1. A method for exchanging commands between an application running on a computer and a data processing device having a processor, which is connected to the computer via an interface and appears to the computer as a data storage device with a corresponding file system to which an operating system on the computer is capable of writing files, the method comprising: generating, using an application program on the computer, a device-specific command for execution by an execution handler running on the processor of the data processing device; storing the command in a special file; requesting the operating system of the computer to write a special file containing the device-specific command to the corresponding file system using a write operation; after the special file is received by the data processing device, executing the device specific command contained in the special file using the execution handler running on the processor of the data processing device; wherein, if the device specific command is of a predetermined type that requires an answer to be generated at the time of the next access of the special file by the operating system of the computer, the device specific demand is executed at the time of the next access of the special file by the operating system of the computer, and an answer to the executed device specific command is written in the special file prior to it being returned to the computer.