TMA11 DECmagtape System

This document, "TMA11 DECmagtape system" (EK-TMA11-TM-002), is a technical manual from Digital Equipment Corporation, first published in December 1974.

It describes the TMA11 DECmagtape System, a magnetic tape handling system designed to interface with the PDP-11 family of processors and peripherals via the Unibus. Its primary purpose is to provide high-volume digital data storage and facilitate serial transfer of data and programs in industry-compatible formats.

The system is composed of three main components:

1. TU10 DECmagtape Transport(s): These devices read and write information on magnetic tape, supporting both 7-channel (200, 556, and 800 bpi) and 9-channel (800 bpi) industry-compatible formats. A single TMA11 Controller can manage up to eight TU10 transports.
2. TMA11 Controller: This acts as the interface between the tape units and the PDP-11 Unibus. It controls command and data transfers, performing direct memory access (DMA) transactions. It is programmable via six device registers.
3. Magnetic Tape: The 1/2-inch, reel-mounted recording medium, featuring end-of-tape (EOT) and beginning-of-tape (BOT) markers, record gaps, and various parity/check characters (lateral, longitudinal, and cyclic redundancy check for 9-channel).

Key system features include a maximum transfer rate of 36,000 characters per second and robust data integrity checks such as automatic read-after-write parity checking, longitudinal parity checks (LPC), and cyclic redundancy checks (CRC) for 9-channel units. It supports various programmable tape operations including read, write, rewind, and spacing.

The manual provides comprehensive information covering the system's introduction, installation procedures, detailed operating instructions (both on-line and off-line), programming information (including device registers, interrupts, and error handling), and a detailed theory of operation for the TMA11 Controller, supplemented by module descriptions and engineering drawings in a companion volume. It serves as an overall system operating guide, with a primary focus on the TMA11 Controller.