Thanks for the feedback. We don't actually have a problem at the moment but we are going through operations automation exercise at the moment and all sorts of 'what-if' questions are being asked. My reaction to this one was 'If the once in 30 years event happens then we will have to deal with it as an exception' but I thought it might be good to canvass the opinion of those wiser than I.
Regards,
Colin Allinson
David Boyes <[EMAIL PROTECTED]> wrote:
I haven’t seen any problems
with “genuine IBM” memory, but we did have a problem with some 3rd
party RAM on our first 9121 that we eventually tracked down to bus speed
mismatch between the 9121 and the modules in the memory card. In
that one case, the symptom affected the entire VM system and showed up
as corrupted page table pointers for paging operations (which made CP *very*
unhappy – flaming death in all directions). That was a long time
ago, and turned me off 3rd party RAM for a long while; it was
a bear to track down, and (of course) it was all VM’s fault, since the
MVS machine didn’t have those problems (and didn’t have the cheaper RAM
either….sigh). Of course, we got the “we told you so” lecture from IBM,
too – but they also promptly rebid the memory upgrade to match the price
of the 3rd party RAM, so I suppose it was a net win (other than
to my sleep cycle).
I’ve never seen a memory error
that affected only one user. Have you checked the integrity of your paging
areas on disk? I have seen a paging area overlapped by a minidisk that
clobbered pages for a rarely used guest (the machine affected got started
at IPL, and then went to sleep until needed. Someone did a off-by-one error
on a minidisk definition and overlaid one cylinder of page space with a
minidisk – when CP tried to page stuff in for that guest, it got
gibberish and the guest promptly died horribly).
