Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!agate!e260-1d.berkeley.edu!c60b-1eq
From: c60b-1eq@e260-1d.berkeley.edu (Noam Mendelson)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Question about different 386's ...
Message-ID: <1991Apr6.050410.16085@agate.berkeley.edu>
Date: 6 Apr 91 05:04:10 GMT
References: <1991Apr5.213536.12925@magnus.acs.ohio-state.edu>
Sender: usenet@agate.berkeley.edu (USENET Administrator)
Organization: University of California, Berkeley
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In article <1991Apr5.213536.12925@magnus.acs.ohio-state.edu> smsmith@hpuxa.acs.ohio-state.edu (Stephen M. Smith) writes:
>c60b-1eq@e260-1f.berkeley.edu (Noam Mendelson) writes:
>akcs.gregc@vpnet.chi.il.us (*Greg*) writes:
>>>Takis Skagos scribbled:
>>>>  Hi.  I've a question about the different chips in the 80386 family
>>>>tree.  I've heard the 386 refered to as 386SX, 386DX, and something
>>>>else that I cannot remember.  Does anybody out there know?
>>>Hi too.. The 80386 is very simple.  386SX is a 16 bit crunching chip.  It
>>>processes 16 bits at a time while the 386DX is a 32 bit crunching chip.  You
>>>are probably better off to get the DX.  But for tight bugets; an SX is the
>>>way to go.
>>I disagree.  Even though the DX has 16 more pins, most of the time they're
>>not being used.  This is due to the fact that most MSDOS programs are 16-bit
>>(with the exception of 386-specific programs).  So unless you actually make
>>use of all 32 pins, a 386SX is not a bad way to go.
>Hmmm.....  Maybe a bit of clarification is needed:
>SX and DX chips are both 32-bit processing chips.  BOTH will
>run 386-specific programs, DOS or otherwise.  The number of
>external pins on the SX does not affect its being a true
>386 processor, nor do they make it incompatible with
>32-bit "protected" mode software.
>The difference in the two chips is that the DX can access anything
>EXTERNAL to the chip via a true 32-bit channel, whereas the SX
>accesses external things via a 16-bit channel.  This includes
>memory, peripherals, or whatever else.

True, but I'm not arguing that.  I was simply pointing out the
differences between them.

>Also, most MSDOS programs are not 16-bit.  They are 8-bit.  How
>else do you think I've been running them on my XT??????

No, MSDOS programs are 16-bit.  If your XT is equipped with an 8088
(instead of an 8086), then you technically have an 8-bit processor;
however, the situation is similar to that of a 386SX.  The bus is 8 bits
wide, but the processor can internally handle 16 bits.

+==========================================================================+
| Noam Mendelson   ..!agate!ucbvax!web!c60b-1eq | "I haven't lost my mind, |
| c60b-1eq@web.Berkeley.EDU                     |  it's backed up on tape  |
| University of California at Berkeley          |  somewhere."             |