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From: kaleb@mars.jpl.nasa.gov (Kaleb Keithley)
Newsgroups: comp.sys.ibm.pc
Subject: Re: 386 Memory question (simms)
Message-ID: <3891@jato.Jpl.Nasa.Gov>
Date: 30 May 90 20:42:30 GMT
References: <5923@buengc.BU.EDU> <4922@plains.UUCP> <3873@jato.Jpl.Nasa.Gov> <7374@fy.sei.cmu.edu>
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Reply-To: kaleb@mars.UUCP (Kaleb Keithley)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
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In article <7374@fy.sei.cmu.edu> bwb@sei.cmu.edu (Bruce Benson) writes:
>In article <3873@jato.Jpl.Nasa.Gov> kaleb@mars.UUCP (Kaleb Keithley) writes:
>>In article <4922@plains.UUCP> kperson@plains.UUCP (Kerry Person) writes:
>>>In article <5923@buengc.BU.EDU> rem@buengc.bu.edu (Robert E. Mee) writes:
>Unless of course your board manufacturer changes the rules via its own
>implementation.  My Mylex board (with DX) can be configured as 1,2,4, or 8 Mb
>using 256K, 256K, 1Mb, 1Mb, simms respectively.  No other combinations are
>allowed - no I haven't checked to see if others are really possible, as there
>seemed no reason for Mylex to "hide" other combinations (they don't sell
>RAM).  Facts are helpful, but implementations tell the whole story.

Bruce, you didn't read the original articles; Robert wanted to use 1MB SIMMs
in his SX, and only wanted 2MB total.  His supplier told him he had to put
a total of 4MB in if he wanted to use 1MB SIMMs.  This is wrong.  Your own 
example uses 256K SIMMs to put 2MB in a DX.  You're mixing apples and oranges 
here.  My friends Mylex requires that SIMMs be put in, in multiples of four, 
and there are 8 total SIMM sockets.  My own SX board requires that SIMMS be 
put in in multiples of two, and also has 8 total sockets.  If you want to
use 1MB SIMMs in a DX, you have to do it in 4MB increments.  If you want
to use 1MB SIMMs in an SX, you can do it in 2MB increments.

Then Kerry said that SIMMS were only 4 bits wide.  Again, this is wrong, 
and I won't go into it again, because I just did in *my* original follow 
up article.

Another netiquet reminder: Read the article, the whole article, and nothing
but the article before following up;-)

kaleb@thyme.jpl.nasa.gov            Jet Propeller Labs
Kaleb Keithley