Patent Application
20050286378
The present invention relates to a data writing method, and more particularly to a data writing method for use with an optical recording apparatus to write data into a rewritable disc such as Digital Video Disk-ReWritable (DVD-RW).
The use of optical recording apparatus such as CD or DVD recorder/rewriter provides a very convenient way for a user to maintain and access data. Nevertheless, lots of efforts have still been made or are to be made for further improvements in various aspects such as higher speed and accuracy in writing and reading, etc. Now, various optical discs are used for storing data for access, and include, for example, CD-R, CD-RW, DVD-R, DVD-RW, DVD+RW, etc. As known, the recordable discs like CD-R and DVD-R can be used to record data for only once, but the rewritable discs such as CD-RW, DVD-RW and DVD+RW can be utilized to repeatedly record and rewrite data. Commonly used writing modes include DAO (Disc-At-Once), SAO (Session-At-Once), Multi-Session Writing, TAO (Track-At-Once) and Packet-Writing, etc.
In the DAO mode, data are continuously written into a disc from “lead-in” to “lead-out”. It is advantageous of no gap between tracks and no linking issues to be handled. In addition, the laser head used in this mode is kept on and the duplicated discs will have identical capacity to the original disc. Since all data written into the disc are continuous and relevant, the data is possibly unable to be correctly read once there is error occurring in the writing process.
The SAO mode, like the DAO mode, will result in no gap between tracks. The SAO writing procedure starts with writing a couple of tracks into the first session, and then suspends the laser head for a while. Meanwhile, the disc is still available for further writing operation. That is, the disc recorder or rewriter can still write data into the blank region of the disc. Afterwards, the SAO writing procedure goes on to write data into next session. In the case that only one writing session processed only for the disc, there is no difference between the SAO mode and the DAO mode.
In the TAO mode, data are written track by track. Accordingly, there will be gaps between tracks. After completing a track of data, the laser head suspends, and then starts again for next track. Between tracks, the writing operation is interrupted and a buffering blank region is reserved to assure the integrity of each track of data. In the writing process, two “run-out” blocks are added when writing is completed for one track. When the laser head is re-actuated for next track, one “link” and four “run-in” blocks are defined, and data are written subsequently.
The Packet-Writing mode differs from the above mentioned modes such as DAO or TAO mode in that each time data are written in fewer blocks. Generally, it can be classified into a Fix-size PacKet Write (FPKT-Write) mode and a Variable-size PacKet Write (VPKT-Write) mode. In the FPKT-Write mode, all packets in the data region have to be with the same number and size of tracks or blocks. On the other hand, for the VPKT-Write mode, the number of blocks in a packet can be adjusted according to data size. Like the TAO mode, there is “link”, “run-in” and “run-out” blocks defined to facilitate continuous reading over different packets. Further, it is advantageous of minimizing discarded space and/or incorrectly read region size resulting from defects.
Comparing the above-mentioned modes, it is understood that writing and reading errors can be reduced by using the Packet-Writing mode because the written unit of the Packet-Writing mode is much smaller than that of the other modes. The writing and reading performance of the optical recording/reproducing apparatus can be further improved by introducing defect management into the writing process. The blocks determined as defective ones according to the defect management will not leave as available spaces in subsequent writing operations. Normal blocks, however, may be improperly determined “defective” due to some unexpected factors, e.g. physical vibration or unstable servo control. In other words, lots of misjudged “defective” blocks are sacrificed although they are likely to be determined normal if detected again.
Therefore, the present invention provides a data writing method for use with a rewritable disc, capable of making use of the disc space while keeping high reading and writing accuracy.
The present invention provides a data writing method for use with an optical recording apparatus to write data into a rewritable disc. In an embodiment, a writing mode is entered and a first packet is written into the rewritable disc, a detecting mode is entered and data of the first packet written into the rewritable disc is read for defect detection, then the writing mode is entered again and a second packet is written into the rewritable disc when no defect of the first packet is detected in the detecting mode, or a rewriting mode is entered and the first packet is written into the rewritable disc again when a defect of said first packet is detected in said detecting mode.
Preferably, a lead-in portion is generated on the rewritable disc before any written packet and a lead-out portion on the rewritable disc after all written packets. And in the rewriting mode, the first packet written into the rewritable disc is erased before written into the rewritable disc again. The first packet and second packet are written into a buffer and then transferred to the rewritable disc. Accordingly, the first packet can have been stored in the buffer be transferred to the rewritable disc in the rewriting mode.
The writing mode, for example, is suitably a Fix-size PacKet Write (FPKT-Write) mode. In general, the first packet written in the writing mode includes link, run-in, data and run-out groups. Then, it is preferred that all of the link, run-in, data and run-out groups are rewritten in the rewriting mode.
In an embodiment of performing the detecting mode, a sub-beam addition signal is generated in response to the light reflected from a currently detected block of the rewritable disc, a low pass filtering operation of the sub-beam addition signal is performed to obtain a low pass sub-beam addition signal, and the currently detected block is determined as defective when an absolute value of an intensity difference between the sub-beam addition signal and the low pass sub-beam addition signal is greater than a threshold value.
In an embodiment, the detecting mode and the rewriting mode are repeated for a predetermined number of times or until no defect of the first packet is detected. The data writing method can further comprise a step of informing a host of writing failure when there is still a defect of the first packet detected after repeating the detecting mode and the rewriting mode for the predetermined number of times.
In an embodiment, the data writing method further comprises a step of writing the first packet to an alternative blank region of the rewritable disc when the writing failure is determined.
The present invention also relates to a data writing method for use with an optical recording apparatus to write data into a rewritable disc, comprising steps of:
In an embodiment, the data writing method further comprises a steps of informing a host of writing failure when said predetermined counted value in said step e) is due and there is still a defect of said first packet detected, and then writing the first packet to an alternative blank region of the rewritable disc when the writing failure is determined.
The above contents of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
Hereinafter, a data writing method according to the present invention is illustrated according to discs with CD-RW format. With reference to
The flowchart of
Referring to
If the packet written into the optical disc is determined to be non-defective in Step S24, the optical recording apparatus will enter the writing mode again and the writing operation will go on for next packet. On the other hand, once the packet written into the optical disc is determined to be defective in Step S24, that defective packet having been written in the optical disc will be erased, and the optical recording apparatus will enter a rewriting mode to rewrite that packet (Step S26). The rewriting procedure is implemented with the data packet previously stored in a buffer, e.g. the buffer 35 integrated in the micro-controller 34 as shown in
On the other hand, after the packet is written or rewritten successfully without defection detected, next packet will be written into the buffer and then recorded into the optical disc by repeating the above steps. Likewise, the newly written packet has to be detected for defects and subject to rewriting and/or other reprocessing steps, if necessary. When all the data have been recorded in the optical disc (Step S28), a lead-out portion is generated to complete writing (Step S29).
By introducing a detecting procedure to check whether the written packet is defective, the defects, if any, can be made up in time before the writing operation proceeds to next packet. Therefore, the correctness of data can be assured. Furthermore, by rewriting the packet a couple of times before giving up the defective block(s), the misjudgment of defective space of the optical disc can be minimized. Moreover, since the rewriting procedure is implemented with the data packet previously stored in the buffer, it won't take too much time to do the rewriting operation.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 093118352 | Jun 2004 | TW | national |
