4.18. What are lipc and nipc, and how can I use nipc instead of lipc?

	/etc/lddrv/lipc is the loadable device driver that implements
System V inter-process communications on the UNIX PC (semget(), etc.).
/etc/lddrv/nipc is a newer implementation of this driver which fixes
an IPC bug, but was never fully tested.  The default driver loaded by
/etc/lddrv/drivers is lipc, and in fact, this is the driver which the
program ipcs looks for when it reports on IPC usage.  No bugs with nipc
have been uncovered since it was made available (87?), and many people
would rather run the "better" driver than stick with the old lipc.

	There are two approaches for replacing lipc with nipc.  The
most obvious way is to edit /etc/lddrv/drivers to replace lipc with
nipc for when the system is next booted, then replacing the in-core
lipc with nipc with the following sequence:

		# cd /etc/lddrv
		# ./lddrv -dv lipc
		# ./lddrv -av nipc

	Unfortunately, ipcs will not find the lipc driver, and so
won't give any IPC status.  This can be overcome by wielding a binary
editor in the general direction of /usr/bin/ipcs, replacing the
hard-coded instances of "lipc" with "nipc".

	Another method is to remove lipc from core (./lddrv -dv lipc),
rename its files to something benign (lipc -> lipc.old, lipc.o ->
lipc.o.old, ifile.lipc -> ifile.lipc.old), rename the nipc files to be
lipc (nipc -> lipc, nipc.o -> lipc.o, ifile.nipc -> ifile.lipc), and
finally reload the new lipc (./lddrv -av lipc).