JP2574251B2 - Alternating recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alternate recording / reproducing apparatus for recording and reproducing information while avoiding a defective portion of a recording medium.

2. Description of the Related Art As a recording medium, a write-once type optical disc (which can be additionally recorded only once) is taken as an example. Optical disks have the advantage of high recording density and large amount of information, and the disadvantage of having many defective areas with defects. Therefore, in practice, a replacement process for recording information while avoiding a defective portion is required. A problem in the replacement process is an addressing method for quickly extracting necessary information.

The information recording area of the optical disc is divided into tracks around one circumference, and each track is further divided into a number of sectors. The replacement process is performed in sector units. Check in advance whether each sector is a recordable normal sector with no defect and a defective sector that is not recordable,
No recording is performed on defective sectors.

Specifically, conventionally, information to be recorded is recorded in order from the first sector to the last sector of the optical disk using only normal sectors.

Here, in order to retrieve the i-th recorded information (sector unit), as a first method, the number of recorded sectors is counted from the head of the optical disc, and the information is reproduced from the i-th recorded sector. There is.

In the second method, where and where the defective sector is located on the optical disk is stored somewhere in the system.
When the information recorded at the i-th position (the information of the logical address i) is taken out from the optical disc, the information i is recorded at what track and at what sector (the physical address of the disc) by referring to the position information of the defective sector. You can take it out directly.

Problems to be Solved by the Invention In the above-described conventional method, the first method as an addressing method has a problem that it takes a very long time to extract necessary information. When fetching certain information, the number of recorded sectors must be counted from the beginning of the disk. Therefore, in order to fetch the information of the latter half of the disk, the counting time to reach the latter becomes very long.

In the second method of storing the position information of the defective sector in the system, necessary information can be quickly retrieved. This method can be used if the recording medium is fixedly incorporated into the system (such as a fixed disk device). However, assuming that many disks can be freely inserted into and removed from many devices like optical disks. However, a method of managing defect position information of all disks in each device is not practical at all.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and has as its object the purpose of not managing systematically the defect position information of a recording medium, but the average access time required to retrieve necessary information. An object of the present invention is to provide an alternate recording / reproducing apparatus that is sufficiently short.

Means for Solving the Problems Therefore, according to the present invention, a recording medium that divides a recording area into tracks and divides each track into a number of sectors, a means for checking in advance whether the sector is a normal sector or a defective sector, Means for recording information in a sector, for each normal sector, address management means for storing a track number to which the sector belongs and a sector number counted by skipping a defective sector from the first sector in this track, and when reproducing information, Reading the two types of numbers of the normal sector in which desired information is stored from the address management means,
Firstly, a reproducing means for scanning the track to which the normal sector belongs by the track number, then counting the inside of the track by the sector number, searching for the normal sector and reproducing desired information.

Operation Since information for only (MN) sectors is recorded on one track, it is directly known which track j and which k the i-th information was recorded. Therefore, when extracting information i, the number of recorded sectors on track j is counted from the beginning,
The information of the k-th recorded sector may be reproduced.

Embodiment A write-once optical disk is taken as an example similarly to the conventional example. FIG. 1 shows a configuration example of a user area in an information recording area of an optical disk. In this example, there are 20,000 tracks, and the track numbers 1, 2, 3,... 15 tracks at equal intervals
, And are sector numbers 1, 2, 3,... 15 in the clockwise direction from the reference point on the circumference.

The last three sectors of each track (sector numbers 13, 14,
15) Make the track a spare sector. Each track has
Information for 12 sectors shall be recorded.

Here, the track is a physical track, but a virtual track in which a plurality of physical tracks is one track may be assumed.

When recording information on a certain track, the track is first scanned to determine whether each sector is a normal sector or a defective sector. Then, the 12 pieces of information are recorded in ascending order of the sector number using only normal sectors. That is, if there is a defective sector, it is skipped and recorded in the next normal sector. This is the same for the spare sector.

Therefore, if there is no defective sector in the portion of sector numbers 1 to 12, twelve pieces of information are recorded in this portion in order, and the spare sectors of sector numbers 13, 14, and 15 remain unused.

