An apparatus for testing internal combustion engine valves is provided. Information is stored as a stripe including a collection of a data strips and associated parity strips, the stripe distributed across data and parity nodes. Each of the gate tracking lines has first portions, auxiliary portions and junction portions, wherein the junction portion and the first portion are formed in different layers. The image may be displayed in the user’s field of view or in the video image. The pressure pulse generator can include a control device that generates at least one pulse in the drilling fluid by selectively altering flow of the control fluid.