This (short) paper presents the Clockwise, a mixedmedia file system. The primary goal of the Clockwise is toprovide a storagearchitecturethat supportsthe storage and retrieval of best-effortand real-time file system data. Clockwiseprovides an abstraction called a dynamic partition that groups lists of related (large) blocks on one or more disks. Dynamic partition can grow and shrink in size and reading or writing of dynamic partitions can be scheduledexplicitly. With respect to scheduling, Clockwise uses a novel strategy to pre-calculate schedule slack time and it schedules best-effort requests before queued real-time requests in this slack time.
Peter Bosch, Sape J. Mullender, Pierre G. Jansen