On 2019-12-05 01:34, Paul Koning wrote:
On Dec 4, 2019, at 6:15 PM, Kevin Handy <[email protected]> wrote:
What it sounds like you need, is for simh to detect the shutdown interrupt
itself, and then save the current state of everything in the machine to a file.
Upon power-up, it then needs to restore back to that state.
You;d have to save the current configuration settings, state of memory, cpu
registers, device structures, etc., and then be able to read it all back in and
restore everything back to a working state. Could get complicated, for example
the disk drive have a timer in them so that they don't respond instantly to
read requests, so this type of thing would need to be saved.
Is it possible to manually do this right now? Store the state of a machine,
them restore it back using simh commands to individually reset all the devices?
On a PDP11, this could be handled via a power fail interrupt, assuming the OS
you have supports power fail and recovery. RSTS-11, with core memory (so you'd
want to persist the memory across restarts) does. I'm not sure if others do.
(RSTS/E does not.)
Right. And all members of RSX do handle power fail and recovery.
Individual programs can also be notified if a power fail even happened
while they were running, in case there is something they need to do
under such circumstances.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: [email protected] || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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