JP2000021106A - Rotary type storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve data transfer performance in the continuous access to a plurality of tracks. SOLUTION: The optimum value of a skew value 14 which is a relative interval of the heading position in the circumference direction between data tracks corresponding to the switching head is obtained for individual head based on the actual measured value of the head off-set and head switching time in order to generate a skew value table corresponding to the skew value 14 for each head. Using this skew value table, the heading sector 7a and the final sector 7b of the data sector 7 of each data track 6 corresponding to each head are arranged in the optimum manner at the time of formatting, position of heading sector 7a coming immediately after the head switching between adjacent heads is optimized at the time of continuous access to a plurality of data tracks 6, and the time required for continuous access of a plurality of data tracks 6 is shortened to improve data transfer performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary storage technology, and more particularly, to optimization of a track format in a magnetic disk drive or the like having a rotary storage medium such as a magnetic disk, and more particularly to data optimization at the time of head switching. The present invention relates to a technique which is effective when applied to optimization of a skew value for determining a sector arrangement.

[0002]

2. Description of the Related Art For example, a magnetic disk device, which is a kind of a rotary storage device, has a data track provided concentrically on a recording surface of a magnetic disk, and an arbitrary position is determined by positioning a magnetic head on the data track. Record and play back data on the data track. In order to position the magnetic head on the data track, the recording surface of the magnetic disk
The position signal is recorded intermittently. The magnetic head detects this intermittent position signal and recognizes the current position through the position signal demodulation circuit. Based on the error amount between the recognized current position and the target data track position, the voice coil motor is driven, and by controlling the voice coil motor operation amount by feedback closed loop control of the detected current position, the magnetic head is moved to the target data track. Position on track. Using the positioned magnetic head, data is recorded / reproduced on data tracks on the recording surface of the magnetic disk.

At this time, when transferring data continuously, data over a plurality of data tracks is read or written continuously. In order to move from a data track to the next data track, it is necessary to switch the head, but switching of the head requires a switching time. This switching time is
The head-to-head offset depends on the head-to-head offset, which is a component of the relative position of the head in the disk radial direction. It takes a lot of time, and conversely when the offset between heads is small, it takes less time. For example, when reading and transferring data exceeding the track size continuously, the processing of reading data of a certain track, switching heads, and reading and transferring the data of the next track is repeated. At this time, considering the time required for head switching,
The transfer time is shortened by delaying the start position of the data of the track from the start position of the data of the track before the head switching so that the start position of the data of the next one track comes immediately after the head switching. The amount by which the start position of the data is delayed is called a skew value.

In the conventional reference technology, the skew value is set in consideration of the variation in the offset between heads, and even when the offset between heads is large, the head with the maximum offset between heads is set so that the head switching time can meet the skew value. Set the skew value based on the head switching time of
The set constant skew value was used uniformly.

[0005]

The above-mentioned head-to-head offset varies from head to head and from device to device. However, since a constant skew value has conventionally been used uniformly, even if the head-to-head offset is small, the head-to-head offset is small. The same head switching time is required as when the inter-offset is large. That is, when reading and transferring data over two or more tracks, the processing of reading the data of one track, waiting for the time corresponding to the skew value, and reading the data of the next track is repeated, and the offset between the heads is large. Even if it is small or small, it is necessary to wait for the skew value. The same is true for writing data of two or more tracks. As the waiting time of the skew value becomes shorter, the amount of data that can be read or written per unit time increases, which leads to improvement in the continuous transfer performance of the device.

In the conventional reference technique, a constant skew value is used as described above, and a time longer than the head switching time when the head-to-head offset is large is skewed so as to meet the head switching time when the head-to-head offset is large. Since the values are uniformly set, the same head switching time is required when the offset between heads is large and when the offset between heads is small, as when the offset between heads is large. Therefore, when the head-to-head offset is small, even if the head switching time is in time even with a skew value smaller than the set skew value,
The same wasteful waiting time as the skew value when the head-to-head offset is large is required, which hinders continuous transfer speed improvement.

To reduce the skew value, the head-to-head offset may be set to zero. However, considering the actual manufacturing process and the variation in parts, the head-to-head distance between all heads of all the produced magnetic disk drives is considered. It is practically impossible to set all offsets to zero. For this reason, conventionally, the maximum required head switching time is determined from the maximum possible head-to-head offset in consideration of the manufacturing process and the variation in parts, and the maximum head switching time is set within the time of the skew value, that is, (Maximum required head switching time) ≤
(Skew value).

