Hi All,
VOL has some position keywords like PRIVIATE, RETAIN, could any one help me on understadning the usage?
from IBM onle help manual, i can see PRIVETE is to "Requests a private volume", "The system is not to allocate an output data set to the volume unless the volume is specifically requested, such as in a VOLUME=SER subparameter", does this mean following step wont work?:
and another one: "If tape, the volume is to be demounted after the data set is closed, " - what does "demounted" mean? the dataset will be "logically" removed from TAPE?
Joined: 22 Apr 2006 Posts: 6250 Location: Mumbai, India
Hi,
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 - JES3 systems will honor RETAIN only if the volume is actually used in a later job step.
Note: a tape drive may still be de-allocated and used by another job even though RETAINed volume is mounted on it if it is not specifically allocated by a subsequent job step in the same job.
Thanks Anuj, however i am still little confused about why using PRIVATE, how to understand "demounted ", kind of deleted?
in our shop, some huge amount data will be processed like this:
Joined: 22 Apr 2006 Posts: 6250 Location: Mumbai, India
Hi,
Quote:
how to understand "demounted "
Consider your Personal Coputers' 'Hard disk (HDD)', in a crude sense you can say that HDD is permanantly 'MOUNTed' to Your PC, now compare this HDD with DASD of Mainframes, DASDs are 'continuously' in service of Mainframes. TAPE drives are bit different, TAPE Drives are 'standing' some where ir racks & when your JOB request for some TAPE drive, a Robot arm 'put that TAPE in service of' your JOB & when your JOB is over it'll be DEMOUNTed i.e. back to rack, as Jack said...
Quote:
Demounted means the tape reel is removed from the drive.
Ah..I'm not a System Engineer but this should be the meaning of DEMOUNT. Expat, a moderator here & System Guy, might confirm it further, if He hapeen to see this thread...Good Luck.
Quote:
and what is the advantage of specifying BUFNO here explicitly?
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.
