Path: utzoo!attcan!uunet!sjsca4!poffen
From: poffen@sj.ate.slb.com (Russell Poffenberger)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: Difference between a 386 and a 386sx
Message-ID: <1990Sep20.185214.780@sj.ate.slb.com>
Date: 20 Sep 90 18:52:14 GMT
References: <935@sppy00.UUCP> <1477@sirius.ucs.adelaide.edu.au> <1412@svin02.info.win.tue.nl> <4388@bwdls58.UUCP>
Reply-To: poffen@sj.ate.slb.com (Russell Poffenberger)
Organization: Schlumberger Technologies, San Jose, CA.
Lines: 21

In article <4388@bwdls58.UUCP> mlord@bwdls58.bnr.ca (Mark Lord) writes:
>>This suggests that a way to distinguish a 386dx from a 386sx in software
>>would be to put some value in existing memory at address 0x00xxxxxx
>>and read it from address 0x01xxxxxx. If it comes out the same you would
>>be running on a 386sx (not having the upper 8 bits of address bus),
>>otherwise a 386dx.
>
>But not many machines have physical memory in the hundreds of megabytes
>ranges.. so regrettably, I doubt that this would work in practice.
>
>Use virtual memory you say?  Well.. in that case a 386sx will do the
>exact same internal translation as a 386dx, producing no observable 
>differences either.  Better luck next time.

In addition, I think you would have to be in protected mode. This complicates
things. In real mode, I believe the addresses "wrap around" at 1Mb.

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
Schlumberger Technologies       UUCP:   {uunet,decwrl,amdahl}!sjsca4!poffen
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