Why IDCAMS is only used for creating VSAMs?

Virtual Storage Access method - ESDS, KSDS, RRDS & LDS. Basic direct access method, Basic sequential -, Queued sequential -, Basic partitioned -, Indexed sequential -, Object - access method.
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Umar Abdulla
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Why IDCAMS is only used for creating VSAMs?

Post by Umar Abdulla »

I usually used IDCAMS when needed to create VSAM datasets. But can anybody tell me why we use IDCAMS for this? It is a "Access Method Services" and not a "utility" then why don't we use any other utility to create VSAMs?

Perhaps I confused it all but that's why I am posting this question. Can someone please share their thoughts :)
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Robert Sample
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Re: Why IDCAMS is only used for creating VSAMs?

Post by Robert Sample »

How high is up?

We use IDCAMS to define VSAM data set because IBM created IDCAMS to (among other things) define VSAM data sets. And don't get too hung up on the name -- IDCAMS is a utility just like IEBGENER or IEBCOPY. From the DFSMS bookshelf manual Access Method Services for Catalogs:
1.0 Topic 1. Using Access Method Services
Access method services is a utility you can use to establish and maintain catalogs and data sets.
So the manual tells you, in the very first sentence of the first chapter, that it is a utility. Probably it is called "access method services" because it allows you to work with catalogs (which are used by all the access methods) along with data sets -- but the reason it is called what it is called was decided within IBM so no one may ever know for sure where the name came from.

And IDCAMS is not used "only" for creating VSAM data sets. System programmers use it extensively to manage catalogs. Storage management may use the DCOLLECT command of IDCAMS to collect data about disk data sets.
Umar Abdulla
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Re: Why IDCAMS is only used for creating VSAMs?

Post by Umar Abdulla »

Thanks for the explnation Robert.
Robert Sample wrote:And IDCAMS is not used "only" for creating VSAM data sets. System programmers use it extensively to manage catalogs. Storage management may use the DCOLLECT command of IDCAMS to collect data about disk data sets.
But for a software engineer, I think there is no more use of it.
enrico-sorichetti
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Re: Why IDCAMS is only used for creating VSAMs?

Post by enrico-sorichetti »

But for a software engineer, I think there is no more use of it.
why not lurk Yourself the the guide and reference manuals
to see all the things that can be done using IDCAMS ???

by the way
( just to make You understand the odd looks of the IBM programs, messages, components )
OUAT ( Once Upon A Time ) somebody in IBM decided to classify things by assigning a three letters component name
so that it could be easy for the user to navigate around things

xxx the component code
zzzz something sometimes understandable, sometimes not

...
IDC - component code
AMS - Access Method Services

...
for the OLD assembler F ( the main program )
IFO - component code
X00 - somebody might know :mrgreen:
cheers
enrico
When I tell somebody to RTFM or STFW I usually have the page open in another tab/window of my browser,
so that I am sure that the information requested can be reached with a very small effort 8-)
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Robert Sample
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Re: Why IDCAMS is only used for creating VSAMs?

Post by Robert Sample »

But for a software engineer, I think there is no more use of it.
The use of IDCAMS, even by software engineers, is limited only by the imagination. LISTCAT can be used to determine the existence of a particular generation of a GDG (or the existence of a data set) -- run the LISTCAT with the LEVEL option to select the data sets, pass the output to the next step of the job where a program written in the language of your choice scans the LISTCAT output to pick out data set names.
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