XVM System Reference Manual

This document is the "XVM system reference manual" (EK-15XVM-OP-001) from Digital Equipment Corporation, published in June 1976.

It provides a comprehensive technical reference and operational guide for the XVM 18-bit computer system, covering its architecture, peripheral devices, system operation, and installation/maintenance.

The manual details:

1. XVM Processor: Describes the Central Processing Unit (CPU) including its arithmetic unit, registers (Accumulator, Program Counter, Index Register), and the XVM Control Console features. It thoroughly explains the various addressing modes (Direct, Indirect, Auto-Increment, Indexed) and how the Memory Processor Unit (MPU) handles virtual to real address mapping (Direct, Relocated, Shared, Boundary mapping).
2. System Processors: Introduces the XM15 Memory Processor, which arbitrates memory access, features an Instruction Pre-fetch unit, Automatic Priority Interrupt (API) logic, and Memory Management (MMGR) logic. It also covers the integration of a PDP-11-based Peripheral Processor (Unichannel Link) for I/O and a Floating Point Processor (FP15) for high-speed arithmetic operations.
3. Peripherals: Lists and provides detailed specifications and IOT (Input/Output Transfer) instructions for a wide range of I/O devices compatible with both the XVM's I/O bus and the Unibus, including analog-to-digital converters, card readers, line scanners, graphics processors, printers, disk and tape storage systems, and plotters.
4. System Operation: Guides users through the operation of the XVM system from the console, including power-on procedures, program loading, memory examination and data storage, manual instruction execution, and specific steps for using the PC15 high-speed paper-tape reader and punch.
5. System Installation: Offers extensive planning information for setting up the XVM system, covering pre-delivery considerations, site preparation (space, environmental conditions like temperature, humidity, and static electricity), electrical planning (power supply, wiring, and grounding), unpacking and inspection procedures, cabinet installation, and an overview of Digital Equipment Corporation's maintenance and service options.
6. Instruction Formats: Provides a detailed reference to the XVM's instruction set, categorizing them into memory reference instructions and augmented instructions (Operate, IOT, Extended Arithmetic Element, and Index instructions), with in-depth explanations of their functions and timing.

In essence, this document is an exhaustive guide for technical professionals involved in the deployment, programming, and upkeep of the XVM computer system.