The AS/400 (later IBMInternational Business Machines — a major computer and enterprise technology company since the early 20th century. i) ran RPG and COBOLCommon Business-Oriented Language — a language designed for business data processing on mainframes. business apps on hardware IBMInternational Business Machines — a major computer and enterprise technology company since the early 20th century. upgraded for decades without breaking software — a model of backward compatibility enterprise ITInformation technology — the use of computers, networks, and software in organizations. valued. Thousands of banks, manufacturers, and retailers still run workloads on its descendants. Backend developers in IBMInternational Business Machines — a major computer and enterprise technology company since the early 20th century. midrange shops learned RPG, DB2, and green-screen terminals on this platform.

The AS/400 was IBMInternational Business Machines — a major computer and enterprise technology company since the early 20th century.'s flagship integrated business system for small and mid-sized enterprises.

It demonstrated extreme software compatibility across hardware generations in production datacenters.