Features include a menu-driven interface, multi-user support, terminals (IBM 5250[?]) that are (in the grand IBM tradition) incompatible with anything else including the IBM 3270 series, and an extensive library-based operating system, OS/400.
The machine survives because its API layer allows the operating system and application programs to take advantage of advances in hardware without recompilation and which means that a complete system that costs $9000 runs the exact same operating system and software as a $2 million system. There is a 64-bit RISC processor operating system implementation.
Programming languages include RPG, assembly language, C, COBOL, SQL, BASIC, and REXX. Several CASE tools are available: Synon[?], AS/SET[?], Lansa[?].
It was designed as the successor of the IBM System/38[?]
wikipedia.org dumped 2003-03-17 with terodump