dent on the amount of buffer space available at the client. We introduce an algorithm that uses bufJer space available at the server for smoothing disk transfers of variable bit-rate streams. Previous smoothing techniques prefetched stream data into the client buffer space, instead. However, emergence of personal computing devices with widely different hardware configurations means that we should not always assume abundance of resources at the client side. The new algorithm is shown to have

more »

... mal smoothing effect under the specified constraints. We incorporate it into a prototype server, and demonstrate significant increase in the number of streams concurrently supported at different system scales. We also extend our algorithm for striping variable bit-rate streams on heterogeneous disks. High bandwidth utilization is achieved across all the different disks, which leads to server throughput improved by severalfactors at high loads. In this paper, our goal is to maximize the average number of users supported concurrently in video server systems, by applying smoothing techniques and combining them appropriately with disk striping and admission control policies. Thus, we introduce a stream smoothing algorithm that prefetches data into server buffers, which has several important advantages: ability to provide the benefits of smoothing even to clients with minimal memory resources (such as inexpensive mass-produced specialized devices), ability to limit the requirements for disk bandwidth, which is estimated to increase at rates an order of magnitude slower than network link bandwidth [9], Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page, To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee.