this paper, we will consider only a retrieval environment and primarily focus on the strong interaction between the architecture, data layout, data compression, and scheduling. In particular, we will present distributed multilevel data layout, scheduling and playout control schemes developed in conjunction with our architecture. These schemes allow all clients to access the same data without data replication and support both buffered as well as bufferless clients. Also, they provide strict Large Scale Multimedia Servers 2 deterministic guarantees to each active client during normal playout as well as a full spectrum of interactive stream control operations (namely, fast forward, rewind, frame advance, slow play, slow rewind, pause, stop-and-return and stop). Our implementation of the stream control operations requires no extra bandwidth reservation and provides acceptable operation latency of a few hundread milliseconds. The rest of this paper is organized as follows: Various service models that are possible for a ondemand multimedia server are illustrated in Section 2. The basics of our prototype implementation of a large scale server are presented in Section 3. Section 4 describes the distributed and hierarchical data layout scheme. Next, our basic multilevel scheduling scheme is illustrated in Section 5. Various ways of implementing playout control operations and their implications on scheduling are described in Section 6. This section also presents modifications that must be made in the basic scheduling scheme to achieve smooth transition between normal playout and operations such as ff and rw
