> I've been wondering.. would it be possible to improve the error handling
> and/or passing error status to user level programs from the kernel and
> drivers?

Changing the error codes that are reported via errno when system calls
fail is tough, since you'd be changing the low-level behaviour of
system calls.  I think that doing what you suggest is a good idea, but
implementing without breaking old programs or losing POSIX compliance
would probably involve adding a second errno-like interface that
provided more detail about the error that occurred.  This is something
that would bear thinking about long and hard before any hacking
starts.

			       _MelloN_