This paper provides an overview of the digital television (DTV) data broadcast service and interactive service technologies that have been deployed over the last ten years. We show how these trials have led to the development of data protocol and software middleware specifications, worldwide. Particular attention is given to the series of standards established by the Advanced Television System Committee. Experimental deployments to both Personal Computer(PC) and Set-Top-Box (STB)/spl I.bar/receivers are considered, with an emphasis on the services that have introduced new business models for DTV operators.

A method is devised for maintaining the continuing availability of a vital service in a real-time shared-memory multiprocessor fault-tolerant computer system. The essential characteristics of the service to be provided are given. The service can be correctly provided by any one operational processor acting alone. The job of selecting the processor to provide the service is the real-time leader election problem. Two protocols are given which solve this problem in shared-memory systems. Each tolerates the failure of any subset of the processors. The first protocol is extremely simple and has running time linear in the number of processors. The second is slightly more complicated and has running time logarithmic in the number of processors. Both protocols use space that is linear in the number of processors.>

Fragmentation and query decomposition are considered important issues in a distributed database environment. For a semantic data model (ECR data model), the types of fragmentation and the criteria they should follow is provided along with how global queries in a high-level language, GORDAS, are decomposed into local queries on the fragments. This technique may be used in a heterogeneous distributed database, where the global schema presented to the user is in the high-level ECR model.