Predicting Future File-System Actions From Prior Events

We have adapted a multi-order context modeling technique used in the data compression method Prediction by Partial Match (PPM) to track sequences of file access events. From this model, we are able to determine file system accesses that have a high probability of occurring as the next event. By prefetching the data for these events, we have transformed an LRU cache into a predictive cache that in our simulations averages 15% more cache hits than LRU. In fact, on average our four-megabyte predictive cache has a higher cache hit rate than a 90 megabyte LRU cache.