HP OpenVMS IO User's Reference Manual

This document is the "HP OpenVMS I/O User's Reference Manual" for OpenVMS I64 and Alpha Version 8.2, published in January 2005. It serves as a comprehensive reference guide for system programmers on how to utilize and program OpenVMS Input/Output (I/O) drivers.

The manual is structured into chapters covering specific I/O interfaces and device types:

• ACP-QIO Interface: Details the Queue I/O (QIO) interface to file system Ancillary Control Processes (ACPs), including file information blocks (FIBs), subfunctions (directory lookup, access, extend, truncate, attributes), and major file operations (create, access, modify, delete, mount).
• Device Drivers: Provides in-depth information on Disk Drivers (supported devices/controllers, features like dual-pathing, data checks, error recovery, SCSI disk class driver, function codes), Magnetic Tape Drivers (supported controllers/drives, streaming tape systems, data checks, error recovery, function codes), Mailbox Drivers (operations, message formats, function codes), Terminal Drivers (supported devices, features like input/output processing, dialup support, control characters, LAT port driver interface, function codes), and Pseudoterminal Drivers (operations, features, functions).
• Shadow-Set Virtual Unit Driver: Explains HP Volume Shadowing for OpenVMS, including configurations, read/write functions, and error processing for disk mirroring.
• OpenVMS Generic SCSI Class Driver: Describes the architecture, access methods, port features (data transfer mode, disconnection, command retry, timeouts), and device configuration for SCSI devices.
• Local Area Network (LAN) Device Drivers: Covers LAN terminology, supported VAX, Alpha, and I64 LAN devices, industry standards, I/O architecture (data structures, APIs), addressing, frame formats, and function codes.
• Optional Features for Improving I/O Performance: Introduces "Fast I/O" and "Fast Path" for OpenVMS Alpha and I64, detailing their benefits, use of buffer objects, and management to optimize I/O performance and reduce CPU overhead.

The appendices summarize I/O function codes, describe the IO$_DIAGNOSE function for SCSI, list the DEC Multinational Character Set and terminal escape sequences/modes, and outline pseudoterminal control connection routines. The manual targets system programmers who require detailed knowledge of I/O drivers for direct interaction with devices and advanced application development.