JP3606746B2 - Information recording medium and information recording / reproducing apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an information recording medium and an information recording / reproducing apparatus method, and more specifically, by using a specific arrangement of absolute codes as an address mark, the area of the medium used for recording the address mark can be reduced. The present invention relates to an information recording medium capable of increasing an information recording capacity, and an information recording / reproducing apparatus used for recording or reproducing information on the information recording medium.
[0002]
[Prior art]
In an information recording medium such as a hard disk used in a computer system, in order to improve the recording capacity and store a larger amount of information, a narrow information recording track is formed at a high density as the recording density in the circumferential direction increases. Therefore, the improvement of the recording density in the radial direction is demanded. On the other hand, in such an information recording medium, when the track density is increased, an error in the relative position between the head and the medium due to vibration or thermal expansion becomes a problem.
[0003]
Therefore, in a high-density information recording medium, a position signal is recorded on the medium in advance, this signal is read by the head, and tracking control is performed so that the head is always positioned on the information recording track. Servo burst signals and address marks are used as position signals for tracking control, and these signals are recorded in gaps between consecutive data blocks over each track, that is, relative running of the head on the medium. Arranged intermittently along the direction.
[0004]
The servo burst signal is a signal used to accurately position the head at the center of the track, and the address mark is a signal that gives information on what track the head is positioned on. In addition, the address mark may include a sector number indicating which servo signal recording unit corresponds to one rotation while the head is passing.
[0005]
[Problems to be solved by the invention]
In recent years, with an increase in track density, a tracking servo requires a response frequency of about 2 kHz, and accordingly, an error signal also requires a high frequency of about 20 kHz. For this reason, the necessary servo signal recording section exceeds 100 per rotation, and the number of bits of the address mark increases with the increase in the number of tracks. As a result, the area of the control signal recording unit is enlarged, and there is a problem that the area that can be used for information recording is limited.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the area of a medium used for recording an address mark by using a specific arrangement of absolute codes as an address mark. And an information recording / reproducing apparatus used for recording or reproducing information on the information recording medium.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the information recording medium of the present invention is composed of a plurality of tracks in which data blocks in which information is recorded and address marks in which control addresses are recorded are alternately arranged, and In an information recording medium in which these tracks are arranged in parallel and in parallel with the traveling direction, the address mark is created by a predetermined arrangement of code bits constituting an absolute code and is constant in a direction perpendicular to the traveling direction. The arrangement pattern is a pattern in which a code string read along each track repeats a portion that changes in a direction orthogonal to the traveling direction and a portion that does not change at a constant pitch, and includes a plurality of patterns. When reading with a head equipped with information reading means, reading with one or a set of information reading means When the code information obtained in this way changes in the direction orthogonal to the traveling direction, the code information obtained by reading with another or other set of information reading means is arranged in such an arrangement pattern that does not change in the direction orthogonal to the traveling direction. It is characterized by being.
[0008]
That is, in the above information recording medium, the address mark is read using a plurality of information reading means provided in the head simultaneously. At that time, the specific arrangement pattern set in the absolute code constituting the address mark makes it possible to specify the address with a small number of code bits by combining each output information of the information reading means.
[0009]
Further, in a preferred aspect of the above information recording medium, the absolute code of the address mark is created by an arrangement of code bits constituting a gray code and an identification code, and an arrangement pattern in a direction orthogonal to the traveling direction of the gray code is: The code string read along each track is set to a pattern in which a portion that changes in a direction orthogonal to the traveling direction and a portion that does not change are alternately repeated at a constant pitch, and the identification code is read out along each track. It is constituted by a code for identifying whether or not the code is a code of a portion that changes in a direction orthogonal to the traveling direction.
[0010]
That is, when the address mark is read on the information recording medium, the gray code changes bit by bit in the changing portion, and the identification code specifies whether or not the gray code changes in the portion. For this reason, the combination of the gray code and the identification code can prevent a reading error and specify the address more reliably.
