[gclist] memory protections and system calls

[Nick Barnes]

> I'm not sure I understand your point.  What in particular is it about the
> structure of current operating systems that makes this dangerous?  Is it
> that they're not multithreaded, hence can't stop in the middle of a system
> call and let a user process fix a problem, because the OS will lock up?
> Or is it something else?  Why do you need capabilities (or whatever) to
> fix it?

I agree with Paul. It seems from David Chase's note about the register
spilling code in SunOS/Solaris that this mechanism is _exactly_ what
was intended there (and would have been provided were it not for a
minor bug).

Nick B