Object Directory Design for a Fully Distributed Persistent Object System

In large persistent object systems it is possible to have many million (or eventually billion or more) objects in existence. These objects must be managed to enable their e ective and convenient use. At the heart of this management problem is the structure which maintains information about the objects and provides services on the objects using the information it maintains. We refer to this structure as a directory of objects. In a transparently distributed object system the directory must contain entries for all objects in the system regardless of their location. To ensure both e ciency and reliability any implementation of a global directory of objects (GDO) must be done carefully. This paper details the design of a GDO for a fully distributed persistent object system that is currently being built in a single shared address space. The design of the directory o ers e cient, scalable, and reliable services across a distributed environment. Further, although it is designed for a speci c (and somewhat unusual) environment, the implementation ideas are applicable to other distributed object systems.