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sureshmurali
Warnings : 1
New User
Joined: 25 Nov 2010
Posts: 70
Location: Sivakasi, India
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Hi
This question is in general. Please excuse if u feel it is not jcl related.
But i have this doubt for some days. Can we write files directly on Tapes? If it can be done, do we need to use any utility for that. Also i am told that the files in DASD will automatically be migrated to TAPE after certain period of time if we dont use them at all. When we want to use them again, it just restores them on the DASD. Is it possible to view the contents of TAPE files without restoring back it to DASD ?
Also if there is any related material to know about this please suggest me.
Thanks in advance! |
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Robert Sample
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Joined: 06 Jun 2008
Posts: 8700
Location: Dubuque, Iowa, USA
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If your JCL has an output DD name that points to a tape with the correct (for your site -- some parameters can be site-specific) values, the data will be written to the tape. No utility is required as the operating system understands how to write tapes.
Files on DASD automatically migrating to tape is an archive process, typically done under the control of HSM or other storage management utility. The archived data on tape cannot be directly read and understood since it is compressed to save space. Typically, archive tapes are handled differently than data tapes written by an application.
However, if your program writes data to a tape, you can use a utility such as IDCAMS or IEBGENER to print the data on tape. |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19243
Location: Inside the Matrix
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Hello,
Your topic has been relocated to the SMS & VSAM part of the forum.
The original post mentions JCL, but was posted in the COBOL part of the forum. I believe this part of the forum may be more suited. If you'd like to have this moved, just post a reply.
When working with data on tape, keep in mind that data from tape usually must be copied (entirely or in part) to dasd to be worked with online. Batch jobs can read data tapes (rather than backup/archive volumes) directly. |
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sureshmurali
Warnings : 1
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Joined: 25 Nov 2010
Posts: 70
Location: Sivakasi, India
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Yes Dick. I need to move this to the respective forum. Please kindly move.
Thanks. |
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Anuj Dhawan
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Joined: 22 Apr 2006
Posts: 6248
Location: Mumbai, India
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Pete Wilson
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Joined: 31 Dec 2009
Posts: 590
Location: London
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Suggest you talk to your Storage pr System Programmers as typically there are certain UNIT names or DATACLAS names to code in the JCL when you want to write to TAPE and these are site specific.
Remember that TAPE files are always Sequential.
Once a dataset is written to tape and cataloged you can just reference it by the tape dataset name and DISP=OLD. If it is not cataloged you have to code the VOLSER and UNIT name as well as dsname to be able to access it.
Be careful that you specify the correct EXPDT in the JCL as this can affect the way the tape file is retained (or not) in the Tape Management System.
For DASD datasets migrated by DFHSM or FDRABR type products you only have to try and open the file and that will invoke DFHSM to recall the file from archive back to DASD after which you can access it as normal. |
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