A Design for File Access in a Mobile Environment

Abstract

Reducing communication cost is important-in a mobile enuironment, because transmission of data over the radio link is slow, expensive, and unreliable. Providing data consistencg is crucial because-many mobile applilcations are database applications which rely on consistent data. In this paper we propose a design for a fiIe access mechanism specific to a mobile environment. Our two main design goals are to reduce communication cost and to provide data consistency. We reduce the amount of communication by extensive use of caching, profile inforrnation (files the user accesses), a proxy process, delayed writes, and availability of loose-reads. We provide data consistency by using the prony services, a centralized data rnanager with callbacks, and strict-reads. Our design is general enough to suit the needs of both mobile database and office applicati,ons.