JPH06251493A - Information recording/reproducing device - Google Patents

Abstract

PURPOSE:To provide an information recording and reproducing device capable of setting a suitable value from among several kinds of transfer speeds and storage capacities in a user side in perticular related to the information recording and reproducing device of a magnetic disk device, a magnetic tape device, an optical disk device and a magneto-optical disk device, etc. CONSTITUTION:One system is selected from several kinds of modulation systems prepared with the modulation systems of a modulation circuit 19 and a demodulation circuit 21 by a modulation system control circuit 27 by the instruction of a disk controller 28 according to the mode setting from a user, and simultaneously a relative speed between a magnetic head 6 and a recording medium 7 is switched by a mechanical system control circuit 25. Thus, since the recording density on a recording medium is held to a proper value by properly switching the relative speed between a recording and reproducing element and the recording medium, the linear recording density and the transfer speed peculiar to several kinds of modulation systems are obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording device such as a magnetic disk device and a magnetic tape device, and an information recording / reproducing device such as an optical disk device and a magneto-optical disk device, and more particularly to a transfer speed and a storage capacity which can be changed. The present invention relates to a technology for providing an information recording / reproducing device.

[0002]

2. Description of the Related Art An information recording / reproducing apparatus is composed of many elemental technologies. Here, a magnetic disk device will be taken as an example, and its general configuration will be described with reference to the functional block diagram of FIG.

Reference numeral 29 is a control CPU of the magnetic disk device,
Commands are exchanged with the disk controller 18 to control the magnetic disk device. A control program is stored in the ROM 31. The RAM 30 is used as a temporary storage place for data when recording / reproducing in the magnetic disk device. The interface controller 1 exchanges commands between the host computer and the magnetic disk device and controls the bus. The input data consists of position information of recording tracks, various commands, and user data to be recorded, and is interpreted by the CPU 29 or the interface controller 1 to perform various controls or data transfer.

The disk controller 18 has a CPU 29.
And sends a command to the control circuit such as the mechanical system control circuit 15 to give an instruction. The mechanical system control circuit 15 controls the mechanical system driver 14 based on the track information and the servo information read from the magnetic head 6 and the target track information input from the disk controller 18, drives the seek mechanism 5, and The magnetic head 6 is positioned on the target track on the magnetic disk 7. Further, the mechanical system driver 14 drives the rotating mechanism 13 connected to the magnetic disk 7 to control the magnetic disk 7 to rotate at a predetermined rotation speed.

In response to a recording request, first, the magnetic head 6 is positioned on the recording track designated by the recording position information. The input recording data is input to the modulation circuit 2 and converted into a recording code synchronized with the recording clock.
The recording clock is supplied from the recording clock control circuit 16. The recording code is subjected to predetermined code conversion and phase adjustment of the code pulse in the data pre-processing unit 3, converted into a recording current by the current driver inside the recording / reproducing amplifier 4, and recorded by the electromagnetic conversion element of the magnetic head 6. It is converted into a magnetic field and recorded as magnetization information on the rotating magnetic disk 7. The frequency of the recording clock may be controlled to an appropriate value according to the recording area (recording radius, etc.) on the magnetic disk 7.

At the time of reproduction, the magnetization information recorded on the magnetic disk 7 is converted into a reproduction signal by an electromagnetic conversion element mounted on the magnetic head 6, amplified by the recording / reproducing amplifier 4, and then predetermined by the AGC amplifier 8. Is adjusted to the amplitude of. After that, the output signal is sampled by the A / D converter 9 into a digital value synchronized with the reproduction clock, and converted into a reproduction code by the digital signal processing circuit 10. Further, the reproduction code is converted into reproduction data by the demodulation circuit 12.
The signal processing parameter control circuit 17 controls the circuit parameters of the digital signal processing circuit 10 to appropriate values according to the reproduction area (reproduction radius, etc.) on the magnetic disk 7.

In the magnetic disk device configured as described above, the transfer rate TR of data input / output to / from the device
(BPS: bit per second), the maximum value of the magnetization reversal density on the magnetic disk 7 (linear recording density) LD
(BPI: bit per inch), the rotational speed N of the magnetic disk 7 (rpm: round per minu)
te) and the recording / reproducing radius R (m) have the following relationship.

TR = LD * N * R * 4.12 Alternatively, the relative speed V of the magnetic head 6 and the magnetic disk 7
(Inch per second), TR = LD * V where V = N * R * 4.12 From the above equation, these are not independent parameters. For example, two of TR, LD, and V are set. You can see that once you decide, the other one is decided. These relationships are shown in FIG.
As shown in, the horizontal axis represents the linear recording density, and the vertical axis represents the transfer speed. A straight line having an inclination V is drawn from the origin, and a perpendicular line is drawn from one point on the straight line to each coordinate axis.

