clipped from: blogs.sun.com   

With my supercomputer-as-art background from Thinking Machines, I'm perhaps pre-disposed to appreciate nicely done computers and computer installations. I was blown away when I saw the photos below of MareNostrum, currently the 9th largest supercomputer in the world and the largest in Europe, which is installed in a former chapel at the Barcelona Supercomputing Center (BSC). Wow.

[marenostrum at the barcelona supercomputing center, view1]
[marenostrum at the barcelona supercomputing center, view2]
[marenostrum at the barcelona supercomputing center, under floor]
[marenostrum at the barcelona supercomputing center, rear view]
MareNostrum's Myrinet interconnect fabric requires four cabinets. Myricom did a nice job of reducing the cable count as much as they could by using quad-link ribbon cables between their switch elements.
Contrast this with Sun's Constellation System approach, which uses one large, ultra-dense InfiniBand switch (therefore no inter-switch cabling) and node connections that are bundled three per-cable and connected directly to Constellation's ultra-dense blade chassis.
This takes complexity management to the next level and makes petascale computing systems an achievable goal.