VAXcluster Maintenance Student Workbook Volume 2

This document, "VAXcluster Maintenance Student Workbook Volume 2," provides a comprehensive overview of Digital Equipment Corporation's HSC50 and HSC70 intelligent mass storage controllers. It covers their hardware components, system software, initialization processes, diagnostic tools, operational procedures, and their role within the Digital Storage Architecture (DSA) as controllers.

Key areas covered include:

• HSC50/70 Overview: Describes the controllers' features, including host and storage unit connections, the CRONIC operating system, various diagnostic types (inline and offline), and error indicators. It also highlights differences between the HSC50 and HSC70 models and details the Operator Control Panel (OCP) functions and power distribution.
• HSC Module Description: Explains the specific hardware modules within the HSC, such as the I/O Control Processors (P.ioc for HSC50, P.ioj for HSC70), Memory Modules (M.std/M.std2), Data Channel Modules (K.sdi/K.sti), Port Processor Module (K.pli), Port Buffer Module (PILA), and Port Link Module (ILI). Each module's function, block diagrams, and LED indicators are detailed.
• HSC System Initialization: Outlines the boot sequence for both HSC50 and HSC70, covering ROM-based tests, offline media loading (tape/diskette), and system media loading. It provides flowcharts and descriptions for understanding the initialization phases and troubleshooting boot errors.
• HSC Offline Diagnostics: Discusses diagnostics run when the HSC is disconnected from the cluster. It introduces the Offline Diagnostic Loader (ODL), its commands (e.g., HELP, EXAMINE, DEPOSIT, SIZE), and various test commands (e.g., TEST CACHE, TEST MEM, TEST K) used to evaluate internal HSC components.
• HSC System Operation: Details the HSC's operating system, CRONIC, and how to interact with it via the console (KMON prompt, ODT, uODT). It lists console commands for running diagnostics, setting parameters, managing programs, and describes the System Configuration Table (SCT) and various HSC processes like DISK, TAPE, DUP, and HOST.
• HSC Inline Diagnostics: Explains diagnostics that can run while the HSC remains online and operational within the cluster. These can be initiated on demand, periodically, or automatically, and include tests for memory, disk/tape channels, and compatibility.
• HSC as a DSA Controller: Introduces the Digital Storage Architecture (DSA), defining key protocols like MSCP (Mass Storage Control Protocol), SDI (Standard Disk Interconnect), and STI (Standard Tape Interconnect). It contrasts DSA and Non-DSA devices, describes the DSA perspective from the host, controller, and unit views, and provides an overview of the Digital Standard Disk Format (DSDF), including bad block replacement.
• HSC Utilities: Categorizes and describes various maintenance and operational utilities available under the CRONIC operating system, such as VERIFY, FORMAT, BACKUP, RESTORE, DKCOPY, PATCH, RXFMT, DKUTIL, and VTDPY. These utilities are used for hardware verification and data integrity.

Overall, the document serves as a guide for understanding, troubleshooting, and maintaining Digital's VAXcluster mass storage controllers.