OpenVMS System Services Reference Manual

This document is the first part of the OpenVMS System Services Reference Manual (covering routines A through $GETMSG). It provides technical reference information for system services used by the OpenVMS operating system to control resources, manage process communication, handle I/O, and execute other OS-level functions. The manual includes comprehensive descriptions of each system service, detailing their purpose, format, input/output arguments, required privileges/quotas, related services, and the specific condition values they return. It also incorporates specific guidance for using these services in both VAX and Alpha environments, including support for 64-bit addressing on OpenVMS Alpha.