Optical disk, and information recording/reproduction apparatus

An optical information recording/reproduction apparatus by which information is recorded onto and/or reproduced from an optical disk comprising first and second tracks which are formed on the same recording plane, and said first track is a groove-like track in which information is recorded into the groove and said second track is a land-like track in which information is recorded onto the land sandwiched by said first track,

• said optical disk comprising:
• a spare area in which a defective sector is to be alternatively recorded;
• a defect list area in which a defect list including a set of addresses of said defective sector and an alternate sector of said spare area is to be recorded;
• and
• an information record area in which information is to be recorded,
• said apparatus comprising:
• an optical head which irradiates said tracks with a light beam;
• track designation means for selecting one of said first and second tracks;
• focus means for focusing the light beam of said optical head on said recording plane;
• tracking means for tracking said first or second track;
• track search means for searching a target track;
• address reproduction means for reading out an address signal of said track;
• read/write gate generation means for selecting a target sector of said first and/or second tracks in accordance with an output of said address reproduction means, and for actuating an operation of recording or reproducing information on said target sector;
• data recording/reproduction means for conducting recording and/or reproduction of data on the target sector in accordance with an output of said read/write gate generation means;
• record verify and alternation means for verifying data which are recorded by said data recording/reproduction means, alternating a detected defective sector in said spare area and managing a recording and/or reproduction of a defective sector on the basis of contents of defect list storage means;
• said defect list storage means for storing as a defect list a defective sector address and an alternate address which are results of the alternation operation of said record verify and alternation means;
• and
• apparatus control means for outputting control commands to said means, for monitoring states of said means, and for controlling operation of recording, reproducing, and verifying information on said optical disk.