Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!amdcad!ames!sri-spam!rutgers!aramis.rutgers.edu!athos.rutgers.edu!hedrick
From: hedrick@athos.rutgers.edu (Charles Hedrick)
Newsgroups: comp.lang.lisp
Subject: Re: Ada,Lisp,Flames
Message-ID: <675@athos.rutgers.edu>
Date: 28 Jan 88 01:22:26 GMT
References: <5084@well.UUCP> <5223@utah-cs.UUCP>
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 39

>2.  CMU is the only university to produce an effectively Steele-complete
>version of CL, aka Spice.  (I don't know how complete Hedrick's DEC-20
>Common Lisp is.  Charles?)

DEC-20 Common Lisp is a port of CMU's Spice.  It is as complete as
Spice was at the time it was done.  The part we did is complete, but
that is low-level functions and the compiler.  I was never able to be
sure how complete the stuff we took from CMU was, as we were depending
upon the CL validation suite to do final checkout.  As far as I can
tell, it never materialized.  Had the DEC-20 survived, we would have
kept manpower on the project and made sure it was complete, but it
didn't seem worth doing.  (DEC-20 CL was really built for the Jupiter.
There was at least one design tradeoff made on the basis of
preliminary instruction timings, and it was built to take advantage of
the bigger virtual address space simply by changing some contants.
Once the Jupiter was cancelled, our enthusiasm waned rapidly.  In my
view, the existing model isn't quite powerful enough for CL.  Typical
configurations just don't have enough memory to deal with a number of
users running CL, though one or two people can run it without trouble.
I understand it was actually used for coursework at Stanford.  We
never had that much courage.)

Certainly all the low-level primitives, compiler technology, etc., is
there, so it's just a matter of updating the Lisp system code to the
newest version of the CMU stuff.  

It is quite true that a complete CL is beyond the ability of the
typical university hacker to produce.  However if you start with Spice
Lisp, producing a CL is probably not much worse than any other Lisp
dialect.  It's certainly within the realm of a team with a few good
people in it.  It doesn't need anything like the resources that were
used to produce some recent big systems, e.g. X.  However if you had
to do it from scratch (i.e. without Spice Lisp), and you had to do it
within a couple of years (Spice Lisp took far longer to produce
something complete - which is why so many CL's based on Spice Lisp
started out as half-baked), it would probably require a team that only
a couple of big-name institutions could put together.  It's a fact of
life that software is getting bigger.  It's hard for one guy to
produce a major package these days (except if he's RMS).