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Is there any difference between Region=0M and Region=0K ?
Posted: Tue Dec 02, 2014 4:44 pm
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?
Re: Is there any difference between Region=0M and Region=0K
Posted: Tue Dec 02, 2014 5:17 pm
by Robert Sample
If you check the JCL Reference manual, the syntax indicates 0K and 0M are the same.
Re: Is there any difference between Region=0M and Region=0K
Posted: Thu Dec 04, 2014 2:04 pm
by Vijay Ingle
So they are just same way of saying the same thing (to the system)?
Re: Is there any difference between Region=0M and Region=0K
Posted: Fri Dec 05, 2014 3:37 pm
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!
Re: Is there any difference between Region=0M and Region=0K
Posted: Fri Dec 05, 2014 5:01 pm
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 ?
Re: Is there any difference between Region=0M and Region=0K
Posted: Fri Dec 05, 2014 5:26 pm
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.
Re: Is there any difference between Region=0M and Region=0K
Posted: Fri Dec 05, 2014 10:29 pm
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
Re: Is there any difference between Region=0M and Region=0K
Posted: Sat Dec 06, 2014 2:57 pm
by Anuj Dhawan
Rightly said, William. And I'm still trying to understand the statement there about 0 Petabytes!
Re: Is there any difference between Region=0M and Region=0K
Posted: Sun Dec 07, 2014 6:14 am
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.
Re: Is there any difference between Region=0M and Region=0K
Posted: Sun Dec 07, 2014 6:09 pm
by Anuj Dhawan
I do agree, William.