The data sector has an ID or LBA (Logical Bloom) so that the sector position can be recognized.
ck Address: logical block address). Usually, these are recorded on the recording surface of the disk when formatting the magnetic disk device. At this time, in order to determine the positional relationship of the data sectors between the data tracks, formatting is performed in consideration of the skew value. That is, the time from the last sector of the plurality of data sectors on the data track on the recording surface of a certain head to the head sector of the plurality of data sectors on the data track on the recording surface of the next head is the skew value. Similarly, the ID or LBA of the data sector is recorded. Formatted magnetic disk drives have a
In order to process data in the order of data sectors ordered by ID or LBA, if head switching is completed within the skew value, data is continuously transferred from the previous head to the next head with a head switching process interposed therebetween. Can be transferred. Conventionally, a constant skew amount is uniformly used for the format, and the skew value is based on the case where the offset between heads is large.
When the offset between heads is small, even if the skew value is smaller than the set skew value, the head switching time is enough, but the same waiting time as the skew value when the offset between heads is large is required, and the continuous transfer speed is improved. Was hindered.

An object of the present invention is to provide a rotary storage technique capable of improving data transfer performance in continuous access of a plurality of tracks.

Another object of the present invention is to improve the data transfer performance in continuous access to a plurality of tracks at low cost without strictly controlling the head assembling process more than necessary to reduce the offset between heads. It is an object of the present invention to provide a rotation type storage technology capable of being operated.

Another object of the present invention is to provide a rotary storage technique capable of improving data transfer performance in continuous access to a data set spanning a plurality of tracks.

It is another object of the present invention to provide a rotary storage technology capable of shortening the time required for data backup and data restoration by continuous access of a plurality of tracks.

Another object of the present invention is to provide a low-cost, data-backup or data-restore by continuous access to a plurality of tracks without strictly controlling the head assembly process more than necessary to reduce the head-to-head offset. Another object of the present invention is to provide a rotary storage technology capable of shortening the required time in the above-mentioned operation.

[0014]

In the rotary storage device according to the present invention, the head-to-head offset between each head, which is supported by the head positioning means and accesses the rotary storage medium, is measured, and the head-to-head offset and the head switching time are measured. From the correlation of, the head switching time corresponding to each head-to-head offset is taken into consideration, an optimum skew value corresponding to each head-to-head offset is obtained, and a skew value table in which the skew value is associated with each head is created. By arranging the data sectors using this skew value table, the head position of the data sector after head switching is optimized.

Alternatively, the head switching time between each head is measured, and the skew value is set so that the head switching time is shorter than the skew value time, thereby obtaining an optimum skew value corresponding to each head. A skew value table in which a skew value is made to correspond to each head is created, and a data sector is arranged using the skew value table, thereby optimizing a data sector head position after head switching.

More specifically, as an example, a magnetic disk for recording data, a spindle motor for supporting and rotating the magnetic disk, a magnetic head for recording and reproducing data on each recording surface of the magnetic disk, and a magnetic disk An actuator for supporting the head on the recording surface of the magnetic disk; a voice coil motor for driving the actuator to move and position the magnetic head on an arbitrary data track of the magnetic disk; and a magnetic disk for recognizing the data track position of the magnetic disk A voice coil using the head position signal recorded above, a position signal demodulation circuit for demodulating a head position signal read by a magnetic head through a position signal sampler, and a position signal demodulated by the position signal demodulation circuit. A positioning controller that outputs the motor operation amount is provided. A closed loop control system that controls the voice coil motor drive current and positions the magnetic head on any data track on the magnetic disk based on the data, and writes data on each data track concentrically formed on the disk surface. In a magnetic disk drive for recording / reproducing and transferring data continuously, an offset between heads caused by a relative displacement in a radial direction of each magnetic head corresponding to each data track is measured, and a head switching time according to the offset between heads is measured. In consideration of the above, a skew value table in which the skew value at the time of head switching is assigned to an optimum value for each head is created, and by using this skew value table, the skew value is set to the shortest value for each head. It was done.

Alternatively, in the above-mentioned magnetic disk drive, the head switching time generated at the time of head switching of each magnetic head corresponding to each data track is measured, and the head switching time is set so that the head switching time becomes shorter than the time of the skew value. A skew value table in which the skew value is assigned to an optimum value for each head is created, and the skew value is set to the shortest value for each head by using this skew value table.