When the relative speed V between the magnetic head 6 and the magnetic disk 7 is constant, the transfer speed TR increases in proportion to the linear recording density LD. However, the transfer speed TR and the linear recording density LD are the same as those of the recording / reproducing circuit units 2, 3, 4, 8, respectively.
It is limited by the circuit band of 9, 10, 11, 12, and 16, the processing speed, or the magnetization reversal density at which recording / reproduction is possible on the magnetic disk 7. This is the transfer rate TR
(BPS) is proportional to the recording clock frequency F (Hz),
The linear recording density LD (BPI) is the magnetization reversal density D (FCI:
It is related to proportional to the flux change per inch).

TR = CR * F LD = DR * D Here, CR is called the code rate of the modulation system, DR is called the recording density ratio of the modulation system, and these two constants are the modulation systems used in the modulation circuit 2. Has a unique value for.

Therefore, the maximum recording clock frequency that can be processed by the recording / reproducing circuit of the magnetic disk device is Fm (H
z), if the maximum magnetization reversal density that can be recorded / reproduced with a sufficient signal S / N is Dm (FCI), the feasible range of the transfer speed TR and the linear recording density LD is limited, and the range is defined by the following equation. Can be represented.

TR ≦ CR * Fm LD ≦ DR * Dm From the above, in the conventional magnetic disk device shown in FIG. 2, the transfer speed CR * Fm (BPS) and the linear recording density DR are set.
* Dm (BPI) is the maximum performance. However, in order to bring out this maximum performance, the relative speed V between the magnetic head 6 and the magnetic disk 7 should be set to an appropriate value, and accordingly, the flying height of the magnetic head 6 should be set appropriately, and the data preprocessing section It is necessary to optimize the performance of each element by properly setting the recording system and the reproducing system by means of 3 and the signal processing parameter control circuit 17, etc.

[0013]

The conventional information recording / reproducing apparatus has been designed to be roughly tuned to the above-mentioned maximum performance in order to pursue cost performance by utilizing available elemental technologies. Further, in order to reduce costs, development and production are conducted by focusing on products with limited specifications. As a result, conventionally, information recording / reproducing devices such as magnetic disk devices supplied from manufacturers are limited to some typical product specifications that meet the requirements of the majority of users.

However, the optimum information recording / reproducing apparatus for the user's system differs for each user. Some users request an information recording / reproducing apparatus with a large device capacity even if the transfer rate is slow, and some users request an information recording / reproducing apparatus with a high transfer rate even if the device capacity is small. In order to meet the demands of individual users, products of various specifications have to be prepared, which is difficult as a practical problem. Further, when various kinds of products are prepared, there is a problem that the product cost increases as a result. Therefore, the user has no choice but to select the optimum device from the information recording / reproducing devices having the limited specifications.

The object of the present invention is to record information on a magnetic disk device or the like which can be optimized for the user's system by setting the transfer speed and the device capacity arbitrarily from a certain range on the user side or at the time of product shipment. It is to provide a reproducing apparatus.

[0016]

In order to solve the above problems, the information recording / reproducing apparatus of the present invention is a modulation circuit capable of selecting at least two types of modulation systems and a demodulation circuit corresponding to the modulation systems. And a means for switching the relative speed of the recording / reproducing element and the recording medium, a means for selecting one of the above-mentioned modulation methods, and a means for controlling each of the selecting means. As the selectable modulation method, it is desirable that a modulation method having a relatively high code rate has a relatively small recording density ratio. Further, it has a recording clock frequency adjusting means and a signal processing parameter adjusting means as needed. Further, if necessary, a memory for storing parameters relating to the recording density on the recording / reproducing recording medium is provided.

In order to solve the above problems, the magnetic disk device of the present invention has a modulation circuit capable of selecting at least two types of modulation systems, a demodulation circuit corresponding to the modulation systems, a magnetic head and a magnetic head. It has means for switching the relative speed of the disk, means for selecting any one of the above modulation methods, and means for controlling each of the above selection means. As the selectable modulation method, it is desirable that a modulation method having a relatively high code rate has a relatively small recording density ratio. Further, it has a recording clock frequency adjusting means, a magnetic head flying height adjusting means, and a signal processing parameter adjusting means, as necessary. Further, if necessary, a memory is provided for storing parameters relating to recording / reproducing magnetization reversal density or parameters relating to the rotating mechanism and head flying height control means.

A feature of the first invention is (1) a recording / reproducing element, a recording medium, and means for relatively moving them, and information is recorded by using the recording / reproducing element and the recording medium. In an information recording / reproducing apparatus for recording / reproducing data, a modulation circuit and a demodulation circuit capable of selecting at least two types of modulation systems, and a means for selecting one of the modulation systems are provided. Correspondingly, the information recording / reproducing apparatus has means for controlling the relative speed of the recording / reproducing element and the recording medium.

