On 2010-07-19, Jon Danniken wrote:
DoN. Nichols wrote:


How about comparing it to the Intel 8088 used in the original
IBM PC about that time? *That* one *was* stuck with an 8-bit bus.

That must have been an upgraded version.

Nope! For from being an upgraded version of the 8086, it was a
more restricted one. The 8088 was an 8-bit package to make it easier to
make systems like CP/M systems which were on the 8080 (and later the
Z80), but with the newer instruction set which assumed 16-bit bus, but
was made to work on the 8-bit bus for simpler hardware compatibility.

The trailing '6' in 8086 meant "16-bit bus", and the trailing
'8' in 8088 meant "8-bit bus".

I've still got my PS/2-25 sitting
around here with the 8086 in it (and Windows 1.04 on floppy).

PS/2 was *not* the first IBM PC by a long ways. The first one
was built on the 8088 (the choked 8086), with a hardware limit of an
amazingly small amount of memory. The maximum (without playing games
with memory on plug-in cards) was something like 64KB on the system
board and up to three 64KB plug-in cards for 256 KB.

The original PC came out with only 5-1/4" floppy drives at most
-- or it could work from audio cassette tapes for storage. It was
introduced August 12 1981.

The PC-XT had the same 8088 CPU, but had an internal 10MB hard
drive and a floppy drive. It was introduced in march 1983.

The PC-AT moved to the Intel 80286 and had more memory and was
faster. It was introduced August 1984

For a history of the various machines prior to the PS/2 line,
look at:

http://en.wikipedia.org/wiki/IBM_Personal_Computer#XT

Sometime a bit after that did the PS/2 come along -- April 2
1987.

http://spider.seds.org/ps2/ps2hist.html

Enjoy,
DoN.

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