Efficient support for handling of objects is required in multimedia, CAD, CAM, CIM, expert system, software engineering, and office automation. Recently, object-oriented DBMSs and extended DBMSs are proposed for those applications. These DBMSs have been mainly implemented on top of existing storage systems. Such an approach leads a serious problem from the viewpoint of performance and functionality. This paper proposes a storage system for an object-oriented database management system. Its design and implementation is explained.
The storage system is composed of physical I/O layer and buffer management layer. The physical I/O layer supports variable-sized extent, which consists of physically sequential pages, each extent is used as a unit of storage allocation. The variable-sized extent has an advantage regarding storage utilization and clustering. The buffer management layer support abstract view of storage by using storage objects which are unformatted variable length storage. The storage object can retrieve, update, insert, append and delete in any position. The storage system was implemented on a UNIX operating system. Wisconsin Storage System(WiSS) was rewritten to build the storage system. The storage system has better performance in the view point of clustering and gives easier view of storage object for user than existing storage system for object oriented database.
object oriented database.
