Abstract: A graphics processing system, methodology, and signal structure are disclosed wherein commands are transmitted from a graphics controller system to a graphics display system along with frame data and synchronization information. The commands instruct the graphics display system to perform certain operations, such as performing video processing on the frame data, controlling parameters of the display, performing power management operation, and well as send information back to the graphics controller system. The signal structure entails transmitting the command signal from the graphics controller system to the graphics display system during the vertical synchronization width and/or horizontal synchronization width respectively of the vertical and horizontal synchronization signals and when a data enable signal is asserted.

Abstract: A simulator, for use with stereoradiographs, as a neurosurgical aid in locating potential paths for the implantation of probes in selected locations of the brain. It has a support, on the top surface of which is mounted a pair of radiographs disposed for stereoscopic viewing. An elongated ruler lies over the stereoradiographs and is movable in translation over them. A pair of transparent flat plotting plates are mounted on the ruler and are slidable therealong. Each plotting plate has a circular hole and a transparent circular disc is rotatable around this hole; a radial line extending from the center of the disc giving a "floating line" in the stereoscopically viewed model to simulate a probe to be implanted in the brain.