F-13(57A) TapeCtl Sep63

This document describes the Digital Equipment Corporation (DEC) Automatic Magnetic Tape Control Type 57A, designed for use with the Programmed Data Processor-4 (PDP-4) and other PDP series computers.

The Type 57A control enables the PDP-4 to manage up to eight standard IBM-compatible magnetic tape transports. It supports various data densities (200, 556, and 800 bits per inch) and operates in both BCD and binary parity modes.

Key features and functions include:

• Comprehensive Tape Operations: It provides a wide range of commands for writing (normal, end of file, blank tape, continuous, gather) and reading (normal, compare, continuous, scatter) data, along with tape movement commands such as rewind, unload, and spacing.
• Operational Modes: Tape motion can be controlled in "Record" mode, which stops at the end of each record, or "Continuous" mode, for uninterrupted operations.
• Programming and Control: Commands are transmitted via the PDP-4's accumulator, allowing for programmed control and monitoring of tape functions and error conditions.
• Automatic Safeguards: The system incorporates features like end-point and load-point detection, format control, and write-lock protection to ensure reliable operation.
• Hardware and Interface: The control unit consists of 75 System Modules housed in a standard DEC cabinet and is designed for easy interface with PDP series computers.

The document includes detailed programming instructions, sample program sequences, flowcharts for various operations (like write, read, and continuous modes), and descriptions of internal registers and control logic, concluding with a block diagram of the Type 57A control system.