UNIX Futures

[Doug Kingston]

Shell layers is a way to get around not having true windowing.  If you
have a real windowing system, then you don't need shell layers.  As has
been mentioned by others, shell layers are deficient in several areas.

As for Berkeley job control, this is another matter.  As a mechanism
for handling multiple jobs simultaneously, it is a poor second to
a true windowing system.  I know.  I use BLIT terminals and SUN-like
workstations every day.  However, this does not mean I want to give
up the ability to STOP and RESTART jobs.  By STOP, I mean really stop
the job and take it from the RUN queue.  This is a very powerful
process control facility.  This is an orthogonal capability to windowing
or layers.  The two are complementary.  One of my favorite uses for
BSD job control is taking core dumps of processes in infinite loops
or which have gone "catatonic".  In order to get a consistent coredump
you must insure the process is NOT running.  Job control allows you
to accomplish just that.  It is then possible to safely collect the
processes context from /dev/*mem (using the "gcore" program in 4.2BSD).
You can then continue the process afterwards with no ill effects.
There are numerous other examples where this type of process control
is useful.

In summary, look at the broader uses of BSD job control before condemning
its usefulness.  Its not just for allowing simultaneous processing.  I would
urge other vendors to seriously consider adding this type of process
control facility.  I believe that the BSD facilities and many more are
provided through /dev/proc on V8 Unix, although they may not be as efficient.

Cheers,
	-Doug-

	Doug Kingston, CWI ("mcvax"), Amsterdam