JPS62283473A - Block access method - Google Patents

Abstract

PURPOSE:To recognize a reliable address and to simplify a processing and a hardware by previously comparing a desired object address and an encoded and added correction code with a reproduced address and an error code. CONSTITUTION:The object address supplied to an optical disk device through an input terminal 6 from a host computer or the like is previously encoded by an ECC encoder 7, an error correction code is added and a set of the object address and the error correction code is fed to a comparison circuit 5. It is simply compared with the set of the address and the error code in a reproducing signal obtained from an address reading circuit 3 by an optical pickup head 2 from an optical disk 1 in the circuit 5, if there is a coincidence within a prescribed allowable range, it is decided to be the object address and a coincidence output is fed to a terminal 9. Thereby, the address recognition maintaining the same reliability as the case when a decoding processing is carried out can be performed, a processing can be simplified and a hardware can be easily simplified.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention A. Industrial Application Field The present invention is applicable to a recording medium such as an optical disk or an optical card in which a recording area is divided into blocks such as a plurality of sectors. The present invention relates to a block access method for accessing a block at a desired target address.

B1 invention (the existing invention is a method for accessing a lock of a desired target address for a recording medium that is divided into multiple blocks and in which an address and an error detection or correction code are recorded for each block) Then, the target address is encoded in advance and the above error detection or correction code is added, and the result is simply compared with the address of the reproduced block and the above error detection or correction code, and the comparison result shows that the difference is within a predetermined range. A patent that features highly reliable block access even if unnecessary signal processing, such as error correction decoding processing, is omitted by accessing the block currently being played as a block at the target address also reduces the hardware required for decoding. This simplifies the hardware configuration.

C1 Conventional technology-m, disk-shaped optical recording media such as optical disks and magneto-optical disks have concentric or spiral trunks, and one track is divided into a plurality of sectors. ing.

Further, in a card-shaped recording medium such as an optical card, for example, a strip-shaped recording area is divided into a plurality of recording tracks. Each predetermined position of each of these recording blocks such as each sector and each recording track, for example, each start position, is subjected to so-called formatting and tinging processes prior to the start of use of a new disc, and so-called pre-printing processes performed by the disc or card supplier. By formatting processing etc., synchronization pattern, address, C
A so-called identification signal including an RC error detection code and the like is recorded. The address information of such an identification signal allows random access to recorded data.

The identification part of each block (sector, etc.) in which this identification signal is recorded is also called an ID part or an address part in a broad sense.For example, in an optical disc, a CRC error detection code is added to an address consisting of a trunk address and a sector address. The first weight (one unit date) of the identification information to which is added is recorded in multiple writing (for example, triple writing).

D1 Problems to be Solved by the Invention Incidentally, in such conventional recording forms of identification signals, error detection codes such as CRC have been used as error codes. It has also been proposed to add an error correction code to cope with the situation. When accessing a predetermined sector on the disk due to signal recording and playback, the movement of the pickup head is always controlled while reproducing the identification signal and confirming the current address. When reproducing an address, the above-mentioned decoding processing such as error detection or error correction is always executed. For this reason, signal processing during address reproduction becomes complicated, and especially when multiple writing such as the above-mentioned triple writing is performed, the address is processed using majority logic after error checking or error correction is performed for all parts. Determination processing must be performed, the algorithm and hardware for decoding processing become 1M more complex, and the time required for arithmetic processing becomes longer, which may impede high-speed access.

The present invention was made in view of the above circumstances, and it is possible to confirm the target address without performing decoding processing such as error detection or error correction when accessing a block (sector, etc.) of a desired target address. The present invention aims to provide a method for accessing a block of target addresses that can be realized with high reliability and that can simplify the hardware configuration required for decoding.

Means for Solving the E1 Problem In order to solve the above-mentioned problems, the block access method according to the present invention provides a method for solving the problem described above, in which each block in a recording medium divided into blocks such as a plurality of sectors is placed at a predetermined position.
In a method of reproducing an address signal recorded in a form with an error detection or correction code added and accessing a block of a desired target address, the target address is encoded and the error detection or correction code is added. , simply compares the address of the reproduced block and the above error detection or correction code, and when the comparison result shows a difference within a predetermined range, for example, when the number of different bits is less than or equal to a predetermined value, the currently reproduced block address is The feature is that the block inside is accessed as the block of the target address.

