PO herehng motivation productivity of peop S use of microcompt~rs f l tomation of routine tasks, {uisition and commumcatiofr ormation, and the inttlligen% t of decision making. For tli~ to ppen, microcomputers must to process and distribute the information that people no*3 | ndle and must offer inforoxessing and communication s similar to those people sed manually. Today's micropit tsor-based personal computers pride comprehensive support for t as a medium. There are a wide variety of text editors, formatters, databases, mail systems, and printers. These capabilities are available at sufficiently low cost that small businesses and even many households are able to purchase them. However, people naturally create and exchange information by means of a wide variety of media. They talk to each other, draw pictures, label diagrams, write notes, and point to things. Thus, in addition to text, they seek computer-based support for graphics, voice, and combinations of these media. The SRI Command and Control Workstation project, which is supported by the United States Navy, has as one of its major goals the creation and application of computer-based, multimedia information systems to support naval command and control ,ased,

CCWS: A Computer-Based, Multimedia Information System

A prototype implementation has been built as part of the Heterogeneous Computer Systems project at the University of Washington. This service supports RPC binding and other applications in our heterogeneous environment. Measurements of the performance of this prototype show that it is close to that of the underlying name services, due largely to the use of specialized caching techniques.

A name service for evolving heterogeneous systems

Computer-supported collaborative work (CSCW) involves the concurrent sharing of application packages by various geographically distributed users, the sharing of common databases, and the sharing of electronic messages. MOSAIC (multimedia open system for augmented interactive collaboration), a model for CSCW systems, is described in detail. A prototype designed to support collaborative decision-making is discussed. The main contribution of MOSAIC to CSCW is the delineation of how user interfaces, user collaboration, and information management functions fit together. This model differs from others in that special attention is paid to the dialogue between system users and the ways in which the system can augment that dialogue. The authors suggest that this model can provide a development framework much as the ISO reference model has in the development of standardized protocols for communication systems. >

An open-systems model for computer-supported collaboration

The X.400-series of recommendations specifies the elements, protocols, and services of the e-mail system associated with the Open Systems Interconnection (OSI) protocol stack. The paper looks at the various reasons that led to X.400's failure to gain the widely expected level of market acceptance. A brief literature review suggests that common explanations for success in a standards battle cannot explain the demise of X.400. The same holds for two popular explanations for the victory of Internet over OSI. Therefore, alternative reasons are proposed and discussed, including poor timing of the standardisation activity, inadequate first implementations, and an ill-advised paradigm shift that occurred in the cause of events. Finally, some lessons to be learned for the future are identified.

Why then did the X.400 e-mail standard fail? Reasons and lessons to be learned

Operating a Mail Interchange Service for a large and widely dispersed user community involves a considerable maintenance overhead. The routine tasks include updating of routing tables, checking network connections, processing ‘undeliverable’ mail, checking log files, analysing statistics, responding to user queries and arranging charging and accounting. Whilst gateways provide mail system connectivity, they suffer from a lack of transparency and do not provide full functionally between mail systems. This gives rise to specific problems such as how a user should quote his address when this depends on the mail system of his correspondent; name clashes can occur when disjoint networks become connected; message loops can be caused by information lost in gateways. In the longer term, a strategy to both reduce the maintenance overhead and improve the service for the users is the adoption of International Standards for Message Handling (currently CCITT X.400 Recommendations).

Practical experience with high level gateways for mail transfer

Message-Handling Systems provide store-and-forward electronic mail services. In 1984, CCITT will approve a set of Recommendations defining standards to interconnect systems throughout the world. This paper describes international efforts to develop the standards which are necessary for a worldwide electronic mail system. The system architecture, protocol structure, implementation options, and message transfer and interpersonal messaging services are described.

http://ieeexplore.ieee.org/iel5/5/31332/01457059.pdf

I. Cunningham

Papers

Message-handling systems and protocols