Simultaneous regions: a framework for the consistent monitoring of distributed systems

A technique is presented by which state information can be organized into unified, consistent representations of the system state through the creation of simultaneous regions. This method provides a general, yet efficient means of establishing the simultaneous relationship necessary for the monitoring and recognition of event occurrences. The types of events for which a computation can be monitored are described. The methods of utilizing logical clocks and global snapshots are then presented and the reasons why they are not appropriate for use in event evaluation are discussed. The technique for establishing simultaneous regions is then presented and the behaviour of the monitoring and recognition protocol is examined in the context of specific monitoring examples. The correctness of the protocol is proved.<<ETX>>