JP2002140873A - Data recording/reproducing circuit, and its control circuit and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the effective data recording area on a recording medium, namely, to improve the format efficiency by reducing the gap area for absorbing the delay time of data conversion caused at the time of writing and reading the data of a data recording/reproducing device. SOLUTION: A data sector generating circuit 16 generates a write data sector signal 19 showing the timing to record the data in the data recording area in accordance with a servo sector signal 10, and the data are transmitted to both of a delay circuit 17 and a selector 18 of two inputs and one output. A read data sector signal 20 delaying the write data sector signal in the specified period is outputted by the delay circuit 17. The constitution such as inputting these two signals to the selector 18 is adopted. The selector 18 outputs the write data sector signal 19 when a write mode signal 21 is active, and outputs the read data sector signal 20 as a data sector signal 15 when the write mode signal is inactive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording / reproducing apparatus using a magnetic disk, a magneto-optical disk, an optical disk, a magnetic tape, and the like, and more particularly, to a recording / reproducing circuit for reducing a gap between sectors generated when recording / reproducing data. And its control circuit and method.

[0002]

2. Description of the Related Art A recording / reproducing operation of a conventional data recording / reproducing apparatus will be described by taking a magnetic disk drive as an example. The present invention is not only a magnetic disk device, but also a data recording / reproducing device that divides a series of data strings into one or more blocks and records data on a data storage medium with an interval before or after the block. Therefore, the present invention is effective for reproducing data using a reproducing head that moves to face a recording medium.

[0003] A magnetic disk device forms concentric recording areas called tracks on a magnetic disk as a recording medium, and records and reproduces data using information on the tracks. On this track, there are a servo area intermittently arranged on the circumference at equal intervals and a data recording area arranged between the servo areas, and the data recording area is usually
Includes multiple data sectors. There is a gap between the sectors to adjust the fluctuation of the rotation of the disk medium and the processing delay time of the electronic circuit. Therefore, data cannot be stored here.

Each data sector is composed of an ID part and a data part. The ID section includes a synchronization pattern for discrimination at the time of data reproduction, ID information for identifying a data sector, an error check code for detecting an error in the ID information, and the like. One data portion is composed of a synchronization pattern for discrimination during data reproduction, data information, an error correction code (ECC), and the like.

A recording / reproducing circuit for performing the recording / reproducing operation of these data portions is constituted by a read circuit, a write circuit, and a data control circuit. The read circuit performs a reproducing operation from the ID section and the data section, and the write circuit performs a recording operation to the data section. In particular, the data control circuit generates a data sector signal generated in accordance with the synchronization pattern start position of the ID section based on the servo sector signal of the servo area, and controls the recording / reproducing operation of the entire apparatus.

In the data recording processing, the ID section is reproduced based on the data sector signal, and after confirming that the recording sector is the recording sector, the data is recorded in the data section by the write circuit. On the other hand, in the data reproducing operation, after confirming that the data is the reproducing sector by reproducing the ID portion, the reproducing operation of the subsequent data portion is performed by the read circuit to obtain desired data of the sector.

More specifically, the data control circuit activates the read gate signal within an appropriate range of the synchronization pattern of the ID section based on the data sector signal.
The read circuit synchronizes with the signal recorded in the data section according to the read gate signal, performs data demodulation of the signal recorded in the data section, acquires ID information, and outputs the ID information to the data control section. After verifying the error check code of the ID information, the data control circuit temporarily turns off the read gate and activates the read gate signal again at an appropriate position in the synchronization pattern of the data section following the ID section. After that, the read circuit synchronizes the data section and demodulates the data, and outputs reproduced data to the data control circuit. When the demodulation of the error correction code section (ECC) of the data section is completed, the data control circuit turns off the read gate and waits for a data sector signal to demodulate the next ID section.

In a series of data recording / reproducing operations, a recording position shift due to a rotation fluctuation of a magnetic disk as a data storage medium, a recording position deviation due to a magnetic tape running fluctuation in a magnetic tape device, a data recording delay of a write circuit. In order to absorb a data reproduction delay of the read circuit, a gap area is provided between data sectors or before and after the ID section and the data section.

In general, the rotation speed of a magnetic disk is controlled on the basis of a clock generated by a crystal oscillator, and is constantly stable. However, when an external shock, vibration, or seek operation accompanies, the seek speed is reduced. The rotation speed fluctuates due to vibration resonance and fluctuations in the power supply voltage. The rotation fluctuation of the magnetic disk generated at this time is about 0.1%, and the gap area is provided between the sectors on the track and before and after the ID section and the data section in order to prevent data destruction due to the rotation fluctuation. Needed.

