Microtape Manual

Summary This manual describes the Microtape system, an input/output storage device designed for use with PDP-1 and PDP-4 computers. The system consists of two main components: the Type 550 Microtape Control Unit and the Type 555 Dual Microtape Transport Unit.

Key Features and Capabilities:

• System Integration: Provides the flexibility, speed, and storage capacity of magnetic tape while maintaining the portability and convenience of paper tape.
• Program Control: The Type 550 Control Unit utilizes program break control, allowing word-by-word data transfer. It manages timing, logical functions, and status monitoring.
• Storage and Data Handling: Supports storage of programs and data, editing, and on-line system data handling. The system features bidirectional reading and writing with random access to data on the tape.
• Operating Modes: Includes Search, Read, Write, and Move modes.

• Technical Specifications:

  • Uses 3/4-inch Mylar tape on 3-1/2 inch reels.
  • Features a 10-track recording head (5 duplexed channels).
  • Word transfer rate is approximately one 18-bit word every 200 microseconds.
  • Includes built-in error checking through "prerecorded" timing and mark tracks.

• Maintenance: The manual provides detailed procedures for both preventive maintenance (cleaning and visual inspection) and corrective maintenance (troubleshooting using oscilloscopes and multimeters, and marginal checks for identifying failing components).

• Programming: The system is supported by various subroutines (Microtog and Microtrieve) and specific IOT instructions for control, data transfer, and status monitoring on both the PDP-1 and PDP-4 architectures.