[comp.sys.intel] 386sx chip

baer@uwovax.uwo.ca (07/26/90)

I was recently told by a systems hardware salesperson (trying to
push 386 DX systems over 386 SX systems) that there are software 
compatibility issues for 32-bit software and SX-based systems.
He implied that OS/2 2.0 will probably not run on an SX, and 32-bit
applications most certainly will not, because of the memory addressing
limitations of the SX (he said that software developers *could* rewrite
32-bit applications to make them run on the SX, but software designed 
for DX-based systems could crash on SX systems.  Could anyone provide
information on this issue?   I understood the 386sx chip to be completely
compatible (except for slower memory addressing due to the 16-bit path),
but is there a limitation around the amount of memory the SX is capable
of addressing, or how it addresses this memory?



---------------------------------------------------------------------
Douglas Baer,  Dept. of Sociology,
University of Western Ontario, London, Canada N6A 5C2
Internet: BAER@UWO.CA    Bitnet: BAER@UWOVAX

mlord@bwdls58.bnr.ca (Mark Lord) (07/27/90)

In article <6533.26ae1cf6@uwovax.uwo.ca< baer@uwovax.uwo.ca writes:
<I was recently told by a systems hardware salesperson (trying to
<push 386 DX systems over 386 SX systems) that there are software 
<compatibility issues for 32-bit software and SX-based systems.
<He implied that OS/2 2.0 will probably not run on an SX, and 32-bit
<applications most certainly will not, because of the memory addressing
<limitations of the SX (he said that software developers *could* rewrite
<32-bit applications to make them run on the SX, but software designed 
<for DX-based systems could crash on SX systems.  Could anyone provide

A big crock of potent hooved mammal excretions.

It is almost impossible for software to even tell the difference between
the two processors.  I have yet to hear of a program which does, although
I do have an idea of how to go about it (I'm not telling, though).

It ain't easy for software to distinguish at all, since, except for speed,
they are 100% identical.  And speed varies depending on other system 
characteristics, so that is not a reliable indicator at all (my 386sx is
faster than a lot of 16-mhz 386dx machines).

In hardware, sure, so we can't connect as many megabytes of memory to
the 386sx as to a 386dx.. big deal.  By the time I can afford that much
memory, It'll be time to upgrade to the cheap 486's anyway (since the 586
will likely exist by then, pushing down prices).

-- 
 ___Mark S. Lord__________________________________________
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UD157912@NDSUVM1.BITNET (Felix Wong) (08/01/90)

In PC Magazine, July 1990, coloumn Tutor, there is a page about how to
detect different CPU (80x86). But it didn't say anything about how to tell
the different between 80386DX and 80386SX. Since 80386DX can address more
RAM than 80386SX, my guess is to check the address bus (24 bit or 32 bit).
Am I guessing it right?