A model of a modular interactive system

摘要

A computer utility provides to its users a computational facility in which programs and data may be stored. When the ability to share information is added, it becomes possible to use the work of others in carrying out one's own work.

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We wish to be able to construct objects, called modules, which can be used as "black boxes" by other modules in a computational facility. This requirement for "black-box"-ness is called modularity [1]. It requires that a module should behave the same way regardless of who is making use of it, when that use is made, or what other activities are taking place in the system concurrently. To use a module, one should need to know only what its interface is, and nothing about how it is constructed.