DECsystem 5500 Technical Manual

This "DECsystem 5500 Technical Manual," published by Digital Equipment Corporation in January 1991, provides a comprehensive overview of the DECsystem 5500. It details the functional, physical, and environmental characteristics of the KN220-AA CPU module set and MS220-Ax memory expansion modules. The manual is intended for customers, design engineers, and application programmers familiar with Digital's extended LSI-II bus (Q22-bus) and the VAX instruction set.

The document is organized into five chapters and nine appendices:

1. KN220-AA Subsystem Overview: Introduces the core components: the KN220-AA CPU module (featuring the R3000 RISC processor, a floating-point accelerator, and a two-level cache for high-speed, multiuser, and multitasking functions) and the KN220-AA I/O module (with built-in DSSI, SCSI, and Ethernet controllers). It also covers the MS220-Ax memory modules and outlines the system's firmware capabilities for initialization, self-testing, console emulation, and booting.

2. Installation and Configuration: Provides step-by-step procedures for installing the KN220-AA CPU, I/O, and MS220-Ax memory modules in Q22-bus backplanes and system enclosures. It explains how to configure modules, including changing node names and DSSI unit numbers.

3. KN220-AA Architecture: Delves into the detailed architecture of the KN220-AA. This includes an in-depth description of the R3000 RISC processor (its instruction set, coprocessors, and memory management via Translation Lookaside Buffer - TLB), cache memory organization and operation, and the main memory system with error detection and correction. It also covers the console serial line, boot and diagnostic facilities (ROM, battery-backed RAM), I/O module specifications (including DSSI, SCSI, and Ethernet interfaces), various system registers (e.g., SSC, ADMTR, SSCCR, SPR, BDR), programmable timers, and the complex Q22-bus interface with its address translation, interprocessor communication, and error handling mechanisms.

4. Firmware Specification: Outlines the environment and capabilities of the KN220-AA firmware. It describes initial power-up tests (for both CVAX and R3000 processors), the role of operation and function switches, interprocessor interaction, and the detailed power-up sequences. The chapter also covers operating system bootstrapping procedures, supported boot devices (disk, tape, Ethernet), and console features including command language, security mechanisms (passwords, privileged/unprivileged modes), and error reporting via LEDs and the console.

5. System Specification: Provides comprehensive functional, electrical, physical, environmental, and performance characteristics for the entire DECsystem 5500 line. This includes detailed specifications for system building blocks, various enclosures (BA430, BA213), power supplies, memory modules, disk drives (RF71-A, RZ56-FA), tape drives (TK70-A), mass storage controllers (TQK70-SA), asynchronous communication devices (CXA16-AA, CXB16-AA, CXY08-AA), and line printer interfaces (LPV11-SA).

Appendices offer supplementary detailed information, including Q22-bus signal assignments and protocols, physical and reliability specifications, system block diagrams, PROM entry points, supported boot devices, exit and maintenance guidelines, CVAX diagnostic processor instruction sets, address assignments, and an overview of Prestoserve (a disk cache technology).