JPH10255202A - Information recording and reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent information from being lost due to thermal fluctuation while realizing a high recording density by detecting reference information which indicates change over a lapse of time in information recorded on a recording medium and, when the reference information is determined to indicate a predetermined value, rerecording information corresponding to the reference information on the recording medium. SOLUTION: When recording and accumulation of information starts, a reference signal is recorded on a reference signal region 25 by a magnetic head 1. At the same time, a recording time at which the reference signal is recorded is stored on a non-volatile memory 5 via a host interface 10 based on external time information. A reference signal monitoring section 26 stores a change in quality of the reference signal over a lapse of time on the non-volatile memory 5, and informs a hard disk controller HDC 6 of a recorded information at the time when the signal quality is determined to deteriorate by a reference signal quality determination section 27. The HDC 6 reproduces information in a corresponding recording regino on a recording medium 3 by the magnetic head 1 to perform re-recording, thereby preventing deterioration of signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an information recording / reproducing device such as a hard disk device.

[0002]

2. Description of the Related Art In recent years, magnetic recording / reproducing devices such as hard disk devices have been widely used in the field of computers as large-capacity external storage devices that can be randomly accessed. With the expansion of usage, demands for a larger storage capacity and a higher recording density are increasing. Therefore, research and development are being carried out from various fields in order to meet such demands.

In general, as a hard disk device, a plurality of magnetic disks each having a magnetic layer provided on a non-magnetic substrate are mounted on one rotating shaft, and a recording / reproducing head is mounted on each disk mounted on an arm. 2. Description of the Related Art There is known a structure in which an arm is arranged on a surface and an arm is moved by an actuator to position a head. When recording and reproducing information with a hard disk device having such a structure, the head does not directly contact the disk surface rotating at a high speed, but accesses a desired position on the disk surface while slightly floating. Are located. Then, information is recorded on or reproduced from the concentric circular tracks on the disk surface by the head.

In the above-mentioned hard disk drive, in order to meet the demand for a large storage capacity, the recording density is improved by, for example, increasing the linear recording density of the disk, that is, the density in the track length direction. Attempts have been made to increase the recording density by narrowing the width and increasing the track density.

In recent years, research and development of magnetic materials for media, such as thinning of recording media, high coercive force, miniaturization of magnetic particles, etc., have been promoted in order to increase the recording density. Alternatively, development of contact recording that records and reproduces a signal almost in contact with a recording medium has also been performed.

In order to increase the sensitivity of signal reproduction, active heads such as MR heads utilizing the magnetoresistance effect have been actively developed. An MR head is a head that converts the magnetic flux from a recording medium into an electric signal by using the property that the electric resistance of a soft magnetic material such as permalloy is changed by an external magnetic field. Since the reproducing sensitivity of the head is proportional to the magnitude of the sense current flowing through the soft magnetic material in order to convert a resistance change into a voltage change, a large output can be obtained even when the relative speed between the head and the medium is small. The reproducing MR head and the recording induction type head are combined and formed on the slider at an interval.

In order to increase the signal-to-noise ratio (S / N) and improve the recording density, it is necessary to make the magnetic particles of the recording medium finer. However, miniaturization of the magnetic particles makes the magnetization of each particle more susceptible to a thermal disturbance, and causes a thermal fluctuation phenomenon in which the magnetization is attenuated with time. The thermal fluctuation phenomenon of the magnetic particles can be suppressed by increasing the magnetic anisotropy of the magnetization, but in this case, the coercive force of the recording medium increases, and it becomes very difficult to record, Even saturation recording can be difficult. It is known that this thermal fluctuation phenomenon becomes more remarkable at high temperatures and increases its influence.

Therefore, in the conventional magnetic recording / reproducing apparatus, by miniaturizing the magnetic particles for higher density, the magnetization tends to fluctuate due to heat, and the magnetization recorded as a signal attenuates with time. The recorded information may not be able to be reproduced, and if the magnetic anisotropy of the magnetization is increased to avoid attenuation, there is a problem that it becomes difficult to record the information.

[0009]

As described above, in the conventional magnetic recording / reproducing apparatus, the magnetization is easily fluctuated by heat by miniaturizing the magnetic particles for high density, and the signal is recorded as a signal. The magnetization may be attenuated with time, and the recorded information may not be reproduced. In addition, if the magnetic anisotropy of the magnetization is increased in order to avoid the attenuation, there is a problem that it becomes difficult to record the information. SUMMARY OF THE INVENTION It is an object of the present invention to provide a highly reliable magnetic recording / reproducing apparatus capable of preventing information loss due to thermal fluctuation while achieving high recording density.

