A Non-blocking Minimum-process Checkpointing Protocol for Deterministic Mobile Computing Systems

The term Distributed Systems is used to describe a system with the following characteristics: i) it consists of several computers that do not share memory or a clock, ii) the computers communicate with each other by exchanging messages over a communication network, iii) each computer has its own memory and runs its own operating system. In the mobile distributed system, some of the processes are running on mobile hosts (MHs).A checkpoint algorithm for mobile computing systems needs to handle many new issues like: mobility, low bandwidth of wireless channels, and lack of stable storage on mobile nodes, disconnections, limited battery power and high failure rate of mobile nodes. These issues make traditional checkpointing techniques unsuitable for such environments. Minimum-process coordinated checkpointing is an attractive approach to introduce fault tolerance in mobile distributed systems transparently. In this paper, we propose a minimum-process coordinated checkpointing algorithm for deterministic mobile distributed systems, where no useless checkpoints are taken, no blocking of processes takes place, and anti-messages of very few messages are logged during checkpointing. We try to reduce the loss of checkpointing effort when any process fails to take its checkpoint in coordination with others.