ADAPTIVE READ-AHEAD AND BUFFER MANAGEMENT FOR MULTIMEDIA SYSTEMS

摘要

Multimedia systems support the storage and retrieval of heterogeneous types of data, ranging from static data files to large video streaming files. Accordingly, a multimedia server must provide not only fast retrieval of small, static data files, but must also guarantee the bandwidth for video streaming files. To enable guaranteed service for these systems, we focus on improving the coordinated read-ahead mechanism and buffer management, with consideration given to requested data types and the needs of I/O-intensive applications. We classify data requests into two types: one for fast response, the other for guaranteed bandwidth. The read-ahead size is then dynamically adjusted for the streaming file, by monitoring the consumption time and the disk I/O time for its request. Additionally, we manage the buffer cache efficiently for its data type. Compared to a conventional file server, our file server shows a 14% faster average response time for static data requests, while guaranteeing the bandwidth of video streaming requests.