Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!elroy!usc!nunki.usc.edu!sawant
From: sawant@nunki.usc.edu (Abhay Sawant)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why unix doesn't catch on
Message-ID: <3718@nunki.usc.edu>
Date: 3 May 89 01:15:44 GMT
References: <7632@phoenix.Princeton.EDU> <256@jwt.UUCP> <2496@bucsb.UUCP> <274@tree.UUCP> <552@rna.UUCP> <13546@watdragon.waterloo.edu>
Reply-To: sawant@nunki.usc.edu (Abhay Sawant)
Organization: University of Southern California, Los Angeles, CA
Lines: 58

In article <13546@watdragon.waterloo.edu> afscian@violet.waterloo.edu (Anthony Scian) writes:
>In article <552@rna.UUCP> kc@rna.UUCP (Kaare Christian) writes:
>>In article <274@tree.UUCP>, stever@tree.UUCP (Steve Rudek) writes:
>>> This is *Microsoft*,
>>> people: You know--the company which markets perhaps the best optimized 
>>> C compiler in the world.  And they aren't writing OS/2 in C; or even
>>> You suppose they're just stupid?
>
>Yes. A company that ignores history is doomed to repeat it....
>It is beyond comprehension
>how anybody can develop an OS in assembly language this day and age.

Objection 1: Microsoft C is certainly not the best optimized C
compiler in the world.  Apart from evidence from benchmarks etc.
(after discounting for stuff like the Sieve which are worn out enough
for the compiler to "recognize" them), the sheer *intelligence* of TC
code is mind blowing.  Try disassembling a .exe created with msc and
compare with what you see with tc.  That is what really sold the issue
to me (apart from tc being better whenever *i* did a comparison).

Objection 2: I think it's childish bashing microsoft along the lines
"every sane person on the planet knows writing OS's in C is the best,
surely they're being outrageously stupid to be writing on in
assembly".  Like everything else about writing an OS, the decision of
assembly vs. C is one of the tradeoffs before the designer.  I think
there is little doubt that assembly offers speed while losing
portability and becoming more expensive (time, people, money).  You may 
choose to differ in the relative importance of these two to you: it's 
just that the people out there in Microsoft chose to think different.  
There is no absolute answer to this tradeoff, as with essentially any 
engineering tradeoff.

I'm pretty certain that the performance which MS-DOS extracts out of
it's hardware could not have been got by writing in C.  So writing 
MS-DOS in assembly (all the way through version 3.3 by which time
every PC in the world had all the memory a monster might need) cost them 
more but the bux they made on near 10 million PCs seems to suggest 
that the extra effort was well deserved.  A monstrosity of a slow, 
bulky OS would've certainly impeded the success of the PC.  *I*, think 
it was a great tradeoff.  In engineering, "principles" are pretty
meaningless: getting the job done well is all that matters (that is a
principle).  And what is "well" is a function of the design objectives 
at hand.

*I* think writing OS/2 in assembly is an excellent idea.  I've seen a
big application like Ventura yearn for more computing punch on a 16 MHz 
286: it's pretty clear that even with a single user single task machine, 
we need all the punch that we can get.  So i'm thrilled that microsoft 
felt there was enough money in the PS/2 market to justify spending a 
lot on hand-writing in assembly.  I'd like a lot of bang for my buck 
when i buy a PS/2 (not yet plonked the cash :-) ).

Just my opinions...
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You're never too old to have a happy childhood.

ajay shah (213)745-2923 or sawant@nunki.usc.edu
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