Joined: 15 Dec 2002 Posts: 637 Topics: 43 Location: Bengaluru, INDIA
Posted: Thu Sep 25, 2003 3:04 am Post subject:
Neo,
For example, in DFSORT, even if you do not code DCB, the dataset will automatically have the correct DCB values. It is done by DFSORT itself. So, it seems, the DCB (in the JCL) was overriden by the program that created the dataset. What program was being used to create that dataset? COBOL program? Try looking into the program.
I cannot say anything about SPACE. Every shop has its own ways to deal with SPACE. _________________ ALL opinions are welcome.
Debugging tip:
When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
-- Sherlock Holmes.
Joined: 26 Nov 2002 Posts: 12378 Topics: 75 Location: San Jose
Posted: Thu Sep 25, 2003 3:17 am Post subject:
neoframer,
Are you sure that the one step shown above is referring the dataset. I bet there is a pgm probably writting a report to the dataset. recfm=fba are usually reports with carriage control character.
Code:
// SPACE=(0,(500,800),RLSE),
It indicates an average record length of 0 bytes, a primary quantity of 500K (500* 1024) records, and a secondary quantity of 800K (800* 1024) records.
You are missing another Parameter AVGREC=K in your dataset definition
Joined: 26 Nov 2002 Posts: 12378 Topics: 75 Location: San Jose
Posted: Thu Sep 25, 2003 10:36 am Post subject:
Cogito,
You are right about DFSORT calculating the DCB parameters.
Quote:
I cannot say anything about SPACE. Every shop has its own ways to deal with SPACE.
This is partially true when you are using DATACLAS parameter. But if you are coding space allocations using SPACE parameter, it does not differ from shop to shop.To explain in detail
let us say you have coded the following space parameter
Here the dataset will allocate 30 primary cylinders + 15 times 10 secondary cylinders irrespective of the mainframe shop.If volume runs out of space the job will abend with either a SB37 OR SE37.
In this case we are using the dataclas parameter to allocate space, Our shop is SMS managed and it assigned a class FBSML (Fixed block SMALL). This is to be used when the dataset size is 0 t0 10MB ( 1 TRKS - 20 CYLS).
The use of dataclas parameter has the following advantages.
Code:
Never having to determine correct blocksize. With DATACLAS you automatically receive SDB (System Determined Blocksize).
Eliminates the SPACE parm if allocation is LT 400MB (500 CYLS)
Eliminates "RECFM, UNIT, and MODEL" portion of DCB parm.
By using DATACLAS, you will be reducing DASD space allocations by using optimum blocking factors, regardless of device type.
Joined: 15 Dec 2002 Posts: 637 Topics: 43 Location: Bengaluru, INDIA
Posted: Thu Sep 25, 2003 10:48 am Post subject:
Kolusu,
I was not hinting at DFSORT. But, my aim was to point that, the DCB parameters can be (and, often is) set by the program rather than JCL parameters.
I have had experience with SPACE parameter. That is why I posted that, it is often shop dependent. I posted a query at mvshelp which is directly opposite to your first example. The query was based on a experience at my former shop. _________________ ALL opinions are welcome.
Debugging tip:
When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
-- Sherlock Holmes.
Joined: 07 Feb 2003 Posts: 266 Topics: 1 Location: Edison, NJ USA
Posted: Thu Sep 25, 2003 3:17 pm Post subject:
Getting back to neoframer:
Quote:
// SPACE=(0,(500,800),RLSE),
uses the blksize selected by the system when you used dcb=blksize=0 to allocate the space you requested, i.e. enough disk space to accommodate 500 primary blocks of 3325 bytes each and 800 secondary blocks x 16 (max) secondary space. In this case I don't think the AVGREC param is needed.
Neoframer, you might want to research "DCB merge". It describes the relationships among DCB info in the d/s label, catalog, JCL, and pgm. It tells you which source is used to fulfill your request.
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