That is, using the skew value table, a skew value at the time of formatting is set as a skew value set for each head, and a skew value of a plurality of data sectors on a data track on a recording surface of a certain head is set to a next head The data sector ID or LBA is set so that the time to the first sector of the plurality of data sectors of the data track on the recording surface of the data track becomes the skew value set for each head.
Record

In the magnetic disk device thus formatted, during continuous transfer, data is processed in the order of data sectors ordered by ID, LBA, or the like. Therefore, if head switching is completed within the above skew value, the previous head will be processed. The data can be continuously transferred from the first head to the next head with the head switching processing interposed. By using a skew value table in which the skew value is associated with each head in consideration of the head-to-head offset for each head, a head with a small head-to-head offset and a short head switching time has a short skew value and a large head-to-head offset. A head having a long head switching time has a long skew value.

Conventionally, all heads have been uniformly set to a constant skew value in accordance with a skew value when the head-to-head offset is large. In the present invention, however, there is a head that can be set to a shorter skew value. The distribution of the actual head-to-head offset is close to the normal distribution. When the head-to-head offset is large, the distribution is near 3σ of the distribution. In consideration of this, according to the present invention, the average value of the skew value can be set to 1/2 or less of the conventional skew value. That is, the waiting time due to the skew value during the continuous transfer can be reduced, and the continuous transfer performance can be improved.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a conceptual diagram showing an example of the operation of a magnetic disk device as an embodiment of the rotary storage device of the present invention, FIG. 2 is a conceptual diagram showing an example of the configuration, and FIG. FIG. 4 is a diagram illustrating an example of the operation, and FIG. 4 is an explanatory diagram illustrating an example of the operation. FIG. 5 is an explanatory diagram showing an example of the configuration of a skew value table held as control information by the magnetic disk device of the present embodiment, and FIG. 6 is a diagram illustrating an example of the operation of the magnetic disk device of the present embodiment. 7, 8 and 9 are flowcharts showing an example of the operation of the magnetic disk device of the present embodiment.

As exemplified in FIG. 2, the magnetic disk device of the present embodiment has a magnetic disk 1 for recording data.
A spindle motor 8 supporting and rotating the magnetic disk 1; a magnetic head 2 for recording and reproducing data on each recording surface of the magnetic disk 1; and supporting the magnetic head 2 on a magnetic disk recording surface. An actuator 3 and the actuator 3 are driven to move the magnetic head 2 to the magnetic disk 1.
, A voice coil motor 4 for moving and positioning on an arbitrary data track 6, a head position signal 9 recorded on the magnetic disk 1 for recognizing the position of the data track 6 on the magnetic disk 1, and a sampler. A position signal demodulation circuit 10 for demodulating a head position signal 9 read by the magnetic head 2;
A positioning controller 11 that outputs the operation amount of the voice coil motor using a position signal demodulated by 0;
Is provided.

A closed loop control system for controlling the driving current of the voice coil motor based on the head position signal 9 and positioning the magnetic head 2 on an arbitrary data track 6 of the magnetic disk 1 is constituted. Disc 1
The data is transferred to and from an external information processing device (not shown) by recording and reproducing data in data sectors 7 arranged on data tracks 6 concentrically formed on the surface of the data track 6.

In each of the plurality of magnetic disks 1, among a plurality of data tracks 6 provided concentrically on the recording surface facing the magnetic head 2, the radii thereof are substantially equal, and the plurality of data tracks 6 are provided without displacement of the actuator 3. That can be continuously accessed only by the switching operation of the magnetic head 2 are managed as cylinders, and one data track 6
When storing a data set such as a file having a size exceeding the capacity of a plurality of data tracks 6 in the same cylinder,
Is used to fill in order. This is because the switching operation of the electric magnetic head 2 requires much shorter time and the access efficiency is improved than the seek operation of moving the magnetic head 2 to another data track 6 (cylinder) in the radial direction. is there.

Therefore, in the case of sequential access of large data exceeding the cylinder size, access to a plurality of data tracks 6 in a certain cylinder by sequential switching operation of the magnetic head 2 and movement to an adjacent cylinder (seek operation) ) Will be repeated.

In operations such as backup and restoration of data stored in the magnetic disk 1, read / write for backup / restore in units of data tracks 6 in addition to units of data sets such as files. Access may also be performed. In this case as well, a plurality of data tracks 6 in a certain cylinder are
The operation of sequentially accessing by the switching operation described above and then moving to the adjacent cylinder is repeated.

Therefore, in the magnetic disk drive of the present embodiment, in order to improve the efficiency of continuous access to a plurality of data tracks 6 within a cylinder or between cylinders by switching operation of the magnetic head 2 as described above, an example is given. The following control is performed.

