IBM i and AS400 Resource Library

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AS400 vs IBM i

AS400 is a hardware brand name from 1988. IBM i is the current official name for the operating system that runs on IBM Power hardware. They are the same lineage, different names. Understanding the distinction matters for licensing, support conversations, and upgrade planning.

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IBM Power11 Overview

IBM Power11 is the latest generation of IBM Power Systems hardware, released in 2024. Power11 delivers new performance gains, energy efficiency improvements, and full compatibility with IBM i workloads from AS400-era applications forward.

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Is AS400 Still Used?

Yes. AS400 ... now called IBM i on IBM Power Systems ... is still actively used by thousands of organizations worldwide. IBM continues to invest in the platform with new hardware releases and OS updates.

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What Is AS400?

AS400 is IBM's mid-range business computing platform introduced in 1988. Despite multiple name changes over the decades, AS400 remains the most widely used search term for IBM i, iSeries, and IBM Power systems worldwide.

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What Replaced AS400?

IBM i on IBM Power Systems hardware replaced the AS400. The operating system evolved through iSeries, System i, and IBM i naming. IBM Power10 and Power11 are the current hardware generation. The workloads never disappeared ... only the brand names changed.

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AS400

IBM's mid-range business computer platform introduced in 1988. The original name that persists as colloquial shorthand for IBM i and IBM Power Systems worldwide.

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CPW

Commercial Processing Workload. IBM's benchmark metric for measuring the relative processing performance of IBM i systems. Used to compare AS400/IBM i hardware generations and models.

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DB2 for i

The integrated relational database built into IBM i (AS400). DB2 for i is not a separate product ... it is part of the OS. One of the AS400 platform's defining architectural advantages.

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Green Screen

The text-based character interface used to interact with AS400 and IBM i systems. Named for the green monochrome display terminals originally used. A key modernization target.

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IBM i

The current official name for the operating system that runs on IBM Power Systems. Successor to OS/400 and i5/OS. The OS lineage of the AS400 platform.

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IBM Power Systems

The IBM server hardware platform that runs IBM i (and AIX and Linux). The hardware successor to the AS400, iSeries, and System i platforms.

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iSeries

The brand name IBM used for the AS400 hardware platform from 2000 to 2006. Replaced by System i in 2006 and IBM Power Systems in 2008.

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OS/400

The original operating system for the AS400 platform, released in 1988. Renamed to i5/OS in 2004 and IBM i in 2008. The OS lineage that all IBM i releases trace back to.

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Power11

The current generation of IBM Power Systems hardware, released in 2024. Runs IBM i 7.3, 7.4, and 7.5. The latest hardware for AS400/IBM i environments.

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RPG

IBM's primary programming language for AS400 and IBM i. Report Program Generator, now evolved into a modern structured language (ILE RPG / RPGLE) still in active use.

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System i

IBM's brand name for the AS400/iSeries platform from 2006 to 2008. Part of IBM's unified Systems branding. Replaced by IBM Power Systems.

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AS400 Basics FAQ

Answers to the most common AS400 questions from IT professionals, executives, and administrators new to the IBM i platform.

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Midland Information Systems

Midland Information Systems is a certified IBM Business Partner specializing in IBM Power Systems, IBM i environments, and AS400 upgrades. Midland provides hardware procurement, IBM i support, upgrade planning, and Power11 migration services.

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