[XCSSA] updating a kernel without rebooting

[xcssa@xcssa.org]

On 8/17/06, xcssa-admin@xcssa.org <xcssa-admin@xcssa.org> wrote:
> OS/9 was a Unix-like OS.  It was definitely not based on anything in
> CP/M.

CP/M was based on Unix.  QDOS was based on that, and MS-DOS on that.
Hence, the cd command, among others.

> In any case, OS/9 was very modular, in very much the way that Linux
> isn't.

IIRC, it was classified as a microkernel.  Wasn't minix too?

> The problem is that the core kernel itself has to install itself in
> the system call vectors, of which there is only one set at the kernel
> level.

If you're doing the kernel upgrade in supervisor mode as an atomic
operation, this is no problem.  Nobody is making system calls.
Hardware interrupts are another story.

> Also, drivers in the kernel must be compiled with
> dependencies on symbol locations in the kernel, even in a fullly-
> modular kernel.

Sort of like dynamic libraries?  You resolve the symbols at load time.

> The most important question is "Why?"  If the answer is "to keep my
> k3wl uptime!" then it's a waste of time.  If the answer is "high
> availablity", then the reply is "if you need HA so badly, why are you
> tinkering around hoping you can make something work, rather than
> paying money to someone who already has it working?"

People with money pay the people who tinker around.  Sometimes.
-- 
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