That is, the head-to-head offset 12 between the magnetic heads 2 is measured, and from the correlation between the head-to-head offset 12 and the head switching time 5, the head switching time 5 corresponding to each head-to-head offset 12 is taken into consideration. An optimum skew value 14 corresponding to each head-to-head offset 12 is obtained. The head-to-head offset 12 is a position error 16 obtained by demodulating the head position signal 9 by the position signal demodulation circuit 10.
The position error 16 immediately after the head switching is the head-to-head offset 12.

After switching the heads, the positioning controller 11
The head is retracted to the center position of the data track 6 and is controlled so that the position error 16 becomes zero. FIG. 3 shows the time response of the position error 16 at this time. The head switching time 5 is the time from the head switching until the position error 16 enters the positioning completion determination slice 17 or less. The larger the head-to-head offset 12, the longer the time required for the position error 16 to enter the positioning completion determination slice 17 or less. That is, as the head-to-head offset 12 is larger,
The head switching time 5 becomes longer. The head switching time 5 must be shorter than the skew value 14. In consideration of these, from the measured head-to-head offset 12,
A skew value table 15 in which a skew value 14 is associated with each head is created.

The skew value 14 corresponding to the head-to-head offset 12 is previously written in a memory in the positioning controller 11 as a correspondence table (skew value table 15). The required skew value 14 is selected from the measured head-to-head offset 12 using the above correspondence table. By measuring the head-to-head offset 12 for each magnetic head 2 and selecting a required skew value 14 for each measurement result obtained, a skew value table 15 for each head is obtained as illustrated in FIG. Can be created. The above operation is the flowchart of FIG. The skew value table 15 is written in the memory of the positioning controller 11, and is formatted by referring to the skew value table 15 at the time of formatting as described later.

Alternatively, as shown in the flowchart of FIG. 8, the head switching time 5 at the time of head switching between the heads is measured, and the optimum skew value 14 for each head is determined from the measurement result of the head switching time 5. Ask. The head switching time 5 is the time from the head switching until the position error 16 enters the positioning completion determination slice 17 or less. This time is monitored and measured by the positioning controller 11. The head switching time 5 must be shorter than the skew value 14. In consideration of this point, an optimum skew value 14 is obtained for each head, and a skew value table 15 for each head can be created. The skew value table 15 is written in the memory of the positioning controller 11, and the skew value table 15 is formatted by referring to the skew value table 15 at the time of formatting described later.

When the skew value 14 is determined by measuring the head switching time 5, the position at which the head switching time 5 is measured may be determined by appropriately setting the STEP value in the flowchart of FIG. , The center cylinder, and the innermost cylinder, and the measurement result at each position is stored in the skew value table 15 as illustrated in FIG. 5. At the cylinder position, a necessary skew value may be determined and used by a method such as linear interpolation or curve interpolation.

By arranging the first sector 7a and the last sector 7b of the data sector 7 using the skew value table 15, the position (arrival timing) of the first sector 7a of the data sector 7 after head switching is optimized. . That is, as illustrated in the flowchart of FIG. 9, the skew value 14 at the time of formatting is set to the skew value 14 set for each magnetic head 2 by using the skew value table 15 and the skew value 14 is set on the recording surface of a certain head (N). Last sector 7b of a plurality of data sectors 7 on data track 6
Then, the data sector 7 is set so that the time until the head sector 7a of the plurality of data sectors 7 of the data track 6 on the recording surface of the next head (N + 1) becomes the skew value 14 set for each magnetic head 2. Record the ID or LBA. This operation is repeated for all cylinders. At this time, as described above, the optimum value may be determined by a method such as interpolation according to the cylinder position to which the data track 6 to be formatted belongs.

The magnetic disk device formatted using the skew value 14 set as described above processes data in the order of the data sectors 7 ordered by ID or LBA during continuous transfer.
If the head switching is completed within this time, the head switching process is interposed between the previous head (N) and the next head (N + 1).
Data can be transferred continuously. That is, in FIG. 1, the data of the head (N) is read from the head sector 7a in the direction of the arrow shown in FIG. 1 and processed in the direction of the arrow shown in the write direction. Execute head switching to (N + 1),
After the head switching is completed within the time of SKEW (N) in FIG. 1, the data is read from the head sector 7a of the data of the head (N + 1) and processed in the direction of the arrow shown in the writing direction. At the time of continuous data transfer, the above is used for the head (N),
Head (N + 1), Head (N + 2), Head (N +
3),... Are executed for each head. By using the skew value table 15 in which the skew value 14 is associated with each head in consideration of the head-to-head offset 12 for each head, a head having a small head-to-head offset 12 and a short head switching time has a short skew value. A head having a large offset 12 and a long head switching time has a long skew value.