(2) In (1), the ratio of the number of bits before modulation to the number of bits after modulation of two or more types of modulation methods (the number of bits before modulation / the number of bits after modulation) is CR.
, CR2, ..., and the ratio of the number of bits before modulation per minimum interval of the recording information recorded on the recording medium when the modulation method is used is set as DR1, DR2 ,. When there is a relation of CR1>CR2> ..., It is preferable to have a relation of DR1 <DR2 <...

(3) In (1) or (2), the ratio C
Changing the relative speed of the recording / reproducing element and the recording medium in proportion to the ratio CR / DR of R and the ratio DR g
a Preferred.

(4) In (1), (2) or (3), there is provided means for storing a parameter relating to the recording / reproducing recording density D and a parameter relating to the clock frequency F processable by the recording / reproducing circuit. It is preferable to change the relative speed of the recording / reproducing element and the recording medium in proportion to the ratio F / D.

A feature of the second invention is (5) having a recording / reproducing element, a recording medium, and means for relatively moving them, and using the recording / reproducing element and the recording medium, information is recorded. In an information recording / reproducing apparatus for recording / reproducing information, any one of a means for storing at least two or more kinds of parameters with respect to the relative speed of the recording / reproducing element and the recording medium, and one of the two or more kinds of parameters. An information recording / reproducing apparatus having means for selecting one of the parameters and means for controlling the relative speed of the recording / reproducing element and the recording medium corresponding to the selected parameter.

The feature of the third invention is that (6) at least two types of modulation methods are selected: a magnetic head, a seek mechanism of the magnetic head, a magnetic disk, a rotating mechanism of the magnetic disk, a memory. A modulation circuit and a demodulation circuit that can
In the magnetic disk device having a means for selecting any one of the modulation methods, the memory has at least a rotation speed of the magnetic disk and a parameter relating to a maximum magnetization reversal density that can be recorded / reproduced at the rotation speed. It is stored in the information recording / reproducing apparatus for changing the relative speed of the magnetic head and the magnetic disk by means of changing the rotational speed of the magnetic disk in accordance with the modulation method.

In (7) and (6), the ratio of the number of bits before modulation to the number of bits after modulation of two or more modulation methods (the number of bits before modulation / the number of bits after modulation) is CR.
, CR2, ..., and the ratio of the number of bits before modulation per minimum interval of the recording information recorded on the recording medium when the modulation method is used is set as DR1, DR2 ,. When there is a relation of CR1>CR2> ..., It is preferable to have a relation of DR1 <DR2 <...

(8) In (6) or (7), the ratio C
It is preferable to change the relative speed of the recording / reproducing element and the recording medium in proportion to the ratio CR / DR of R and the ratio DR.

(9) In (6), (7) or (8), there is provided means for storing the parameter relating to the recording / reproducing recording density D and the parameter relating to the clock frequency F processable by the recording / reproducing circuit. It is preferable to change the relative speed of the recording / reproducing element and the recording medium in proportion to the ratio F / D.

In (10) and (6), it is preferable to have means for controlling the head flying height in accordance with the modulation method.

In (11) and (6), it is preferable that the recording surface of the magnetic disk is concentrically divided into a plurality of areas, and the outer peripheral area is recorded with a high frequency signal.

[0029]

In the information recording / reproducing apparatus of the present invention, two or more types of modulation methods are used. When the selectable modulation methods are modulation method 1, modulation method 2, ..., Modulation method n, the respective code rates and recording density ratios are (CR1, DR1),
(CR2, DR2), ..., (CRn, DRn).
However, n is the number of selectable modulation methods. Also, a case will be described below in which there is a relationship of DR1 <DR2 <... <DRn if there is a relationship of CR1>CR2>...> CRn, but this is not necessarily required for the effects described below. Here, assuming that the maximum recording clock frequency that can be processed by the recording / reproducing circuit of the information recording / reproducing device is Fm, and the maximum recording density on the recording medium that can be recorded / reproduced with a sufficient signal S / N is Dm. The range of transfer rates and linear recording densities possible with each modulation method is as shown in FIG. 4 (FIG. 4 shows the case where n is 5).

From FIG. 4, each modulation system has an area of transfer rate and linear recording density that cannot be realized by other modulation systems, and a plurality of modulation systems can be selected. It can be seen that the range of recording density is expanded. Then, by switching the relative speed of the recording medium and the recording / reproducing element to an appropriate value, the transfer speed and linear recording density unique to each modulation system can be realized. At this time, if the frequency of the recording clock is changed as needed, an arbitrary transfer rate and linear recording density can be selected within the feasible range of FIG.
In particular, in order to obtain the maximum performance of each modulation system, the relative speed Vk of the recording medium and the recording / reproducing element should be set according to the following formula for the modulation system k (k = 1, 2, ..., N). Good.

