A tablet computer is provided, which includes a sensor section operable to detect positional input by a human operator and output a positional input signal; a display, laid over the sensor section, operable to receive and display a video signal; and a processor, coupled to a memory storing programs for running an operating system (OS) and executing software loaded to the memory, the processor being operable to receive and process the positional input signal from the sensor section and to output a video signal of the OS and the software to the display. The tablet computer further includes a sensor signal filter capable of selectively communicating the positional input signal from the sensor section to the processor, to a separate external processor, or to neither the processor nor the separate external processor; and a display switch capable of coupling the display to the processor or to the separate external processor.