[CALUG] Saving/restoring process states

[junekis at comcast.net]

What you are wanting to do is often refered to as checkpoint/restore

It was a practice that was common back when computers were slow and unreliable and processes ran for a long time before completing.

Checkpoint/restore let a user recover part of the work that had been done in the event of a machine crash.

Try these utilities:

http://mantis.lbl.gov/blcr/doc/html/BLCR_Users_Guide.html

http://www.ncl.cs.columbia.edu/research/migrate/crak.html

JRU
 -------------- Original message ----------------------
From: "Jason C. Miller" <jason.c.miller at gmail.com>
> 
> My questions are rarely simple...and here's another one.  ;)
> 
> Does anybody know of a method (or backdoor hack) that would allow a user 
> to dump the current state of a process and then restore it later?  Kind of  
> analogous doing a <ctrl>-Z and then an 'fg' later when you want to 
> unsuspend the proc except, in my instance, the process would be kill()ed 
> for later resurection.  Kinda like high-level context switch.  
> 
> If you're still confused as to what I mean, here's the example that 
> started me wondering...
> 
> I was using a game emulator that doesn't have a "save/restore game state" 
> function.  I figured it wouldn't behoove me too terribly much to try to 
> come up with something on my own.  Say I've been playing for hours and I'm 
> tired.  I really don't want to use the game's actual "Save" utility 
> because it might start me at some predetermined checkpoint the next time I 
> started the game (eg: metroid, zelda).  So, I'd use this magical utility 
> that I would like to save the current state of the process somewhere on 
> non-volatile storage.  Later (after so many days and so many reboots), I 
> restore that process and continue exactly where I left off.  
> 
> Questions:
> 1. Does UNIX already have a method for doing this that I don't know about?
> 2. My OS fundamentals are rusty.  Any reason why an OS wouldn't be able to 
>    support this? (waiting for the OS profs out there to chime in on this 
>    one).  I understand that register values and such would be a problem, 
>    but if the process was suspended first, would that make a difference?
> 3. Any ideas anyone?
> 
>                                     -jason
> 
> 
> 
> 
> -- 
> 
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