FIG. 10 shows the case of the conventional reference technology. In the conventional reference technology, all magnetic heads 2 use the same skew value 14 uniformly, and the SKEW (N) shown in FIG.
Constant skew value 14 corresponding to the skew value 14 when the head-to-head offset 12 is the maximum.
nst. For this reason, even when the head-to-head offset is small and the head switching time is short, the data transfer waits for a fixed time SKEWconst for an unnecessary time.

In the magnetic disk drive according to the embodiment of the present invention, the magnetic head 2 can be set to a shorter skew value 14 as compared with a conventional reference technique for setting a uniform skew value. The actual distribution of the head-to-head offset 12 is close to the normal distribution as shown in FIG. 6A, and therefore, the distribution of the skew value 14 obtained from the measurement result of the head-to-head offset 12 is the absolute value of FIG. As a result, the right half of the normal distribution appears as shown in FIG. 6B. That is, the head-to-head offset 12 is +
In the case of L (N) or -L (N), the skew value 14 becomes SKEW (N), and similarly, + L (N +
1) and -L (N + 1) for both SKEW (N +
1), and in the case of + L (N + 2) and -L (N + 2), both become SKEW (N + 2). As a result, the distribution of the skew value 14 is such that the right half of the normal distribution appears as shown in FIG. When the head-to-head offset 12 is large, it is near 3σ of the normal distribution. In consideration of this, in the magnetic disk drive of the embodiment of the present invention, the average value of the skew value 14 can be set to 1/2 or less of the conventional skew value. That is, the waiting time due to the skew value 14 during the continuous transfer can be greatly reduced,
The data transfer performance in continuous access can be improved.

As described above, according to the magnetic disk drive of this embodiment, each head can be obtained from the correlation between the actually measured head-to-head offset 12 and the head switching time 13 or from the actual measurement result of the head switching time 13. Considering the head switching time 13 corresponding to the head offset 12, the optimum skew value 14 corresponding to each head offset 12
And a skew value table 15 in which a skew value 14 is made to correspond to each magnetic head 2 is used. Using this skew value table 15, the first sector 7a and the last sector 7b of the data sector 7 are optimally variably arranged for each head. By performing such a format, optimization of the head position of the data sector after head switching can be realized. For this reason,
In the magnetic disk drive of the present embodiment, a shorter skew value 14 can be set as compared with the conventional reference technology.

For example, according to the magnetic disk drive of this embodiment, the average value of the skew value 14 can be reduced to half or less of the skew value of the conventional reference technology. That is, the waiting time due to the skew value during continuous transfer can be reduced, and the data transfer performance during continuous access can be improved.

Therefore, for example, the data transfer performance in the sequential access of a data set such as a large file and the backup / restore of data in units of six data tracks is improved, and the access time is shortened.
It is possible to significantly reduce the work time for data backup / restore and the like.

Further, in order to reduce the skew value from the viewpoint of the device structure, it is not necessary to control the head assembling process more strictly than necessary in order to reduce the offset between heads. Thus, it is possible to reduce the time required for data backup, data restoration, and the like due to the access.

In the magnetic disk drive according to the embodiment of the present invention as described above, for example, when a data signal at the time of sequential reading over a plurality of data tracks 6 is observed, the magnetic head 2 corresponding to a certain data track 6 receives the data signal. The time interval from the moment of switching to the next magnetic head 2 (the timing of the assertion of the head switching signal) to the timing of the start of the start of data reading of the next data track 6 is observed to be different from each other. Therefore, it is considered that a magnetic disk device that can obtain such observation results implements the present invention.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments and can be variously modified without departing from the gist thereof. Needless to say, there is.

For example, the rotary storage device is not limited to the magnetic disk device exemplified in the above embodiment, but can be widely applied to a general storage device having a rotary storage medium accessed by a head. it can.

[0045]

According to the rotary storage device of the present invention, it is possible to improve the data transfer performance in continuous access of a plurality of tracks.

Further, it is possible to improve the data transfer performance in continuous access of a plurality of tracks at low cost without strictly controlling the head assembling process more than necessary to reduce the offset between heads.
The effect is obtained.

Further, there is an effect that data transfer performance in continuous access to a data set spanning a plurality of tracks can be improved.

