TOPS-10/TOPS-20 USAGE File Specification

This document specifies the format and use of USAGE files for TOPS-10 and TOPS-20 operating systems, detailing how computer resource utilization data is recorded for accounting and billing purposes. It is aimed at application programmers who develop or modify billing/accounting programs. The document describes the various entry types within USAGE files, such as System Restart, Session, Incomplete Session, Disk Usage, and Device Mount entries, outlining the data they contain and noting differences in implementation between TOPS-10 and TOPS-20.

Data collection mechanisms are explained, including periodic "checkpointing" and "event-driven" processes. TOPS-10 uses the ACTDAE program, while TOPS-20 employs its monitor and the CHKPNT program to gather and write data into USAGE files. Common data fields, such as dates, times, and program versions, are defined. The document also covers downstream billing programs (USAH20 and USAG20 for TOPS-20) that process these files to generate reports and calculate charges, including instructions for running them and setting billing rates. A detailed appendix provides the specific record formats for all USAGE file entries.