Is there any difference between Region=0M and Region=0K ?

JES2/3, JCL, utilities.
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Vijay Ingle
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Is there any difference between Region=0M and Region=0K ?

Post by Vijay Ingle »

Hi,

Is there any difference between Region=0M and Region=0K ? Is not it that in both the cases the all available storage will be allocated to the job or step?

Then is there any difference at system level?
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Robert Sample
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Re: Is there any difference between Region=0M and Region=0K

Post by Robert Sample »

If you check the JCL Reference manual, the syntax indicates 0K and 0M are the same.
Vijay Ingle
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Re: Is there any difference between Region=0M and Region=0K

Post by Vijay Ingle »

So they are just same way of saying the same thing (to the system)?
Vijay Ingle
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Re: Is there any difference between Region=0M and Region=0K

Post by Vijay Ingle »

Actually, I read an online discussion eles where and someone in there states like this:
REGION=0K requests only one-thousandth as much as REGION=0M. In some of my JCL members, I use variously REGION=0M or REGION=00M. I have JCL tailoring scripts that treat the constructs differently and substitute different non-zero values for the two.

Sometimes I substitute REGION=16385K to allow allocating storage above-the-line, but not very much.
Isit really true! :shock:
enrico-sorichetti
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Re: Is there any difference between Region=0M and Region=0K

Post by enrico-sorichetti »

If you check the JCL Reference manual, the syntax indicates 0K and 0M are the same.
So they are just same way of saying the same thing (to the system)?
wasn' t the reply clear enough ?

wasn' t the manual clear enough ?

and why bother with somebody else incompetent ramblings ?
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: Is there any difference between Region=0M and Region=0K

Post by Robert Sample »

The manual makes it clear that whoever you quoted is completely and totally WRONG:
| value=0M or 0K

| A value equal to 0K or 0M -- gives the step all the storage available
| below and above 16 megabytes. The resulting size of the region below
| and above 16 megabytes depends on system options and what system
| software is installed. When REGION=0K/0M is specified, the MEMLIMIT
| is set to NOLIMIT.

| Note: This may cause storage problems. See the Considerations When
| Using the REGION parameter section for more information.
REGION=0K and REGION=0M allocate precisely the SAME amount of storage. And both of them allow use of storage above the line as well as below the line.

And you should not be using either without direction from your site support group -- there can be system issues with REGION=0M/K.
William Collins
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Re: Is there any difference between Region=0M and Region=0K

Post by William Collins »

The original gibberish is actually from IBM-MAIN :-)

Note the prescient comment later:
I picture a newbie searching google or the archives in the future being
very confused by this thread. :-)

--
Mark Zelden - Zelden Consulting Services - z/OS, OS/390 and MVS
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Anuj Dhawan
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Re: Is there any difference between Region=0M and Region=0K

Post by Anuj Dhawan »

Rightly said, William. And I'm still trying to understand the statement there about 0 Petabytes! :)
Thanks,
Anuj

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William Collins
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Re: Is there any difference between Region=0M and Region=0K

Post by William Collins »

Zero is zero, no matter what the units. The guy saying 0K is 1000 times smaller than 0M is being silly (it isn't even 1024 times smaller). Taking that "logic", zero petabytes is big, but of course it isn't.

In this case, zero doesn't even mean zero. Zero means "I'm not limiting the memory my program requires, give it all available" which is not necessarily such a good idea. The gibberish post is so full of rubbish, it is not worth pulling apart.
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Re: Is there any difference between Region=0M and Region=0K

Post by Anuj Dhawan »

I do agree, William.
Thanks,
Anuj

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