A method for transmitting data by means of a data processing system, the system being capable of supporting an operating system and at least one application and having access to a memory and a network interface device capable of supporting a communication link over a network with another network interface device, the method comprising the steps of: forming by means of the application data to be transmitted; requesting by means of the application a non-operating-system functionality of the data processing system to send the data to be transmitted; responsive to that request: writing the data to be transmitted to an area of the memory; and initiating by means of direct communication between the non-operating-system functionality and the network interface device a transmission operation of at least some of the data over the network; and subsequently accessing the memory by means of the operating system and performing at least part of a transmission operation of at least some of the data over the network by means of the network interface device.