Is 4.2BSD a failure?

[Dick Dunn]

>      4.2BSD is an experiment that seems to have failed.

Careful here.  An experiment which fails is one which produces no results
or conclusions.  I think that 4.2 has given us a wealth of information.  
Arguably it may have produced more information than code with long-term
usefulness, but that's too early to tell.

>...I am speaking only of 
> the kernel, not the rest of the system here.  The much-touted ``fast file 
> system'' does not seem to deliver anything like the promised order of magnitude 
> performance improvement; in fact, overall 4.1BSD seems to slightly outperform 
> 4.2.

The kernel work was the most ambitious, yet it seems to be the best of the
work.  There were mistakes in the kernel.  My suspicion is that the fast
file system actually has some significant improvements which are masked by
some screwups and some changes elsewhere.  There hasn't been a lot of
real-world experience reported (outside of Berkeley, for the sake of non-
biased views and replication) to judge by.  Still, the kernel work is an
both genuinely useful and an order of magnitude better than what went on in
other areas--some of it best described as blind hacking that we'll be
finding and fixing for the next couple of years at least.

>...4.2BSD has a huge resident kernel because of the large number of new and
> in many cases little used features...

Software development goes in cycles.  You try out a bunch of new ideas and
cobble something together to see if the ideas will really work.  Things get
screwed up here and there; the code gets hacked over and balloons on you.
Finally someone comes along, extracts the concepts from the mess, makes
everything nice and orthogonal and small.  Then the cycle starts over,
trying new ideas on top of the old ones and making a mess (but learning a
lot of new good stuff in the process).  Personally, it seems like UNIX
became generally known (in the V6/PWB/V7 time frame) when it was a fairly
tight, clean system.  4.2 is out on the limb of a lot of experiments.  It's
time to admit that some of the ideas didn't work and the rest need cleaning
up.

Perhaps the biggest mistake made with 4.2 is the attempt to treat it,
unmodified and not carefully debugged, as a production system.  That
mistake can hardly be laid completely at Berkeley's door, by the way.
People who just port 4.2 to their machine without any tuneup, cleanup, or
bug fixing are asking to be seriously embarrassed.

>      What are other's thoughts?  Was all the trouble worth it?  Should
> further work proceed from a 4.1 base?  A system V base?  Or what?

If any more Research systems see the light of day, we might find another
base for development there.  Someone MIGHT even consider taking the
concepts and starting over from scratch.  It's been done before:-)
-- 
Dick Dunn	{hao,ucbvax,allegra}!nbires!rcd		(303)444-5710 x3086
   ...A friend of the devil is a friend of mine.