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How can VSAM file be opened in I-O mode?

 
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niks_jude
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PostPosted: Fri Feb 08, 2008 12:22 pm    Post subject: How can VSAM file be opened in I-O mode?
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How is OPEN I-O possible on empty VSAM file as we have to read once before writing in I-O mode and as we know we cannot do a read on an empty VSAM file.
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expat

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PostPosted: Fri Feb 08, 2008 12:59 pm    Post subject:
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Then you have answered your own question.

This has been discussed before, open in write mode, write dummy record, close, open I-O mode delete dummy record. The file is then initialised.

Why, oh why, most sites do not impose a key '00'X header and key 'FF'X trailer rule when a file is set up I will never know.
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niks_jude
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PostPosted: Fri Feb 08, 2008 1:06 pm    Post subject:
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Hi Expat,

I just read that you can open an empty VSAM file in I-O mode, when the access mentioned is random or dynamic. If we do a READ in I-O mode, would not it fail?
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dick scherrer

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PostPosted: Fri Feb 08, 2008 8:22 pm    Post subject:
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Hello,

Have you coded as Expat suggested?
Quote:
open in write mode, write dummy record, close, open I-O mode delete dummy record. The file is then initialised.
Did it work?

Did you try to issue a read without writing the "dummy record"? What happened?
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superk

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PostPosted: Fri Feb 08, 2008 8:34 pm    Post subject:
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expat wrote:
Why, oh why, most sites do not impose a key '00'X header and key 'FF'X trailer rule when a file is set up I will never know.


Every site I've ever worked at did/does.
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