The implementation of networking technology in work settings offers numerous opportunities for improving the transmission of information and the sharing of resources within and between organizations. Its success in integrating distributed working activities, however, rests on how well the users of a network can coordinate their activities with respect to each other. This paper examines the communicative and interactive processes that take place when a typical breakdown occurs in a networked environment. A detailed analysis is presented which interprets the events that unfold in relation to the sociocognitive issues of shared understanding, the transmission of knowledge and distributed problem-solving.

: We present a security mechanism designed for use with object-based multi-user applications. This mechanism - the private access channel - provides the same level of fine grain object-based security as the capability scheme. Whereas capabilities have been applied only to limited sets of objects with identical operations, we propose a generic protection mechanism that can be applied to any object, whatever its operations. Our mechanism is provided at the object level which makes it available for direct use by multi-user applications. It has the additional advantage that clients need not be aware of the presence of access control. We discuss the use of the private access channel in the context of two distributed multi-user applications. 1 Introduction Object-oriented programming languages provide powerful tools for defining interactive applications for single users. The effectiveness of these tools can be harnessed to provide interactive multi-user applications by adding the ability ...

Synchronous groupware applications let users collaborate over distance through their computers. Since these applications are difficult to build, groupware toolkits have been constructed to help developers with their tasks. Some of the building blocks supplied by these toolkits are a set of abstractions for sharing data between sites. Yet different toolkits use different strategies to share the data: some replicate the data at all sites, while others store it at a central site. The correct choice of data sharing strategy is not obvious, as different strategies affect data consistency as well as the performance of applications built using the toolkit. We argue that data sharing should be flexible and that the developer should be able control the data sharing by selecting from default strategies or creating new ones to meet the requirements of their application. We use a technique called open implementations to provide this control. We have built a prototype groupware toolkit called GEN that demonstrates the feasibility of flexible data sharing. Using GEN, six different forms of data sharing have been constructed, more than any other toolkit currently available.