Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2001-03-23
2002-08-20
Hindi, Nabil (Department: 2653)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S275300
Reexamination Certificate
active
06438084
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data recording apparatus and method for writing data to an optical disc, data playback apparatus and method for reading data from an optical disc, and an optical disc.
2. Description of the Related Art
There has become popular a CD (compact disc) system in which an optical disc having an outside diameter of about 120 mm and a thickness of about 1.2 mm is used as a recording medium and a signal is read from, or written to, the optical disc by projecting a light converged by an objective lens onto a signal recording surface of the optical disc.
The CD system has initially been developed as a recording and playback system for digital audio data. As this technology has been accepted very widely, a wide variety of CD systems have so far been proposed for various applications.
Recently, the personal computers have been used as an information processing means in more and more ordinary households. Along with this tendency, a read-only optical disc called “CD-ROM (read-only memory)” has become popular to have recorded therein data handled in the personal computer.
Also, a recordable optical disc such as CD-R (recordable) and rewritable optical disc such as CD-RW (rewritable) have been developed and used in practice as optical discs interchangeable with the CD-ROM.
Data is recorded to the CD-R and CD-RW by the so-called “Track At Once” method by which data is written in units of a track, and the so-called “Packet Writing” method by which data is written in units of a packet which is a smaller unit than the track. When either the “Track At Once” or “Packet Writing” method is used to record data to the CD-R or CD-RW, a plurality of data linking blocks is provided between tracks or between packets, each being a unit in which data is continuously recorded, according to a predetermined linking rule. That is, in case data is recorded by the “Track At Once” method or “Packet Writing” method, it will be written with a plurality of data linking blocks appended to each unit of data which is to be continuously written.
The reason why the plurality of data linking blocks is appended between tracks or packets is that the CD-R and CD-RW adopt a convolution type cross coding method called “CIRC (cross interleaved Reed-Solomon code)” and a data discontinuity takes place at a linking position because of the CIRC interleaving. That is, the data linking blocks are provided at a linking position of data as a guard area in which data missing is prevented in linking interleaved data to each other.
The amount of data handled in the personal computer has increased more and more, and thus the CD-ROM, CD-R and CD-RW as recording media for recording data have strongly been required to have an increased storage capacity.
To meet such a requirement, the so-called double-density CD-R and CD-RW maintaining the CD format and having a recording density about 2 times higher than the current CD format are under development.
In the double-density CD-R and CD-RW, the EFM modulation and demodulation methods and wobble signal frequency applied to the CD-R and CD-RW having the current format (will be referred to as “normal-density CD-R” and “normal-density CD-RW”, respectively, hereunder) are not changed but the track pitch is decreased while the linear density is increased, to whereby elevate the recording density up to about double that of the normal-density CD-R and CD-RW.
In the double-density CD-R and CD-RW whose recording density is increased by reducing the track pitch while increasing the linear density, a defect such as scratch to a recording mark will be larger than that in the normal-density CD-R and CD-RW. That is, in the double-density CD-R and CD-RW, the burst error length will be larger than in the normal-density CD-R and CD-RW.
Therefore, the double-density CD-R and CD-RW will be more susceptible to a burst error than the normal-density CD-R and CD-RW. So, proper the CIRC error correcting method used in the current normal-density CD-R and CD-RW is adopted as it is in the double-density CD-R and CD-RW, an error cannot be corrected in some cases, which will highly possibly lead to an improper reading of data.
To positively correct the burst error, it is effective to increase the interleaving length by setting a large delay parameter indicative of a CIRC unit delay. However, with an increased interleaving length, the linking rule adopted in the current normal-density CD-R and CD-RW is not capable of accurately linking data. Therefore, to write data to the double-density CD-R and CD-RW, it is necessary to adopt a suitable linking rule for the double-density CD-R and CD-RW.
Also, the optical disc drive for such a double-density CD-R or CD-RW has to be able to properly write and read data to and from a double-density CD-R or CD-RW and to the normal-density CD-R or CD-RW as well. Namely, the optical disc drive for the double-density CD-R and CD-RW is required to be able to support also the normal-density CD-R and CD-RW, that is, they have to be compatible with the latter also.
OBJECT AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome the above-mentioned drawbacks of the prior art by providing a data recording apparatus and method in which a linking rule suitable for use with an optical disc having a high recording density is used to link data, thereby permitting to realize a proper data recording to the optical disc, a data playback apparatus and method which can read an optical disc having data recorded therein according the above-mentioned linking rule, the data recording and playback apparatuses and methods being able to support an optical disc having a current format as well, and an optical disc having recorded therein a program of the above data recording and playback.
The above object can be attained by providing a data recording apparatus for recording data to a conventional standardized optical disc as well as to an optical disc having a higher recording density than the former optical disc, the apparatus including according to the present invention:
means for appending a plurality of data linking blocks to each unit of data going to be continuously written to the optical disc;
means for error-correction coding, including interleaving, of the data in the data unit having the data linking blocks appended thereto by the data linking block appending means;
means for continuously writing the data having been subjected to the error-correction coding by the data-correction coding means to the optical disc at each unit of data having the plurality of data linking bocks appended thereto by the data linking block appending means; and
an optical disc discriminator for judging to which the data is going to be written by the data writing means, the conventional standardized optical disc or the optical disc having a higher recording density than the former optical disc.
In the above data recording apparatus according to the present invention, when the optical disc discriminator has judged that data is going to be written by the data writing means to the conventional standardized optical disc, the data linking block appending means appends a plurality of data linking blocks, including two run-out blocks, to each unit of data going to be continuously written to the optical disc, and the error-correction coding means interleaves the data with a unit delay of four frames. When the optical disc discriminator has judged that the data is going to be written by the data writing means to the optical disc having the higher recording density than the conventional standardized optical disc, the data linking block appending means appends a plurality of data linking blocks, including three run-out blocks, to each unit of data going to be continuously written to the optical disc, and the error-correction coding means interleaves the data with a unit delay of seven frames.
In the above data recording apparatus, when the optical disc discriminator has judged that the data is going to be written to the conventi
Inokuchi Tatsuya
Kawashima Tetsuji
Sako Yoichiro
Shishido Yukio
Hindi Nabil
Maioli Jay H.
Sony Corporation
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