03/01/1992 09:00 AM
Computer Engineering
The optical jukebox emerges as the economic choice for storing huge quantities of data objects in today\'s electronic libraries. Sequential access to collections in an electronic library with a very large number of holdings significantly limits library response when requests are frequent, as found in large-scale library systems. Therefore, we consider an alternative scheduling method which takes advantage of specific user and application characteristics found in a library environment. In this paper, we address the performance benefits of cyclic scheduling of user requests in electronic libraries where retrievals are the primary tasks. An approximate model of the retrieval performance is developed in terms of average waiting times for retrieval of objects from an optical jukebox using a cyclic service strategy. This model considers variability in service and its evaluation involves an iterative approach. In addition, the goal of the approximation is motivated by providing a user-interface prompt which indicates the expected waiting times for requested documents.
