[Beowulf] Mare Nostrum (not quite COTS)

[Patrick Geoffray]

Hi Vincent,

Vincent Diepeveen wrote:
> Which myrinet cards are in Mare Nostrum?

Single link PCI-X D cards, with 4 MB of SRAM to be comfortable with 
multiples routes between a lot of nodes. The NICs for the BladeCenter 
have a specific format: smaller than regular half-size PCI boards, NIC 
is // to the mainboard and has no fiber transceiver (goes to the OPM via 
the Bladecenter backplane). Available only via IBM.

> What one way pingpong latency can it get from 1 end of the machine to the
> other end of the machine?

I don't know, I didn't work on this machine. It would depend on the 
number of crossbars and lengths of fiber. I uses the new switches with 
32-port crossbars, so the max path should not be longer than 7 hops if 
my memory is right. At one time, the PCI-X on the JS-20 blades was 
clocked at 100 MHz, I don't know if it has been bumped to 133 MHz since.

Patrick
-- 

Patrick Geoffray
Myricom, Inc.
http://www.myri.com