The delay time of processing of the write circuit and the read circuit depends on a data conversion method (code format) for modulating data and a signal reproduction for reproducing a signal on a data storage medium (here, a magnetic disk medium). Varies by method. The code format of the data conversion is the conventional 2-7 RLL
Instead of using 1-7 RLL codes, block codes such as 8-9 or 16-17 conversion with high code conversion efficiency have been increasingly used. The signal reproduction method is a PRML method (Pa) for reproducing a low S / N ratio signal.
rtial Response Maximum-Likelihood) or EPRML (Extended Partial Response Maximum-Likelihood)
The use of many has come to be seen. As the data conversion code and the signal reproducing method become more complicated, the time required for the conversion / inversion processing increases, and the processing time required for transmitting the reproduced data signal from the read circuit to the data control circuit (data recording delay, Playback delay) increases.
Here, the data control circuit cannot start processing of the next data portion or ID portion until the demodulation of the ECC of the recording data is completed. A gap area for the processing delay time was required.

FIG. 7 shows a track format of a conventional magnetic disk drive. The data recording / reproducing operation is performed based on one data sector signal (at the time of writing and reading) which is a timing signal. On the track, areas indispensable for data recording and reproduction of the data section, such as a servo section and a SYNC pattern, a data recording area, a gap area for absorbing rotation fluctuation, a processing time of a write circuit or a read circuit (data conversion delay time) ) Are intermingled with the gap region that absorbs). And media
The write data to be recorded on the medium, the data on the medium to be actually recorded, and the read data for reading the data on the medium each have a time delay.

Further, as disclosed in Japanese Patent Application Laid-Open No. Hei 5-3033836, there is a technique of delaying and outputting an index signal and a sector signal except at the time of formatting in order to avoid a write splice occurring at the time of formatting. However, merely changing the timing of generation of the sector signal between the time of formatting and the time of non-formatting has no effect of reducing the gap area (area not used for storing information) on the medium.

[0013]

In the prior art, the recording (write) and reproduction (read) operations of the data section are started on the basis of the data sector signal generated from the servo signal. The data was generated at the same timing in both reading and writing. In such a conventional data recording / reproducing control method, the above-mentioned gap area is determined by the sum of the fluctuation of the relative motion (rotation) of the medium, the write processing delay and the read processing delay. The gap area is not a data information area by nature, but the data storage area that can be used effectively decreases as the gap area increases.

An object of the present invention is to expand an effective data recording area on a recording medium by eliminating a gap portion that does not contribute to data storage.

Another object of the present invention is to improve data recording efficiency by reducing a gap portion for absorbing a processing delay time generated during reading or writing.

[0016]

In the data recording / reproducing method according to the present invention, in order to achieve the above object, a data sector signal indicating a data writing start position is different between data reading and writing. Data sector generating means for outputting at the timing is provided. Here, the data sector signal means a signal generated in one-to-one correspondence with the sector. The data sector generation means may output a signal at a different timing from the same signal, or prepares two types of signals having different timings in advance and outputs the two types of signals by using an input signal as a trigger. May be.

Further, in order to reduce a gap portion for absorbing a processing delay time generated at the time of reading, a data sector signal for starting reading of the next data sector is generated before data output of the data sector is completed. A data sector generating means for enabling data reproduction to be started and a data reproducing means are provided.

Before the data output of the data sector is completed, a data sector generating means for starting pull-in and reproduction of the synchronization pattern of the next data sector and a data reproducing means may be provided.

Further, in order to reduce a gap portion for absorbing a processing delay time generated at the time of writing, a data sector signal for starting writing of the next data sector is generated before data output of the data sector is completed. There is provided a data sector generating means for causing the data sector to be generated. As a result, the gap portion can be substantially eliminated, and the data recording efficiency on the medium can be improved.

[0020]

FIG. 1 is a block diagram showing one embodiment of a magnetic disk drive to which the present invention is applied. The operation of the reproduction process and the recording process will be described.

The data reproduction process is performed as follows. The data and servo information stored on the data disk 1 are read by the magnetic head 2 as a read signal 8 which is an analog signal, and input to the read circuit 3 and the servo sector generator 5.

The servo sector generator 5 outputs a read signal 8
The servo sector signal 10 indicating the starting point of the servo information recording area is output to the data sector generator 6 based on the servo information included in the data sector generator 6. The data sector generator 6 outputs a data sector signal 15 (digital signal) indicating a reference timing for recording / reproducing a data recording area from the servo sector signal 10. The data sector signal 15 is input to the data control circuit 7, and the data control circuit 7 outputs a read gate 11 which is a digital signal indicating a range for taking in data based on the data sector signal 15. The read circuit 3 operates while the read gate 11 is active.
The read signal 8 is demodulated and output to the data control circuit 7 as read data 12.

