New NOTIFY system call! Queued at kernel. Duplicate messages (with same source
and type) are overwritten with newer flags/ arguments. The interface from
within the kernel is lock_notify(). User processes can make a system call with
notify(). NOTIFY fully replaces the old notification mechanism.
sync after install in case of trouble while shutdowning
Make use of vectored virtual copy system call
Added 2 checks to mapping function - one for overflow (virtual address +
size wraparound), one to see if the size fits in the designated segment.

It seems this check wasn't done. This came to light when trying to pre-check
the users buffer for read() and write() in using the vectored virtual
copy system call in servers/fs/read.c.
Initialisation required for optional debugging code.
. fixed a recently introduced scheduler (run-queue) bug in proc.c
. a little (optional) debugging code added to proc.c and associated
  data in proc.h
added a debugging functionality in system/debugging.c (to check sanity of
run queues) and associated prototype in system.h
fixed compile breakage
Fixed some minor issues with the NOTIFY call.
this test breaks on the new pre-i/o i/o buffer check. it wants to read
more than its buffer allowed, so it is reasonable that it breaks. reducing
read request size 'fixes' it.
Optimized scheduling code. Old code is still available withing DEAD_CODE
and NEW_SCHED_Q definitions. Some minor problems are being traced at the
moment. This commit is meant to backup my files.
  --- Jorrit
Improved NOTIFY system: fixed a minor error, ignore pending notifications
on SENDREC system calls. To be done: resource (buffer pool) management;
make it structurally impossible to run out of buffers.
Fixed a bug in PM: sending of reply messages didn't check if destination
process is still alive. This caused a panic in some situations, e.g., when
all processes are killed on a shutdown.
Created ECHO system call for testing purposes.
Furthermore, a quick way to get one's own process number.
Kinfo counts lock_notify() and lock_send() calls.
Improved shared device driver code: use SELF instead of 'getprocnr'.
Fixed PM send() failed warning: don't reply to killed process that did reboot.

:  `VS: Enter Log.  Lines beginning with `CVS:' are removed automatically
Imported kermit v2.11
Fixed clear_proc(): properly release resources (IRQ hooks, notify buffers);
Cleaned up comments in proc.c (old code still present for comparison);
SENDREC now always has flag FRESH_ANSWER to prevent pending notifications
to be used as answer to a SENDREC call.