The Application of Workstation Caching to Information Systems
Information retrieval (IR) systems provide individual remote access to centrally managed data. The current proliferation of personal computer systems, as well as advances in storage and communication technology, have created new possibilities for designing information systems which are easily accessible,
economical, and responsive to user needs. This paper outlines methods of integrating personal computers (PCs) into large information systems, with emphasis on effective use of the storage and processing capabilities of these computers. In particular we discuss means for caching retrieved data at PC-equipped user sites, noting that caching in this environment poses unique problems. An event-driven simulation program is described which models information system operation. This simulator is being used to examine caching strategies. Our studies show that the limiting factors in caching eectiveness are the speed of the communication channel and the proportion of session time during which that channel is idle. When these values are low, unrestricted caching can seriously degrade performance. However, when they are sufficiently high, caching becomes a viable means of distributing data to users.