A Reliable and Portable Multimedia File System
In this paper we describe design and implementation of a database-assisted multimedia file system, named as XPRESS (eXtendible Portable Reliable Embedded Storage System). In XPRESS, conventional file system metadata like inodes, directories, and free space information are handled by transactional database, which guarantees metadata consistency against various kinds of system failures. File system implementation and upgrade are made easy because metadata scheme can be changed by modifying database schema. Moreover, using well-defined database transaction programming interface, complex transactions like nonlinear editing operations are developed easily. Since XPRESS runs in user level, it is portable to various OSes. XPRESS shows streaming performance competitive to Linux XFS realtime extension on Linux 2.6.12, which indicates the file system architecture can provide performance, maintainability, and reliability altogether.