System Troubleshooting and Diagnostics
5.2 Product Fault Management and Symptom-Directed Diagnosis
These conditions cover all of the cases which will eventually be handled by the
OpenVMS error handler. The OpenVMS error handler will generate entries
that correspond to the machine check exception, hard or soft error interrupt
type, or polled error.
5.2.2 OpenVMS Operating System Error Handling
Upon detection of a machine check exception, hard error interrupt, soft error
interrupt or polled error, the OpenVMS operating system will perform the
following actions:
• Snapshot the state of the kernel.
• In most entry points, disable the caches.
• If it is a machine check and if the machine check is recoverable, determine
if instruction retry is possible.
Instruction retry is possible if one of the following conditions is true:
1. If PCSTS <10>PTE_ER = 0:
Check that (ISTATE2 <07>VR = 1) or (PSL <27> FPD = 1)
Otherwise crash the system or process depending on PSL <25:24>
Current Mode.
2. If PCSTS <10>PTE_ER = 1:
Check that (ISTATE2 <07>VR = 1) and (PSL <27>FPD = 0) and
(PCSTS <09>PTE_ER_WR = 0)
Otherwise crash the system.
ISTATE2 is a longword in the machine check stack frame at offset (SP)+24;
PSL is a longword in the machine check stack frame at offset (SP)+32; VR
is the VAX Restart flag; and FPD is the First Part Done flag.
• Check to see if the threshold has been exceeded for various errors (typically
the threshold is exceeded if 3 errors occur within a 10 minute interval).
• If the threshold has been exceeded for a particular type of cache error,
mark a flag that will signify that this resource is to be disabled (the cache
will be disabled in most, but not all, cases).
• Update the SYSTAT software register with results of error/fault handling.
• For memory uncorrectable Error Correction Code (ECC) errors:
If machine check, mark page bad and attempt to replace page.
Fill in MEMCON software register with memory configuration and
error status for use in FRU isolation.
System Troubleshooting and Diagnostics 5–5
