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COND statement in the first step of JCL


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Rahul_kumar
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Joined: 24 Jun 2006
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PostPosted: Sat Mar 19, 2011 12:03 am
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Q1 -
ESDS - Batch applications,is there any specific application where esde is preferred?
KSDS -0nline processing
RRDS - Don't know

Q2 -
I want to execute a job in MVS exclussively?Is there any parameter which can be specified in the job card which will execute my job only?

Q3 - In JCL which one is better for controlling the job step execution ( COND or IF statement).

Q4 - Can I code a COND statement in the first step of JCL?what happens if my step fails on a particular step say STEP50 & I want to restart but have coded COND for that step?
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Akatsukami

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PostPosted: Sat Mar 19, 2011 12:08 am
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And your answers were...?
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expat

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PostPosted: Sat Mar 19, 2011 5:03 pm
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Actually, the idea of this particular forum is for YOU to give your answer to the questions and then seek guidance from other members.

Q2 - what on earth do you mean exclusively. Surely you do not want to be the sole job running on a whole mainframe.

THe JCL manuals, easily reached from the top of ANY page will yield all of the answers you need.
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Rahul_kumar
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PostPosted: Sat Mar 19, 2011 11:23 pm
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okay....with answers

Q1 -
ESDS - Batch applications,is there any specific application where esds is preferred? I said where we need to process all the records we use esds but KSDS can also be used sequentially.Is there any specific advantage we have over KSDS.I think might be the size is less since index component is not present?
KSDS -0nline processing, for random access?
RRDS - Don't know

Q2 -
I want to execute a job in MVS exclussively?Is there any parameter which can be specified in the job card which will execute my job only?I said that I can give high priority through CLASS but he wanted the job to be run exclusively.I have a doubt whether he wanted to listen that multithreading is not possible in batch?

Q3 - In JCL which one is better for controlling the job step execution ( COND or IF statement). I feel that it's IF conditions as we use IF's to abend in case of abnormal return?

Q4 - Can I code a COND statement in the first step of JCL?what happens if my step fails on a particular step say STEP50 & I want to restart but have coded COND for that step? don't know ...
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Robert Sample

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Location: Dubuque, Iowa, USA

PostPosted: Sun Mar 20, 2011 12:38 am
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Q1: KSDS and RRDS both are used for direct acess in batch as well as online -- for example, looking up code values that are kept in a file. ESDS can be handy when doing logging (batch or online again).

Q2: technically, it is not possible to run one job exclusively. There's quite a number of started tasks that are always running. I suppose it would be possible to waste a lot of resources by shutting down all job classes except one, and devoting only one initiator to that job class -- but why would anyone want to do that anyway? This is another example of a stupid interview question (maybe we should start a collection of them, since we see so many?)

Q3: A lot of people believe that the IF statement in JCL is easier to understand compared to the convoluted logic used by the COND parameter.

Q4 answer from the JCL Language Reference manual:
Quote:
16.5.4 Location in the JCL


You can specify the COND parameter on any EXEC statement in the job. However, the system evaluates a COND parameter on the first EXEC statement in a job as false.

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