[0011]
The information recording / reproducing apparatus of the present invention is an information recording / reproducing apparatus for recording or reproducing information on the above-mentioned information recording medium from which an address mark is read by two information reading means, and tracks one recording surface. The head is provided with at least two information reading means arranged in a direction orthogonal to the traveling direction, and the arrangement interval of these information reading means is a portion where the arrangement pattern changes in the direction orthogonal to the traveling direction and a portion where the arrangement pattern does not change The information reading means reads out the sign bits of different address marks at the same time in tracking.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view showing the main part of the information recording medium according to the present invention, showing an example of the configuration of address marks between data blocks and an arrangement pattern of address marks across tracks. FIG. 2 is a schematic arrangement diagram showing in simplified form the code principle used for the address mark in FIG. 1 and the code information obtained by the multi-channel head. FIG. 3 is a schematic arrangement diagram showing code information obtained by an address mark similar to that in FIG. 2 and a head of another aspect. FIG. 4 is a perspective view showing an example of a recording / reproducing head provided with two head gaps.
[0013]
As shown in FIG. 1, the basic format of the information recording medium of the present invention is substantially the same as that of the conventional information recording medium, and the data block (1) where information is recorded and the address where the control address is recorded. It is constituted by a plurality of tracks (tracks are illustrated by lines (I to VIII) in the figure) formed by alternately arranging the marks (2), and these tracks are the running of the medium. They are arranged in parallel and parallel to the direction (the direction indicated by the arrow (v) in FIG. 1). In addition, a servo burst signal recording unit (3) as a control signal for positioning the head (4) is arranged in a gap between tracks that are continuous in a direction orthogonal to the traveling direction.
[0014]
The information recording medium of the present invention is a medium that is sought by a so-called multi-channel head (4) having a plurality of head gaps (5) (information reading means). For example, as shown in FIG. 4, the head (4) includes two head gaps (5a, 5b) arranged in parallel along a direction orthogonal to the traveling direction. The upper surface of the head (4) shown in FIG. 4 is the surface on the medium side. Generally, a pair of head gaps is provided in advance in the recording / reproducing head so that the other head gap can be used when one head gap is defective. The present invention effectively utilizes the two head gaps (5a, 5b) of the head (4) produced as described above.
[0015]
As shown in FIG. 1, the address mark (2) provided intermittently in each track is created by a predetermined arrangement of code bits constituting an absolute code. Information on track numbers and sector numbers can be recorded by the absolute code. For the purpose of using the multi-channel head as described above and specifying an address with a small number of code bits, the address mark (2) has a fixed arrangement pattern in a direction orthogonal to the traveling direction.
[0016]
The arrangement pattern described above is a pattern in which a code string read along each track repeats a portion that changes in a direction orthogonal to the traveling direction and a portion that does not change at a constant pitch (G). Moreover, when the above-described arrangement pattern is read by a multi-channel head (4), when the code information obtained by reading with one head gap (5a) changes in a direction orthogonal to the traveling direction, The code information obtained by reading in (5b) is set to an arrangement pattern that does not change in the direction orthogonal to the traveling direction.
[0017]
It should be noted that the “changed portion” in the array pattern refers to a region where the code string changes as the head (4) moves in any direction. In the code string at both ends of the area where the code string changes, the code changes only by movement in one direction. For example, in the change area set for four track pitches as described later, the head (4) The actual number of code changes due to movement is 3 times. In the figure, the moving direction of the head (4) is indicated by arrows in both directions.
[0018]
The information recording medium of the present invention will be described more specifically. In the information recording medium suitable for the two-channel head (4) as shown in FIG. 4, the absolute code of the address mark (2) is as shown in FIG. Further, it is created by an arrangement of sign bits constituting a gray code (GC) and an identification code (ID). For the sake of simplicity, for example, a gray code (GC) along a track is created by at least two code bits.
[0019]
In the address mark (2) shown in FIG. 1, binary codes 00, 01, 11, and 10 are written as gray codes (GC) of the tracks (I to IV), respectively, and these are read. , Each is configured to output four types of numerical information from 0 to 3. By using such a gray code (GC), when the head (4) is moved in a direction orthogonal to the traveling direction, the change in the code accompanying the movement is limited to a single code bit, so that the code information is stable. Output is obtained.
[0020]
Further, the arrangement pattern of the gray code (GC) in the direction orthogonal to the traveling direction has a constant pitch (G) between a portion where the code string read along each track changes in the direction orthogonal to the traveling direction and a portion which does not change. The pattern is repeated alternately. Specifically, the gray code (GC) arrangement pattern in the simplified example is set to a pattern in which a portion that changes in a direction orthogonal to the traveling direction and a portion that does not change repeat every four track pitches. The
[0021]
For example, in the information recording medium shown in FIG. 1, as described above, the gray codes (GC) are respectively set to 00, 01, 00 for the tracks (I to IV) corresponding to the first pitch (G) area. 11 and 10 are written, and 11 is written for each of the tracks (V to VIII) corresponding to the area of the next pitch (G).
