I don't think 'FS' is meaningful. Not wrong, just pointless. If unblocked, all blocks contain exactly one record.
. . J.O.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 323-715-0595 Mobile 626-543-6132 Office ⇐=== NEW robin...@sce.com -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of J R Sent: Thursday, January 05, 2017 5:22 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: (External):Re: IEC141I 013-A8: how to read VS data sets? What does RECFM=FS mean? How does it differ from RECFM=F? Sent from my iPhone > On Jan 5, 2017, at 20:12, Bill Woodger <bill.wood...@gmail.com> wrote: > > Yet in modern times the S for F has its uses. If a C/C++ program is going to > use a "seek" for a file, if the file is F/FB, then the file will be read from > the start to satisfy the seek (because there may be those embedded short > blocks), but if the file is FS/FBS (guarantee, by the person who put the S in > the RECFM, to not have embedded short blocks) then the seek is able to > calculate the position of he block containing the sought record, and then > only have to read within the block. > > I'm sure all C/C++ programmers who want to use seek on z/OS know that, since > it is documented. Yeah. Right. (at risk of starting war) people who want to > code seek to save a bit of thinking are exactly the ones who read the manuals. > > What this means is "if you are using seek in a C/C++ program to access > fixed-length records, ensure RECFM=FS/FBS. If you haven't done that, do it, > and compare the resource usage. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
