Method and apparatus for correctly storing data recorded on a rotational disc-shaped recording medium despite occurrence of clock synchronization disorder

An information processing apparatus in which

• a disc-shaped recording medium is rotated at a constant angular velocity, the recording medium having a record area formed in a plurality of tracks,
• the record area divided into a plurality of zones depending on the radial position, each zone having an assigned base clock frequency so that an outer zone has a higher frequency than an inner zone, and blocks of
• data are recorded or reproduced in each zone in accordance with the base clock of the assigned frequency, said information processing apparatus comprising:
• a VFO (variable frequency oscillator) controller reproducing a VFO signal recorded on said recording medium together with data and producing a VFO clock which is synchronous with the reproduced VFO signal;
• a reproduced data memory storing reproduced data, which follows the VFO signal, in response to the VFO clock;
• and
• a controller detecting a sync-disorder of the VFO clock, and, at detection of sync-disorder, controlling storing of data in said reproduced data memory so that data reproduced from said recording medium subsequent to data reproduced during sync-disorder of said VFO clock is stored in response to the VFO clock despite the detected sync-disorder.

An optical disk storage apparatus in which

• an optical disk medium having a record area formed in a plurality of tracks is rotated at a constant angular velocity,
• the record area of said optical disk medium is partitioned into a plurality of zones depending on the radial position, base clock frequencies are assigned to the zones so that an outer zone has a higher frequency than an inner zone, and
• an optical head signal sensor senses light beam from said optical disk medium so that blocks of data are reproduced in accordance with the base clock of the assigned frequency, said optical disk storage apparatus comprising;
• a phase lock circuit which reproduces VFO signals that have been recorded on said recording medium, each VFO signal corresponding to one of the blocks of data, and which produces a VFO clock for each VFO signal which is synchronous with the reproduced VFO signal;
• a memory storing reproduced data which follows the VFO signal in response to the VFO clock;
• and
• a controller detecting sync-disorder of the VFO clock, and, at detection of sync-disorder, controlling data storing to said reproduced data memory so that reproduced data corresponding to recorded data reproduced subsequent to a block of data reproduced during sync-disorder is introduced in response to the VFO clock despite the detected sync-disorder.