Vk = (CRk * Fm) / (DRk * D
m) k = 1, 2, ..., N Further, when the relative speed is optimized in the initial setting, the change in the relative speed due to the change in the modulation method is the ratio CRk /
It may be performed in proportion to DRk.

In the case of the magnetic disk device, the relative speed of the magnetic disk and the magnetic head can be switched by switching the rotational speed N of the magnetic disk or the recording / reproducing radius R.

In the magnetic disk device, when the relative speed V between the magnetic disk and the magnetic head is switched, the flying height of the magnetic head may change. When the relative speed V increases, the flying height of the magnetic head increases, and the recording / reproducing performance often deteriorates. In this case, it is necessary to correct the maximum recordable / reproducible magnetization reversal density as a function of the flying height of the magnetic head. When this correction coefficient is c (V), the maximum linear recording density is DRk * Dm * c (v). The relative velocity at this time is calculated by the equation V = (CRk * F
m) / (DRk * Dm * c (V)) may be satisfied. In advance, the maximum magnetization reversal density D with respect to the relative speed V
The relationship of m may be obtained, and the relative speed V and the maximum magnetization reversal density Dm may be switched at the same time when the modulation method is switched.

The most desirable method for the above problem is to prevent the flying height of the magnetic head from changing when the relative speed is switched. For this purpose, a magnetic head having a structure in which the flying height of the magnetic head does not depend on the relative speed is used, or a control mechanism for keeping the flying height of the magnetic head within a predetermined range is used.

As described above, in the information recording / reproducing apparatus of the present invention, a means for switching from two or more types of modulation methods to an arbitrary modulation method and, at the same time, switching the relative speed of the recording medium and the recording / reproducing element. Since it has a means, it is possible to select the transfer speed and the linear recording density from a wide range.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic disk device of the present invention will be described with reference to FIG. FIG. 1 shows a modulation system switching mechanism, a magnetic disk rotation speed adjusting mechanism, a recording clock frequency adjusting mechanism, a magnetic head flying height adjusting mechanism, a signal processing parameter adjusting mechanism, and each adjusting mechanism. Any one of the large capacity mode, the intermediate mode, and the high speed transfer mode is provided by including a circuit control mechanism for adjusting and a memory for storing the maximum magnetization reversal density, the maximum recording clock frequency and the parameters necessary for controlling the control adjusting mechanism. This is a magnetic disk device that can be set by the user.

The disk controller 28 inputs the switching signal from the mode switching switch. This signal is a signal corresponding to the high-speed transfer mode, the intermediate mode, and the large capacity mode, and any one signal is input by selecting an external switch. The disk controller 28 exchanges commands with the CPU 29 to at least the mechanism system control circuit 25, the recording clock control circuit 16, the signal processing parameter control circuit 17, and the modulation method control circuit 27.
Give instructions to. The modulation method control circuit 27 uses the run length limited (0, 3) code when the mode switching signal is in the high-speed transfer mode, the run length limited (1, 7) code when in the intermediate mode, and the large capacity mode. Instructs the modulation circuit 19 and the demodulation circuit 21 to perform modulation and demodulation with the run length limited (2,7) code. Further, the modulation system control circuit 27 gives an instruction to the data preprocessing unit 20 to perform the recording compensation process with the recording compensation parameter corresponding to the selected modulation system. The mechanical system control circuit 25 instructs the mechanical system driver 14 so that the rotation speed of the magnetic disk 7 becomes a predetermined value corresponding to the selected modulation method. The head flying height control circuit 26 instructs the head flying height control mechanism 22 to fly the magnetic head 6 so that the flying height of the magnetic head 6 falls within a predetermined range regardless of the set number of rotations of the magnetic disk 7. Control the amount. Further, when the recording surface of the magnetic disk 7 is concentrically divided into a plurality of areas, the recording clock control circuit 16 switches the recording clock frequency according to which area the recording is performed. The signal processing parameter control circuit 17 switches the parameters of the digital signal processing circuit 10 according to the modulation method and the reproduction area.

