ABSTRACT

Distributed snapshots are an important building block for distributed systems, and are useful for constructing efficient checkpointing protocols, among other uses. Direct application of these algorithms to mobile systems is not feasible, however, due to differences in the environment in which mobile systems operate, relative to general distributed systems. The mobile computing environment introduces new challenges in the area of fault-tolerant computing. Compared to traditional distributed environments, wireless networks are typically slower, providing lower throughput and latency, comparing to wireline networks. In addition, the mobile hosts have limited computation resources, are often exposed to harsh operating environment that makes them more likely to fail, and can roam while operating. Over the past two decades, intensive research work has been carried out on providing efficient checkpointing protocols in traditional distributed computing. Recently, more attention has been paid to providing checkpointing protocols for mobile systems. Some of these protocols have been adapted from the traditional distributed environment; others have been created from scratch for mobile systems. Checkpoint is defined as a designated place in a program at which normal processing is interrupted specifically to preserve the status information necessary to allow resumption of processing at a later time. Checkpointing is the process of saving the status information. This paper surveys the algorithms which have been reported in the literature for checkpointing in Mobile Distributed systems.