Definition: AS/400

(Application System/400) The first generation of IBM's midrange business computers, which evolved into the Power Systems family. Introduced in 1988, the AS/400 served as a host or intermediate node to other AS/400s, as a remote system to mainframes and as a network server to PCs. Today, the Power Systems successors to the AS/400 are IBM's non-mainframe computer family. See Power Systems.

Designed to Consolidate
The AS/400's unique feature was its OS/400 environment, which included an integrated relational database, a feature of the earlier System/38. The AS/400 ran System/38 applications intact, but System/36 programs had to be recompiled. See OS/400, System/36 and System/38.

In 1994, IBM introduced the AS/400 Advanced System/36, a PowerPC-based version of the AS/400 that natively ran the System/36 SSP operating system and its applications. Starting that year, IBM's POWER CPUs were used in AS/400 models. See POWER CPU.

An Early AS/400

The AS/400 has been used in businesses of all sizes, and thousands of applications were written for it. (Image courtesy of IBM.)