> Mark Hittinger writes:
> >
> >Something that the old DEC took a few stabs at was the idea of a
> >"checkpoint" feature where a process or a series of processes could be
> >put in a quiesced state. This would page out the process or processes
> >into the swap space, allow a hardware shutdown, and after a reboot allow
> >the restart of the checkpointed process(es).
> >
>
> I did something like this for Philips while I was at UniSoft. It
> depended on some special hardware features (turning off/losing power
> generated an interrupt, there was a small UPS in the box along with
> battery-backed SRAM to save various kernel structures).
>
> Turning off the power caused all memory to be saved to disk (the kernel
> turned off the UPS after it was done). Upon a restart the kernel noticed
> that memory had been saved, read the contents in from disk, futzed around
> with some structures, and restarted what was curproc at the time of
> shutdown. It even worked ;-)
>
> Philips never did anything with it.
Out of pure curiosity, what did you do with pending interrupts, partially
completed DMA transfers and other such state information?
Pat.
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Patryk Zadarnowski <[EMAIL PROTECTED]> University of New South Wales
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