Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!asuvax!noao!arizona!shack
From: shack@cs.arizona.edu (David Michael Shackelford)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: '386's SX's and DX's
Message-ID: <364@caslon.cs.arizona.edu>
Date: 24 Jul 90 20:11:13 GMT
References: <31122@eerie.acsu.Buffalo.EDU> <1773@cs.rit.edu> <1990Jul22.234030.25727@utstat.uucp> <1776@cs.rit.edu>
Distribution: usa
Organization: U of Arizona CS Dept, Tucson
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In article <1776@cs.rit.edu> jdu4855@cs.rit.edu (Unrue Jack D) writes:
>
>But isn't the 386sx restricted in the amount of memory it can address? If
>that's the case, then would a 386sx be able to run OS/2 ver 2.0 ? I guess
>I'm wondering if the SX includes ALL the 32 bit machine instructions of a
>DX? Furthermore, what is the size of the data path between a 386SX and a
>387SX?
>

I might be mistaken, but the *only* difference between the SX and DX chips
is the *data* bus size, 16 for SX and 32 for DX.  This results in the
requirement for SX's to do two physical memory accesses for each 32 bit
instruction.  The address bus sizes are the same (I think--haven't seen
the actual chips)  and the SX contains all instructions and registers
from the DX.

The effect of all of this is:  OS/2 2.0 should run on an SX the same as
any other 386 specific software would: slower for memory access, but otherwise
identically.

Additionally, even if the system bus has a 24 bit address size, OS/2 v2.0
would run in 16Mb easily.  It would work better on more memory, but I think
the minimum will be about 8mb if they follow the historical path.

This is all opinion, I don't have the spec sheets sitting before me!

Dave.