Automatic prefetching in a WAN

File systems have become slow relative to processor, memory and network speeds. The high latencies of distributed file systems (particularly wide area file systems) have only exacerbated the problem. The authors believe that file system prefetching provides an effective method for alleviating the latency bottleneck. File system prefetching requires knowledge of future file accesses. The authors are currently investigating efficient methods for accurately predicting future file activity automatically without application intervention. They have designed and implemented a system which uses past file activity to predict future file system needs. The initial results indicate that reasonable accuracy can be obtained even when relatively simple algorithms are employed.