[0010]

In order to solve such a problem, an information recording / reproducing apparatus according to the present invention has a recording medium on which information can be recorded by magnetism, and records the information on the recording medium. An information recording / reproducing device having a recording head and a reproducing head for reproducing information from the recording medium, wherein reference information recorded on the recording medium by the recording head and indicating reference information indicating a temporal change of the information is detected. Reference information detection means, and a determination means for determining whether the reference information by the reference information detection means has shown a predetermined value,
The information corresponding to the reference information determined to indicate a predetermined value by the determining means is recorded again by the recording head.

Further, the present invention has a recording medium on which information can be recorded by magnetism, a recording head for recording the information on the recording medium, and a reproducing head for reproducing information from the recording medium. An information recording / reproducing device,
Reference information quality determination means, which is configured to detect reference information indicating a temporal change of the information recorded on the recording medium by the recording head and to set a re-recording time for re-recording information from the temporal change of the reference information, A time measuring means for measuring an elapsed time since each information recorded by the recording head is recorded on the recording medium; and an elapsed time by the time measuring means elapses a re-recording time by the reference information quality judging means. Re-recording time elapse determining means for determining whether or not the re-recording time has elapsed by the re-recording time elapse determining means. .

[0012] The reference information is recorded in a predetermined area of the recording medium. Note that the reference information is a plurality of recording magnetization patterns including the shortest wavelength of information recorded on the recording medium.

The re-recording time is changed each time the reference information is set by the reference information quality judging means, and each time the re-recording time is changed by the re-recording time elapse judging means. It is characterized in that it is determined whether or not the time has passed the re-recording time.

According to the present invention, it is determined whether or not the reference information (reference signal) has reached a predetermined value. By re-recording the recorded information, it is possible to prevent information loss due to thermal fluctuation while achieving high recording density.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the configuration of an information recording / reproducing apparatus according to one embodiment of the present invention. The magnetic head 1 is arranged at the tip of a driven actuator arm 2 and records and reproduces signals (information) on a recording track 4 of a rotating disk-shaped recording medium 3. On the recording medium 3, a reference signal area 25 is formed. The information recording / reproducing apparatus 100 includes a recording medium 3 on which a signal is magnetically recorded, a recording head for recording a signal on the recording medium 3, and a reproducing head (for example, MR) for reproducing a magnetic signal from the recording medium 3. And a magnetic head 1 integrally formed with the magnetic head 1.

(Embodiment 1) FIG. 2 is a block diagram for explaining functions relating to the information recording / reproducing apparatus of the present invention. The information recording / reproducing apparatus 200 includes, for example, a non-volatile memory 5 as a memory for storing a time at which the information is recorded for each information recording unit recorded on the recording medium 3, and a hard disk controller (not shown) for controlling the information recording / reproducing operation. Hereafter, HD
C) 6 and a microprocessor (hereinafter referred to as MPU) 7 for controlling the entire hard disk drive including servo control and signals. The servo signal information obtained from the magnetic head 1 is a PES (Position)
A voice coil motor (VCM (Voice)) that drives the actuator 2 via a digital-to-analog (DA) converter 12 as positioning control information in a MPU 7 is converted into position error information by an n Error Signal demodulator 11. Coil Moto
r)) It is transmitted to the driver 13. The rotation control signal of the recording medium 3 is transmitted from the MPU 7 to the spindle driver 15 via the spindle controller 14, and controls the rotation of the spindle motor 16.

(Recording) When information or a reference signal (reference information) is recorded on the recording track 4 or the reference signal area 25 on the recording medium 3 via the channel IC 8 and the head IC 9, each recording information unit is used. The time at the time of recording (information recording time) is stored in the non-volatile memory 5 based on time information provided from a clock incorporated in an external personal computer (PC) via the host interface 10. It is memorized. The information recording time stored in the non-volatile memory 5 is monitored by the elapsed time measuring unit 17 and the host interface 1
Compared with the current time provided from the outside via 0, the elapsed time from when the information is recorded on the recording medium 3 is calculated.

