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What is Job Pack Area


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Hunny Sachdeva

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PostPosted: Wed Jun 17, 2009 2:43 pm
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What is Job Pack Area?
In system search order it comes earlier than steplib.
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Anuj Dhawan

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PostPosted: Wed Jun 17, 2009 3:13 pm
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Quote:
In system search order it comes earlier than steplib
Not sure if you're making a statement or asking...well, program search order for MVS uses the following program libraries in the order given:

1. JOB Pack Area (already loaded programs)
2. Private task library, if specified.
3. STEPLIB library, if specified.
4. JOBLIB library, if specified, AND no STEPLIB is specified
5. Link Pack Area (PLPA)
6. System Link List (i.e., SYS1.LINKLIB and the data sets concatenated to it).
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Hunny Sachdeva

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PostPosted: Wed Jun 17, 2009 3:17 pm
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Anuj,

i know Job Pack Area comes first but i am not very sure what it is exactly
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Robert Sample

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PostPosted: Wed Jun 17, 2009 5:09 pm
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Google is your friend -- the link to this material was on the first page of results from "job pack area":
Quote:
Job pack area (JPA)

A program in JPA has already been loaded in the requesting address space. If the copy in JPA can be used, it will be used. Otherwise, the system either searches for a new copy or defers the request until the copy in JPA becomes available. (For example, the system defers a request until a previous caller is finished before reusing a serially-reusable module that is already in JPA.)
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Anuj Dhawan

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PostPosted: Wed Jun 17, 2009 5:12 pm
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Robert -- in a crude sense, I believe, one can say JPA is equivalent to "Nucleus"?
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Robert Sample

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PostPosted: Wed Jun 17, 2009 5:17 pm
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Anuj -- NO! Nucleus refers to the kernel of the operating system, some of which is loaded into each address space -- but a lot of which runs in the master JCL address space. Application programs, once loaded into memory, are also part of the JPA.

There is also a specific data set, SYS1.NUCLEUS, which contains the operating system components -- normally referring to nucleus means some or all of this data set.
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dbzTHEdinosauer

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PostPosted: Wed Jun 17, 2009 5:19 pm
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Anuj,

I always thought that Nucleus was OPS Sys modules.
whereas JPA is 'application' modules.
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Anuj Dhawan

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PostPosted: Wed Jun 17, 2009 5:41 pm
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Thanks Robert.

I was trying to search the basic definition for JPA and come across a link where in they said, program will be searched in JPA, LPA and Nucleus -- their explanation seems to be correct but my inference about that was not correct. (not saved the URL that time but now it seems that I should search again)

ah..Google does not seem to be friend today , "that no" is too profound..!
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Anuj Dhawan

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PostPosted: Wed Jun 17, 2009 5:41 pm
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Thanks Dick, does that mean scope of JPA is local to JOBs?
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dbzTHEdinosauer

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PostPosted: Wed Jun 17, 2009 5:44 pm
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probably Started Tasks are also included,
but my understanding is from an application developers perspective,
know enough about the environment to know who to get to fix things.
In this case, Robert is the person to know.
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Robert Sample

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PostPosted: Wed Jun 17, 2009 5:52 pm
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JPA scope is address space -- I haven't investigated them much but I would include TSO sessions, started tasks, batch jobs all under the umbrella of "address space". I suspect (but as I said am not sure) that JPA doesn't really apply to Unix System Services address spaces, although there may something similar involved.
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Hunny Sachdeva

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PostPosted: Wed Jun 17, 2009 6:18 pm
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All-

Can anybody explain in layman terms to somebody who has never heard of What is Job Pack Area? Where is it?
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dbzTHEdinosauer

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PostPosted: Wed Jun 17, 2009 6:32 pm
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Quote:
Where is it?


in duh computr's memry.
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Anuj Dhawan

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PostPosted: Wed Jun 17, 2009 6:32 pm
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Dare I answer in again but others are around to correct us... icon_smile.gif