The modulation method that can be selected by the magnetic disk device of the present invention is not particularly limited, but in the present embodiment, the modulation method is the (2,7) code from the run length limited (RLL) codes. , (1,7) code, (0,
3) The case where any one of the codes can be selected will be described as an example. This RLL code is bit 1 of the converted recording code.
It is a code configured to always include d to k bits 0 inclusive. Since the RLL code includes the redundant bit 0 as described above, the number of bits after modulation n is usually larger than the number of bits before modulation m. The ratio of the number of bits before and after the modulation (= m / n) becomes the above-mentioned code rate CR, CR = 1/2 for the (2,7) code, CR = 2/3 for the (1,7) code, (0 , 3) CR = 8 in code
/ 9. Therefore, if the same data is modulated, this 3
Among the two modulation methods, the number of bits is the largest when the (2,7) code is used. On the other hand, the minimum interval of bit 1 of the modulated data is (1 + d) times the bit period,
Based on the bit period of the data before modulation, CR * (1
+ D) times. Therefore, the number of bits before modulation that can be recorded per minimum magnetic reversal interval of the magnetic disk is CR.
It can be seen that it can be represented by * (1 + d). This ratio becomes the above-mentioned recording density ratio DR, and it is considered that the larger this ratio is, the more suitable for high-density recording. Recording density ratio is (2,7)
DR = 3/2 in code, DR = in (1,7) code
For 4/3, (0,3) code, DR = 8/9,
It can be seen that the (2,7) code is suitable for high density recording. The data transfer rate is proportional to the recording clock frequency (modulated data clock frequency) and the code rate. The upper limit of the recording clock frequency is limited in relation to the circuit band of the recording / reproducing system of the magnetic disk device and the signal processing speed. From such a reason, it is understood that a code having a large code rate (0, 3) is suitable for high-speed transfer.

According to the above relationship, the recording clock frequency is F
(Hz), the recording / reproducing radius is R (m), and the number of rotations of the magnetic disk is N (rpm).

[0040]

[Table 1]

If the upper limit of the magnetization reversal density on the magnetic disk is Dm (FCI), the linear recording density is the maximum DR.
* Selectable up to Dm (BPI). If the upper limit of the recording clock frequency is Fm (Hz), the transfer rate can be selected in the range of up to CR * Fm (BPS). From the above, the range of the linear recording density and the transfer rate that can be selected in each modulation method is as shown in FIG. Figure 5
Therefore, (0,3) code is suitable for high-speed transfer, and (2,7)
It can be seen that the code is suitable for high density recording.

Next, the effect of this embodiment will be described by taking a configuration of a 3.5-inch magnetic disk device as an example. Here, the maximum magnetization reversal density that can be recorded and reproduced is 45 kFCI,
The maximum recording clock frequency that can be processed by the recording / reproducing circuit is 3
0 MHz, the portion where the recording / reproducing error is most likely to occur is the innermost circumferential area, and the innermost radius of the magnetic disk is 23 mm,
The number of cylinders is 1500. The recording clock frequency is constant on all data surfaces. Therefore, in this case, the switching control of the recording clock frequency can be dispensed with. It is also assumed that the head flying height is controlled so that recording / reproduction can be performed at the above-mentioned maximum magnetization reversal density even if the rotation speed of the magnetic disk changes due to mode switching. At this time, the operation area of the transfer speed-linear recording density coordinate is as shown in FIG. The operating point in the operating region of each mode is determined by the number of rotations of the magnetic disk and the recording clock frequency, and it is possible to select any point by setting. It is desirable to operate in the vicinity of the optimum operating point of each mode indicated by a circle in FIG. When operated at the optimum operating point, the transfer speed (MByte / s) of each mode
ec), storage capacity per magnetic disk surface (MByt
e), the magnetic disk rotation speed (rpm) is as follows.

[Mode] [Transfer speed] [Memory capacity] [Rotation speed] High-speed transfer mode 3.33 42.7 7030 2. Intermediate mode 2.50 64.0 3515 3. Large capacity mode 1.88 72.0 2343 Furthermore, the data plane as described in Electronic Design, November 13, 1986, pages 141 to 144 is divided into a plurality of concentric regions, and the magnetization reversal density is increased in each region. If the method of appropriately adjusting the recording clock frequency so as to be uniform and the method of the present invention are used together, the storage capacity can be further increased. For example, when the data surface is concentrically divided into three regions, recording / reproduction is possible in each region with a magnetization reversal density of 45 kFCI. As shown in FIG. 7, if the operating point is controlled as indicated by the bold line on the transfer speed-linear recording density coordinate, the transfer speed (MByte / sec) of each mode and the storage capacity (MByte) per surface of the magnetic disk The magnetic disk rotation speed (rpm) is as follows.

[Mode] [Transfer speed] [Memory capacity] [Rotation speed] High-speed transfer mode 2.19 to 3.33 53.8 4620 2. Intermediate mode 1.64 to 2.50 80.7 2310 3. Large-capacity mode 1.23 to 1.88 90.8 1540 As described above, in the magnetic disk device of the present embodiment, any one of the three modulation methods can be selected, and correspondingly, the magnetic disk of the magnetic disk can be selected. Since the number of rotations can be controlled to an appropriate value, these characteristics can be set in a wide range including the transfer speed or the storage capacity, which cannot be achieved by the conventional magnetic disk device using the single modulation method.

