The operating system for Columbia is Red Hat Linux 2.4. Previously, NASA has been used IRIX for supercomputing on SGI Origin servers. It moved to Red Hat when SGI brought out its more powerful Altix server line that runs on Linux. SGI are now shifting to SUSE Linux and NASA will follow suit.
"Linux doesn't yet have all the features of IRIX quite yet but it is getting there rapidly," said Ciotti. "Linux is maturing more rapidly than IRIX."
A total of 20 SGI Altix servers make up Columbia. NASA's supercomputer includes eight of the latest Altix models. This is known as the Altix 3700 Bx2. This version doubles the processor density and available bandwidth. As well as Linux and Itanium 2, it has 9 MB cache, 64 processors per rack, and scales to 256 processors in a single system image (SSI).
"Such a large SSI creates really good environment for code development," said Walt Brooks, division chief, advanced supercomputing division, NASA. It offers low latency and is user friendly."
SGI NUMAlink 4 interconnect technology has been introduced to Altix produces 6.4GB/sec. Altix also uses a shared memory architecture called NUMAflex that overcomes bottlenecks. All nodes operate on one large shared memory space that eliminates data passing between nodes. Big data sets can fit entirely in memory and less memory per node is required.
Another feature of the storage environment is enhanced system cooling. The eight Altix 3700 Bx2's have double the density of previous models posing worries about overheating.
"As we were stretching the limits of cooling, the server doors are specially designed to have cool air fed through them," said Brooks. "Chilled water is brought in and coupled into radiator loops within the door to keep them cool."
Columbia recently smoked the competition in recent LinPack benchmark tests. It achieved 42.7 trillion calculations per second, making it the fastest in the world at the time.
"The science that already has been produced has been extraordinary," said Brooks. "Instead of scientists queuing up for supercomputing resources, we now have the enough capacity for everybody."
He gives an example of simulations showing a decade's worth of changes in ocean temperatures and sea levels that used to take a year to model. But using the modernized storage environment, scientists can now simulate this in a day or two.