On Mon, 13 Nov 2023 19:09:26 -0500, Tony Harminc <t...@harminc.net> wrote:
>Not all z/OS UNIX filesystems are VSAM linear datasets, nor do such >datasets directly match the UNIX file semantics. ZFS and HFS are filesystems, not files so why would they match UNIX file semantics? Files in z/OS filesystems match file semantics within a Unix filesystem. >> This is conjecture because logic for BSAM communications to the Unix file >> subsystem is not made publicly. > >I think you're muddling interface levels >clearly the xSAM interfaces do not talk directly to an underlying VSAM >filestore, if there is one. I said UNIX file subsystem. Of course xSAM doesn't use VSAM because all UNIX file reads and writes are thru a single address space which manages everything.in a single address space. >>A Unix file is always 1 logical record. BLKSIZE has no meaning in this >>context. xSAM works because UNIX files are 1 logical record and it's I/O methods makes each byte of that logical record easily addressable. A single read can read starting at any byte location desired for 1 byte, 1,000 bytes or to the end of that record. It's up to xSAM to determine the most suitable interface to the file. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
