Conventional wisdom holds that reducing disk latency
leads to higher disk utilization, maximizing disk 
utilization leads to higher throughput, and employing 
a faster disk leads to better performance.  All of 
this is true when building a conventional file or 
database system. In this paper we show that these 
principles can be misleading when applied to a media server.
To design such a server, we propose a cost-based 
approach that focuses on the per-stream costs.  We 
give various examples to illustrate the design process.