Kamil Iskra
                 Argonne National Laboratory

           "ZeptoOS: Small Linux for Big Computers"

The issue of a suitable operating system for the upcoming petascale
computing platforms is a matter of debate. Largest massively parallel
systems currently available use custom kernels such as BLRTS and
Catamount. These have very little jitter ("noise"), but their functionality
is limited as well.

Within the ZeptoOS project, Argonne National Laboratory and its
collaborators are attempting to evaluate the viability of running
a Linux kernel on the compute nodes of massively parallel systems.

In my presentation, I will talk about IBM Blue Gene and the challenges
of running Linux on this platform.  I will present noise measurements we
have conducted on several concurrent platforms, and will show the results
of a noise injection study performed on a 32,000-CPU IBM Blue Gene/L system,
where we evaluated the performance of MPI collective operations at varying
noise levels.