We used it in 1978 on OS/MVT to write fixed-length tape reels in multi-reel files, with a checkpoint after each reel ( Assembler application). If a tape went bad we could restart the job that created the tape at the checkpoint just before that reel was written, and not have to rerun the entire job.
Mike Shaw MVS/QuickRef Support Group Chicago-Soft, Ltd. On Sun, Jun 18, 2023, 11:39 AM Seymour J Metz <[email protected]> wrote: > Checkpoint is an old (as in OS/360 old) facility that comes with > restrictions that make it less useful than it might otherwise be. I'm not > sure what the use case is these days. > > > -- > Shmuel (Seymour J.) Metz > http://mason.gmu.edu/~smetz3 > > ________________________________________ > From: IBM Mainframe Discussion List [[email protected]] on behalf > of Bernd Oppolzer [[email protected]] > Sent: Sunday, June 18, 2023 7:57 AM > To: [email protected] > Subject: Re: Checkpoint/restart in COBOL applications? > > I don't understand what's the implication of z/OS here; > we are using Smart/Restart, too, but IMO this is only application > programming, > no support from the OpSys needed. > > Applications running with Smart/Restart write Checkpoints with every DB2 > Commit, > that is, they record the keys involved with the controlling DB2 cursors > AND the read and > write positions of the sequentials files in a Smart/Restart specific > Checkpoint area > (which can be a DB2 table, but also sequential files). On restart, the > DB2 cursors need to be repositioned, > same goes for the sequential files. But IMO that's all application > business ... > > I don't see how the OpSys is involved here ... other than the basic > services > (DB2 Commit and positioning of files) must be provided. > > Kind regards > > Bernd > > > Am 18.06.2023 um 09:59 schrieb Binyamin Dissen: > > On Sat, 17 Jun 2023 19:50:01 -0700 Tom Ross <[email protected] > > > > wrote: > > > > :> Does anyone know if there are people/applications using > checkpoint/restart in > > :>COBOL applications? The doc only shows it is usable in programs that > use SORT, > > :>I have not heard of customers doing this in years, but someone in > IBMMAIN would > > :>know better than me! The reason for the question is that IBM is > considering > > :>removing that capability from z/OS and we are wondering how much of an > impact, > > :>if any, this would be on COBOL applications? (Actually PL/I also, but > I work > > :>in COBOL so kind of focused on that :-) > > > > The Smart/Restart product uses it and runs COBOL applications. > > > > -- > > Binyamin Dissen <[email protected]> > > > http://secure-web.cisco.com/1GniwzBgRoLp7A9NK0WTyHfEFUAyQhFsOyav0rbPRy22MjTjKDzBHd_wIr6AzOFiFwhjTrH30w20GBSsOSabXvJ2Eyl4SXW2nD4Mb1Em0aK6kMuXvkd7KIYArV-yc-rCXdpzQp_pulUrvwZqpWub5By1wb3FW0dXeGo04gTQWwyqNOtfiBjLVMbL1V03gwK7e6sRqArSfa4PwyOkIEanDgB5-P5XUB4qdwzh6hCPyf6J8XFIcSX2QwKZyAX4pOnMjBl7O0Ff57m3jJ8Q9r7R6BiVns2OTCMESuJY2KXP0mfvXHSqSzIfr4WYWZgQ0evHVf3LItLxPT8XcTlc5zGVxV24YdFo7MKdH-4Z5IDStoyplwZf3mmRi4DS8xftPdgjeu9Nf2KTD4T93i41j2uPvkVAbspqHctl-YarIQpU-030/http%3A%2F%2Fwww.dissensoftware.com > > > > Director, Dissen Software, Bar & Grill - Israel > > > > ---------------------------------------------------------------------- > > 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 > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
