SIMMS in SS2

[karl anderson]

In v10n13, phillips at sparky.lcs.mit.edu (Mike Phillips) writes:

>We just got a bunch of SS2's and were having trouble figuring out if the
>4Mbyte simms from our SS1's would work.  I think the official Sun answer
>(as far as I could figure out from our salesperson) is no.  Anyway, I
>tried them and they seem to be working fine.  We've added an extra 16Meg
>of 4Meg simms to each of 4 SS2's and nothing terrible has happened yet.
>The simms we used are 80ns (well, I think so - they have a little "80"
>printed on them amongst a lot of other numbers).

My Sun "pre-sales" tech support guy told me that the SS2 was designed with
very close tolerances for memory access time.  Most "80ns" DRAM is
actually 80 +/- 2 ns, but the SS2 will have problems if the access time is
even slightly greater than 80 ns; "80 +0/-2" is the way he characterized
the requirement.  This is a matter of quality control in DRAM manufacture,
so hopefully there are some open-market sources of certified "80 +0" ns
SIMMs out there.  If you have some, give them a try; if there are no
problems, then no problem.  When shopping for them, you should insist that
the vendor warrant them for use in the SS2.  Of course, you may pay a
premium for this degree of assurance; you may even find that Sun's prices
are competitive 8^).

Karl A. Anderson		| Internet: karl at forest.gsfc.nasa.gov
NASA/GSFC code 923 (STX)	| voice: (301) 286-3815
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