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From: eps@toaster.SFSU.EDU (Eric P. Scott)
Newsgroups: comp.sys.next
Subject: 4MB SIMMs from Chip Merchant: 4MBx9 yes 4MBx8 no
Message-ID: <1324@toaster.SFSU.EDU>
Date: 16 Feb 91 11:19:31 GMT
Reply-To: eps@cs.SFSU.EDU (Eric P. Scott)
Organization: San Francisco State University
Lines: 39

In our last stroll down Memory Lane, our requisition for
Peripheral Outlet memory turned into a Purchase Order to Chip
Merchant, thanks to an "alert" employee who "saved us" $4 per
SIMM.

Chip Merchant's using Samsung chips* on a generic PC board.
(There are no markings other than an inspection stamp.)
They're about 1/8" taller than the 1MB SIMMs.

   ----------  ----------  ----------  ----------  ----------
  |          ||          ||          ||          ||          |
   ----------  ----------  ----------  ----------  ----------
         ----------  ----------  ----------  ----------
        |          ||          ||          ||          |
         ----------  ----------  ----------  ----------
  U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U 

*NeXT currently ships "genuine" Samsung 1MBx8 SIMMs in
 8MB NeXTstations.  Traditional cubes came with Toshiba SIMMs.

The 4MBx9 (parity) SIMMs work fine in the NeXTstation.
The 4MBx8 (non-parity) SIMMs didn't; the machine was convinced
that they were defective parity SIMMs.  Visually, they appear
to be identical to the 4MBx9 SIMMs, but with one chip missing:

   ----------  ----------  ----------  ----------  ....  ....
  |          ||          ||          ||          |    o  o
   ----------  ----------  ----------  ----------  ....  ....
         ----------  ----------  ----------  ----------
        |          ||          ||          ||          |
         ----------  ----------  ----------  ----------
  U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U 

Not knowing the specifics of how the machine determines what
kind of SIMM it has, I don't know if these are trivially
fixable (add a jumper/cut a trace?).  We're probably going to
send these back next week and give them another chance.

					-=EPS=-