Method of recording and reproducing data on a disk

Claim 1

A disk data recording method for recording an input data at a data clock signal having a specific clock period on a disk recording medium in a form of position information of leading and trailing edges of marks with a laser beam, the input data being composed of alternately occurring mark data parts and space data parts, said method comprising the steps of: generating a mark start end pulse for a predetermined period at a start end of a mark data part of the input data; generating a mark termination end pulse for the predetermined period at a termination end of the mark data part; generating a train of intermediate pulses occurring at equal intervals of a predetermined duration; arranging in order the mark start end pulse, the train of intermediate pulses and the mark termination end pulse to obtain a recording signal; driving a laser beam source according to the recording signal to produce a laser beam whose power becomes a first power for the predetermined period at a portion corresponding the mark start end pulse and at a portion corresponding to the mark termination end pulse and becomes the first power and a second power alternately at equal intervals of the predetermined duration at a portion corresponding to the train of intermediate pulses; and irradiating the disk recording medium with the laser beam to form a mark, wherein said method further comprises a step of determining a position of the mark start end pulse according to both a length of a space data part immediately before the mark data part and a length of the mark data part.