3 Jun
2013
3 Jun
'13
7:14 p.m.
On 3 June 2013 23:23, Fred Cisin <cisin at xenosoft.com> wrote:
Ah, fair point. I didn't notice.
They do? How so?
I wonder what specific changes rendered it incompatible.
I think that the 486 added a few small instructions, and the Pentium a
few more. Part of it is also code optimisation - the 386 is a simple
in-order CPU, the 486 is scalar, the Pentium superscalar and the
Pentium Pro & successors decompose x86 code to microinstructions,
reoder them for out-of-order execution and then re-sequence the
results.
I am not entirely surprised that kernel code designed for the latter
won't work on the former.
Oh my yes. One of the big missed chances. I've read some of Raskin's
design papers. Inspiring stuff. Already, 30y ago, looking to break
away from the tyranny of "programs" and "documents" into a real of a
machine that could intelligently do arbitrary work on whatever you
happened to be looking at. Literally amazing.
--
Liam Proven ? Profile: http://lproven.livejournal.com/profile
Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven
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Tel: +44 20-8685-0498 ? Cell: +44 7939-087884
On 3 June 2013
20:04, Fred Cisin <cisin at xenosoft.com> wrote:
>> > 80386, oddly, is far from "long dead".
> On Mon, 3 Jun 2013, Liam Proven wrote:
>> It is in any market I *ever* see.
> depends on your definition(s) of "long"
> Is this Pentium running XP not really a 386 at heart?
> Seems like there are quite a few around.
On Mon, 3 Jun 2013, Liam Proven wrote:
Ah, but that is not what is being discussed here.
True
I changed the Subject slightly, Since I knew that I was tangenting off of
statements taken out of full context. When 486 and Pentium came out, they were treated as
fast 386s, and seemed
to stay that way for a very long time.
Well, they are. The instruction set
didn't change from the 80386 in
1985 until the Pentium-MMX in about 1996. FWIW, today, 32-bit 386-ISA code is generally
called x86-32 and 64-bit
x86 is x86-64, or (and I dislike both) "AMD64" or "X64".
all of which seem to attempt to oversimplify the differences. Which versions of Windoze will not install on a 386?
(never mind issues
of "adequate performance"!) (386-SX is out just due to its 16M RAM limit)
Windows 2000 was the last version that would boot, install or run on a
486, I believe. Circa 13y ago. Time flies. I had been told, apperently incorrectly, and
didn't check for myself, that
everything that installed from an "I386" directory was still 386
compatible.
Not for many years, sadly. About a decade and a third, roughly.
Jobs was part
of the Mac team, you know; indeed he is largely
responsible for it being what it is. Jef Raskin's original design was
radically different.
and wonder how things might otherwise have gone, . . .
I was not a complete fan of Jef's ideas, and the Cat, but they were
impressive.