1. Field of the Invention
The present invention relates to an optical information storage medium and a recording/reproducing method thereof, and more particularly, to an optical information storage medium on which optical information have the same channel characteristics or different recording speed information is recorded thereon, and a recording/reproducing method for the optical information storage medium.
2. Description of the Related Art
Optical discs or optical information storage media are widely used in optical pickup devices that record/reproduce information in a non-contact manner. Types of optical discs include compact discs (CDs), digital versatile discs (DVDs), and high density DVDs (HD-DVDs). Optical discs which are capable of recording, erasing, and reproducing data include CD-R, CD−RW, DVD−RW, DVD-RAM, and DVD+RW.
With an increase in recording density of such optical discs, the performance of a disc drive is improved. Since recording characteristics of such an optical disc match the recording speed of the disc drive, data can be reliably recorded or reproduced where the disc drive satisfies the recording characteristics of the optical disc. While a conventional disc drive can reliably record data on a low speed disc, it does not satisfy the recording characteristics of a high-speed disc, and thus it may frequently damage user data. On the other hand, a conventional disc drive for a high-speed disc can also damage user data when recording the user data on a low speed disc.
Accordingly, the recording speed information is needed to reliably record data. To obtain such information, a recording speed of a disc is recorded in a predetermined region of the disc, and a disc drive recognizes the recording speed of a desired disc and records data at a predetermined recording speed of the desired disc. For example, in a case of a 2×-speed disc, a recording speed of the disc is recorded in a predetermined region of the disc prior to its shipment, and thus a disc drive can record data referring to recording characteristics according to the recording speed of the disc recorded thereon.
However, quite frequently, a recording speed of a disc does not reach a nominal recording speed of the disc during a testing. For example, after a 4×-speed disc is manufactured and a recording speed thereof is recorded in a predetermined region of the disc, the true recording speed of the disc does not actually reach the 4× speed. At this time, such a disc cannot be used as a 4×-speed disc, but it may be appropriate as a 3×-speed disc or a 2×-speed disc. However, a disc drive will still recognize the disc as the 4×-speed disc because the recorded recording speed is 4× speed, and will try to record user data at the 4× speed. In such a case, since the recording speed does not actually reach the 4× speed, the user data cannot be recorded normally and can be damaged. Consequently, the 4×-speed disc, which may be appropriate as a 3×-speed disc or a 2×-speed disc instead, is discarded as a defective disc.
Accordingly, a method of using such a disc is needed, and a subsequent operation is needed to handle a case where a recording speed of the disc decreases due to various manufacturing conditions of the disc.