Caching and Scheduling for Broadcast Disk Systems

Unicast connections lead to performance and scalability problems when a large client population attemps to access the same data. Broadcast push and broadcast disk technology address the problem by broadcasting data items from a server to a large number of clients. Broadcast disk performance depends mainly on caching strategies at the client site and on how the broadcast is scheduled at the server site. An on-line broadcast disk paging strategy makes caching decisions without knowing access probabilities. In this paper, we subject on-line paging algorithms to extensive empirical investigation. The Gray algorithm [KL98] always outperformed other on-line strategies on both synthetic and Web traces. Moreover, caching limited the skewness needed from a broadcast schedule, and led to favor efficient caching algorithms over refined scheduling strategies when the cache was not small. Prior to this paper, no work had empirically investigated on-line paging algorithm and their relation with server scheduling. (Also cross-referenced as UMIACS-TR-98-71