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From: Terje Mathisen <terje.mathisen@tmsw.no>
Newsgroups: comp.arch
Subject: Re: the 286, Byte ordering
Date: Sun, 5 Jan 2025 22:01:36 +0100
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MitchAlsup1 wrote:
> On Sun, 5 Jan 2025 20:01:25 +0000, John Levine wrote:
>=20
>> According to Anton Ertl <anton@mips.complang.tuwien.ac.at>:
>>> Anyway, while Zilog may have taken their sales, I very much believe
>>> that Intel was aware of the general-purpose computing market, and the=

>>> iAPX432 clearly showed that they wanted to be dominant there.=C2=A0 I=
t's an
>>> irony of history that the 8086/8088 actually went where the action
>>> was.
>>
>> I have heard that the IBM PC was originally designed with a Z80, and
>> fairly late
>> in the process someone decided (not unreasonably) that it wouldn't be
>> different
>> enough from all the other Z80 boxes to be an interesting product. They=

>> wanted a
>> 16 bit processor but for time and money reasons they stayed with the 8=

>> bit bus
>> they already had. The options were 68008 and 8088. Moto was only
>> shipping
>> samples of the 68008 while Intel could provide 8088 in quantity, so th=
ey
>> went
>> with the 8088.
>>
>> If Moto had been a little farther along, the history of the PC industr=
y
>> could have been quite different.
>=20
> If Moto had done 68008 first, it may very well have turned out
> differently.

But neither of these were possible (i.e. available) when IBM picked=20
their CPU.

I do believe that IBM did seriously consider the risk of making the PC=20
too good, so that it would compete directly with their low-end systems=20
(8100?).

At least, that's what I assumed when the PC-AT only ran at 6MHz on a CPU =

which was designed for 8 MHz. I fondly remember a bunch of overclocking=20
hacks on various 286 machines, most of them ran at 9 MHz, and I don't=20
think I saw any that didn't handle 8 MHz.

Terje

--=20
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"