IBM Announced in late 80’s, as a newest member of midrange computers. Started with System/3 which supported only batch processing ,Later System 32. In 1978 System/34(multiuser computer to offer interactive processing using display stations) and then came System 38 (predecessor of AS400). Finally evolved the AS400 and its operating system is called OS/400.

Security Levels & Architecture

• 10 – No longer supported on new systems

• 20 – Control who can sign on to system

• 30 onwards – Require username and password and checks authorization on objects or resources

• 40 and 50 – prevents users from accessing system objects.

• 50 – Prevents passing  invalid parameters.

• Libraries – The most important concept in AS400.

• A library is just a container with a name.

• In other systems, it can be called as a folder or a directory.

• System libraries and User libraries.

Key Objects are:

• • Files (*FILE)

  • Programs (*PGM)

  • Commands (*CMD)

  • Job Queues (*JOBQ)

  • Message Queue (*MSGQ)

  • Data areas (*DTAARA)

  • Output Queues(*OUTQ)

  • User Profiles (*USRPRF)

  • It is a unique way to locate objects in the system.

  • When you manipulate an object with any command, the system uses the library list to

    find the object from the library list.

Data Description Specifications

      1)    Physical Files

  2)   Logical Files

  3)   Display Files

  4)   Printer Files

The languages used in the Systems are RPG LE & CL.