On Wed, Sep 01, 2021 at 03:18:52PM -0400, Jim Mulder wrote: > The use of REFR for storage error recovery was only > in predecessors of MVS, and that was before my time > at IBM. I only know about that because of Shmuel's > posts about it.
I remember a mention in MVT/360 of the REFR attribute being used by the machine check handler. I don't remember any other uses of REFR in MVT/360. > Although it was before my time, I would guess that the > key 0 protection for RENT programs from APF authorized > libraries was added only because it was required for > system integrity, and limited to APF authorized libraries in > order to avoid migration impediments that would have > resulted from breakage to existing self-modifying RENT > programs in non-APF authorized libraries. That would > have been consistent with MVS's emphasis on compatibility, > and thus is not astonishing to me. This subpool 252 usage goes back to at least MVT/360 too. > The probability of a storage machine check on current machines > is so low that, if anything, we would be simplifying or removing > storage error machine check processing in z/OS, not enhancing it. Unlike the 360/91KK at UCLA with 4M of core memory and only parity checking. While there likely were memory errors (and spare memory modules in the FE area), memory errors don't stand out. I remember more other problems and "old machine" flat cable (silver whiskers) shorts, perhaps because they took longer to fix and/or were more recent. There were many more software problems, many local code and/or local modification related. After reading many dumps and many software fixes, the software limit was out of SQA (system wait state E04). Two memory leak fixes later the system uptime became mostly hardware limited. The 360/91 was very old when it was replaced with a 3033 (the 370/168 wasn't fast enough, the 360/91 already had many of the 168 performance features). ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
