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How to know the no of Track & Block Size with No. of Rec


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er.manishawasthii

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Joined: 24 Oct 2008
Posts: 6
Location: Pune

PostPosted: Wed Jan 07, 2009 10:47 am
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I'm working in data loading project .
at times i recieve task to load data into PDS or ps file.

I would like to know if i have X records to laad in a file . Then how much storage space . , Track size and block size to allocate....

The X varies from diffrent to diffrent tasks.......

Is there any formula to calculate it...................

Regards
Manish Awasthi
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Terry Heinze

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Joined: 14 Jul 2008
Posts: 1249
Location: Richfield, MN, USA

PostPosted: Wed Jan 07, 2009 10:58 am
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What is the LRECL and DSORG of the file?
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satishk

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Joined: 20 Jul 2007
Posts: 7
Location: Hyderabad

PostPosted: Wed Jan 07, 2009 11:06 am
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Hi Manish,

As i could see these kind of Q's will not be answered, but, since..u r a new member, i am answering this Q.

A Max of 6 PS files can be alocated in a PDS.
hence,number of recs is defined as ' LRECL * Blocking Factor '
This number of recs is under the constraint with the LRECL, RECFM =(Any of F,FB,V,FB)

For Example:-
LRECL= 80 then BLKSIZE = 80*100; this 100 is Blocking Factor which determines the number of recs.

The RECFM = F or FB or V or VB, since RECFM is associated with RDW-Record Descriptor Word which always occupies 4 BYTES irrespective of its Record Length and it stores the description of the Record Integer.

Henceforth, u can get the complete details of the number of Records followed by BLKSIZE.

Note: Manish, if u r defining the SPACE parameter any of TRK/CLY/BLKSIZE, then only u focuss on No. of Tracks.

Hope u know understood the basics of the BLKSIZE.

I request you to refer to the JCL basics..so that u may not ask these fundamentals.

--

SatishK.
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expat

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Joined: 14 Mar 2007
Posts: 8797
Location: Welsh Wales

PostPosted: Wed Jan 07, 2009 12:42 pm
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The basis of your answer is based on record format, record length and the number of records.

INTEGER(27998 / record length) gives the number of records per 3390 optimum block. There are two blocks on a track.

Dividing the number of records expected by the number that will fit on one track gives the number of tracks required.

Divide by 15 to find the number of cylinders required.

EXAMPLE, 391,227 records of FB LRECL=90
INTEGER(27998/90) = 311. Therefor 622 records will fit one track.
391227 / 622 = 628.9823 = 629 tracks required.
629 / 15 = 41.93333 = 42 cylinders required to store your data.

When creating a new dataset code only RECFM and LRECL to allow the system to automatically use the optimum blocksize for each device.

satishk wrote:
As i could see these kind of Q's will not be answered, but, since..u r a new member, i am answering this Q.

And why would these questions not be answered ?

Quote:
A Max of 6 PS files can be alocated in a PDS.

Well my PDS has 734 members in it which sort of blows that duff information out of the water. A directory block will contain 6 members (more if ISPF statistics are not used) and using 3390 format DASD a track will have 45 directory blocks (Except for the first track which only has 44).

Quote:
hence,number of recs is defined as ' LRECL * Blocking Factor '
This number of recs is under the constraint with the LRECL, RECFM =(Any of F,FB,V,FB)

Why bother with a blocking factor, SDB does it all for you for DASD and tape files. What constraints do you mean - please explain.

Quote:
For Example:-
LRECL= 80 then BLKSIZE = 80*100; this 100 is Blocking Factor which determines the number of recs.

See previous note for SDB

Quote:
The RECFM = F or FB or V or VB, since RECFM is associated with RDW-Record Descriptor Word which always occupies 4 BYTES irrespective of its Record Length and it stores the description of the Record Integer.

F format records do not use RDW. This is not clear in your reply.
What is a record integer ?

Quote:
Henceforth, u can get the complete details of the number of Records followed by BLKSIZE.

I do not understand this, please elaborate.

Quote:
I request you to refer to the JCL basics..so that u may not ask these fundamentals.

Not so much as ask fundamentals, but it would prevent you from being given wrong or misleading replies.
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