Hi Mike, Good idea, unfortunately ours is set to NOBLOCK0.
Rex -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Mike Schwab Sent: Wednesday, June 15, 2022 10:33 AM To: [email protected] Subject: [EXTERNAL] Re: SMS confusion on when system determined blocksize is used https://urldefense.com/v3/__https://www.ibm.com/docs/en/cobol-zos/6.2?topic=entries-block-contains-clause__;!!KjMRP1Ixj6eLE0Fj!oJY-2fhgmnSNMdOJkIfL_jo2PmgBjGAwMAZ2SwMPSSymNSwsNvBUlpJ3DEw4OT319g1w6TmoFYKmOtRok3CSuqVxmg$ Is BLOCK0 specified as a compiler option? For a way to apply BLOCK CONTAINS 0 to QSAM files that do not already have a BLOCK CONTAINS clause, see the description of the compiler option, BLOCK0 in the Enterprise COBOL Programming Guide On Wed, Jun 15, 2022 at 8:34 AM Seymour J Metz <[email protected]> wrote: > > No, RECFM=F is unblocked, whether you use BSAM, QSAM or something else, > regardless of whether it is on DASD or tape and regardless of whether it is > SMS managed.. It means that the access method makes no attempt to block or > unblock logical records. Think of it as RECFM=FB with LRECL and BLKSIZE the > same. > > > -- > Shmuel (Seymour J.) Metz > https://urldefense.com/v3/__http://mason.gmu.edu/*smetz3__;fg!!KjMRP1I > xj6eLE0Fj!oJY-2fhgmnSNMdOJkIfL_jo2PmgBjGAwMAZ2SwMPSSymNSwsNvBUlpJ3DEw4 > OT319g1w6TmoFYKmOtRok3B6Cb1how$ > > ________________________________________ > From: IBM Mainframe Discussion List [[email protected]] on > behalf of Rob Schramm [[email protected]] > Sent: Tuesday, June 14, 2022 11:43 PM > To: [email protected] > Subject: Re: SMS confusion on when system determined blocksize is used > > Pretty sure the Using Data Sets should describe what is happening. > > I do not understand is the Non-sms data set that you say is unblocked. > What does that even mean? If it is on disk and QSAM .. it is blocked. > SDB should work regardless of SMS or non-sms as long as blksize=0 and > the other caveats in the SDB section are met. > > Also.. you say that the Tape data set is unblocked.. I question that as > well. But I don't see that you included the data set information for the > non-sms and the tape data sets. > > Rob. > > > On Tue, Jun 14, 2022 at 6:07 PM Pommier, Rex <[email protected]> > wrote: > > > Hi list, > > > > I had a strange one thrown to me from a developer and I'm hoping > > somebody can point me to something to explain why this is happening. > > Environment is z/OS 2.4 and Cobol 6.3,pretty vanilla. I've read > > through SDB explanations in several manuals but haven't found the > > explanation as to why this is happening. > > > > We have a Cobol program with record length 200, and the developer > > inadvertently omitted the BLOCK CONTAINS 0 RECORDS clause which > > according to the Cobol manual says the file is supposed to be > > unblocked. Developer runs the program in batch using a DD card like > > this for the unblocked dataset. > > > > //VSF DD DSN=TEST.DATASET.NAME, > > // DISP=(NEW,CATLG,DELETE), > > //* UNIT=VTS, > > // UNIT=SYSDA, > > // SPACE=(CYL,(5,20),RLSE), > > // DCB=MDCB.TEST.DATASET.NAME > > > > The only DCB information provided is in the MDCB statement which > > looks like this: > > > > % XT Device Dsorg Recfm Lrecl Blksz > > ---------------------------------------------- > > MDCB.TEST.DATASET.NAME > > 0 ? 0 3390 FB 200 0 > > > > Sorry for the lack of formatting, BLKSIZE=0, LRECL=200, RECFM=FB. > > > > If he runs his job with the DD card as above, going to an SMS > > managed dataset, he gets half track blocking. If he runs it > > changing it to UNIT=VTS, he gets an unblocked dataset, and if he > > runs it against DASD with an unmanaged dataset name, he also gets it > > unblocked. Definitely makes it look like something in the SMS > > configuration, however, our SMS dataclas that this dataset falls > > under does not specify to use SDB that I could find. So my > > questions are how to explain what's happening here? Why does the > > MDCB specification of SDB seem to override the Cobol program in the > > case of the SMS managed dataset but the Cobol program overrides the MDCB > > for the non-SMS datasets? > > > > TIA, > > > > Rex > > > > -------------------------------------------------------------------- > > -- The information contained in this message is confidential, > > protected from disclosure and may be legally privileged. If the > > reader of this message is not the intended recipient or an employee > > or agent responsible for delivering this message to the intended > > recipient, you are hereby notified that any disclosure, > > distribution, copying, or any action taken or action omitted in > > reliance on it, is strictly prohibited and may be unlawful. If you > > have received this communication in error, please notify us > > immediately by replying to this message and destroy the material in > > its entirety, whether in electronic or hard copy format. Thank you. > > > > > > -------------------------------------------------------------------- > > -- For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO > > IBM-MAIN > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send > email to [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send > email to [email protected] with the message: INFO IBM-MAIN -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- The information contained in this message is confidential, protected from disclosure and may be legally privileged. If the reader of this message is not the intended recipient or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any disclosure, distribution, copying, or any action taken or action omitted in reliance on it, is strictly prohibited and may be unlawful. If you have received this communication in error, please notify us immediately by replying to this message and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
