Portal | Manuals | References | Downloads | Info | Programs | JCLs | Mainframe wiki | Quick Ref
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Profile Log in to check your private messages Log in
 
Need explaination on VOLUME sub-parameters

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM
View previous topic :: :: View next topic  
Author Message
coria

New User


Joined: 09 Oct 2006
Posts: 36

PostPosted: Thu Dec 13, 2007 2:30 pm    Post subject: Need explaination on VOLUME sub-parameters
Reply with quote

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?:
Code:
//SORTIN   DD DSN=A.B.C,
//         DISP=SHR                             
//******** INPUT FILE                           
//SORTOUT  DD DSN=D.E.F,   
//******** OUTPUT FILE
//            DISP=(NEW,CATLG,DELETE),         
//            VOL=(PRIVATE,,,59),               
//            LRECL=100                         

I tried however it works.

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?

here is the link from IBM:
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/iea2b670/12.67.2?ACTION=MATCHES&REQUEST=volume&TYPE=FUZZY&SHELF=EZ2ZO10J&DT=20070427231644&CASE=&searchTopic=TOPIC&searchText=TEXT&searchIndex=INDEX&rank=RANK&ScrollTOP=FIRSTHIT#FIRSTHIT

Thanks!
Back to top
View user's profile Send private message

Anuj Dhawan

Senior Member


Joined: 22 Apr 2006
Posts: 6258
Location: Mumbai, India

PostPosted: Thu Dec 13, 2007 3:08 pm    Post subject:
Reply with quote

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.
Back to top
View user's profile Send private message
coria

New User


Joined: 09 Oct 2006
Posts: 36

PostPosted: Thu Dec 13, 2007 5:19 pm    Post subject:
Reply with quote

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:

//SORTOUT DD DSN=A.B.C(+1),
// DISP=(NEW,CATLG,DELETE),
// UNIT=TAPECR,
// VOL=(PRIVATE,,,59),
// STORCLAS=NULLTAPE,
// DATACLAS=DATAF,LRECL=100,
// BUFNO=10

Could you please hlep to explain why PRIVATE is used here? and what is the advantage of specifying BUFNO here explicitly?

Thank u!icon_smile.gif
Back to top
View user's profile Send private message
mmwife

Super Moderator


Joined: 30 May 2003
Posts: 1592

PostPosted: Thu Dec 13, 2007 8:58 pm    Post subject:
Reply with quote

Demounted means the tape reel is removed from the drive.
Back to top
View user's profile Send private message
Anuj Dhawan

Senior Member


Joined: 22 Apr 2006
Posts: 6258
Location: Mumbai, India

PostPosted: Fri Dec 14, 2007 3:38 pm    Post subject:
Reply with quote

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.
Back to top
View user's profile Send private message
coria

New User


Joined: 09 Oct 2006
Posts: 36

PostPosted: Sat Dec 15, 2007 8:22 pm    Post subject:
Reply with quote

thank u guys! but how to understand this stmt about private volume:

"this prevents MVS from allocating an output data set to the volume until it is specifically requested " ?

in my example, the volume number is not specified, however the output dataset is allocated... please let me know if i misunderstood something.
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
This topic is locked: you cannot edit posts or make replies. Selecting two copybooks of different ... Vignesh Sid COBOL Programming 8 Tue Sep 05, 2017 7:28 pm
No new posts RMM: scratching a volume that RMM thi... Hervey Martinez IBM Tools 0 Mon May 15, 2017 8:51 pm
No new posts LISTCAT on a dataset with symbolic pa... shreya19 JCL & VSAM 5 Fri Apr 07, 2017 5:43 pm
No new posts Storing huge volume of data, compare ... Pradeep K M All Other Mainframe Topics 3 Mon Jan 16, 2017 5:08 pm
No new posts CICS NEW SIT PARAMETERS CICS BEHAVIOR... Kyle Carroll CICS 0 Fri Nov 04, 2016 11:55 pm

Facebook
Back to Top
 
Job Vacancies | Forum Rules | Bookmarks | Subscriptions | FAQ | Polls | Contact Us