On broadcast disk paging

Abstract

A deterministic algorithm that uses prefetching to achieve an O(n log k) competitive ratio for the broadcast disk paging problem, where k denotes the size of the client's cache, is designed. A matching lower bound of Ω(n log k) that applies even when the adversary is not allowed to use prefetching is shown. In contrast, when prefetching is not allowed, no deterministic online algorithm can achieve a competitive ratio better than Ω(nk). A lower bound of Ω(n log k) on the competitive ratio achievable by any non-prefetching randomized algorithm against an oblivious adversary is presented. Results showed that in the broadcast disk paging, prefetching is a perfect substitute for randomization.