The compute nodes of the Blue Gene family of supercomputers run CNK (for Compute Node Kernel), a lightweight kernel that runs on each node and supports a single application running for a single user on that node. For the sake of efficient operation, the design of CNK was kept simple and minimal, and it was implemented in about 5,000 lines of C++ code.[1] Physical memory is statically mapped and the CNK neither needs nor provides scheduling or context switching, given that at each point it runs a single application for a single user.[1] By not allowing virtual memory or multi-tasking, the design of CNK aimed to devote as many cycles as possible to application processing.[2] CNK does not even implement file I/O on the compute node, but delegates that to dedicated I/O nodes.[2]
The I/O nodes of the Blue Gene family of supercomputers run INK (for I/O Node Kernel).[2] INK is based on a modified Linux kernel.
^ abcEuro-Par 2004 Parallel Processing: 10th International Euro-Par Conference 2004, by Marco Danelutto, Marco Vanneschi and Domenico Laforenza ISBN 3-540-22924-8 pages 835
^ abcdeEuro-Par 2006 Parallel Processing: 12th International Euro-Par Conference, 2006, by Wolfgang E. Nagel, Wolfgang V. Walter and Wolfgang Lehner ISBN 3-540-37783-2 page