The information recording / reproducing apparatus 200 of the present invention
At the time when the recording and accumulation of information is started, a reference signal is recorded in the reference signal area 25 by the magnetic head 1, and at the same time, the reference signal recording time is based on time information provided from outside via the host interface 10. Is stored in the nonvolatile memory 5. In addition,
As the reference signal, a data sequence including a bit pattern that is easily affected by thermal fluctuation is recorded. This includes, for example, a sequence of magnetic transitions continuous at the shortest magnetic transition interval, a dibit pattern, and the like. Note that a random sequence signal or the like may be used as the reference signal. The quality of the reference signal is monitored by the reference signal monitoring unit 26 as an output of the head IC 9 or the channel IC 8 using the magnetic head 1 at predetermined time intervals.

Note that the signal quality of the reference signal is determined by measuring the amplitude value of the reference signal, the noise voltage, the signal-to-noise ratio (S / N), the signal amplitude variation at the data identification point, and the signal quality value of the error rate (BER). At least one,
Or a signal quality value directly related to it. The signal quality of the reference signal is periodically monitored by the reference signal monitoring unit 26, and the time change of the reference signal quality is stored in the nonvolatile memory 5. Then, by monitoring the state of deterioration of the signal quality over time, the reference signal quality determination unit 27
It is determined whether the deterioration of the signal quality is lower than a predetermined value (for example, the reproduction signal output is 70% of the average reproduction output immediately after recording).
Etc.). Then, the MPU 7 searches the non-volatile memory 5 for information recorded at the same time as the reference signal whose signal quality has been judged to be degraded by the reference signal quality judging section 27, and finds the corresponding information in the HDC 6.
Notify.

The HDC 6 having received the signal for re-recording from the non-volatile memory 5 reproduces the recording information of the corresponding recording area on the recording medium 3 by the magnetic head 1 and temporarily stores it in the buffer 19. The same recording is performed again in the same recording area or a different free area on the recording medium 3. At this time, the time when this information is re-recorded is similarly stored in the nonvolatile memory 5. The old information recording time for the re-recorded information may be rewritten. Also, by performing the re-recording process at a timing when there is no recording or reproduction access request to the disc,
The data transfer performance of the disk is not adversely affected.

Then, as described above,
Only by monitoring the signal quality of the reference signal,
The state of signal deterioration of actual data due to thermal fluctuation can be found in advance, and the reliability of decoding recorded information can be increased while miniaturizing the apparatus.

(Embodiment 2) In the second embodiment, the first
Although the configuration is almost the same as that of the embodiment, the difference is that the limit elapsed time determination unit 18 is newly provided.

FIG. 2 is a block diagram for explaining functions relating to the information recording / reproducing apparatus of the present invention. The present information recording / reproducing device 3
Reference numeral 00 denotes, for example, a non-volatile memory 5 as a memory for storing the time at which the information was recorded for each information recording unit recorded on the recording medium 3, and a hard disk controller (hereinafter, referred to as HDC) for controlling the information recording / reproducing operation. 6
And a microprocessor (hereinafter referred to as MPU) 7 for controlling the entire hard disk drive including servo control and signals. The servo signal information obtained from the magnetic head 1 is a PES (Position Error).
(Signal) demodulator 11 converts the information into position error information, and MPU 7 performs DA (Di) as positioning control information.
A voice coil motor (V) that drives the actuator 2 via a digital to analog converter 12
It is transmitted to a CM (Voice Coil Motor) driver 13. The rotation control signal of the recording medium 3 is transmitted from the MPU 7 to the spindle driver 15 via the spindle controller 14, and controls the rotation of the spindle motor 16.

(Recording) When information or a reference signal is recorded on the recording track 4 or the reference signal area 25 on the recording medium 3 via the channel IC 8 and the head IC 9, the recording time is recorded for each recording information unit. Time (information recording time) of the host interface 10
Via an external personal computer (PC)
Is stored in the non-volatile memory 5 based on time information provided by a clock built in the memory. Non-volatile memory 5
The information recording time stored in the storage medium 3 is monitored by the elapsed time measuring unit 17, compared with the current time provided from the outside via the host interface 10, and the time elapsed since the information was recorded on the recording medium 3. Is calculated.

The information recording / reproducing apparatus 300 of the present invention
At the time when the recording and accumulation of information is started, a reference signal is recorded in the reference signal area 25 by the magnetic head 1, and at the same time, the reference signal recording time is based on time information provided from outside via the host interface 10. Is stored in the nonvolatile memory 5. In addition,
As a reference signal, a data sequence including a bit pattern that is easily affected by thermal fluctuation is recorded. This includes, for example, a sequence of magnetic transitions continuous at the shortest magnetic transition interval, a dibit pattern, and the like. Note that a random sequence signal or the like may be used as the reference signal. The quality of the reference signal is monitored by the reference signal monitoring unit 26 as an output of the head IC 9 or the channel IC 8 using the magnetic head 1 at predetermined time intervals.

