On 2025-06-21 14:22, Charlie Dennett wrote:
On Sat, Jun 21, 2025 at 1:44 PM Chris Adams <linux@xxxxxxxxxxx <mailto:linux@xxxxxxxxxxx>> wrote:During the last solar max cycle (like 2002 or so IIRC), a bunch of some particular model Cisco routers were crashing and/or rebooting in ISP networks because Cisco went cheap (relatively speaking, still expensive routers) and didn't use ECC RAM. And the cycle before that (around 1990) it was Sun servers crashing.As long as we're trading stories, back in the 1980's (yeah, I'm old) I was working on HP's MPE3000 systems. The model 64 had special memory that held the microcode. The microcode was constantly being checked for errors. It was usually pretty good but every once in a while there would be some kind of error and the system would halt. One day an HP engineer was in replacing the microcode memory and I jokingly said the problem was probably a stray cosmic ray. He looked at me and said "you're not far from the truth." Turns out the memory chips were in ceramic cases and there was some radioactive decay and a stray alpha (or is it beta?) particle would hit one of the bits, flip it, and cause the error.
Does anyone remember IBM/370? The CPU logic had redundant circuitry for exactly this purpose. Operations were done in parallel and then the results were compared. It there was a discrepancy, the instruction was simply repeated and the process continued. If the same discrepancy was encountered 3 times in a row, the CPU stopped with the machine exception.
Cheers Frank -- <listfrank1@xxxxxxxxx> -- _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
