Abstract: An optical data read/write apparatus is disclosed for use in reading a rotating optical disc having at least one concentric reference track and circular data tracks thereon. The apparatus includes an optical head which includes separate tracking and data beams directed onto the disc. The optical head is supported on a carriage which is movable by a linear actuator for movement radially relative to the disc. A substantially continuously operable closed loop servosystem which includes the linear actuator causes the tracking beam to follow the reference track. The data beam is movable relative to the tracking beam and is moved so as to follow a selected data track. A plurality of concentric reference tracks may be included on the disc in which case the linear actuator is supported on a second carriage movable in the same direction as the carriage that supports the optical head.

Abstract: An integrated circuit component having an array of rows and columns of programmable coupling elements, the rows being coupled to a plurality of independent input signals and the columns being coupled to output ports through a plurality of selectors. With such circuit component the independent input signals may be selectively coupled to the output ports in accordance with the programmed state of the programmable coupling elements and in accordance with control signals fed to the selectors. Therefore, if it is desired to change the coupling of the input signals to the output ports for the given control signal a different circuit component having differently programmed coupling elements may replace the previously programmed circuit component without requiring changes to printed circuit board connectors.