Note that the signal quality of the reference signal is calculated based on the amplitude value of the reference signal, the noise voltage, the signal-to-noise ratio (S / N), the signal amplitude variation at the data identification point, and the signal quality value of the error rate (BER). At least one,
Or a signal quality value directly related to it. The signal quality is periodically monitored by the reference signal monitoring unit 26, and the time change of the reference signal quality is stored in the nonvolatile memory 5.

By monitoring the deterioration of the signal quality of the reference signal as time passes, the reference signal quality judging section 27 determines the signal quality (corrected in advance) for which it is difficult to accurately decode the recorded information. Is obtained, and is stored in the nonvolatile memory 5. That is, the limit elapsed time is determined by the information recording / reproducing device 3
00 is determined by reflecting the signal deterioration status according to the actual use environment of the 00. Therefore, when used in a high temperature environment,
It can be a short limit elapsed time, and in a low temperature environment, a long limit elapsed time.

(Reproduction) When reproducing the data signal, the limit elapsed time determination unit 18 should compare the elapsed time calculated by the elapsed time measurement unit 17 for each data signal with the above-mentioned limit elapsed time and re-record. It detects that the time has elapsed and notifies HDC 6.

A signal for requesting re-recording is sent to an elapsed time judgment section 18.
The received HDC 6 reproduces the recording information of the corresponding recording area on the recording medium 3 by the magnetic head 1, temporarily stores the information in the buffer 19, and returns to the same recording area or a different empty area on the recording medium 3 again. Record the same. At this time, the time when this information is re-recorded is similarly stored in the nonvolatile memory 5. The old information recording time for the re-recorded information may be rewritten. Also, by performing the re-recording process at a timing when there is no recording or reproduction access request to the recording medium,
The data transfer performance of the recording medium is not adversely affected.

Then, as described above,
Even if there is a thermal fluctuation phenomenon in which the recorded signal attenuates with time, it is possible to estimate in advance the state of signal degradation of actual data due to thermal fluctuations based on the limit elapsed time obtained from the degradation state of the reference signal. However, by performing re-recording before deterioration, the reliability of decoding the recorded information can be increased. Therefore, it is possible to provide an information recording / reproducing apparatus having high recording density and high data reliability.

In the above embodiment, the limit elapsed time is the time until the reference signal becomes equal to or less than the predetermined value, but may be updated repeatedly. More specifically, the reference signal quality is the same as that of the second embodiment, but the signal quality of the reference signal is degraded and it is determined by the reference signal quality determination unit 27 that the reference signal quality has reached a predetermined value. After the determination unit 27 determines the limit elapsed time, the reference signal is repeatedly recorded and monitored. Each time, the limit elapsed time is determined, and the limit elapsed time recorded in the nonvolatile memory 5 is repeatedly updated.

For example, if the use environment temperature at the time of starting recording and accumulating data in the information recording / reproducing apparatus 300 is 50 ° C., the initial limit elapsed time is four years, and the use of the information recording / reproducing apparatus 300 is started. After four years have passed,
The re-recording operation is performed sequentially from the record information four years after the recording. The reference signal is re-recorded after determining the limit elapsed time, and a second limit elapsed time is likewise determined. Hereinafter, similarly, the third and fourth limit elapsed times are repeatedly determined and sequentially updated. After the first limit elapsed time is determined, the use environment temperature rises to 55 ° C. due to the relocation of the information recording / reproducing device 300 or the like. As a result, the quality of the reference signal deteriorates quickly, and the second limit elapsed time is determined by the reference signal. The limit elapsed time determined by the quality determination unit 27 to be three years and stored in the non-volatile memory 5 is updated from the previous value of four years to three years. Until the update is completed, the recording information is re-recorded according to the limit elapsed time before the update.
After the update of the limit elapsed time, after the new limit elapsed time is determined, the elapsed time measurement unit 17 determines the timing of re-recording based on the new limit elapsed time, and performs re-recording.

