NetNews Usenet Archive 1992 #16/NN_1992_16.iso/spool/comp/sys/ibm/ps2/hardware/1389

Internet Message Format | 1992-07-28 | 2.2 KB

Path: sparky!uunet!elroy.jpl.nasa.gov!usc!zaphod.mps.ohio-state.edu!news.acns.nwu.edu!uicvm.uic.edu!u54346
Organization: University of Illinois at Chicago
Date: Tuesday, 28 Jul 1992 20:29:45 CDT
From: Jeff Calusinski <[e-mail]>
Message-ID: <[e-mail]>
Newsgroups: comp.sys.ibm.ps2.hardware
Subject: Re: 4 Mbytes memory modules on a PS/2 55sx: Help!
References: <[e-mail]>
 <[e-mail]> <[e-mail]>
Lines: 28

Okay Here is the scoop. A SIMM stands for a Small in line Memory Moduel. There
are 36 bit simms and 9 bit simms. PS/2 50 or greater use 36 bit simms.
( 34 data 4 parity). Most clones use nine bit simms( 8 data 1 parity)
MOst of the time if you are to try to put a nine bit simm in a ps/2 it will
not fit. And during the POST it will scream at you with errors.
As for the addressing lines, ALL 55sx have 24 address lines giving them a total
of 16 Meg of DMA. All 55sx's can use 1, 2, or 4 Meg SIMM's. When buying memory
from third party vendors make sure you tell them they model number of the
computer. The difference between the memory in the back of magazines is the
speed at which they operate. No sencne in puttting a 70 ns 2 meg simm in a
Model 50 Z when it can only use 85 or 80 ns memory.
If the memory you have installed is not working right, try one of the following
  1. Boot your reference disk and check to see that it is a 4 Meg simm.
     if not thee is your problem...
  2. If it is a 4 meg Simm, it might be bad, or part of it. All micro channel
      PS/2 will map out the bad memory, which might be the case.
       Boot the reference and test the memory.
  3. If these both turn out neative and you have tested the complete system
      with the reference disk, take it in to be serviced.
        Might even be an engineering change on your model.
Hope this help, and clears any confusion,

--
Jeff Calusinski (IBM Collegiate Marketing Representative)
University of Illinois at Chicago Team | Telephone: [phone]
One IBM Plaza  15/JYD                  | PhoneMail: [phone] x4901
Chicago, IL 60611                      |  Internet: [e-mail]
STD. DISC.