F9 action Since the target address is encoded in advance and an error detection or correction code is added, it is simply compared with the reproduced address and error detection or correction code, so decoding processing is not required and signal processing algorithms and operations are and the hardware configuration can be further simplified.

G. Embodiment FIG. 1 is a diagram for explaining an embodiment of the block access method of the present invention. In FIG. 1, signals are recorded and reproduced on an optical disc l as an example of a recording medium by an optical recording medium 2. As shown in FIG. The signal from the optical pickup head 2 is sent to an address reading circuit 3 to read the address of the block (sector) currently being reproduced, and the read address signal is sent to a comparison circuit 5.

By the way, as a specific example of a signal recording format in a sector that is one block on the optical disk l, the one shown in FIG. 2 has been proposed. In Fig. 2, one track on the optical disk l is stretched out linearly, and the identification part (so-called ID part) of one sector is enlarged and schematically shown. , one sector consists of, for example, a preformatted identification part IDR and a data part DTP as an area in which -C sector data is recorded. At the beginning position of the identification part +DR, a synchronization signal (the recording part of PLO song LO3 is placed at the beginning) is used to stabilize the operation of the clock generation PLL circuit etc. when reading data.
Continuously in the recording part of this synchronization signal PLO5, there are 3 unit UTs, which are one recording unit of sector identification address information.
It is overwritten and arranged. That is, three units UTISUT2 and IJT3 with the same content, which are recording units of sector identification address information, are sequentially arranged following the synchronization signal PLO3, and each recording unit or unit UT
The address mark SPA of the sync pattern is placed at the beginning, the address AD consisting of the trunk address TA and the sector address SA is placed, and then the error correction code E consisting of the CRCHp error detection code or, for example, BC (code) is placed.
It consists of CC. Here, as an example of the bit dispersion of each part, the address AD is 24 bits in total, consisting of 16 bits of the track address TA and 8 bits of the sector address SA, and the error detection or correction code ECC is
The length of is 24 bits, which is equal to the total address data.

When a host combinator or the like records or reproduces a data signal on an optical disk l having sectors (blocks) in such a recording format, the block (sector) at the target address for recording or reproduction is recorded. ) is required. In order to access the sector of this target address, conventionally, when reading the identification part (ID part) of each sector and reproducing the address signal, each address AD of each unit LITI to UT3 is detected by error detection or Those detected or corrected using the correction code ECC are compared with each other, and if these address values are different, the one with the highest number (
The matching address value (in the case of triple writing, two of the three address values are lost) is adopted as the effective address at the current position, and this effective address is compared with the above target address to determine the address value. I am trying to control the movement of Binokanophenod so that it approaches the block of addresses. However, with this method, the current address cannot be determined until all of the addresses of each unit written in multiple M units have been decoded, and decoding processing is required continuously, which imposes a heavy burden on the hardware.

Therefore, in this embodiment, as shown in FIG. 1, the purpose (target) address A D is supplied from the host computer etc. to the optical disk device via the input terminal 7-6.
t is encoded (encoded) in advance in the ECC encoder 7 to add an error correction (or error detection) code ECC, and send the set of the target address ADL and the error correction code ECC to the comparison circuit 5, It is simply compared with the set of address and error correction code in the reproduced signal obtained from the address reading circuit 3, and if a match is found within a predetermined tolerance range, it is determined that it is the target address and a match output is output. I am trying to send it to terminal 9.

Here, FIG. 3 is a diagram for explaining the above-mentioned comparison operation, and similarly to the recording format of FIG. An example of a reproduced signal obtained by reproduction (however, synchronization signals and the like are omitted) is shown. In this Figure 3, the above unit UTI written in triplicate
, UT2, and UT3, the sets of addresses and error correction codes that make up each of ADI, ECC1, and A
C3, ECC2, AC3, and ECC5 are reproduced in this order, and first, the set of ADI and ECCl is compared with the set of the target address AD and error correction code ECC. The comparison operation at this time is a simple comparison of each bit, and out of a total of 48 bits (24 bits of address and 24 bits of error correction code), the number of different bits is a (for example, a=4).
), it is determined that the block (sector) currently being reproduced is the block of the target address ADL. That is, it is determined whether or not the bit number a matches a so-called permissible range or a dark value (threshold).

