A mechanism for supporting client migration in a shared window system

Abstract

Migrating collaborative applications to or near the workstations of active users can offer better performance in many scenarios. We have developed a client migration mechanism for centralized shared window systems that does not require changes to existing application and system software. It is based on logging input at the old site and replaying it at the new site. This approach raises several difficult questions: How should the log size be kept low? How should response time be kept low while migration is in progress? How should applications that depend on the rate at which input is received be accommodated? How should the transition from the replay phase to the play phase be detected at the new site? How should the software at the old and new sites be synchronized? We have developed a series of alternative approaches for answering these questions and implemented them in the XTV [1] shared window system. In this paper, we motivate, describe, illustrate and evaluate these approaches, an...