Data recording/reproducing method and apparatus using a recording medium having clock marks recorded in a wobbled track for read/write synchronization

A data recording/reproduction apparatus comprising:

• a recording medium having track guide grooves wobbled in a track scanning direction at a predetermined wobbling frequency;
• a light source;
• means for irradiating an optical beam emitted from said light source to said recording medium;
• means for recording arbitrary user data by forming, on said recording medium with said optical beam, recorded regions in such a manner that a specific code word contained in said arbitrary user data is recorded at respective ones of rear and front edges of each of said recorded regions and also to record predetermined known data by forming, on said recording medium, further recorded regions in such a manner that said specific code word is recorded at front and rear edges of each of said further recorded regions so as to represent said predetermined known data;
• means for reproducing said arbitrary user data from reflected beams or transmitted beams of said recording medium;
• means for detecting offtrack from said reflected beams or transmitted beams;
• and
• means for correcting offtrack from said offtrack detected by said offtrack detection means.

An optical data recording/reproduction method for a recording medium, each track of which is divided into a plurality of zones, and each track having a clock mark for generating a clock for every angle of rotation of said recording medium, comprising the steps of:

• identifying said zones for recording/reproducing data;
• setting a rate of revolution of said recording medium to a rate of revolution corresponding to said zone identified;
• and
• effecting recording/reproduction of data to and from said recording medium by the use of said clock generated in synchronism with said clock mark.