Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uwm.edu!lll-winken!claris!drc
From: drc@claris.com (Dennis Cohen)
Newsgroups: comp.sys.mac
Subject: Re: Simm installation
Message-ID: <10736@claris.com>
Date: 11 Dec 89 20:27:04 GMT
References: <1989Dec6.215849.16064@cunixf.cc.columbia.edu> <1989Dec11.112101.213@isis.educ.lon.ac.uk>
Organization: Claris Corporation, Santa Clara CA
Lines: 33

tejtemw@isis.educ.lon.ac.uk (EARL WILLIAMS) writes:

>In article <1989Dec6.215849.16064@cunixf.cc.columbia.edu> reyes@cunixf.cc.columbia.edu (Alex Reyes) writes:
>>
>>I recently received four 1 meg simms from the chip merchants for my IICX.
>>I figured that I would leave the four original 256k simms in bank A and
>>install the four new 1 meg simms in bank B. When I booted the system it 
>>would indicate only 2 megs total ram. I then reinstalled the four 1 meg
>>simms in bank A and the 256k simms in bank B. When I booted the system
>>again I got the correct configuration of 5 megs total ram. Was it really
>>necessary to install the 1 meg simms in bank A and the smaller 256 in
>>bank B or was it just an odd coincidence?

>Installing SIMMs is not just a matter of snapping them in; you have to 
>attach/detach the correct resistors or set the jumpers correctly.  This
>may have caused the variation in recognized RAM you got.  If you post
>your hardware configuration (i.e. what Mac you have), someone can probably
>tell you which resistor/jumper setting to use.

There are no resistors to detach or jumpers to set on a II, IIx, IIcx, or
SE/30.  It is explicitly stated (at least in TN 176) that the higher capacity
SIMMs need to be in Bank A.  The same sort of thing, in addition to the
resistor/jumper, is true in the 68000 boxes (Plus and SE).  The thing I find
annoying is that Bank A on an SE without jumpers is the bank closest to the
CPU and on a jumpered SE is the bank furthest from the CPU.  The fact that
they didn't relabel them as Bank A and B rather than living them as SIMM 1-4,
in the same order, just makes things worse when trying to train someone.

Dennis Cohen
Claris Corp.
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Disclaimer:  Any opinions expressed above are _MINE_!
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