This paper presents the design, implementation, and evaluation of IO-Lite, a uni ed I O bu ering and caching system for general-purpose operating systems. IO-Lite uni es all bu ering and caching in the system, to the extent permitted by the hardware. In particular, it allows applications, interprocess communication, the lesystem, the le cache, and the network subsystem to share a single physical copy of the data safely and concurrently. Protection and security are maintained through a

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... n of access control and read-only sharing. IO-Lite eliminates all copying and multiple bu ering of I O data, and enables various cross-subsystem optimizations. Experiments with a Web server on IO-Lite show performance improvements between 40 and 80 on real workloads.