An area of main storage containing reenterable routines from system libraries. Their presence in main storage saves loading tim or in other words, an area of virtual storage that contains reenterable routines that are loaded at IPL time and can be used concurrently by all tasks in the system.
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Hunny Sachdeva

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PostPosted: Wed Jun 17, 2009 6:41 pm
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Anuj-

Your defination is more of LPA. How is JPA different from LPA?

dbzTHEdinosauer-

When i say where is it.. i meant common area or private.. i thought that was obvious
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enrico-sorichetti

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PostPosted: Wed Jun 17, 2009 6:41 pm
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publib.boulder.ibm.com/infocenter/zos/v1r9/index.jsp?topic=/com.ibm.zos.r9.ieaa600/iea2a67051.htm

the job pack area is the collection of load modules
loaded using the standard MVS Load Services

for more info on the subject search read and meditate on

ABC of System Programming ( s390 )
vol01 sg245597.pdf
vol02 sg245652.pdf
vol03 sg245653.pdf
vol04 sg245654.pdf
vol05 sg245655.pdf

ABC of System Programming ( zOS )
vol01 sg246981.pdf
vol02 sg246982.pdf
vol03 sg246983.pdf
vol05 sg246985.pdf
vol06 sg246986.pdf
vol07 sg246987.pdf
vol08 sg246988.pdf
vol09 sg246989.pdf
vol10 sg246990.pdf
vol11 sg246327.pdf

zOS basics
vol01 sg246366.pdf
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dbzTHEdinosauer

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PostPosted: Wed Jun 17, 2009 6:46 pm
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Quote:
When i say where is it.. i meant common area or private.. i thought that was obvious


only thing that was obvious to me was that you were to lazy to learn any terminology, so I did not want to confuse you with any technical terms.

as to common area or private - what are you talking about?

there is no such thing as common area, and private - private to what? a task?
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dbzTHEdinosauer

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PostPosted: Wed Jun 17, 2009 7:31 pm
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Quote:
there is no such thing as common area, and private - private to what? a task?


actually, that is incorrect.

what I should have said is there is no discrete common area or private area.
Common is not used, and private is not used in conjunction with area - space is normally used - and not without an adjective such as address.
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nevilh

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PostPosted: Wed Jun 17, 2009 8:19 pm
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Quote:
The common area contains system control programs and control blocks. The
following storage areas are located in the common area:

Prefixed storage area (PSA).
Common service area (CSA).
Pageable link pack area (PLPA).
Fixed link pack area (FLPA).
Modified link pack area (MLPA).
System queue area (SQA).
Nucleus, which is fixed and nonswappable.

Full description can be found in Init and tuning guide
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dbzTHEdinosauer

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PostPosted: Wed Jun 17, 2009 10:38 pm
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nevilh,

good catch. sorta hoping that the TS would have seen it, but you were faster.
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mmwife

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PostPosted: Thu Jun 18, 2009 5:47 am
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OK Hunny,

The link below should give you more than you want to know about the JPA.

publib.boulder.ibm.com/infocenter/zos/v1r9/index.jsp?topic=/com.ibm.zos.r9.ieaa600/iea2a67051.htm
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haohao

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PostPosted: Thu Jun 18, 2009 10:08 am
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how many common area exist in the whole z/OS system?
only one common area that shared by all address space or every address space has one copy?
when modules defined in the linklist to be executed,where these modules should be load into? the common area or the private area?

these questions have puzzled me for a long time,please help me make it clear,thanks in advance!! icon_biggrin.gif
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Hunny Sachdeva

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PostPosted: Thu Jun 18, 2009 10:32 am
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dbzTHEdinosauer-
every address space has private area and common area that it shares with other address spaces..

and all the manuals say it as AREA which you are not aware of i think..

nevilh-
that means Job pack area is not a part of common area.. so is it under private area..

anuj-
did not hear from you again.. LPA<-->JPA

all-
i had no idea of what a job pack area is.. so i posted this query hoping that somebody will give a clear answer..
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