[0022]
The identification code (ID) is configured by a code for identifying whether or not the gray code (GC) read along each track is a code of a portion that changes in a direction orthogonal to the traveling direction. That is, in the simplified example as described above, the identification code (ID) is created by at least one sign bit.
[0023]
For example, in the medium shown in FIG. 1, when reading with one head gap (5b) as an identification code (ID) in a track (I to IV) corresponding to the area of the first pitch (G), a gray code is obtained. For example, code 0 indicating that (GC) is a changing portion is written. A code 1 indicating that the gray code (GC) is not changed is written as the identification code (ID) in the track (V to VIII) corresponding to the area of the next pitch (G).
[0024]
The information recording medium of the present invention is recorded or reproduced by the multi-channel head as described above. In this case, the interval between the information reading means of the heads is set to an odd multiple such as 1, 3, 5,... That is, in the two-channel head (4) of the above-described example, the two head gaps (5a, 5b) are arranged at an interval (P) equal to four times the track pitch in the direction orthogonal to the traveling direction.
[0025]
As described above, the address mark (2) on the medium is normally recorded in binary code as shown in FIG. 1, but when this is read out as code information by the head (4), it is shown in FIG. Can be expressed as follows. In FIG. 2, in the address mark column, a configuration example of the address mark (2) on the medium is indicated by numerical values from 0 to 3 for convenience, and in the output information column, the head gap (5a) ( Code information obtained by each reading is shown by channel A) and head gap (5b) (channel B).
[0026]
In the configuration of the address mark (2) illustrated in FIG. 2, the output information of the head gap (5a) (channel A) matches the recording code on the medium. As shown in FIG. 2, according to the arrangement of the address marks (2), the combinations of the outputs of the channels A and B appear without overlapping one by one, and the code changes due to the movement of the head (4). A bit is only one bit.
[0027]
FIG. 3 shows an output example when the address mark (2) having the configuration shown in FIGS. 1 and 2 is read by the head (4) of another mode. The head (4) shown in FIG. 3 is a head in which the interval (P) between the two head gaps (5a, 5b) is set to 12 times the repetitive pitch (G) of the array pattern, that is, the track pitch. In the example of FIG. 3 as well, in the same way as in FIG. 2, the combinations of the outputs of channels A and B appear without overlapping each other, and which code bit changes due to the movement of the head (4)? Only one bit of.
[0028]
That is, in the present invention, a plurality of head gaps (5a, 5b) provided in the head (4) are used at the same time, and in the direction in which the code string is orthogonal to the traveling direction with respect to the absolute code constituting the address mark. When the code pattern obtained by reading with one head gap (5a) changes in a direction orthogonal to the traveling direction, the arrangement pattern repeats the changing portion and the non-changing portion at a constant pitch (G). Since an arrangement pattern is provided so that the code information obtained by reading with the other head gap (5b) does not change in the direction orthogonal to the traveling direction, combining the output information of the head gap (5a, 5b) An address can be specified with fewer sign bits. In addition, a more systematic code can be formed in the absolute code.
[0029]
In particular, when the absolute code of the address mark (2) is composed of the gray code (GC) and the identification code (ID) as described above, the gray code (GC) changes bit by bit in the changing portion. Since the identification code (ID) specifies whether or not the gray code (GC) to be read is a code in a changing region, the combination of the gray code (GC) and the identification code (ID) can prevent a reading error. Thus, the address can be specified more reliably with fewer code bits than in the prior art. Therefore, in the information recording medium of the present invention, the recording area of the address mark (2) as the control signal can be reduced, and the area of the data block (1) used for information recording can be increased.
[0030]
The information recording / reproducing apparatus of the present invention is an information recording / reproducing apparatus for recording or reproducing information on the above information recording medium, and tracks one recording surface as shown in FIGS. The head (4) includes at least two head gaps (5a, 5b) (information reading means) arranged in a direction orthogonal to the traveling direction,
The arrangement interval of the head gaps (5a, 5b) is set to an interval that is an odd multiple of the repetitive pitch between the portion where the arrangement pattern changes and the portion where the arrangement pattern does not change in the direction orthogonal to the traveling direction. In the example shown in FIG. 1, the arrangement interval is set to 4K times the track pitch (where K is an odd number). Such an information recording / reproducing apparatus can specify an address with a small number of code bits by simultaneously reading different address marks (2) depending on each head gap (5a, 5b) in tracking.
