If we specify block contains zero what happens

chenchi · Posted: Fri Jun 18, 2004 3:51 pm

hi
1.if we don't specify 'block contains ' clause in fd section...what will happen
2.if we specify block contains zero what happens..

plz answer

rick · New User Joined: 18 Jun 2004 Posts: 59 Location: Chennai

Hi,

If u specify Block contains 0 in COBOL pgm the JCL decides the block size with the BLOCKSIZE parameter.

sats456 · New User Joined: 29 May 2005 Posts: 12

Do you mean to say if we specify BLOCK CONTAINS 0 RECORDS in a COBOL program,the value specified in BLKSIZE part of DCB parameter from JCL will be picked up ??
If that is the case what is the point in specifying in COBOL pgm ?

priya · Posted: Sun Jun 05, 2005 12:38 am

Aditya Bhardwaj · Posted: Mon Jun 06, 2005 1:51 pm

Hi Chenchi,

If we say BLOCK CONATAINS 0 RECORDS, then in that case, the most optimum BLOCK SIZE for that particular LRECL is decided by MVS and that particular BLOCKSIZE is allocated. IF you want to check it, just run a program with BLKSIZE SIZE 0 and then see the properties of the output file created, it will automatically have a BLKSIZE allocated.

And one more thing, there is a tool called BLKSIZE calculator, which is available, just give your LRECL and expected number of records in that file and it will provide U with the optimum number of BLKSIZE to be specifieed for that file.