Paradigms in Fault Tolerant Checkpointing Protocols in Distributed Mobile Systems

Distributed mobile systems are ubiquitous now-a-days. These systems are important building blocks and are useful for constructing efficient protocols for client -- server systems, transaction processing, web applications, and scientific computing [5,11]. Distributed mobile systems are not fault tolerant. They introduce new challenges in the area of fault tolerant computing. The vast computing potential of these systems is often hampered by their susceptibility to failures. Mobile computing highlights many issues, such as lower throughput and latency, low bandwidth of wireless channels, lack of stable storage on mobile hosts, connection breakdowns and inadequate battery life that make the classical check-pointing protocols incongruous. Many techniques like group communication, transactions and rollback recovery have been developed to add reliability to such systems [12]. This paper surveys the algorithms which will restore the system back to a consistent state after a failure.