Re: Hot swap kernel

Kalle Andersson (
Wed, 21 Jan 1998 21:44:45 +0100 (CET)

> The problem is that new versions of the kernel change data structures in
> memory and add new features (changing the position of code in kernel memory).
> The only way it could be feasible to change the kernel with the current
> system
> design is if the new kernel had the same internal data structures, and the
> same code size as the old kernel. To have a kernel match these criteria it
> would not only have to be the same version, but compiled with the same
> options
> (so it would be a null upgrade).
> Some work has been started on process migration. This if completed will
> allow you to migrate processes around in a cluster of machines. It may be
> possible to migrate processes off a machine, reboot it, and then migrate them
> back on.

Many portables has got a feature which allows you to turn of the machine and
restart it without needing to boot again. Basically I think it flushes the
memory and info about processes.. Before it does that it probably syncs the
discs etc. This feature didn't work to well on Linux but the theory...
I am not sure (as usual) but if it would be possible to freeze the system,
flush all interesting info including the entire memory and make the new kernel
cooperate with the "old" info..
Perhaps it would only operate if we killed all processes perhaps even umounting
all filesystems. This wouldn't be bad at all. I can imagine this won't take
more then perhaps 10 seconds. A major time saving compared to a complete
reboot... But then all network connections would be lost, but it is at least a
start =)

YOU!!  Give me the CUTEST, PINKEST, most charming little VICTORIAN
DOLLHOUSE you can find!!  An make it SNAPPY!!

------------------------------------------------------------------------------ Kalle Andersson