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From: david@ztivax.UUCP
Newsgroups: net.arch
Subject: Missionary Position .vs. 69
Message-ID: <2900019@ztivax.UUCP>
Date: Mon, 14-Jul-86 04:49:00 EDT
Article-I.D.: ztivax.2900019
Posted: Mon Jul 14 04:49:00 1986
Date-Received: Tue, 15-Jul-86 05:03:34 EDT
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Nf-ID: #N:ztivax:2900019:000:1877
Nf-From: ztivax!david    Jul 14 09:49:00 1986

>> jdg@elmgate.UUCP (Jeff Gortatowsky) writes:
>>It was always
>>my feelings that, if a CPU manufacturer were to write the language compilers
>>first, THEN generate a CPU design to run it, we'd all be alot happier.

I do NOT agree.  I first thought it made sense, but no longer.  Here
is why:

I know of one system which was completely developed like this.  Some
software people wrote "the perfect language" and the "perfect OS
concepts" and then some smart HW folks developed the hardware to
support it.  It has some really neat features, but (of course) it has
some problems too.  More good things than bad, but there is one BIG BAD
PROBLEM.  It has got to be the world's most un-portable system.  Since
the whole world is making advances in chips, the state of the art
tends to advance faster (over a long time) than any one company can, no
matter who they are.  If a system is un-portable, then it may be great
for awhile, but over time, it will fail to keep up with the state of
the art, and will end up getting tossed in the trash can of history.

This sort of bothered me, but perhaps this is the reason:

> rb@cci632 (?) writes:
>Most programmers today are "top down" trained, and not used to thinking
>in terms of primitives.

I think we can all come up with dozens of examples of how systems
which are collections of useful primitives are better for developing
new solutions to problems than systems with a poor choice of
primitives.  UNIX is an obvious one.

In other words, a bottom up design allows the top levels (the "user"
language) to work better, nd to be more flexible: the user is not
tied to one language which may be applicable to one use, but can
develop or choose other languages which have better primitives for the
problem at hand.

(slight pause to don flame-proof suit)

Top-down sucks, bottom up is better.


David Smyth

seismo!unido!ztivax!david