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What is Z (compress) command does actually?

 
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Escapa

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PostPosted: Wed Oct 01, 2008 11:03 am    Post subject: What is Z (compress) command does actually?
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Often while copying member in the pds if i get X37 (space error)
If i issue Z command for PDS and tried copying member it works.
What does compress comand does actually?
does it zip the file or or rearranges file data blocks to make unusable free space available? Or anything else icon_confused.gif icon_confused.gif icon_confused.gif icon_question.gif
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Anuj Dhawan

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PostPosted: Wed Oct 01, 2008 11:17 am    Post subject:
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To reclaim the unused and unavailable space in a partitioned data set that results from deleting or modifying members by moving all unused space to the end of the data set.
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Anuj Dhawan

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PostPosted: Wed Oct 01, 2008 11:24 am    Post subject:
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If it's your persoanl PDS, try using PDSE to overcome X37.

BTW, in X37 ..X stands for ?
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Escapa

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PostPosted: Wed Oct 01, 2008 11:39 am    Post subject:
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Quote:

To reclaim the unused and unavailable space in a partitioned data set that results from deleting or modifying members by moving all unused space to the end of the data set.


Thanks for this info. But do you mean to say that if we keep on adding members in PDS (with out deleting or modifying existing members in it)
compress wont have any effect?




Quote:
BTW, in X37 ..X stands for ?

I ment here B37 or D37.
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Anuj Dhawan

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PostPosted: Wed Oct 01, 2008 3:14 pm    Post subject:
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I didn't realize that above said can be an inference of my previous explanation. No I don't mean this
Quote:
if we keep on adding members in PDS (with out deleting or modifying existing members in it)
compress wont have any effect?
This may be true if all the 16 extents for that PDS are exhausted fully..
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gcicchet

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PostPosted: Wed Oct 01, 2008 4:17 pm    Post subject:
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Hi,

Quote:
Thanks for this info. But do you mean to say that if we keep on adding members in PDS (with out deleting or modifying existing members in it)
compress wont have any effect?


If the above occurs then there is no space to be reclaimded.


Gerry
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dick scherrer

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PostPosted: Wed Oct 01, 2008 8:03 pm    Post subject:
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Hello,

Quote:
if we keep on adding members in PDS (with out deleting or modifying existing members in it)
compress wont have any effect?
Compress removes "dead" space when members are replaced. If you only add new membersm there will be no "dead" space. When you replace a member with "save" in the editor for example, a new member is written and the old space for the member is left stranded. A compress removes all of this dead space, moves the existing members "up" and leaves all of the available free space "at the bottom".

FWIW - a standard pds with only 1 member may be "full" because the member has been replaced so many times that all of the free space has been used.

Quote:
BTW, in X37 ..X stands for ?
While they have different specifics the x37 abends are space related. Saying x37 is just another way of saying space abend.

FWIW - There are some systems that run a product called StopX37 that intercepts these abends and prevents many production jobs from abending.
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Escapa

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PostPosted: Thu Oct 02, 2008 4:16 pm    Post subject:
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Thanks all for explaining concept so well
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