For the most part the catalog lets you locate your dataset no matter which volume you put it on. For non-vsam, that is about all that is stored, dataset characteristics are in the VTOC. And with non-SMS volumes you can have uncataloged datasets on DASD or tape.
VSAM came from the Future Systems development as a complete replacement, Lynn Wheeler has posts about that. It was cut back to be an addition to MVS, then combined with CVOL catalogs to ICF. On Thu, May 23, 2024 at 9:32 PM Phil Smith III <[email protected]> wrote: > > I'm curious whether any of you old-timers can explain why we have both VTOCs > and catalogs. I'm guessing it comes down to (a) VTOCs > came first and catalogs were added to solve some problem (what?) and/or (b) > catalogs were added to save some I/O and/or memory, back > when a bit of those mattered. But I'd like to understand. Anyone? > > > ---------------------------------------------------------------------- > 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