Here, when the first unit UTI of each triple-written unit is played back, a match (
If one loss within the acceptable range is confirmed, the remaining two
What is necessary is to determine that it is the above target address without performing the above comparison etc. for the two units UT2 and UT3, and the reproduction signal of the next unit) UT2 is not found in the first unit UT1. When the above defeat is confirmed in , the remaining unit UT3 may be ignored.

In this case, if a 24-bit BCH code is used as the error correction code ECC, the inter-code distance is 12 and the error correction capability is 5, so the error within, for example, a = 4 bits can be completely corrected. The result will be a loss to the above target address. Therefore, decoding (
Compound) Even without processing, the playback address can be confirmed with the same degree of reliability as when decoding is performed.
A desired target sector (block) can be accessed.

Next, when playing (one after another) and recording signals to the disk (
For example, when the above-mentioned darkness value is set to a when the signal is reproduced (successive), the tolerance range or darkness value (threshold) for determining the loss may be set to be different depending on when the signal is played (writing). The threshold value S at the time of recording (writing) is smaller than the dark value a (b<a), that is, the allowable range is narrowed and the matching condition is made stricter. This is because when reproducing a signal, there is a request to read out the data even if it is difficult to read the address because the data has already been stored, whereas when recording the signal, the data is difficult to read later. This is because, in order to increase the memory size, it is better to avoid writing data three times into a bad block (sector) whose address is difficult to read.

In addition, as a specific example of the above-mentioned darkness value, a=4. Examples include b=1.

Next, in order to further improve the reliability, the above-mentioned -
It may be determined that the address currently being played is the above-mentioned target address only when a defeat (match within the dark value a) is confirmed.In this case, the above-mentioned unit written n times There is no need to wait until all of the units have been played, and it is not necessary to wait until all of the units are played. Just do it like this.

By the way, the movement control operation of the optical pickup head 2 until it reaches the target address can be performed in the same manner as in the past. For example, in the comparator circuit 5, the address value read from the address reading circuit 3 and the target address value are compared. and drive the head movement drive morph 12 via the head movement control circuit 11 according to this difference,
Optical pickup head 2 via head support plate 13 etc.
The difference between the reproduction address and the target address may be reduced by controlling the movement of the disc in the radial direction of the disk (in the direction of arrow A). The address reading circuit 3 in this case may have the same configuration as the conventional one, but
Based on the reference address previously read and determined from the preceding sector of the optical disc l, the address of the sector currently being played following the preceding sector is determined by calculation (for example, by adding l), and this estimated Compare the address obtained with the address obtained by actual playback,
A circuit may be used that outputs the reproduced address or estimated address as a correct determined address when these addresses match. In addition, the pre-encoded estimated address is compared with the reproduced address and a set of error detection or correction codes, and if they match within a predetermined tolerance range, the estimated address is output as the correct one. A reading circuit 3 may also be used.

Note that the present invention is not limited to the above-mentioned embodiments, and can be applied to card-shaped recording media such as optical cards in addition to disc-shaped recording media, and can also be applied to blocks such as sectors of discs. The recording format of the identification section (10 copies) is also not limited to the illustrated example.

H1 Effects of the Invention According to the block access method of the present invention, a desired target address is encoded in advance and a detection or correction code is added thereto, and the result is simply compared with a set of reproduced address and error code. With this simple processing, address confirmation can be performed with the same degree of reliability as when conventional decoding processing is involved, and it is possible to easily simplify the processing and hardware.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a circuit configuration for explaining a block access method according to an embodiment of the present invention, and FIG. 2 shows an example of a signal recording formatter on an optical disk used in the embodiment. The figure shown in FIG. 3 is a diagram for explaining a comparison operation between a reproduced signal obtained by reproducing the optical disc having the recording format shown in FIG. 2 and a signal obtained by encoding the target address. ■...Optical disc 2...Optical pink-up head 3...Address reading circuit 5...Comparison circuit 6...Target address input terminal 7...ECC encoder 9...-Failure signal output terminal

Claims (1)

[Claims] A block with a desired target address is transferred to a recording medium in which a recording area is divided into a plurality of blocks, and each block is recorded with a corresponding block address added with an error detection or correction code. In the access method, the encoded target address and the error detection or correction code added are compared with the reproduced block address and the error detection or correction code, and the result of this comparison is determined within a predetermined tolerance range. When the difference is within
A block access method characterized by accessing the block currently being played as a block at a target address.