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Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!decwrl!ucbvax!pasteur!ames!amdahl!pyramid!prls!philabs!pwa-b!mmintl!franka
From: franka@mmintl.UUCP (Frank Adams)
Newsgroups: comp.arch,comp.lang.misc
Subject: Re: Universal OS (was Re: Survey of
Message-ID: <2845@mmintl.UUCP>
Date: 29 Apr 88 16:58:22 GMT
References: <769@imagine.PAWL.RPI.EDU> <76700017@uiucdcsp> <843@actnyc.UUCP> <762@l.cc.purdue.edu>
Reply-To: franka@mmintl.UUCP (Frank Adams)
Organization: Ashton-Tate Corporation, East Hartford Development Center
Lines: 39

In article <762@l.cc.purdue.edu> cik@l.cc.purdue.edu (Herman Rubin) writes:
>The language ... should ... try to include it _all_.

The problem with this is that the more things you throw into a language, the
harder it is to write a compiler for it.  And harder, when it comes to
software, means it takes longer.

Suppose we define this super-duper, all inclusive language.  Now a new
machine comes along.  Two years after its introduction, we want to run our
program on it.

In case 1, the program was written in some relatively simple language,
perhaps C.  The compiler writers got a compiler working in 6 months; they
have now had 18 months to optimize the output it generates.

In case 2, the program was written in our all-inclusive language.  In this
case, two years is barely enough time to write the compiler.  No
optimization has been done at all.  Furthermore, there are probably bugs in
the less used features of the language; if our program takes such features
into account, it will likely not work.

The result: although we have taken advantage of language features which
theoretically give us, say, a 10% speed improvement, the lack of
optimization makes the program run 30% slower.

The situation doesn't get much better.  However much optization has been
done on our huge-language compiler, that much more has been done on the C
compiler.  Maybe ten years after the introduction of the machine, the curves
will cross (*if* development continues on the compiler for a language which,
all things considered, is not being used much), but by then the hardware is
obsolete.  (It may still be in use, but if performance is our main concern,
we will have gone to something else.)

The desire to throw everything and the kitchen sink into a language is a
very natural temptation, but it is a mistake.
-- 

Frank Adams                           ihnp4!philabs!pwa-b!mmintl!franka
Ashton-Tate          52 Oakland Ave North         E. Hartford, CT 06108