Comparing disk scheduling algorithms for VBR data streams

We compare a number of disk scheduling algorithms that can be used in a multimedia server for sustaining multiple variable-bit-rate (VBR) data streams. A data stream is sustained by repeatedly fetching a block of data from disk and storing it in a corresponding buffer. For each of the disk scheduling algorithms we give necessary and sufficient conditions for avoiding underflow and overflow of the buffers. In addition, the algorithms are compared with respect to buffer requirements as well as average response times.