Although the above-described three run length limiting codes are used in this embodiment, the effect of the present invention is not limited to the case of using these codes. The effects of the present invention can be obtained by arbitrarily combining two or more types of modulation systems in which the modulation system having a relatively higher code rate has a relatively smaller recording density ratio. Further, the requirements for obtaining the effect of the present invention are that several kinds of modulation methods can be selected and the relative speed of the magnetic head and the magnetic disk corresponding thereto can be set. Therefore, other control mechanisms such as the head flying height control mechanism and the head flying height control circuit of the above embodiment are not essential requirements of the present invention. However, it is desirable for a higher performance magnetic disk device to readjust the head flying height, signal processing parameters, etc., according to the selected modulation method.

As the head flying height control mechanism, a piezoelectric element-like material is formed in the head arm portion as in the control mechanism described in Japanese Patent Laid-Open No. 4-85772, and the head pressing load is changed by voltage control to change the head pressure. There is a method of controlling the flying height. As in this example, the head flying height can be controlled by forming the head arm from a material that is deformed by voltage or current control, and the present invention can also be applied to the magnetic disk device of the present invention. FIG. 8 shows an example of a configuration in which the head flying height is controlled by deforming the gimbal spring 34 by the piezoelectric element 33 attached to the gimbal spring 34 of the magnetic head 6 to change the pressing load of the magnetic head 6. A head flying height control parameter (coefficient data corresponding to a voltage or current value) with respect to the rotation speed of the magnetic disk 7 is stored in the memory 24. Mode setting (modulation method setting or magnetic disk rotation speed setting)
In addition, the disk controller 28 reads various parameters from the memory 24, sends a head flying height control parameter corresponding to the rotation speed of the magnetic disk 7 to a reference voltage generating circuit 32 corresponding to the head flying height control circuit 26 of FIG. By applying the reference voltage of 1 to the piezoelectric element 33, the flying height of the magnetic head 6 can be set to a predetermined value. The head flying height parameter is the reference voltage generation circuit 32 other than the memory 24.
Alternatively, it may be stored in an element in the disk controller 28.

As another control mechanism for the flying height of the head, it is possible to control the atmospheric pressure of the space in which the magnetic head and the magnetic disk are housed. An example of this method is shown in FIG. The magnetic head of the magnetic disk device and the storage part 29 of the magnetic disk are connected to an exhaust system, and are composed of several kinds of pressure regulating valves 39, an opening / closing valve 38, and a bubble switching circuit 36 for opening any one of the opening / closing valves. It is connected to the pressure system 35. When the mode is set (when the modulation method is set or when the number of rotations of the magnetic disk is set), the disk controller 28
Sends a parameter corresponding to the number of revolutions of the magnetic disk to the bubble control circuit 37 and drives the bubble switching circuit 36 to bring the inside of the storage section 29 to a predetermined atmospheric pressure, thereby setting the flying height of the magnetic head to a predetermined value. Can be set to.

The control method for the head flying height is as described above.
As an example, if the flying height of the magnetic head does not depend on the relative speed between the magnetic head and the magnetic disk, a control unit for the flying height of the head can be omitted. Specifically, there is a head with a structure called a negative pressure head,
Compared with the conventional positive pressure floating type head, the dependence of the flying height on the magnetic head relative speed of the magnetic disk can be made sufficiently small, and by combining with the magnetic disk device of the present invention, cost reduction and high reliability of the device can be achieved.

Further, it is possible to configure the device while allowing a change in the flying height of the magnetic head. For this purpose, the number of rotations and the maximum magnetization reversal density capable of recording and reproducing corresponding to each selectable modulation method are stored in the memory 24, and the number of rotations and the magnetization reversal density can be switched when the modulation method is set. . However, the storage capacity in the high-speed transfer mode is smaller than that when the head flying height is controlled to the optimum value.

