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Ranjithkumar
New User
Joined: 10 Sep 2008 Posts: 93 Location: India
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Whats the advantage of using IDCAMS utility for deleting datasets used in a JCL, instead of BR14 ? Is it advisable to use IDCAMS instead of BR14 utility? |
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PeterHolland
Global Moderator
Joined: 27 Oct 2009 Posts: 2481 Location: Netherlands, Amstelveen
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IEFBR14 doesnt need sysin input.
So if you dont want to use control card libraries or in stream data
IEFBR14 is the way to do it. |
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expat
Global Moderator
Joined: 14 Mar 2007 Posts: 8797 Location: Welsh Wales
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But IEFBR14 WILL recall migrated datasets before deleting them, thus wasting time and resource. |
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PeterHolland
Global Moderator
Joined: 27 Oct 2009 Posts: 2481 Location: Netherlands, Amstelveen
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Thats right expat. |
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Ranjithkumar
New User
Joined: 10 Sep 2008 Posts: 93 Location: India
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Will there be any CPU savings if we used IDCAMS instead of IEFBR14? Or is it the other way around? |
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expat
Global Moderator
Joined: 14 Mar 2007 Posts: 8797 Location: Welsh Wales
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What did you find out when you tried it for yourself ? |
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Ranjithkumar
New User
Joined: 10 Sep 2008 Posts: 93 Location: India
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Its 00 for both utilities when i tried it out . I am not able to differentiate. |
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expat
Global Moderator
Joined: 14 Mar 2007 Posts: 8797 Location: Welsh Wales
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Then I would guess that any difference is negligable |
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Escapa
Senior Member
Joined: 16 Feb 2007 Posts: 1399 Location: IL, USA
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Ranjithkumar wrote: |
Its 00 for both utilities when i tried it out . I am not able to differentiate. |
Have you tried it for migrated dataset? |
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Ranjithkumar
New User
Joined: 10 Sep 2008 Posts: 93 Location: India
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Thank you Expat. I read this somewhere online - "IDCAMS does not cause any tape mounts to uncatalog/delete a data set. Using IEFBR14 to uncatalog a tape data set with JCL with a DISP of DELETE causes a tape mount." Was the statement true? Does tape mounts afffect performance somehow? |
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PeterHolland
Global Moderator
Joined: 27 Oct 2009 Posts: 2481 Location: Netherlands, Amstelveen
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With UNIT=(,,DEFER) for tapes there will be no mounting, cause
IEFBR14 doesnt do anything (like opening datasets).
To uncatalog you have to use the uncatlg parameter of the DISP statement. |
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expat
Global Moderator
Joined: 14 Mar 2007 Posts: 8797 Location: Welsh Wales
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Ranjithkumar wrote: |
IDCAMS does not cause any tape mounts to uncatalog/delete a data set. Using IEFBR14 to uncatalog a tape data set with JCL with a DISP of DELETE causes a tape mount." |
What happens if you try having specified deferred mount in the JCL
Aaaaaaaah, fast fingers Peter has beaten me to that one
Although my testing used MOD,DELETE,DELETE with no mount. |
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gcicchet
Senior Member
Joined: 28 Jul 2006 Posts: 1702 Location: Australia
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Hi Expat,
the mount is still issued and the the tape drive is still allocated,
,,DEFER still allocates the tape drive.
Gerry |
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expat
Global Moderator
Joined: 14 Mar 2007 Posts: 8797 Location: Welsh Wales
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Good thinking Gerry. Thanks for the reminder |
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parsesource
New User
Joined: 06 Feb 2006 Posts: 97
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expat wrote: |
But IEFBR14 WILL recall migrated datasets before deleting them, thus wasting time and resource. |
if you have z/OS 1.11 and set a parm somewhere in parmlib IEFBR14 WILL NOT recall a dataset if the step-termination DISP = DELETE. the first major update for iefbr14 since 1964.... |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006 Posts: 19244 Location: Inside the Matrix
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Hello,
Is this a change to IEFBR14 itself or a change to z/OS to recognize the situation?
Once upon a time, other than standard linkage in and out of the code, the "function" of IEFBR14 was to branch to register 14 and end as quickly as possible. . . |
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parsesource
New User
Joined: 06 Feb 2006 Posts: 97
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dick scherrer wrote: |
Hello,
Is this a change to IEFBR14 itself or a change to z/OS to recognize the situation?
Once upon a time, other than standard linkage in and out of the code, the "function" of IEFBR14 was to branch to register 14 and end as quickly as possible. . . |
because the recall happens before iefbr14 gets control there must be new code outside br14. |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006 Posts: 19244 Location: Inside the Matrix
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Hello,
Quote: |
because the recall happens before iefbr14 gets control there must be new code outside br14. |
Which should mean that this is not realy an update to iefbr14? |
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