On 18 May 2009 13:35:40 -0700, in bit.listserv.ibm-main you wrote: >> -----Original Message----- >> From: IBM Mainframe Discussion List >> [mailto:[email protected]] On Behalf Of Bill Klein >> Sent: Monday, May 18, 2009 1:45 PM >> To: [email protected] >> Subject: Fw: BLOCK CONTAINS >> >> John, >> What happens if you run the exact same test, but instead of >> having the JCL >> for your output as: >> // RECFM=FB,LRECL=80,BLKSIZE=0,DSORG=PS >> you instead JUST coded >> // DSORG=PS >> >> i.e. you leave out the JCL (overrides) for RECCFM, LRECL, and >> BLKSIZE) - I >> think that this is when/where the different BLOCK CONTAINS >> clauses make a >> difference. > >Ah! NOBLOCK had F/80/80 whereas BLOCK1 had FB/80/80. BLOCK0 still had >FB/80/27920. But it is still interesting, to me, that BLOCK CONTAINS 1 and no >BLOCK CONTAINS at all can still create an optimally block dataset with little >effort in the JCL and no program changes.
This is weird because the normal merge is DCB overrides JCL and JCL overrides data set label (DSCB or tape label). The code to distinguish between BLKSIZE=0 in JCL and BLKSIZE not supplied must be interesting to say the least. If I get energetic, I'll check the COBOL Programmers Guide. Talk about ways to confuse the applications programmers and subtle ways to screw up. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
