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From: hays@iSC.intel.com (Kirk Hays)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Question -- 386DX versus 386SX
Message-ID: <1156@intelisc.isc.intel.com>
Date: 16 Feb 91 00:06:21 GMT
References: <1991Feb7.182436.17262@athena.cs.uga.edu> <18685@ists.ists.ca>
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In article <18685@ists.ists.ca>, pasquale@sgl (Pasquale Leone) writes:
|> In article <1991Feb7.182436.17262@athena.cs.uga.edu> boone@athena.cs.uga.edu (Roggie Boone) writes:
|> >I know this has probably been asked before, but I am new to this group.
|> >
|> >Could someone please explain or direct me to an article that explains in 
|> >some detail the difference(s) between a full 80386 microprocessor
|> >(80386DX) and the 80386SX?  Are they both 32-bit processors?  I've 
|> >heard that the main difference is that the SX "talks" to the outside 
|> >world (memory, disk, etc) at 16-bits while the DX uses 32 bits.  Is this
|> >true and is this the only difference?  Are there any limitations on 
|> >the 386SX running 386-specific software?
|> >
|> 
|> You canNot write a program that can distinguish between a 386SX and a
|> 386DX.

You are quite wrong - the prefetch queues on the SX and DX are of different
lengths, and by writing a short sequence of self-modifying code, it is possible to detect the difference - the code in question has been posted to the net.

I (independently, others did it also) invented this technique for distinguishing
between the 8088 and the 8086 in 1983, before I worked for Intel.

|> Intel may have built some pretty idiotic chips in the past but they seem
|> to know what they are doing now.

Oh, thank you for the vote of confidence - I feel so much better now.
-- 
Kirk Hays - NRA Life.
Message for Timothy Fay - "Do not eat things you will not kill."