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From: dmt@pegasus.ATT.COM (Dave Tutelman)
Newsgroups: comp.arch,alt.folklore.computers
Subject: Re: Why IBM went for the 8088 -- The Untold Story
Keywords: S100 IEEE-696 SC-DOS Seattle MS-DOS IBM_PC
Message-ID: <4790@pegasus.ATT.COM>
Date: 25 May 90 11:59:44 GMT
References: <1WWjqN#0SBCWN5sLFYH9X6tz009zLSK=eric@snark.uu.net> <1990May23.154706.16476@sq.sq.com>
Reply-To: dmt@pegasus1.ATT.COM (Dave Tutelman)
Organization: AT&T Bell Labs - Lincroft, NJ
Lines: 52

In article <1990May23.154706.16476@sq.sq.com> ian@sq.sq.com (Ian F. Darwin) writes:
>Eric S. Raymond (eric@snark.uu.net) writes a very interesting tale...
>I can only add one minor quibble...
	... and I'd like to add a minor quibble or two.  In general,
	Ian's article was on the money.

>In fact, dozens or hundreds of people used SC-DOS before IBM bought it from
>Microsoft who in turn bought it from a small company named Seattle
>Computing. Microsoft changed the name to obliterate the history...
	I'm un-fond of Microsoft myself, but let's be fair about
	motive.  Microsoft bought the rights (and the code) from
	Seattle Computing (SC...), and the resulting product was
	Microsoft's (MS...).  I don't think "obliterating history"
	was ever a consideration in the name change.

>SC-DOS was originally a clone of CP/M, but done for the 8086,
>the 8088's faster sibling...
	You're being slightly misleading about the 8086 vs. 8088 here.
	They're software-identical, and both chips were available in
	a variety of clock rates.  At the same clock rate, the only
	difference is that the 8086 has a 16-bit bus to the 8088's
	8-bit bus.  Your impression probably results from the facts that:
	   -	Many 8086 machines of the era were made with the
		8 MHz part, whereas IBM chose either cheap chips
		or very conservative design to run their 8088 at
		4.7 MHz.
	   -	The difference in bus width alone makes 8086 machines
		run "typical" programs about 40% faster than 8088
		machines at the same clock rate.

>...that was becoming the CPU base of many of the
>forgotten micro makers that IBM drove out of business in the first few years
>of selling PC's.
	In fact, there were some 8086-based clones, whose market was
	made, not killed, by the IBM PC.  Consider the AT&T PC6300 (actually
	an Olivetti machine).  It used an 8 MHz 8086, and was as
	faithful a clone as most of the clones of that generation.
	It not only ran the software for the IBM, but accepted its
	(8-bit bus) add-on boards.  Yes, there were a few incompatibilities,
	but there were similar "bugs" in other first-try clones using
	the 8088.

	Does anyone know of any other 8086-based XT clones (not made by
	Olivetti), or is this the only counter-example to Ian's
	statement?

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