Dynamic Extent-Based Allocation Technique for Multimedia File Systems

This thesis investigates the efficiency ofextent-based allocator design to satisfy fileallocation requests in a CDN proxy cache. Theallocator is based on the method inspired by thememory allocators where free space is managed inchunks of varying size or extents. The design istested in a simulation where a trace of allocationand deallocation events from a content server wassubmitted to the allocator. The bottleneck forcontent retrieval often lies on data transfer ratesof the hard disks used in the server. To facilitatefastest possible transfer of a file it must be readsequentially. At the same time given the largequantity of files space wastage due to incompleteutilisation of large allocation units is notdesirable. Our allocator design tries to achieve bothmutually exclusive goals. The design was implementedand the results we obtained in the course ofsimulation show that we managed to achieve thesegoals creating an allocator that displaysproperties favourable for contiguous file placementwhile keeping space wastage at its minimum.