Method of controlling use of resources in a data processing system by at least two processes

Claim 1

In a data processing system including a central processing unit and a main storage capable of executing a plurality of processes concurrently and wherein access to resources is shared by at least two of the processes, and where a first process executing in the central processing unit may be interrupted by a second process, the method of sharing control of the shared resources, comprising the steps of: storing in main storage, by a first process, control information to be associated with a shared resource indicating that an operation comprised of a sequence of steps is being performed by the first process utilizing the shared resource; immediately interrupting the execution of the first process in the central processing unit by a second process and initiating execution of the second process in the central processing unit; determining, by the second process, from the control information associated with the shared resource, whether steps of the operation being performed by the first process on the shared resource remain to be completed; completing, by the second process, the steps of the operation on the shared resource initiated by the first process before commencing a new operation by the second process with the shared resource.