FIG. 4A shows, as the above specific example, the determination of the attenuation curve and the limit elapsed time of the reference signal when the normalized S / N is set to 0.7 (-3.1 dB).
The state of determination of the second limit elapsed time by re-recording is shown.
In this case, from the fourth year after the start of using the information recording / reproducing apparatus 300, the recording information is re-recorded in the order in which the elapsed time after the recording reaches the first limit elapsed time of four years. When the information recording / reproducing apparatus 300 has been used for four years, that is, when the limit elapsed time has been determined, the reference signal is re-recorded,
Thereafter, the limit elapsed time in the next temperature environment is determined.
After the reference signal was re-recorded, the temperature environment rose to 55 ° C., and three years later, the standardized S / N = 0.
7, the second limit elapsed time is determined to be three years, and the value is updated. Thereafter, the recording information is re-recorded in the order of three years after the recording. In other words, until seven years have elapsed since the start of use of the information recording / reproducing apparatus 300, re-recording of the recorded information is performed based on the four-year limit elapsed time. After the seventh year, the second limit elapsed time is three years. Re-recording is performed according to the criteria described above.

Specifically, as shown in FIG. 4B, the information (1) and the information (2) are not re-recorded from the 0th year to the 4th year. However, in the fourth year, the reference signal falls below the signal quality standard (for example, standardized S /
N = 0.7 or less), the information (1) four years after the recording is re-recorded. It also stipulates that information (2) recorded in 3.5 years needs to be re-recorded in 4 years. However, as shown in FIG. 4A, if the second limit elapsed time is determined to be three years, the information (1) re-recorded in the fourth year and originally re-recorded in 7.5 years Information (2) will be re-recorded in the seventh year.

[0035]

According to the present invention, even if a thermal fluctuation phenomenon occurs in which a recorded signal attenuates with time, the recorded information is re-recorded before an error is caused by the signal fluctuation due to the thermal fluctuation. It is possible to suppress the influence of thermal fluctuation, and it is possible to provide an information recording / reproducing apparatus having a high recording density and high data reliability even when used in a high-temperature environment where the influence of thermal fluctuation is large. .

[Brief description of the drawings]

FIG. 1 is a partial sectional perspective view of an information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an information recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 3 is a schematic diagram of an information recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram showing how a reference signal decay curve and a limit elapsed time of the present invention are determined.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetic head 2 ... Actuator arm 3 ... Recording medium 4 ... Recording track 5 ... Non-volatile memory 6 ... HDC (hard disk controller) 7 ... MPU (Microprocessor) 8 ... Channel IC 9 ... Head IC 10 ... Host interface 11 ... PES demodulator 12 ... DA converter 13 ... VCM driver 14 ... Spindle controller 15 ... Spindle driver 16 ... Spindle motor 17 ... Elapsed time measurement unit 18 ... Limited elapsed time judgment unit 19 ... Buffer 25 ... Reference signal area 26: Reference signal monitoring unit 27: Reference signal quality judgment unit 100, 200, 300 ... Information recording / reproducing device

Claims (5)

[Claims] An information recording / reproducing apparatus comprising: a recording medium on which information can be recorded by magnetism; a recording head for recording the information on the recording medium; and a reproducing head for reproducing information from the recording medium. Reference information detecting means for detecting reference information, which is recorded on the recording medium by the recording head and indicates a temporal change of the information, and determines whether or not the reference information by the reference information detecting means indicates a predetermined value. An information recording / reproducing apparatus, further comprising: a determination unit for determining, wherein information corresponding to the reference information determined to indicate a predetermined value by the determination unit is recorded again by the recording head. 2. An information recording / reproducing apparatus comprising: a recording medium on which information can be recorded by magnetism; a recording head for recording the information on the recording medium; and a reproducing head for reproducing information from the recording medium. Reference information recorded on the recording medium by the recording head, the reference information indicating a temporal change of the information, and a reference information quality for setting a re-recording time for re-recording the information based on the temporal change of the reference information. Determining means; time measuring means for measuring an elapsed time since each piece of information recorded by the recording head is recorded on the recording medium; and an elapsed time by the time measuring means being re-determined by the reference information quality determining means. Re-recording time elapse determining means for determining whether or not the recording time has elapsed, and information determined that the re-recording time has elapsed by the re-recording time elapse determining means. Information recording and reproducing apparatus characterized by re-recording by the recording head. 3. The information recording / reproducing apparatus according to claim 1, wherein the reference information is recorded in a predetermined area of the recording medium. 4. The information recording / reproducing apparatus according to claim 1, wherein the reference information is a plurality of recording magnetization patterns including a shortest wavelength of information recorded on the recording medium. 5. The re-recording time is changed each time the re-recording time is set by the reference information quality judging means, and each time the re-recording time is changed by the re-recording time elapse determining means. 3. The information recording / reproducing apparatus according to claim 2, wherein it is determined whether or not a time has not passed the re-recording time.