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multiple read on flat file

 
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s.ayodhyawasi

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Joined: 16 Sep 2006
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PostPosted: Wed Feb 11, 2009 8:00 pm    Post subject: multiple read on flat file
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If a particular flat file is being used for reading in program, and it's defined as disp=shr in jcl. Theoretically it can be shared across multiple job same time.

But could there be any problem in actual running. i mean is there any limit of something, like how many job can read it simultaneously?
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expat

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PostPosted: Wed Feb 11, 2009 8:03 pm    Post subject:
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None that I know of
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Robert Sample

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PostPosted: Wed Feb 11, 2009 8:40 pm    Post subject:
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There's some limit to the number of concurrent accesses one disk and channel can support, but that's probably about the only limit.
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dick scherrer

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PostPosted: Wed Feb 11, 2009 10:57 pm    Post subject:
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Hello,

It is usually not a good practice to use disp=shr for qsam files. . .

Many organizations/systems will not promote jobs to production if sequential files are defined as shr.
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expat

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PostPosted: Thu Feb 12, 2009 12:29 am    Post subject:
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Many organizations/systems will not promote jobs to production if sequential files are defined as shr.

Once worked in a shop that demanded that files were DISP=OLD even for read only. I done an analysis and presented it to mismanagement and gave an estimated reduction of elapsed overnight batch cycle, and lo and behold DISP=SHR was flavour of the month.
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