[rescue] Happy happy happy! Joy joy joy!

Skeezics Boondoggle skeezics at q7.com
Fri May 30 20:46:42 CDT 2003

Doin' the happy dance!

I'm so pleased to report that Wednesday evening the Cray CS6400 I picked
up on Ebay last year booted up and ran flawlessly on the very first try!

And I'm even MORE tickled to report that today I replaced four banks of
Cray-labeled memory with the Sun SIMMs - bog standard 68-pin 32MB SIMMs
common to the SS1000 and SC2000 - and they work fine!

I was 99.44% sure that they would, since the layout, part numbers, RAMs
themselves, almost *everything* was identical, but nobody at Sun or Cray
or the FE Handbook or the Rough Guide To Mbus modules or *any* information
source on the web could confirm with 100% certainty that the plain old
501-2196 parts are, in fact, completely compatible with the Cray
621-4012-001 parts (Sun calls those the 370-2747).

I tried SIMMs with both 60ns and 70ns RAMs - and they're all fine; both
the 40Mhz 1000/2000 and the 50Mhz 1000E/2000E and even the big batch o'
Cray parts from the 55Mhz CS6400 come in both speeds.  (It would seem from
the labeling that the module runs at 80ns, or at least that's how fast
they need to appear to the system, despite the differences in clock rates
among the various sun4d machines; that could explain the variation in chip

Anyway, I'm now satisfied that you CAN in fact use Sun 32MB 68-pin SIMMs,
part number 501-2196, in your Cray CS6400 and they're 100% compatible.  I
am SURE the world will sleep better at night, knowing this to be true.  
Alert the media!  One of life's great mysteries has been solved!

Now, all those interested in the group buy... a gig of Sun-labeled SIMMs
is available for about $80 or so on Ebay.  I just did a search and there
are still some sellers offering those (I didn't completely corner the
market in a spree last month :-) for $19.99 (8 x 32MB, one bank).

With the RAM hurdle cleared, the only other things you'll need are the
JTAG Sbus card (you can make up your own cable, I have the specs), three
phase power, a Cray Solaris distribution and sysid key to generate the
eeprom.image, about 5-tons of cooling (or a big enough basement), and
flooring that can support a thousand pound cabinet...

C'mon, jump on in! :-)

Alright, so the barrier to entry IS still a bit high.  But with one CS6400 
and all this extra memory... well, now I just have to get another one! [0]

-- Chris
<skeezics at boondoggle.com>

[0] My family tells the story about a great uncle of mine who lived near
the boardwalk in Wildwood, NJ.  One day he was at a hot dog stand and
ordered two dogs and a root beer.  Of course, he ran out of root beer
before the dogs were done, so he ordered another; but then he had root
beer left over and no hot dog, so he naturally had to have another hot
dog.  Well, a crowd started to gather as he went back and forth like this
for hours, until he'd had something like 20 or 30 hot dogs and gallons of
root beer... hey, who'd heard of "heart disease" in the 50's? :-)  
Anyway, I now have this extra memory and no Cray to put it in, so...

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