TU58 DECtape II User's Guide

This document is the "TU58 DECtape II User's Guide," a manual published in October 1978 by Digital Equipment Corporation. It provides comprehensive information for users to install, interface, and command the operation of the TU58 DECtape II tape system.

Key aspects covered include:

• General Description: The TU58 is a low-cost, random-access, fixed-length-block mass-storage device. It uses preformatted DECtape II cartridges (modified 3M DC100A) containing 262 kilobytes of data in 512-byte blocks, distributed across two tracks. The unit is compact and mechanically simple, featuring a single-puck drive and an elastomer belt system. It incorporates a microprocessor (µP) on a single circuit board to manage tape handling and communications, reducing the load on the host system.
• Specifications: Detailed performance metrics are provided, including a data transfer rate of 24 kbytes/s on tape, an average access time of 9.3 seconds, and a cartridge life of 5000 end-to-end passes. It operates via a serial host interface at rates from 150 to 38.4 kilobaud, supporting RS-422 and RS-423 standards (compatible with RS-232-C when set to RS-423).
• Operation: Instructions for loading and unloading cartridges, using the write protect tab, and proper storage and care. The only regular maintenance required is cleaning the head and motor puck. It also includes an operator trouble isolation guide. A critical note is provided for cartridge repair (rethreading procedures), emphasizing that this should only be done to copy data from an injured tape, which should then be discarded.
• Programming: A programmer's guide details the high-level command set and the Radial Serial Protocol (RSP) used for communication between the host and the TU58. This includes definitions of message packets (command, data, end) and single-byte protocol management messages (INIT, Continue, XOFF), along with an instruction set for operations like Read, Write, Position, and Diagnose.
• Installation: Detailed instructions for mounting the TU58-CA rackmount version, configuring power (110V/220V selection and fuse installation), and setting up interface standards (baud rates and RS-422/RS-423 jumpers). An operational checkout procedure is also provided to verify interface and command functionality.
• Options: Describes additional features such as a Run Indicator (LED for tape motion) and a Boot Switch (for automatic program loading, noting it's not supported by DEC operating systems).

In essence, the manual serves as a comprehensive technical guide for the hardware aspects of the TU58 DECtape II, covering everything from physical installation and daily operation to low-level programming interface details and basic troubleshooting.