[HECnet] UPS driven OPC$CRASH?

[G.]

On Sun, 31 May 2020 14:30:15 -0400, Thomas DeBellis wrote:

> Can anybody elaborate more on what the VMS power failure options are?  
> OPC$CRASH sure looks like a crash, but what happens before the belly up?

You may want to take a look at the VAX/VMS Internals and Data Structures
manuals on Bitsavers where you could find editions for V3.3, V4.4, and V5.2.

There is a whole part (VII or VIII depending on the edition) completely
devoted to the bootstrap process, initialization, shutdown, power failure
and recovery, and so on :)

See http://bitsavers.org/pdf/dec/vax/vms/training/

Quote from the V5.2 book: «Powerfail recovery support enables a suitably
equipped VMS system to survive power fluctuations and power outages of short
duration with no loss of operation. The support is provided by hardware
features (battery backup) and VMS software routines. VMS support includes a
powerfail service routine that saves the volatile state of the machine when
the power fails, a restart routine that restores that state when the power
is restored, CPU-specific initialization code, and device-specific code
within many VMS device drivers. The VMS software also provides process
notification by means of power recovery asynchronous system traps (ASTs)».

HTH, :)
G.