A method for recording information on and reproducing information from an optical disk which has a first, read-only-type recording zone containing first and second pre-recorded information recorded as microscopic unevennesses readable by an optical head having a laser which is responsive to a drive circuit that is controlled by a control circuit, and at least a second, writable recording zone which is capable of being written upon at least once, for recording bits of information thereon using said optical head,
- said method comprising:
- (a) reproducing information from said first pre-recorded information recorded in said first, read-only-type recording zone by irradiating a spot of about one micron in diameter on said first, read-only-type recording zone with laser light from said optical head at a first, lower power level, detecting changes in quantity of light reflected from said spot as said disk is moved relative to said head, and storing said detected changes in light intensity in memory external to said disk as detected information;
- (b) as a result of conducting step (a), providing said control circuit for said drive circuit with an operational condition with regard to where said optical head is to read from and write to said optical disk, respectively using said first, lower power level and a second, higher power level for said laser;
- (c) thereafter, reproducing information from said second pre-recorded information recorded in said first, read-only-type recording zone by irradiating a spot of about one micron in diameter on said first, read-only-type recording zone with laser light from said optical head at said first, lower power level by using said optical head as driven by said drive circuit under control of said control circuit having said operational condition for detecting changes in quantity of light reflected from said spot as said disk is moved relative to said head;
- (d) thereafter, creating data information utilizing said information reproduced from said second pre-recorded information;
- (e) thereafter, recording said data information onto said second, writable recording zone as bits of information by irradiating a spot of about one micron in diameter on said second, writable recording zone with laser light from said optical head at said second, higher power level by using said optical head as driven by said drive circuit under control of said control circuit having said operational condition to provide changes in quantity of light irradiated onto said disk at said spot as said disk is moved relative to said head, and thereby provide localized changes in light reflectivity on said disk;
- and
- (f) thereafter, reproducing said data information from said second, writable recording zone by irradiating a spot of about one micron in diameter on said second, writable recording zone with laser light from said optical head as driven by said drive circuit under control of said control circuit having said operational condition for detecting changes in quantity of light reflected from said spot as said disk is moved relative to said head.