If there is a defective sector in the sector numbers 1 to 12, the twelfth information is recorded in the spare sector of number 13.
Even if the sector number 13 is normal, if this is a defective sector, it is recorded in the next sector number 14.

As is clear from the above, if three spare sectors are normal, even if there are up to three defective sectors in the sector numbers 1 to 12, 12 pieces of information can be recorded on the track. How many spare sectors are prepared is determined based on the probability of occurrence of defective sectors. However, considering that a shortage may occur in the spare sector, in that case, information may be recorded on a separately determined track. The method is outside the scope of the present invention. In this embodiment, it is assumed that no shortage occurs in three spare sectors.

As described above, if information is recorded by performing the alternation processing in one track, necessary information can be quickly extracted as follows.

Since 12 pieces of information are recorded on one track, the total information of the disc is 12 × 2000 pieces of information. A logical address corresponding to the recording order is added to this information. The logical address directly indicates at what track and at what position the information of the address is recorded.

Therefore, when extracting the k-th information of the track number j, the track number j is scanned, the number of the recorded sectors is counted in order from the top, and the information of the sector whose count value is k is reproduced. do it. This address counting process may be performed for at most 15 sectors (one track), and the time required for this process is sufficiently short. By the way, in the first conventional method, a similar address counting process is performed up to 15 times.
Must be performed for × 20000 sectors. From this, it can easily be seen that the average access time is significantly reduced according to the present invention.

FIG. 2 shows a configuration example of a system for implementing the present invention. 1 is a host computer, 2 is an optical disk device,
3 is an optical disk. When recording information on one or more tracks of the optical disc 3, the area of the optical disc 3 is first scanned, and its reproduction output is compared with a reference value by a defect discriminator 4 to determine whether a normal sector is defective. The information is classified into sectors, and the result is processed by the defect information management unit 5 and transmitted to the address management unit 6. Thus, which sector is defective is recognized in a predetermined format.

Information to be recorded is input from the host computer 1 to the encoding unit 8, where it is encoded for recording and supplied to a recording head (not shown). At this time, the recording address is stored in the address management unit 6 in the host computer 1.
The defect information is controlled based on the logical address and the defective information, and the defective sectors are skipped and recorded sequentially as described above.

When reproducing information of a logical address specified by the host computer 1, first, under the control of the address management unit 6, a track including the address is scanned,
The output is compared with a reference value by a recorded determination unit 9 and the result is processed by a recorded information management unit 10 to count the number of recorded sectors in the track. The count value is input to the address management unit 6, and when reaching the predetermined recorded sector, the reproduction output of the information recorded in that sector is returned to the original signal format by the decoding unit 11, and the host computer 1 Send to

Advantageous Effects of the Invention As described in detail above, according to the present invention, it is not necessary to systematically store and manage defect position information of a recording medium, and it is only necessary to perform a slight preprocessing at the time of recording and reproduction, From the host side, not only can information be handled by logical addresses, but also the average access time becomes sufficiently short, and necessary information can be quickly retrieved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration example of a user area of an optical disc according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration example of a system for implementing the present invention. 3 ... optical disc, 4 ... defect discriminator, 9 ... recorded discriminator

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Keiji Ueki 2-3-8 Shimomeguro, Meguro-ku, Tokyo Matsushita Electric Transmission Co., Ltd. (56) Reference JP-A-56-38652 (JP, A) JP-A Showa 57-198587 (JP, A) Japanese Patent Publication No. 59-53609 (JP, B1)

Claims (1)

(57) [Claims] 1. A recording medium which divides a recording area into tracks and divides each track into a number of sectors, means for checking in advance whether the sector is a normal sector or a defective sector, and records information in the normal sector. Means, for each recorded normal sector, an address management means for storing a track number to which the normal sector belongs and a sector number counted by skipping a defective sector from a head sector in this track, and the address when reproducing information. The two kinds of numbers of the normal sector in which the desired information is stored are read from the management means. First, the track to which the normal sector belongs is scanned by the track number, and then the defective sector is skipped in the track by the sector number. Reproducing means for counting, searching for the normal sector, and reproducing desired information. Substitution recording and reproducing apparatus.