Abstract: Techniques for recording and reading information to/from a recording medium based on positions of a plurality of marks are described herein. Each of the plurality of marks may have the same length. The information may be recorded based on a mark interval between successive marks. Apparatus and a recording medium suitable for use with such techniques are also disclosed.

Abstract: An information recording medium is at least composed of a substrate having a microscopic pattern constituted by a continuous substrate of grooves formed with a groove portion and a land portion alternately, a recording layer formed on the microscopic pattern for recording information, and a light transmitting layer formed on the recording layer. The microscopic pattern is formed with satisfying a relation of P??/NA, wherein P is a pitch of the land portion or the groove portion, ? is a wavelength of reproducing light for reproducing the recording layer, and NA is a numerical aperture of an objective lens. The land portion is formed with wobbling so as to be parallel with each other for both sidewalls of the land portion. An auxiliary information based on data used supplementally when recording the information and a reference clock based on a clock used for controlling a recording speed when recording the information is recorded alternately.

Abstract: An information recording medium 1 at least comprises a substrate 13 having a microscopic pattern 20, which is constituted by a shape of continuous substance of approximately parallel grooves formed with a groove section G and a land section L alternately, a recording layer 12 formed on the microscopic pattern 20 and a light transmission layer 11 formed on the recording layer. The microscopic pattern 20 is formed so as to satisfy a relation of P<?<NA and a thickness of the light transmission layer 11 is within a range of 0.07 to 0.12 mm, wherein P is a pitch of the groove section G or the land section L, ? is a wavelength of reproducing light beam and NA is a numerical aperture of an objective lens.