Placing forced checkpoints in distributed real-time embedded systems

An efficient scheme for placing forced checkpoints in a distributed real-time embedded system so as to eliminate useless checkpoints is presented. The notion of primary non-causal intervals is introduced; these intervals are shown to be the only candidates that need to be considered for inserting a minimum number of forced checkpoints. An efficient algorithm is then used to identify the primary non-causal intervals where forced checkpoints should be inserted. The algorithm first converts the original problem to another problem on a directed graph, which may reflect the existence of useless checkpoints. The new problem can be efficiently solved using existing methods.