Patent ID: 8006252

Claim:
A data processing system comprising: an operating system for supporting processes, the operating system being arranged to output data by addressing the data to a descriptor corresponding to an intended destination of the data; an interface for interfacing between each process and the operating system; a memory including one or more address spaces, there being an address space corresponding to each of the processes for use by the respective process; and a data communication stack for one of the processes, the stack being located in the address space corresponding to the respective process and having a descriptor allocated to it; the interface being arranged to analyze requests to alter the allocation of a descriptor sent by the processes towards the operating system to identify whether such a request relates to altering the allocation of the descriptor allocated to the stack, and if it does, allocate a different descriptor to the stack and subsequently permit the request to be processed by duplicating the descriptor; wherein a failure to duplicate the descriptor by means of a system call executed to duplicate the descriptor is reported to the said respective process as a failure of the said request.