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Pavani.Mala
New User
Joined: 16 Jul 2008
Posts: 2
Location: hydeerabad
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What is a unit parameter in JCL?
What is volume parameter, and how do we use volume parameter when UNIT=TAPE?
Can you please explain the meaning of following statement:
UNIT=TAPE,VOL=(,RETAIN),BUFNO=6 |
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gcicchet
Senior Member
Joined: 28 Jul 2006
Posts: 1702
Location: Australia
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Hi,
The UNIT parameter identifies the type of device a data set is to
reside on.
VOL=(,RETAIN) or VOL=(PRIVATE,RETAIN)
PRIVATE
requests a private volume - this prevents MVS from
allocating an output data set to the volume until it is
specifically requested - the volume will be demounted when
the data set is closed unless the data set is passed or the
RETAIN parameter is specified
RETAIN
for a private tape volume, requests that the volume not be
demounted or rewound when the data set is closed - a public
tape volume will be retained at the tape drive if it is
demounted during the job
Gerry |
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Pavani.Mala
New User
Joined: 16 Jul 2008
Posts: 2
Location: hydeerabad
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Hi,
Thanks for the info. Up to unit parameter i understood. but im unable to understand regarding volume parameter and also the buffer (BUF) can u plz explain me in more detail . |
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Anuj Dhawan
Superior Member
Joined: 22 Apr 2006
Posts: 6250
Location: Mumbai, India
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Hi,
| Quote: |
| unable to understand regarding volume parameter and also the buffer (BUF) |
VOL PARAMETER: This parameter is used to identify the volume serial number on which dataset is reside. The VOL dataset is used with disk and tape datasets.
BUFNO: Supplies the number of buffers* to be assigned for this file when it is opened. The maximum is 255 or the value dictated by the region size. Valid for all access methods except TCAM & GAM.
*Buffer: An area of storage into which data is read or from which it is written. Typically, buffers are used only for temporary storage. |
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Bill Dennis
Active Member
Joined: 17 Aug 2007
Posts: 562
Location: Iowa, USA
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As Gerry explained, RETAIN means the tape should stay mounted on the UNIT at step end. This is usually to allow a following step to process the tape without the operators needing to remount it.
There are many other subparameters for VOL and the MVS JCL Reference manual would be a good place to start. |
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