A protocol for resource locking and deadlock detection in a multi-user environment

In this paper we present a protocol for file locking and deadlock detection in a multi-user Ada environment. It ensures integrity of files concurrently accessed by several tasks belonging either to the same or to distinct Ada programs. In the event of a deadlock, the task responsible for the deadlock can be detected and aborted. When a task within the same program attempts to communicate with the aborted task, an exception is raised in the calling task. In this way, the programmer can define different recovery strategies by providing appropriate exception handlers.