptions of specific DEC modules, and extensive maintenance information (adjustment, calibration, recommended spare parts, and diagnostic programming for troubleshooting).