Microtape

This manual provides comprehensive technical information for the Digital Equipment Corporation Microtape system, which includes the Type 550 Microtape Control Unit and the Type 555 Dual Microtape Transport Unit. The document covers system architecture, operating modes (search, read, write, move), and the recording technique (Manchester/polarity sensing) used for tape storage. It also details programming instructions for PDP-1 and PDP-4 computers, including specific subroutines, IOT (Input-Output Transfer) instructions, and error handling. Furthermore, the manual provides maintenance procedures, including preventive maintenance, marginal checks, and corrective troubleshooting for components.