Subject: Re: persistent/restorable unix procs?
To: Travis Hassloch <>
From: David Leonard <>
List: current-users
Date: 11/29/1995 15:26:55
> Has anyone done any work on (or looking into) how one might dump a process's
> state to disk & restore it, assuming it's a cooperating process?
> E.G. maybe you have a process that wants to save itself on purpose.
> To make it harder, how about an uncooperative process?
> Is this possible under stock Unix (specifically, stock NetBSD)?
> I know there are some issues regarding shared code segments...
> Probably a lot more issues regarding stuff that isn't exactly in it's
> address space...  I'm wondering if someone has attacked this thing already.
>'s just something I've been musing over w.r.t rollbacks and/or
>      window manager "sessions"...
> CC me in replies, thanks....

I seem to recall an `undump' feature of sunos - the perl manpage also talks
about it, essentially the program calls abort() and the core file can be
`undumped' into another executable that when run restores the process
image.  Unsure if netbsd can do this (no manpage on it).

I think there would be problems with file descriptors and such, but i
dont know - I've never tried it. Some prolog engine i built once also
did something similar (`undumped' itself so it initialised quicker).


David Leonard                            BE(Comp)/BCompSc 5th year student
The University of Queensland   
perl -e 'for $c(split(//,"BILLGATES\003")){$s+=ord($c)};print $s."\n"'