An efficient object manager, a middle layer on top of a storage system, is essential to ensure acceptable performance of object-oriented database systems, since a traditional record-based storage system is too simple to provide object abstraction. In this chapter, we design and implement an extensible object storage system, called Soprano, in an object-oriented fashion which has shown great potential in extensibility and code reusability. Soprano provides a uniform object abstraction and gives us the convenience of persistent programming through many useful persistent classes. Also, Soprano supports efficient object management and pointer swizzling for fast object access. This chapter investigates several aspects of the design and implementation of the extensible object storage system. Our experience shows the feasibility of using an object-oriented design and implementation in building an object storage system that should have both extensibility and high performance.
