Interactive television (ITV) is a new form of residential consumer video service that gives viewers far greater control over the contents of programs than is possible with conventional television. There are substantial technical challenges to offering a ITV service on a large scale, both in content creation and delivery. The paper discusses those challenges and presents a new system architecture for offering ITV, along with a broad range of other interactive video services, to consumers in their homes. A new suite of tools to simplify the creation of compelling interactive programming is also described.>

Infuse is an experimental software development environment focusing on change coordination during the maintenance/evolution phase of large-scale software projects. Its core philosophy is to integrate strongly connected modules first and more weakly connected sets of modules later, moving up a hierarchy from singletons to clusters of interdependent modules and, finally, merging the change set into the baseline. The use of Infuse is extended to dynamic consistency, i.e. testing. Unit testing is done for the individual modules at the leaves of the hierarchy, integration testing for the intermediate clusters and acceptance testing at the root. Infuse supports this by partially automating the construction of test harnesses and regression test suites at each level of the hierarchy from components available from lower levels. Infuse is implemented in C and is used to support its own evolution, but the implementation does not yet provide the test management described.>

The executable specification language PAISLey and its environment are presented as a case study in the design of computer languages. It is shown that PAISLey is unusual (and for some features unique) in having the following desirable features: (1) there is both synchronous and asynchronous parallelism free of mutual-exclusion problems, (2) all computations are encapsulated, (3) specifications in the language can be executed no matter how incomplete they are, (4) timing constraints are executable, (5) specifications are organized so that bounded resource consumption can be guaranteed, (6) almost all forms of inconsistency can be detected by automated checking, and (7) a notable degree of simplicity is maintained. Conclusions are drawn concerning the differences between executable specification languages and programming languages, and potential uses for PAISLey are given.

An experimental teleterminal, which is the physical synthesis of an intelligent computer terminal and a six-key telephone set, has been created. The function of its controlling software is to exploit this synthesis in a way that facilitates both voice and data communication. The teleterminai is programmed to support the full functionality of both telephone and terminal plus a fusion of their functions, which provides the means for enhanced telephone services and a more human-oriented interface to services on a host computer. It is compact enough to be used in place of a conventional telephone. This paper describes the user and host computer interface to the teleterminal, and the structure of its controlling software.