Splitting the scheduling headache

The broadcast disk provides an effective way to transmit information from a server to many clients. Information is broadcast cyclically and clients pick the information they need out of the broadcast. An example of such a system is a wireless Web service where Web servers broadcast to browsing clients. Work has been done to schedule the information broadcast so as to minimize the expected waiting time of the clients. This work has treated the information as indivisible blocks that are transmitted in their entirety. We propose a new way to schedule the broadcast of information, which involves splitting items into smaller sub-items, which need not be broadcast consecutively. This relaxes the restrictions on scheduling and allows for better schedules. We look at the case of two items of the same length, each split into two halves, and show that we can achieve optimal performance by choosing the appropriate schedule from a small set of schedules