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From: bagpiper@netcom.com (Michael Hunter)
Subject: Forth (was Re: Real-time systems:  Windows-NT or QNX)
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Date: Thu, 20 Oct 1994 22:22:10 GMT
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Jeff Fox (jfox@netcom.com) wrote:
: In article <bagpiperCxyDBs.F3K@netcom.com> bagpiper@netcom.com
:            (Michael Hunter) writes:

: Cheap rams, NO  cache !  I am talking about 5 or 10ns instruction times
: out of cheap ram, really!  So I am talking about a half dozen to a dozen
: cpu instructions executing out of cheap memory with no cache.

Hmmm...my idea of cheap RAM is the 70 ns stuff I buy mail order or at
Frys.  But I follow what you are trying to say.  The original poster
did specify x86 and 100 Mhz parts are in the future and 200 Mhz are
a fair ways down the road.

: No.  I do not consider Forth in ROM to be Forth hardware, I think of
: this as Forth in firmware.  Forth in hardware means that the CPU
: instruction set IS the Forth language.  This is how you can get
: 100 mips out of cheap memory while drawing 100mw from a $20 chip
: that only has 7K transistors!

: Next year we will double the cpu performance and combine
: multiple chips with on-chip hardware for increased
: performance in a multiprocessor arangement.

OK, as in some of Mr. Moore's work.  I mgiht buy that.  The 5-10 ns
CPU clock seems like it will take more then "cheap" RAMS.  But I follow
and I agree that it might be a very good solution for the robot.

: >If an engineer working for me came up with this comarison I would probably
: >start discounting his advice.  Sorry.  I like and have used Forth and
: >shameless pushing of Forth as you do above is damaging to Forth.

: What part would you discount?

The rampant exageration in the earlier post leads me not to be able to 
believe your claims in this post.  A kindof "the boy who cried wolf".  
If your first analysis would have been reasonable
then I might have been really impressed with this one and followed up
with some interest.  We have some field devices that might benefit from
the type of Forth hardware you are talking about.  Oh well, I've always
had a hard time not getting a bad taste in my mouth from car sales tactics.

: Shameless? Sure why not?  Forth gets a lot of bad press for lots
: of things, and one of them seem to be that people dismiss Forth
: for many reasons.  I just hate to see people trying to solve
: problems in the real world make things so difficult for themselves.

I agree with the last sentence.  What Forth *doesn't* need is to be
proposed for everything so it just gets mentioned.  It also doesn't
need impossible-to-stand-up-to-in-most-cases sales tactics.  Those are
both "bad press".

: I couldn't agree more about the original poster needing to do
: something along this line of analysis.  It should be pretty
: easy to answer an QNX vs WINDOWS for real-time question.  The question is 
: a little more involved if you also bring Forth solutions into the
: picture.  That all, take it or leave it.  (Should I hang my head
: in shame?)

The question is easy no matter how many "options" you are considering.
What needs to be done first is to generate a set of requirements for the
target platform.  After that any options that have debilitating
political opposition in your organization should be cut (this is to save
your stress level).  Then as much information on each option should
be collected.  Any that don't meet your requirements should be cut.
A cost analysis should be done.  Cost includes the cost of training, 
replacement of hardware if vendor goes out of business, etc. beyond the
cost of the actual hardware.  Now go through a little grief making
some subjective tradeoffs and make a decision.  Not too hard if you get
the first step right.  Ugly if you don't.  It also fails if you are
on the bleeding edge and are getting "beta" hardware or choosing
a house to design/build some hardware for you.  

And no, don't hang your head in shame.  You have a point.  Stand behind
it with truth, no exageration.

: I just want people to know that there are a wide range of choices.  If
: it offends people to notice that the emporer has no clothers it isn't
: my fault, I just pointed it out.

It turns out that I agree that there are lots of options.  But you have
to realize that people don't like change.  They would rather use what
they are familiar with.  By banging them over the head with how far out
and wonderful Forth is with numbers that seem out of this world you
are more then likely to turn most people off.

Sorry I've rattled so much...

		mph


-- 
* Michael Hunter	bagpiper@netcom.com or QUICS: mphunter
