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From: mslater@cup.portal.com
Newsgroups: comp.sys.ibm.pc
Subject: Re: Intel 386SX chip & its applications
Message-ID: <6734@cup.portal.com>
Date: 22 Jun 88 01:50:35 GMT
References: <206900116@prism>
Organization: The Portal System (TM)
Lines: 20
XPortal-User-Id: 1.1001.4222

> 386SX a plug-in replacement for the 286 at near 386 speed.

That is NOT what the 386SX is.  First of all, it is NOT pin-compatible
with the 286.  It uses 386-style control signals and timing, and needed
more power and ground pins.  Intel felt that putting it in a 286-compatible
pinout would constrain its performance, and that the real market was for
new machines, not for upgrades.

You can build (and I'm sure several companies will sell) a piggy-back board
with a 386SX and three PALs, which will plug into a 286 socket.  However, this
won't buy you any speed -- it just gets you 386 software compatibility, and
in fact will be a bit slower than a 286 for many applications.

The June issue of Microprocessor Report has a detailed article on the 386SX;
if you'd like a copy, send your US mail address to me and I'll send you one.
An excerpt from this article was posted in comp.arch last week.

Michael Slater, Editor and Publisher, Microprocessor Report
550 California Ave., Suite 320, Palo Alto, CA 94306  415/494-2677
uucp: mslater@cup.portal.com    (sun!portal!cup.portal.com!mslater)