Further, the magnetic disk device of the present invention can easily separate the portion composed of the magnetic head and the magnetic disk. Since the conventional magnetic disk device is adjusted to maximize the performance of the magnetic head and the magnetic disk used, even if the magnetic head and the magnetic disk are replaced even if the magnetic disk device has the same specifications, In some cases, the initial performance may not be exhibited and a reproduction error may be easily caused. Since the magnetic disk device of the present invention stores and manages the characteristics of the magnetic head and the magnetic disk in the memory as the maximum magnetization reversal density capable of recording and reproducing, when the magnetic head and the magnetic disk are exchanged, the maximum memory This can be dealt with by changing the data of the magnetization reversal density. As an example, the first part indicated by 29 in FIG. 1 may be made detachable so that it can be connected to the second part which is the remaining part of FIG. 1 through the interface board. Generally, the first portion is configured to include at least a magnetic head, a seek mechanism of the magnetic head, a magnetic disk, a rotating mechanism of the magnetic disk, and a memory. The second part includes a modulation circuit and a demodulation circuit capable of selecting at least two types of modulation methods, a means for selecting any one of the above modulation methods, and a means for changing the rotational speed of the magnetic disk. Shall be. Then, at least the number of revolutions of the magnetic disk and the parameter relating to the maximum magnetization reversal density which can be recorded and reproduced at the number of revolutions should be stored in the memory. Further, in order to optimize the recording / reproducing system for the magnetic head and the magnetic disk, it is desirable that the memory stores parameters for the data preprocessing unit and the digital signal processing circuit. When the head flying height control mechanism is mounted on the first portion, the head flying height is controlled in the memory in order to control the head flying height via the head flying height control circuit of the second portion. It is desirable to store the parameters.

Next, another effect that is possible with the configuration of the above embodiment will be described. The magnetization reversal density that can be recorded and reproduced on a magnetic disk is the bit error rate (B
It depends on ER). In the above example, (1,
7) The maximum magnetization reversal density of the code is set to 45 kFCI. If this value is for BER of 10 −9, the maximum magnetization reversal density corresponding to BER of 10 −6 will be larger than 45 kFCI. , BER corresponding to 10 −12 power is smaller than 45 kFCI. That is, high reliability and large capacity are contradictory characteristics, and one can be sacrificed and the other can be predominant. For example, consider three modes of high reliability mode, intermediate mode, and large capacity mode according to the difference in BER,
It is assumed that the relationship between the BER of each mode and the maximum magnetization reversal density is as follows.

[Mode] [BER] [Maximum magnetization reversal density] High-reliability mode 10 −12 30 kFCI Intermediate mode 10 −9 45 kFCI Large capacity mode 10 −6 60 kFCI FIG. 10 shows the transfer speed-linear recording density on the coordinates. Therefore, by switching the relative speed of the magnetic head and the magnetic disk to an appropriate value for each mode, it becomes possible to operate at the optimum operating point of each mode. For this purpose, the relative speeds of the magnetic head and the magnetic disk for each mode may be stored in the memory 24 and read by the disk controller 28 for control.

As described above, in the magnetic disk apparatus of this embodiment, any one of the three modulation methods can be selected, and at the same time, the rotational speed of the magnetic disk can be controlled to an appropriate value. Since the number of rotations can be controlled to an appropriate value from the range of the number of rotations that is limited in relation to the bit error rate, the transfer speed or storage capacity that cannot be achieved with the conventional magnetic disk device using a single modulation method is used. Including, those characteristics can be set in a wide range.

The requirements for obtaining the effect of the present invention are that several types of modulation methods can be selected, and the relative speeds of the magnetic head and the magnetic disk corresponding thereto can be set, or simply the magnetic head and the magnetic disk. Is to be able to select and set the relative speed of the above in a predetermined range. Therefore, other control mechanisms such as the head flying height control mechanism and the head flying height control circuit of this embodiment are not essential requirements of the present invention. However, it is desirable for a higher performance magnetic disk device to readjust the head flying height, signal processing parameters, etc., according to the selected modulation method.

Further, considering the requirements of the present invention as described above, it is apparent that the effects of the present invention are not limited to the magnetic disk device. That is, in an information recording / reproducing device such as a magnetic tape device, an optical disc device, or a magneto-optical disc device, which records / reproduces information on / from a recording medium which moves relatively using a recording / reproducing element, several kinds of modulation methods can be selected and at the same time. The above-mentioned various information recording is configured by setting the relative speed of the recording / reproducing element and the recording medium, or by simply selecting and setting the relative speed of the recording / reproducing element and the recording medium within a predetermined range. Also in the reproducing apparatus, the transfer speed or the storage capacity can be set in a wide range, and the same effect as that of the above embodiment can be obtained.

[0056]

The information recording / reproducing apparatus of the present invention can select any one modulation method from two or more kinds of modulation methods, and correspondingly controls the relative speed of the recording / reproducing element and the recording medium to an appropriate value. Therefore, the transfer speed or the storage capacity can be set in a wider range as compared with the conventional information recording / reproducing apparatus such as the magnetic recording apparatus using the single modulation method.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a magnetic disk device of the present invention.

FIG. 2 is a functional block diagram of a general magnetic disk device.

FIG. 3 is a diagram showing a relationship among a transfer speed, a linear recording density, and a recording / reproducing element / recording medium relative speed.

FIG. 4 is a diagram showing a range of transfer rates and linear recording densities according to various modulation methods.

