Treffer: Middleware: A Model for Distributed System Services.

The article classifies various types of middleware, describes their properties, explains their evolution and provides a conceptual model for understanding today's and tomorrow's distributed system software. The computing facilities of large scale enterprises are evolving into a utility, much like power and telecommunications. In the vision of an information utility, each knowledge worker has a desktop appliance that connects to the utility. The desktop appliance is a computer or computer like device, such as a terminal, personal computer, workstation, word processor or stock trader's station. The utility itself is an enterprise, wide network of information services including applications and databases, on the local area and wide area networks. Servers on the local-area network typically support files and file based applications, such as electronic mail, bulletin boards, document preparation and printing. Local area servers also support a directory service, to help a desktop user find other users and find and connect to services of interest.