A Light-Weight Virtual Machine Monitor for Blue Gene/P Jan Stoess, Udo Steinberg, Volkmar Uhlig, Jonathan Appavoo, Amos Waterland, and Jens Kehne In this paper, we present a light-weight, micro-kernel-based virtual machine monitor (VMM) for the Blue Gene/P Supercomputer. Our VMM comprises a small microkernel with virtualization capabilities and, atop, a user-level VMM component that manages virtual BG/P cores, memory, and interconnects; we also support running native applications directly atop the microkernel. Our design goal is to enable compatibility to standard OSes such as Linux on BG/P via virtualization, but to also keep the amount of kernel functionality small enough to facilitate shortening the path to applications and lowering OS noise. Our prototype implementation successfully virtualizes a BG/P version of Linux with support for Ethernet-based communication mapped onto BG/P's collective and torus network devices. First experiences and experiments show that our VMM still shows a substantial performance hit; nevertheless, our approach poses an interesting OS alternative for Supercomputers, providing the convenience of a fully-featured commodity software stack, while also promising to deliver the scalability and low latency of an HPC OS.