Dependable Distributed and Mobile Computing — Utilizing Time to Enhance Recovery from Failures

Abstract

Mobile computing allows ubiquitous and continuous access to computing resources while users travel or work at a client's site. The flexibility introduced by mobile computing brings new challenges to dependability and fault tolerance. Failures that were rare with fixed hosts become common, and host disconnections make fault detection and message coordination difficult. This chapter describes checkpointing and failure recovery procedures that are well adapted to both distributed and mobile environments. The protocols use time to indirectly coordinate the creation of new global states and thereby avoid message exchanges. The mobile protocol uses two different types of checkpoints to adapt to network characteristics. Procedures for integrating adaptive mobile checkpointing with storage management are also described.