Abstract: A drum control system for providing a predetermined incremental lateral spacing on a drum surface to be accessed in response to a request signal therefor in which the degree of rotation of the drum is controlled in response to the request signal to provide the predetermined incremental lateral spacing by selectively optically reading one of a plurality of optically readable encoded discs each of which has a plurality of circumferentially extending bands, with each of the bands being encoded to correspond to a different uniform proportionate degree of incremental rotation of the drum. The discs are optically read by associated selectively energized optical readers, such as photocells, when the band to be read is illuminated by a substantially simultaneously selectively energized light source.