as400 sub systems

Introduction to IBM AS/400 Sub Systems

AS/400 entire system performance is actually carried out in sub systems. All the AS/400 sub systems are specialized.

The main general purpose sub system of AS/400 is known as QBASE.

QBASE – Sub System

This general purpose sub system is provided by IBM

We can configure AS/400 machine to run the entire system operations using QBASE or else we can split the jobs among several sub systems. If we run AS/400 machine is QBASE, all interactive and batch jobs run in QBASE. It has its own advantages as well as disadvantages.

Advantages

• Simplicity in management, here only one sub system needs to be controlled.
• All system functions runs in easy mode, system startup, shutdown, control operations Etc.

Disadvantages

• In this mode of system functioning, only one sub system QBASE is forced to do all the Jobs/system functions Etc.
• In this mode of operations, its tough to tune AS/400 machine well and machine won’t perform well.

Multiple Sub Systems

Running the AS/400 machine with multiple sub systems is always a better choice because each sub system is specialized for certain kind of job and we will get better control over the system. Tuning up AS/400 becomes very easier in multiple sub systems environment.

There is three main sub systems present.

QCTL

OCTL is the controlling sub system. Its called QCTL because it control the system and also another sub system to which the system console is attached.

If the QCTL is ended all the sub systems ends automatically.

QCTL shouldn’t be used for regular application software jobs such as interactive jobs and batch jobs as it will slow down the entire system performance.

It should be reserved for system console only.

QINTER

QINTER is a interactive sub system.

All Interactive jobs should run in QINTER. And batch jobs never run under QINTER.

Never submit a batch job under QINTER. If you ran any batch jobs under QINTER it will slow down machine performance.

We can use QINTER to sign on to all display stations except the system console. Ending the QINTER affects all display stations except the system console.

We can use the below command to end the QINTER sub system.

ENDSBS QINTER (*CNTRLD) or ENDSBS QINTER (*IMMED)

ENDSBS QINTER (*CNTRLD) ends the QINTER and allows all interactive jobs continue to run for a certain amount of time.

ENDSBS QINTER (*IMMED) ends QINTER and all interactive jobs immediately.

Ending QINTER is an easier way to prevent users to access the system

QBATCH

QBATCH is used to process the batch jobs.

Batch jobs are the jobs which are submitted to a job queue for processing.

QBATCH is specially designed to run batch jobs and will perform poorly with interactive jobs.

We can use the below command to end the QBATCH sub system.

ENDSBS QBATCH OPTION (*CNTRLD) DELAY (*NOMAX)

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