Deadlocks in distributed systems: request models and definitions

The paper addresses the problem of deadlock detection in asynchronous distributed systems for system model that covers unspecified receptions and non-FIFO channels. It presents a hierarchy of deadlock models considered till now, and then abstracts away their differences to define a single, general deadlock model. This general model is used to introduce abstract formulation of basic deadlock detection problems, and to specify distributed algorithm which uniformly addresses deadlock detection problem for various request models. Finally, in this context, termination detection problem is also considered