Standard Installation and Division Personnel Reporting System (SIDPERS) was the main database or, rather, databases for personnel accounting by the United States Army. The Active Army, US Army Reserve, and Army National Guard each had separate, largely incompatible databases, each bearing the name SIDPERS or a variation thereof. RC-SIDPERS was nominally designed for both reserve components (Army Reserve and Army National Guard), but was further adapted for use by the National Guard, to create NG-SIDPERS.
Until 1988, RC-SIDPERS was not accessible at the unit level, and unit administrators would mail database correction documents up their chain of command to their respective general officer command in order to update and/or correct SIDPERS. A separate, unconnected database, Unit Level Application System (ULAS, pronounced "you-lass") was available for unit administrators to maintain local personnel information. A PC-based application, built in PC-FOCUS, was fielded for beta testing in late 1988 within the 63rd Army Reserve Command and was expanded USAR-wide the following year. A bridge connected each unit's PC-SIDPERS database with its respective Center Level Application System (CLAS, pronounced "class") database. CLAS, also built in PC-FOCUS, was the successor to ULAS, and offered extensive additional data categories beyond that centrally maintained by RC-SIDPERS, including training data, weapon serial number assignment, protective mask tag number assignment, OER/NCOER rating chain, inter alia.
Other articles related to "sidpers":
... SIDPERS' successor, Regional-Level Application System (RLAS, pronounced "are-lass"), is theoretically a Total-Army system, and essentially meshes with DEERS ...