Programmed Data Processor-7 Users Handbook

This handbook serves as a comprehensive guide for programming and operating the Digital Equipment Corporation (DEC) Programmed Data Processor-7 (PDP-7), a high-speed, stored-program digital computer designed for scientific, computing, and real-time process control applications.

The document is organized into several sections: - System Introduction (Section 1): Provides a high-level overview of the PDP-7's standard configuration, its core components (processor, memory, interface, I/O), and performance specifications, including its 18-bit word length, 4096-word random-access magnetic-core memory with a 1.75 microsecond cycle time, and standard peripheral equipment (teleprinter, paper tape reader/punch). - Functional Description (Section 2): Details the internal organization of the computer, describing the processor's seven major registers (Accumulator, Link, Memory Address Register, Memory Buffer Register, Instruction Register, Program Counter, Major State Generator) and their roles in arithmetic, logic, data flow, and control. It also explains the core memory's operation and the interface for peripheral connections. - Instructions and Basic Programming (Sections 3 & 4): Covers memory reference instructions, augmented instructions (input/output transfer and operate instructions), and fundamental machine language programming concepts such as memory addressing (direct, indirect, auto-indexing), arithmetic operations (one's and two's complement), and input/output control mechanisms (program flags, skip facility, trap, program interrupt, real-time clock, and data break channel). - System Options (Sections 5-12): Describes various optional hardware components and their functions, including the Extended Arithmetic Element (EAE) for high-speed arithmetic, Automatic Priority Interrupt (Type 172) for efficient I/O handling, Data Interrupt Multiplexer (Type 173) for managing multiple high-speed I/O devices, memory increment options, boundary registers, and memory expansion modules. It also details a wide range of standard and optional peripheral equipment such as card readers/punches, line printers, magnetic tape and drum systems (DECtape, various magnetic tape transports, serial drum), plotters and display units (incremental plotters, CRT displays, symbol generators, light pens), analog/digital converters, and data communication equipment. - Programming System (Section 13): Outlines the software tools provided with the PDP-7, including the FORTRAN compiler, Symbolic Assembler, Digital Debugging Tape (DDT), Symbolic Tape Editor, and Bus-Pak II, alongside various maintenance routines and a program library. - Operating Procedures (Section 14): Guides users through the operational aspects of the PDP-7, detailing the operator console's controls and indicators, manual data storage and modification, loading procedures (e.g., RIM loader), and FORTRAN operating protocols, including diagnostic error messages. - Appendices: Provides supplementary reference material, such as program library listings, character codes (ASCII, Hollerith), scales of notation, and a comprehensive instruction summary.