"It's not easy trying to build scalable systems from
commodity hardware designed for assembling desktop computers and
small servers, though. "Lashing together tens or hundreds of
thousands of processors isn't as easy as it appears when you apply
it to real-world problems," says Gary Smaby, a supercomputing
analyst and a principal of Quatris Fund, an investor in Unlimited
Scale. As the number of CPUs in a Beowulf-style cluster-a group of
PCs linked via Ethernet-increases and memory is distributed instead
of shared, the efficiency of each processor drops as more are
added.
Enter Oberlin. Unlimited's solution involves tailoring Linux
running on each node in a cluster, rather than treating all the
nodes as peers. The idea is to free some computers from getting
bogged down in processing interrupt requests from peripherals,
while letting a second set of machines run the full operating
system, furnishing the cluster with networking, job scheduling,
input/output, and other capabilities. Says Oberlin, "On application
nodes, you want the operating system to get out of the way."
