In a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit (P1max) or a longest space (S1max) in a first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit (P2max) or a longest space (S2max) in the second pit row is defined as a second reflectance, the first pit row is formed such that the first reflectance becomes substantially identical with the second reflectance.

There are provided an optical disk and an optical disk recording method which are capable of stable data reading in a case where a recording linear density is increased. According to an optical disk of the present disclosure, a run-in pattern recorded in a groove track and a run-in pattern recorded in a land track are made different patterns so that no great change is caused in the amplitude of an acquired signal due to interference between adjacent recording patterns, and thus, data may be stably read.

In a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit (P1max) or a longest space (S1max) in a first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit (P2max) or a longest space (S2max) in the second pit row is defined as a second reflectance, the first pit row is formed such that the first reflectance becomes substantially identical with the second reflectance.

An information recording method of the present disclosure is an information recording method for recording information on a write-once information recording medium, including one or more recording layers, each of the recording layers being spiral-shaped on which a land track and a groove track are alternately repeated as recording tracks, each of the recording tracks being divided into blocks, each of the blocks being a minimum unit in which recording is performed. The information recording method includes: recording the information on the information recording medium in a unit of each of the blocks; and controlling recording on the information recording medium. In the control step, switching is performed whether to perform recording in a block to be recorded in which the information is to be recorded next among the blocks based on recording conditions of the recording tracks adjacent on both sides of the block to be recorded.

An apparatus comprises a heat-assisted magnetic recording head configured to write to and read from a magnetic recording medium. The head comprises a reader and a writer including a near-field transducer (NFT). The reader comprises a center which is laterally offset relative to a center of the writer to define a reader-writer offset (RWO) therebetween. A magnetic recording medium comprises a plurality of tracks. The plurality of tracks comprises at least one track used as a region to test for a shift in the RWO. A processor is coupled to the recording head and configured to detect the RWO shift.

In a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit (P1max) or a longest space (S1max) in a first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit (P2max) or a longest space (S2max) in the second pit row is defined as a second reflectance, the first pit row is formed such that the first reflectance becomes substantially identical with the second reflectance.