Difference between Tape data set and Dasd Data set

k.pavankumar · New User Joined: 22 May 2006 Posts: 8

Hi People,

Could any body please Explain me what is the exact difference between a Tape data set and a DASD Dataset.

What is the purpose of those 2 categories, in which situation we will use which datasets.

what are the scenarios or steps that will be taken when a job abends that is pointing to a Tape dataset and also same scenario for the DASD dataset.

Advance Thanks
K pavan kumar

Manojudha · New User Joined: 13 Jul 2005 Posts: 13

A DASD dataset is a dataset that is stored in the System Disk mean the Mainframe server.

A tape dataset is a dataset that is stored in a tape. A tape is a device may be like a floppy wherein you can put in so much of data, back ups etc.

Usually as per my experience, tapes are used to take back ups of the datasets.

When you encounter some abend in tape, it could be due to various reasons. But it could be because the tape was not mounted.

Let me know if I answered your question.

k.pavankumar · New User Joined: 22 May 2006 Posts: 8

Hi Manojudha,

Thanks for your reply.

But I have another doubt relating to the Tape datasets.

In Production I have found that all the GDG Base are stored on the Tape.
My doubt is whether it is Compulsary to store the GDG Base on the Tape Data set or it is optional.

Please Reply

Advance Thanks!

creator.abhishek · New User Joined: 07 May 2006 Posts: 32 Location: Pune

i think in any kind of development , first program is preapare n tested in dasd then it move to tape if necessary. m i rt?

Manojudha · New User Joined: 13 Jul 2005 Posts: 13

Using DASD or Tape for Testing is user dependant. It is compulsory to do it in DASD. It is optional and is based on your requirement where you store it.

Regarding GDG bases again, creating in tape or dasd is optional.

Thanks
Manojudha

parikshit123 · Active User Joined: 01 Jul 2005 Posts: 269 Location: India

Hi,

I think that there is no concept like "tape datasets" and "DASD datasets".

Probably, you might like to call the datasets which are stored on tape or DASDs ...

Yes, there is a subtle difference between them.

First and foremore difference is that, Datasets stored on tape can only be processed sequentially. Whereas, datasets stored on DASDs may / may not be processed sequentially.
KSDS datasets can not be stored on tape.

Generally, tapes are used to take back up of the datasets as its a cheaper device as compared to DASDs.