On Fri, 24 May 2024 at 11:31, David Spiegel < 00000468385049d1-dmarc-requ...@listserv.ua.edu> wrote:
> Hi Rex, > VVDSs came with ICF. Before that, VSAM Clusters were ALLOCATED as either > SUBALLOCATION or UNIQUE. > SUBALLOCATION meant that the user ALLOCATED a "cloud" (i.e. DEFINE > SPACE) to hold 1 or more VSAM suballocated Dataset. > Yes, I was about to mention this. All the information for a non-UNIQUE VSAM dataset was kept in the VSAM catalogue. One advantage in those distant days of mountable disk drives was that one could allocate or delete a VSAM dataset with all its details while the disk pack was sitting on the shelf. This could be seriously useful for production jobs where the packs were mounted only when the job ran. But of course the down side - as mentioned here in a slightly different context - was that the disk volume and the catalogue could get out of sync if the disk failed, and with potentially much worse results than just some datasets not being catalogued. It was conceptually similar to a PDS and Members. > I'm not quite seeing that analogy... Have you ever met a PDS with members on different volumes? Regards, > David > Tony H. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
