Method for the operation of a computer system which comprises a data processing unit, a data-connected, touch-sensitive, position-resolving input surface and at least one freely movable input device with the functionality of a computer mouse, wherein the input surface detects the absolute position of touch points on the input surface and wherein at least one freely movable input device detects, by movement along a surface, its relative positional changes along the surface by means of a position change sensor in two coordinates and is data-connected to the data processing unit, wherein - as soon as the input surface is touched with at least one input device for the purpose of providing input to the data processing unit, it delivers a sensor signal to the data processing unit which indicates that it has been touched and which position coordinates the touch point has on it and in the case of positional displacements of the touch point the input surface continuously transmits the absolute position data of the touch point to the data processing unit, - at least one freely movable input device continuously transmits its relative positional change data to the data processing unit during positional displacements on a surface, characterized in that - the data processing unit assigns a freely movable input device to a touch point on the input surface by setting a processing mark if - the appearance of the touch point on the input surface correlates in terms of time with the appearance of a signal of at least one freely movable input device and when on the displacement of the touch point, the continuously transmitted absolute position data of the touch point of the input surface correlates with the continuously transmitted relative positional change data from the freely movable input device, - wherein after the processing mark is set, its position is continuously determined with the data processing unit, in that the data transmitted by the input surface to the data processing unit is matched with the data transmitted from the at least one freely movable input device. - as soon as the input surface is touched with at least one input device for the purpose of providing input to the data processing unit, it delivers a sensor signal to the data processing unit which indicates that it has been touched and which position coordinates the touch point has on it and in the case of positional displacements of the touch point the input surface continuously transmits the absolute position data of the touch point to the data processing unit, - at least one freely movable input device continuously transmits its relative positional change data to the data processing unit during positional displacements on a surface, - the data processing unit assigns a freely movable input device to a touch point on the input surface by setting a processing mark if - the appearance of the touch point on the input surface correlates in terms of time with the appearance of a signal of at least one freely movable input device and when on the displacement of the touch point, the continuously transmitted absolute position data of the touch point of the input surface correlates with the continuously transmitted relative positional change data from the freely movable input device, - wherein after the processing mark is set, its position is continuously determined with the data processing unit, in that the data transmitted by the input surface to the data processing unit is matched with the data transmitted from the at least one freely movable input device.