Re: Switching Kernels without Rebooting?

Kai Henningsen
2001-07-12T07:15:12Z

riel@conectiva.com.br (Rik van Riel) wrote on 11.07.01 in <Pine.LNX.4.33L.0107111913010.9899-100000@imladris.rielhome.conectiva>:

> One thing which always surprises me in this discussion
> (it comes up about once a year, it seems) is that
> nobody participating in this discussion ever starts
> writing any code for it.
>
> Is this a feature which is only wanted by people who
> don't want to code, or is this just a signal that the
> amount of trouble involved just isn't worth it?

Maybe it's a sign that the people who *would* be able to contribute have
all looked at the problem already (surely most people are annoyed how a
reboot interrupts everything), and have already concluded for themselves
that it's not possible with reasonable effort ... but there is a steady
influx of new people who don't understand enough of the problem and have
to ask.

What I'd *really* like (but don't see how to get there) would be a "save
system state, shutdown, change kernel and/or hardware, reboot, restore
state" system (where state is like "I'm logged in on this console, in this
current directory, and under X I have Netscape running and this page
displayed" but I don't care about the exact state of Squid or even if my
ISDN line is dialled in, because those "fix themselves").

I suspect to do this right would need a means of storing per-process state
controlled by the process (because only that process knows what needs to
be saved, and what can easily be reconstructed - for example, open file
descriptors to a place where we store cookies don't need to be saved, just
routinely reopened), and then every user-visible non-transient program
needs to implement it - and I don't see *that* happen in the next ten
years.

But it *does* have the advantage of not needing to save kernel-internal
state.

MfG Kai