If your team says AS400, it probably means the business system that runs your orders, inventory, manufacturing, finance, or ERP work. The current name is usually IBM i on IBM Power. The name alone does not tell you the operating-system release, server model, support status, or upgrade options, so the first useful step is identifying the exact environment.
AS400 names through time
| Period | Common name | What the name describes |
|---|---|---|
| 1988 onward | AS/400 or AS400 | The original integrated hardware and software system. |
| 2000 onward | iSeries | The server family name used during a later hardware generation. |
| 2006 onward | System i | A short-lived IBM server brand between iSeries and IBM Power. |
| 2008 onward | IBM i on IBM Power | The operating system and current hardware family should be named separately. |
People still say AS400 because the applications, database, job flow, and business purpose can survive several hardware and naming changes. That continuity is valuable, but it can also hide how old the operating system or server has become.
What stayed and what changed
| Often preserved | Must be checked now |
|---|---|
| RPG, COBOL, CL, and database business logic | Exact IBM i release and required program temporary fixes |
| Db2 for i data and object-based security | Power machine type, firmware, storage, and adapters |
| Jobs, interfaces, reports, and operating procedures | Application-vendor support, licensing, backup, and recovery |
| The business name AS400 | The real support and modernization decision |
Identify the system before planning an upgrade
- Record the IBM i release. The release decides which direct upgrades are possible and which applications need review.
- Record the machine type and serial number. The model family is not precise enough for release, feature, or maintenance checks.
- List the workload and dependencies. Include partitions, users, batch windows, interfaces, licensed programs, storage, tape, backup, and recovery requirements.
- Decide what problem needs solving. A release upgrade, hardware refresh, interface change, application modernization, and ERP replacement are different projects.
The IBM i version upgrade guide covers the software-release decision. The AS400 upgrade guide covers the hardware move. Use the IBM i modernization chooser when the business problem is broader than either one.
What the AS400 name does not prove
It does not prove that the system is unsupported, that the applications need a rewrite, or that a cloud ERP migration is the right answer. It also does not prove the environment is safe to leave unchanged. The decision comes from the exact release, machine, dependencies, recovery evidence, business plan, and cost of another delay.