FIG. 5 is a diagram showing selectable ranges of linear recording density and transfer rate according to a modulation method.

FIG. 6 is a diagram showing an example of an operation area in each mode.

FIG. 7 is a diagram showing another example of an operation region in each mode.

FIG. 8 is a diagram showing a configuration example of a head flying height control system.

FIG. 9 is a diagram showing a configuration example of a head flying height control mechanism by pressure control.

FIG. 10 is a diagram showing another example of an operation area in each mode.

[Explanation of symbols]

6 ... Magnetic head, 7 ... Magnetic disk, 19 ... Modulation circuit,
21 ... Demodulation circuit, 22 ... Head flying height control mechanism, 23 ...
Rotation mechanism, 24 ... Memory, 25 ... Mechanism control circuit, 26
... Head flying height control circuit, 27 ... Modulation method control circuit, 2
8 ... Disk controller.

Claims (11)

[Claims] 1. An information recording / reproducing device which has a recording / reproducing element, a recording medium, and a means for relatively moving them, and records / reproduces information by using the recording / reproducing element and the recording medium. The device has a modulation circuit and a demodulation circuit capable of selecting at least two or more types of modulation systems, and means for selecting one of the modulation systems, and the recording / reproducing element corresponding to the modulation system. An information recording / reproducing apparatus comprising means for controlling the relative speed of the recording medium. 2. A ratio of the number of bits before modulation to the number of bits after modulation of the two or more types of modulation methods (number of bits before modulation / number of bits before modulation).
The number of bits after modulation is CR1, CR2, ...
In addition, when the modulation method is used, the ratio of the number of bits before modulation per minimum interval of the recording information recorded on the recording medium is set as DR1, DR2, ...
The information recording / reproducing apparatus according to claim 1, wherein there is a relationship of DR1 <DR2 <... when there is a relationship of 1>CR2>. 3. A ratio CR / D of the ratio CR and the ratio DR.
3. The information recording / reproducing apparatus according to claim 1, wherein a relative speed between the recording / reproducing element and the recording medium is changed in proportion to R. 4. A parameter relating to a recording / reproducing recording density D and a clock frequency F processable by a recording / reproducing circuit.
4. The method according to claim 1, further comprising means for storing a parameter relating to, wherein the relative speed between the recording / reproducing element and the recording medium is changed in proportion to the ratio F / D. Information recording / playback device. 5. An information recording / reproducing device which has a recording / reproducing device, a recording medium, and a means for relatively moving them, and records / reproduces information by using the recording / reproducing device and the recording medium. In the apparatus, means for storing at least two or more kinds of parameters with respect to the relative speed of the recording / reproducing element and the recording medium; means for selecting one of the two or more kinds of parameters; An information recording / reproducing apparatus having means for controlling the relative speed of the recording / reproducing element and the recording medium in accordance with the selected parameter of. 6. A magnetic head, a seek mechanism of the magnetic head, a magnetic disk, a rotating mechanism of the magnetic disk, a memory, and a modulation circuit and a demodulation circuit capable of selecting at least two types of modulation systems, In the magnetic disk device having a means for selecting any one of the modulation methods, the memory stores at least the number of revolutions of the magnetic disc and the parameter relating to the maximum magnetization reversal density that can be recorded / reproduced at the number of revolutions. An information recording / reproducing apparatus is characterized in that the relative speed between the magnetic head and the magnetic disk is changed by means for changing the rotational speed of the magnetic disk in accordance with the modulation method. 7. A ratio of the number of bits before modulation to the number of bits after modulation of the two or more types of modulation methods (the number of bits before modulation / the number of bits before modulation).
The number of bits after modulation is CR1, CR2, ...
In addition, when the modulation method is used, the ratio of the number of bits before modulation per minimum interval of the recording information recorded on the recording medium is set as DR1, DR2, ...
7. The information recording / reproducing apparatus according to claim 6, wherein when there is a relation of 1>CR2> ..., There is a relation of DR1 <DR2 <... 8. A ratio CR / D of the ratio CR and the ratio DR.
8. The information recording / reproducing apparatus according to claim 6, wherein the relative speed of the recording / reproducing element and the recording medium is changed in proportion to R. 9. A parameter relating to a recording / reproducing recording density D and a clock frequency F processable by a recording / reproducing circuit.
9. The method according to claim 6, further comprising means for storing a parameter relating to, wherein the relative speed between the recording / reproducing element and the recording medium is changed in proportion to the ratio F / D. Information recording / playback device. 10. The information recording / reproducing apparatus according to claim 6, further comprising means for controlling a head flying height according to the modulation method. 11. The information recording / reproducing apparatus according to claim 6, wherein the recording surface of the magnetic disk is concentrically divided into a plurality of areas, and the outer peripheral area is recorded with a high frequency signal.