[0031]
In the present invention, a head provided with three or more information reading means can be applied. When seeking with a head equipped with three information reading means, as an address mark of the information recording medium, code information obtained by reading with one (or two) information reading means is in a direction orthogonal to the traveling direction. When changing, an absolute code having an arrangement pattern is used so that the code information obtained by reading with the other two (or one) information reading means does not change in the direction orthogonal to the running direction.
[0032]
In addition, when seeking with a head provided with four information reading means, the information reading means is set as two sets of two each, and the address mark of the information recording medium is one set of information reading means. When the code information obtained by reading changes in the direction orthogonal to the traveling direction, the code information obtained by reading by another set of information reading means is an arrangement pattern that does not change in the direction orthogonal to the traveling direction, Moreover, in each set, when the code information obtained by reading by one information reading means changes in the direction orthogonal to the traveling direction, the code information obtained by reading by the other information reading means is a direction orthogonal to the traveling direction. An absolute code having an arrangement pattern that does not change in the above is used.
[0033]
【The invention's effect】
As described above, according to the present invention, a plurality of information reading means of the head are used at the same time, and a specific arrangement pattern is provided for the absolute code constituting the address mark. By combining the output information, the address can be specified with fewer code bits than in the prior art. As a result, the recording area of the control signal in the information recording medium can be reduced, and the area used for information recording can be increased.
[0034]
In particular, when the absolute code is composed of a gray code and an identification code, the gray code changes bit by bit in the changing portion, and it is specified by the identification code whether the gray code is a changing area code or not. Therefore, the combination of these codes can prevent reading errors and specify addresses more reliably. Therefore, the present invention exerts a great effect on a high-density information recording medium that requires more servo signal recording.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a main part of an information recording medium according to the present invention, showing an example of a configuration of address marks between data blocks and an example of an array pattern of address marks across tracks.
FIG. 2 is a schematic arrangement diagram showing the code principle used for the address mark in FIG. 1 and code information obtained by a multi-channel head in a simplified manner.
FIG. 3 is a schematic array diagram showing code information obtained by the same address mark as in FIG. 2 and a head of another mode.
FIG. 4 is a perspective view showing an example of a recording / reproducing head provided with two head gaps.
[Explanation of symbols]
1: Data block 2: Address mark 3: Servo burst signal recording unit 4: Head 5: Head cap (information reading means)
G: repetition pitch of array pattern GC: gray code ID: identification code P: arrangement interval of information reading means

Claims (3)

Information recording composed of a plurality of tracks in which data blocks in which information is recorded and address marks in which control addresses are recorded are alternately arranged, and these tracks are arranged in parallel and parallel to the traveling direction In the medium, the address mark is created by a predetermined arrangement of code bits constituting an absolute code, and has a fixed arrangement pattern in a direction orthogonal to the traveling direction, and the arrangement pattern is arranged along each track. When the code string read in this manner is a pattern in which a portion that changes in a direction orthogonal to the traveling direction and a portion that does not change are repeated at a constant pitch, and when read by a head provided with a plurality of information reading means, The code information obtained by reading by the pair of information reading means is in a direction perpendicular to the traveling direction. When changing an information recording medium characterized by being made to the arrangement pattern, such as unchanged in the direction code information obtained by reading other or other set of information reading means it is perpendicular to the direction of travel. 2. The information recording medium according to claim 1, wherein an absolute code of an address mark is created by an arrangement of code bits constituting a gray code and an identification code, and an arrangement pattern in a direction orthogonal to the traveling direction of the gray code is The code string read along each track is set to a pattern in which a portion that changes in a direction orthogonal to the traveling direction and a portion that does not change are alternately repeated at a constant pitch, and the identification code is read along each track. An information recording medium comprising a code for identifying whether or not the gray code is a code of a portion that changes in a direction orthogonal to the traveling direction. 3. An information recording / reproducing apparatus for recording / reproducing information on / from the information recording medium according to claim 2, wherein the head for tracking one recording surface is at least two information reading units arranged in a direction orthogonal to the traveling direction. And the arrangement interval of these information reading means is set to an interval that is an odd multiple of the repetitive pitch between the portion where the arrangement pattern changes and the portion that does not change in the direction orthogonal to the traveling direction. Recording / playback device.

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