F15B PDP1 Handbook

This document is a manual for the Programmed Data Processor-1 (PDP-1), a high-speed, solid-state digital computer developed by Digital Equipment Corporation (DEC) and copyrighted in 1961.

Key aspects covered include:

• Introduction: The PDP-1 is described as a versatile, single-address, single-instruction, stored-program computer with 18-bit word length and 5-megacycle circuits, capable of 100,000 additions per second. It features a 4096-word magnetic core memory (expandable) with a 5-microsecond cycle time and occupies only 17 square feet.
• Programming PDP-1: Details the computer's architecture (Central Processor, Memory Buffer, Arithmetic, Memory Addressing Elements), its fixed-point binary number system, and its 18-bit instruction format which supports multiple-step indirect addressing. It outlines operating speeds (multiples of 5 µsec memory cycles) and explains the manual controls (push buttons, toggle switches, indicator lights) available on the console for operation and debugging.
• Instruction Set: Categorizes and briefly describes various instruction groups, including Arithmetic, Logical, General, Augmented (Shift/Rotate, Skip), In-Out Transfer, and Operate instructions, with their mnemonic codes, operation codes, and execution times.

• Standard and Optional Equipment:

  • Standard: Includes a 400 lines/second punched tape reader, an alphanumeric typewriter for I/O, and a 63 lines/second punched tape punch, plus a one-channel Sequence Break System for interrupts.
  • Optional: Expands capabilities significantly with items like automatic multiply/divide hardware, additional memory modules (up to 32,768 words), high-speed I/O channels, a 16-channel Sequence Break System, Cathode Ray Tube (CRT) displays with light pen, punched card equipment, magnetic tape transports, line printers, and a real-time clock.

• Program Library: Highlights available software, including DECAL (Digital Equipment Compiler, Assembler, and Linking Loader)—an integrated, open-ended system supporting ALGOL, macros, and floating-point operations. Other programs include assemblers (FRAP), standard function generator subroutines, and utility routines.

• Appendix: Provides detailed lists of instructions (abbreviated and numerical) and alphanumeric character codes (FIO-DEC and Concise Codes).

In essence, the manual serves as a comprehensive guide to the PDP-1, detailing its hardware, architecture, programming model, operational procedures, available peripherals, and initial software offerings.