Optical disk exclusively used for reproduction wherein guide grooves

Abstract

An optical disk exclusively used for reproduction has an optically detectable guide groove in which signals have previously been recorded. One type of optical disk exclusively used for reproduction is interchangeable with an optical disk which allows both recording and reproducing operations or enables information recorded thereon to be erased. If such an optical disk is not provided with a guide groove in an unrecorded region remaining between a data managing information region and a data recording region, problems may arise when the optical head of an optical disk apparatus is positioned in the unrecorded region at the time of starting the operation of the apparatus and when the optical head effects retrieval between the data managing information region and the data recording region. Therefore, the unrecorded region is cut by employing a method which is different from the method of cutting the data managing information region and the data recording region, thereby eliminating the above-described problems, allowing the recorded information to be read out at an increased speed and enabling a master disk for optical disks to be cut at high efficiency.