In this paper, we propose a middleware system for building adaptive migratory continuous media applications. In future computing environments, a variety of objects at home and in offices will embed computers, and various applications will be moved among these computers according to the user's locations. For example, a computer that executes an application may be changed to another computer according to the location of the application's user for monitoring his behavior. However, since the computers may have dramatically different hardware and software configurations, the application cannot be moved without taking into account the configurations of the computers that the application is migrated. Therefore, migratory applications should be aware of environments where they are executed. The paper focuses on middleware for building adaptive migratory continuous media applications that are one of the most important classes of migratory applications. Our middleware consists of three components. The first component is an environment server that monitors computing environments that applications run, and it notifies the changes of the environments to the applications. The second component is a continuous media toolkit that enables us to build adaptive migratory continuous media applications easily. The toolkit enables us to build continuous media applications in a highly configurable way. This makes applications to be adapted to every computing environment by changing their configurations. The third component is a migration manager that makes applications migratory. We also show an example of a migratory application, and describe some experiences with building the application.
Resilient multicast support for continuous-media applications