Abstract: A client arbitrator operates in a multi-processing operating system for monitoring and controlling a client machine's access to one or more devices. The arbitrator includes a) a request monitoring thread instantiated by any process request to begin or to cease accessing a device, for updating a list of monitored processes accordingly; and b) a waiting thread monitoring termination of a monitored process. If a process terminates the waiting thread determines any locked devices to which the terminated process has access, and, responsive to no other monitored process having access to any of the locked devices releases the client machine's access to the devices.