Managing stored voice in the Etherphone system

Abstract

Thevoice managerin the Etherphone system provides facilities for recording, editing, and playing stored voice in a distributed personal-computing environment. It provides the basis for applications such as voice mail, annotation of multimedia documents, and voice editing using standard text-editing techniques. To facilitate sharing, the voice manager stores voice on a special voice file server that is accessible via the local internet. Operations for editing a passage of recorded voice simply build persistent data structures to represent the edited voice. These data structures, implementing an abstraction calledvoice ropes, are stored in a server database and consist of lists of intervals within voice files. Clients refer to voice ropes solely by reference.Interests, additional persistent data structures maintained by the server, serve two purposes: First, they provide a sort of directory service for managing the voice ropes that have been created. More importantly, they provide a reliable reference-counting mechanism, permitting the garbage collection of voice ropes that are no longer needed. These interests are grouped into classes; for some important classes, obsolete interests can be detected and deleted by a class-specific algorithm that runs periodically.