Here, based on the servo information included in the read signal 8, a trigger signal generator 5 '(not shown) generates a trigger signal 10' indicating the starting point of an arbitrary recording area.
The data may be outputted to a data generator 6 ′ (not shown), and the starting trigger signal 15 ′ may be outputted to the data control circuit 7.

Next, data recording processing will be described. The data recording process is performed based on the data sector signal 15 as in the reproduction process. The starting point trigger signal 15 'by the above-mentioned circuit (not shown) may be used.

The data control circuit 7 uses the data sector signal 15 output from the data sector generator 6 as a reference.
The write gate 13 which is a digital signal indicating a data recording range is output. Further, the data control circuit 7 outputs the write data 14 stored on the medium to the write circuit 4 while the write gate 13 is active.
The write circuit 4 includes a write gate 13 and write data 14
Is received, the write data 14 is converted into a data code, and the write data 9 converted into an analog signal is recorded on the data disk 1 by the magnetic head 2.

The data sector generator 6 of the magnetic disk drive constituted by the functional blocks shown in FIG. 1 will be further described with reference to FIG.

The data sector generating circuit 16 receives the servo sector signal 10 and generates a write data sector signal 19 based on the servo sector signal 10. Write data sector signal 19
Indicates the timing at which data is recorded in the data recording area on the medium.

The write data sector signal 19 is input to both the delay circuit 17 and the two-input one-output selector 18. The delay circuit 17 outputs a read data sector signal 20 obtained by delaying the write data sector signal 19 for a certain period. These two signals are input to the selector 18. The selector 18 outputs the write data sector signal 19 as the data sector signal 15 when the write mode signal 21 is active, and outputs the read data sector signal 20 as the data sector signal 15 when the write mode signal is inactive. I do.

The circuit configuration is not limited to the above. That is,
It is sufficient if each signal can be generated at the timing shown in FIG. In other words, these functions are prepared on the data control circuit side, and the write data sector signal 19 is separately delayed for a certain period of time, either synchronously or asynchronously with the generated clock,
Depending on the presence or absence of the write mode signal 21, whether to send a delayed signal or to output the write data sector signal 19 as it is may be selected, or a control circuit may be added to achieve the same function.

FIG. 5 shows the timings at the time of writing and at the time of reading.

When the magnetic disk drive performs a write operation, the write mode signal 21 (FIG. 2) becomes active, and the data sector signal 15 becomes a signal having the timing shown by the write data sector signal 19. Data control circuit 7
Is a data sector signal 15 (write data sector signal 1).
The write gate 13 and the write data 14 are output based on 9), and information is written to the data disk 1. On the data disk 1, a recording position shift occurs due to a processing delay of the write circuit 4. Therefore, the write data sector signal 19 is asserted earlier by the delay time of the write circuit 4. Following the write data sector signal 19, after the write data is sent, after a gap period for absorbing the rotation fluctuation,
Asserted again. As a result, only the region for absorbing the rotation fluctuation is allocated to the gap region, and the gap corresponding to the conventional write processing delay is not included in the gap region.

On the other hand, when the magnetic disk drive performs reading, the write mode signal 21 becomes inactive, and the data sector signal 15 becomes a signal at the timing shown by the read data sector signal 20. The read data sector signal 20 is asserted at a timing delayed with respect to the write data sector signal 19, and is generated at the start position of the recording data on the medium (FIG. 5). The read data 12 is output to the data control circuit 7 after the processing delay of the read circuit 3.

At this time, the read processing delay time can be masked if the read processing delay time is equal to or less than the time of the gap area absorbing the rotational fluctuation, that is, the time required when the magnetic head passes through the gap area. . As a result, the gap region does not need to include the read processing delay time, and the gap portion can be reduced as compared with the related art.

Further, a processing delay time from when a read processing instruction is issued from a higher-level device or an input / output port to when data on a medium is actually read, and a processing delay time for storing data are similarly compensated. can do. That is, the time from when the read signal 8 is started to be taken into the read circuit 3 and the servo sector generator 5 until it is converted into information that can be judged by the data control circuit, or the write data 14 is sent to the write circuit 4. The data control circuit performs predictive control, taking into account the time from the start of the operation until the magnetic field fluctuation corresponding to the analog signal actually starts to be stored in the recording medium, so that the gap on the medium is controlled. The area can be zero.

Data sector generating circuit 1 shown in this embodiment
6, the same purpose can be achieved. For example, it is needless to say that the data sector generating circuit 16 has two circuits, a write data sector generating circuit and a read data sector generating circuit, in advance. Let me
A similar function can be realized by creating a write data sector signal and a read data sector signal, selecting these and outputting them as a data sector signal. The timing between the signals may be as shown in FIG.

