1. AS/400 Architecture

   The AS/400 is a multi-user, multitasking system that includes hardware, software, security and other components. Single Level Storage RAM and DASD is combined into a logical unit (main storage). It is divided into a number of different storage pools.

   AS/400 Hardware and Software -- Licensed Internal Code (LIC) LIC is the main part of the OS/400. LIC is a group of instructions located in storage that control the operations of devices and controllers.

   OS/400 Versions, Releases, Modifications, and PTFs (V4R1M0, V4R4M0, V4R5M0 etc.)

2. Subsystem

   A subsystem is where the system brings together the resources needed to process work.

   A subsystem is defined by a subsystem description (*SBSD).

   Interactive subsystem : QINTER

   Batch subsystem : QBATCH

   The basic unit of work on the AS/400 is called a job.

  Types of jobs: Interactive jobs (checking your e-mail) and batch jobs (sending an e-mail to a friend which goes in an outbox and waits to be processed by the system).

   All jobs on the AS/400 run in a subsystem. Various reports are generated from various jobs.

3. System Values

   System values are AS/400 attributes that allow each installation to customize the machine to the organization’s own needs and specifications. The categories of system values include :

  Date and time, System control Library list values, Editing values, Allocation values, Security values, Storage values, Message and logging values

4. Control Language of CL Commands

   Control Language is a set of commands by which users control operation and request system-related functions on the AS/400.

5. Objects and Libraries

   OS/400 is an object-based operating system.

   An object is anything on the system that has a name and takes up space in storage.

   Objects are categorized by type.

*PGM, *FILE,*CMD,*LIB,*JOBQ,*OUTQ,*MSGQ,*MENU,*USRPRF etc etc.

   Object type is always assigned by the system and is determined by the command used to create the object. A library acts as a holding area for related objects.

   Libraries cannot contain other libraries(with one exception—library QSYS)

   Object qualified name: LIBRARY/OBJECT

   Most IBM-supplied library names begin with the letter "Q"

     QSYS, QUSRSYS, QHLPSYS, QGPL, QSPL, QDOC etc etc.

   A library list is an ordered group of libraries used by a job to search for objects needed for processing.

6. Queues

   Queues are holding areas for messages, printed reports, batch jobs and other work that is waiting to be received, released to the CPU, or accessed by a specific user.

  Message queue, *MSGQ

  Output queue, *OUTQ

  Job queue, *JOBQ