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From: doerschu@rex.cs.tulane.edu (Dave Doerschuk)
Newsgroups: comp.sys.ibm.ps2.hardware
Subject: Re: Getting a free PS/2
Message-ID: <4858@rex.cs.tulane.edu>
Date: 7 Nov 90 06:18:05 GMT
References: <1990Nov1.120159.20396@ioe.lon.ac.uk>
Organization: Computer Science Dept., Tulane Univ., New Orleans, LA
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In article <1990Nov1.120159.20396@ioe.lon.ac.uk> teexmmo@ioe.lon.ac.uk (Matthew Moore) writes:
>(Esa Holmberg) writes:
>>      Once more.. PS/2 model 30 has 8086, not 8088, and
>>      model 30-H has 80286..
>Perhaps the reason that people make this dreadful mistake is that they
>dont know what the difference between an Intel 8088 and 8086 is.
>If its not too much trouble, could you tell us what the differenc eis,
>and why its important?

I didn't write either of the above 2 articles, but I'd be happy to
describe the difference between the 8086 and the 8088.  In a nutshell,
the big difference is the size of the external databus.  Both the 8086
and the 8088 have a 16 bit data word and do their internal computations
with 16 bits as their "native" integer size.  However, the 8088 has
only 8 wires connecting it to the databus, where the 8086 has 16 wires.
To read an integer from RAM memory, for instance, takes the 8088 two
"bus fetch cycles"; that is, it must ask the RAM for 8 bits at a time,
twice.  The 8086 has the advantage of only needing one bus fetch cycle
for this read operation because it can read all 16 bits at one time,
hence it is faster.  This explaination is somewhat simplified, but it
contains the essence.

Hope this helps.

Dave Doerschuk
doerschu@rex.cs.tulane.edu