Dynamic Software Upgrading In Pervasive Environments Based On R-OSGi

Now many large-scale softwares need to run 24 hours a day such as communication systems,finance systems and spaceflight systems which demand high availability. With the consistent development of customer demand,available resource,hardware and developing technology,software vendors need to upgrading their products at all times. And because of the turnover they also have to make sure the right switchover between new and old models developed by different developers. So it is very useful and meaningful to realise dynamic upgrading exactly without stopping a running system.OSGi supplys a service-oriented software developing standard, it has features of modulization, standardization, Dynamicalization etc. Many business applications such as IBM p5 Series Servers,Websphere V6.1, Lotus Sametime, Adobe CS2 and open source projects have adopted OSGi technology which doesn't support distribution application as well as dynamic upgrading of services. To come with the development of research on distributed environment, R-OSGi as a middleware of OSGi is developed. The seamless integration between OSGi and R-OSGi makes OSGi fit for distributed application.Except for inheriting all advantages from OSGi, R-OSGi also get the disadvantage of service search which is based on strict syntactic matching. Customers can not invoke a service until they can get enough information of the service. And many services have the problems with synonyms and homonyms which may cause wrong upgrading in pervasive environments.The dynamic upgrading of software is on the basis of finding the software which should be upgraded. Semantic service described by OWL(Ontology Web Language) is proposed. Semantic information is used to describe R-OSGi Bundles, and to reason and upgrade the relevant Bundles. We develop a dynamic software upgrading module to validate the feasibility of such method.