Further, it is possible to shorten the time required for data backup, data restoration, and the like by successively accessing a plurality of tracks.

In addition, the time required for data backup and data restoration by continuous access of a plurality of tracks is reduced at a low cost without strictly controlling the head assembling process more than necessary to reduce the offset between heads. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of an operation of a magnetic disk device as an embodiment of a rotary storage device of the present invention.

FIG. 2 is a diagram showing an example of a configuration of a magnetic disk device which is an embodiment of the rotary storage device of the present invention.

FIG. 3 is a diagram showing an example of an operation of a magnetic disk device as an embodiment of the rotary storage device of the present invention.

FIG. 4 is an explanatory diagram showing an example of the operation of the magnetic disk device as one embodiment of the rotary storage device of the present invention.

FIG. 5 is an explanatory diagram showing an example of a configuration of a skew value table held as control information by the magnetic disk device according to the embodiment of the present invention;

FIGS. 6A and 6B are diagrams showing an example of the operation of the magnetic disk device according to the embodiment of the present invention in comparison with the case of the reference technology;

FIG. 7 is a flowchart illustrating an example of an operation of the magnetic disk device according to the embodiment of the present invention;

FIG. 8 is a flowchart illustrating an example of an operation of the magnetic disk device according to the embodiment of the present invention;

FIG. 9 is a flowchart illustrating an example of an operation of the magnetic disk device according to the embodiment of the present invention;

FIG. 10 is a conceptual diagram showing a track format according to the reference technology of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic disk, 2 ... Magnetic head, 3 ... Actuator, 4 ... Voice coil motor, 5 ... Head switching time,
6 ... data track, 7 ... data sector, 7a ... top sector, 7b ... last sector, 8 ... spindle motor, 9 ...
Head position signal, 10 ... Position signal demodulation circuit, 11 ... Positioning controller, 12 ... Offset between heads, 13 ...
Head switching time, 14: Skew value, 15: Skew value table, 16: Position error, 17: Positioning completion judgment slice.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Keizo Nakura 2880 Kozu, Odawara-shi, Kanagawa F-term in Storage Systems Division, Hitachi, Ltd. 5D096 AA03 BB01 CC01 DD08 EE03 FF03 FF05 GG01 KK05 WW03 WW04

Claims (3)

[Claims] 1. A rotary storage medium having a recording surface on which a track on which information is recorded is arranged, and recording and reproducing information on the track provided on the recording surface, the recording medium being arranged on each of the recording surfaces. A rotary storage device comprising: a plurality of heads for performing at least one of reproduction; and a head positioning unit for supporting the plurality of heads and positioning the head on an arbitrary track, wherein the head is supported by the head positioning unit. Physical or logical of the track on the recording surface corresponding to the head in the rotation direction of the recording surface in accordance with the magnitude of the relative displacement of each of the heads in the radial direction of the rotary storage medium. Characterized in that the distance between a logical head position and a physical or logical head position of the track on the other recording surface is changed. Location. 2. A rotary storage medium having a recording surface on which a track on which information is recorded is arranged, and recording and recording of information on the track arranged on each recording surface and provided on the recording surface. A rotary storage device comprising: a plurality of heads for performing at least one of reproduction; and a head positioning unit for supporting the plurality of heads and positioning the head on an arbitrary track, wherein each of the heads is selected. The physical or logical track of the track on the recording surface corresponding to the head in the direction of rotation of the recording surface in accordance with the magnitude of the head switching time from when the head starts accessing the track by the head. A rotation type recording device wherein a distance between a head position and a physical or logical head position of the track on another recording surface is changed. Apparatus. 3. A rotary storage medium having a recording surface on which tracks on which information is recorded are arranged, and recording and recording of information on the tracks arranged on the individual recording surfaces and provided on the recording surfaces. A rotary storage device comprising: a plurality of heads for performing at least one of reproduction; and a head positioning unit for supporting the plurality of heads and positioning the head on an arbitrary track, wherein the head is supported by the head positioning unit. The relative displacement of the individual heads in the radial direction of the rotary storage medium, or the head switching time from when an individual head is selected to when the head starts accessing the track; Physical or logical of the track on the recording surface corresponding to each of the heads in the direction of rotation of the recording surface according to the magnitude of Storage means for storing a skew value indicating an interval between a logical head position and a physical or logical head position of the track on another recording surface, and the skew value on the recording surface corresponding to each of the heads When the track is physically or logically formatted, the skew value corresponding to each of the heads stored in the storage means is read to determine the head position. Rotary storage device.