Application System 400 introduction to a

Application System.ppt

1. Application System/400
Mid-range Machine

2. Features
•64 bit RISC processor low cost
mid-range machine.
•64 bit memory addressing.
•Certified “C2” level most secured
system.
•DBCS supports more than 50 world
languages.
•RDBMS integrated with OS/400.
•Multi-user , multitasking OS/400.

3. More Features
•Object based system.
•Net work by TCP/IP, SNA and IPX.
•New iseries supports web
technologies, fax, email.
•LPAR –allows multiple instances
of OS/400.

4. Software on AS/400
•OS/400 V5R1.
•DB2/400 RDBMS.
•Language Compilers RPG IV,
COBOL/400, C/400, C++/400 , BASIC,
PASCAL, CL/400.
•SQL/400.
•Query/400.
•Query Manager.

5. Storage on AS/400
•Single Level storage combines RAM
and DASD into logical units.
•Auxiliary Storage Pool (ASP) is
logical grouping of disk units.
•Everything that is stored on AS/400
as a separate entity is an Object.
•There are around 100 types of
Objects.
•Library: Object to which other objects
belong Logically.

6. Storage Hierarchy
QSYS
System Library
All libraries belong to this
QGPL QRPG QTEMP QCBL Infy Satish
RPG compiler Objects COBOL Compiler Objects
Program/Database
Objects created
by Satish
All Objects belong to any library.

7. iSeries Work management
•Subsystem
•Queues
•Memory Pools
•Jobs

8. Subsystem
•Subsystem is a module of operating
system dedicated to execute particular
type/class of jobs.
•It’s a execution environment for the
grouped jobs who may share resources.
•system can contain several subsystems, all
operating independently of each other.
Subsystems manage resources. Each
subsystem can run unique operations.

9. Controlling subsystem
•The controlling subsystemis the
interactive subsystem that starts
automatically when the system starts,
and it is the subsystem through which
the system operator controls the system
during system startup.

10. Subsystems
•QBASE (controlling subsystem) Qbase
supports interactive, batch, and
communications jobs. It has an
autostart job, which automatically starts
the Qusrwrk, Qserver, and Qspl
subsystems.
QCTL
•QCMN
•QSPL

11. Subsystem: Objectives
•Load Balancing
–Multiple subsystems on one server run
concurrently to run their respective jobs.
•Isolation
–Memory and object resources of
subsystems can be isolated form each
other if so required.
•Security
–User can submit jobs to a subsystem only
to which they have permissions.

12. Subsystem for better performance
•Subsystems are created to improve
performance.
•A system pool/Storage pool is logical
division of main memory reserved for
processing a job or group of jobs by the
OS. It is shared by multiple jobs within
a subsystem.

13. Main storage
•Main storage is divided in two: machine
pool and base pool.
•Base pool is the part of main storage
that remains after allocating machine
pool.
•Base pool is shared pool for all
subsystems.

14. Other shared pool
•*INTERACT :
•*SPOOL
•*SHRPOOL1 to *SHRPOOL10
…

15. Commands
•Creating Subsystem
CRTSBS
•Shared pool sizes are controlled by
CHGSHRPOOL
WRKSHRPOOL
DSPSBSD …Display subsystem description.

16. Jobs
•A Unit of work to which system
resources are allocated for its execution
is called as a job.
•A Job has at least one thread within.

17. Various types of jobs
AutoStart jobs
•An autostart job starts automatically
when the subsystem it is associated
with starts. These jobs generally
perform initialization work that is
associated with a particular subsystem.
Autostart jobs can also perform
repetitive work or provide centralized
service functions for other jobs in the
same subsystem.

18. Add Auto Start Job Entry
•ADDAJE SBSD(subsystem-name)
JOB(REMINDER)
JOBD(DMLIB/DMRMDR)

19. Prestart communications job
•A prestart communications job is a
communications batch job that starts
running before a remote system sends a
program start request.
•A prestart job starts before a work
request is received, either when the
subsystem starts or as a result of the
Start Prestart Jobs (STRPJ) command.

20. Batch jobs
•Batch jobs run in the system
background, freeing the user who
submitted the job to do other work.
•Batch jobs are typically low priority
jobs. Several batch jobs can be active
at the same time.

21. Batch jobs
•The Submit Job (SBMJOB) command
allows a job that is being run to submit
another job to a job queue to be run
later as a batch job.

22. Scheduled Job
•The AS/400 has an excellent job scheduler. It
will submit any job at a pre-scheduled time.
•Use the command Work With Job Schedule
Entries, WRKJOBSCDE.
•From the Job Schedule menu, hit F6 to add a
job. Simply fill in the values to define when and
how often the job runs.
•Add Job Schedule Entry (ADDJOBSCDE)

23. Job Description
•The job description allows you to create
a set of job properties that are saved
and available for multiple uses. The job
description can be used as the source
for some of the job propertiesthat tell
the system how to run a job.
•

24. Job Description
•Job Description object contains set of job
related attributes that can be used by one or
more jobs. The attributes are like.
–JOBQ of job
–OUTQ of job
–Library list
–Job Scheduling priority.
•Thus these are some of the parameters on the
command of creating Job description.

25. Job Description
Commands
CRTJOBDJOBD(BATCH3) USER(*RQD)
JOBQ(NIGHTQ) JOBPTY(4) OUTPTY(4)
ACGCDE(NIGHTQ012345)
RTGDTA(QCMDB) TEXT(’Batch #3 job
description for high pty night work’)

26. Job Queues
•Job queuesare work entry points for batch jobs
to enter the system. They can be thought of as
"waiting rooms" for a subsystem. A number of
factors affect when the job is pulled off the job
queue into the subsystem, such as the job
priority on the job queue, the sequence number
of the job queue, and the maximum active jobs.
When all of these factors work together, the job
will be pulled off the job queue to start running in
the subsystem.

27. JOB Queue Object Type: *JOBQ
•A job queue contains entries for jobs
submitted by using the following
commands that are being processed by
the system:
Start Database Reader (STRDBRDR)
Start Diskette Reader (STRDKTRDR)
Start Printer Writer (STRPRTWTR)
Start Diskette Writer (STRDSKWTR)
Submit Job (SBMJOB)
Submit Database Jobs (SBMDBJOB)
Submit Diskette Jobs (SBMDKTJOB)
Transfer Job (TFRJOB)

28. Creating a JOBQ
CRTJOBQJOBQ(DEPTA)
AUT(*EXCLUDE)
TEXT(’Special queue for Dept A
jobs’)
This JOBQ needs to be added to
any specific subsystem.
ADDJOBQE = add job queue Entry