Next, if the read processing delay time is longer than the time required for the magnetic head to pass through the gap area, a processing circuit as shown in FIG. 3 is required. FIG.
FIG. 2 is a configuration diagram of the read circuit 3 and the data control circuit 7 of FIG. 1. The read circuit 3 includes an analog demodulation 22, a read data synchronization control circuit 23, and a data conversion circuit 24.

FIG. 6 shows the operation timing.

At the time of reading, the data control circuit 7
Based on the data sector signal 15, the synchronous control start signal 25 and the read gate 11 are generated from the falling edge of the write sector signal or the rising edge of the delay sector signal at the time of reading, or from a timing signal obtained by delaying the rising edge of the sector signal at the time of writing. The synchronization control start signal 25 (FIG. 3) is sent to the analog demodulation circuit 22 and the read data synchronization control circuit 23. The read gate 11 is sent to the data conversion circuit 24. When the synchronization control start signal 25 becomes active, the read signal 8 which is an analog signal is demodulated by the analog demodulation circuit 22.

The demodulated data is supplied to a data conversion circuit 24.
And read data synchronization control circuit 23. The read data synchronization control circuit 23 performs data phase synchronization with the synchronization pattern of the read signal 8 to generate a reproduced clock signal. In accordance with the reproduced clock signal, the data conversion circuit 24 takes in the demodulated data, performs data code conversion, and outputs the data as read data 12 to the data control circuit 7.

The data control circuit 7 includes the analog demodulation circuit 2
2 makes the synchronization control start signal 25 inactive when all the read signals 8 have been processed (FIG. 6), and makes the read gate 11 inactive when all the read data 12 has been output. That is, when the reproduction process is continuously performed, the synchronization control start signal 25 becomes inactive at the time when the analog demodulation circuit 22 processes all data of one sector. Therefore, even if the output of data to the data control circuit 7 is not completed, when the synchronous control start signal 25 becomes inactive, the control waits for the next synchronous control start signal, and the next data sector signal 15 controls the synchronous control. When the start signal 25 becomes active, data demodulation and synchronization control can be started.

According to this embodiment, even when the read processing delay time is equal to or longer than the time corresponding to the gap area, the data reproduction operation can be performed without including the data reproduction processing time in the gap area. Can be achieved.

The circuit configuration is not limited to the above. That is,
It is sufficient if each signal can be generated at the timing shown in FIG. In other words, these functions may be prepared on the data control circuit side, or a separate control circuit may be added to achieve the same function.

Next, an embodiment of a circuit for reducing the increase in the gap area due to the processing delay of the write circuit 4 will be described with reference to FIG.

FIG. 4 shows a configuration in which a gate creation circuit 26 is added to the write circuit 4 of FIG. Gate creation circuit 26
Is a circuit for creating a write gate based on a write gate signal 13 (FIG. 5) indicating an output period of digital data, in consideration of a delay time of data code conversion of the write data 14. That is, even when the write gate signal 13 is turned off at the time when the transmission of the write data 14 from the data control circuit 7 to the write circuit 4 is completed, the gate creation circuit 26 Creates a write gate until the recording on the recording medium (disc) is completed. For this reason, the write circuit 4 writes the write data 9 after the data code conversion of the write data 14.
(Analog signal) can be continuously sent to the magnetic head.

In this embodiment, a magnetic disk device has been described as an example. However, a gap function can be reduced by a similar function in a magneto-optical disk device or a magnetic tape device, not limited to a magnetic disk device.

Further, the method according to the present invention can be applied not only to a device for recording and reproducing data but also to an LSI such as a data recording / reproducing circuit and a control circuit, which are components of the device. A similar function can be achieved.

[0047]

According to the data recording / reproducing method of the present invention, the timing of data processing provided on a recording medium can be reduced by performing timing correction such that the processing delay is relatively canceled between writing and reading. The gap region for absorption can be eliminated or reduced. Therefore, it is possible to improve the data recording efficiency, that is, expand the effective data recording area on the recording medium.

[Brief description of the drawings]

FIG. 1 is a block diagram of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a data sector generator 6 of FIG.

FIG. 3 is a block diagram showing a configuration of a read circuit 3 of FIG.

FIG. 4 is a block diagram showing a configuration of a write circuit 4 of FIG. 1;

FIG. 5 is a diagram showing read and write timings of the present invention.

FIG. 6 is a diagram showing the timing of a read operation according to the present invention.

FIG. 7 is a diagram showing conventional read and write timings.

[Explanation of symbols]

1: data disk, 2: magnetic head, 3: read circuit, 4: write circuit, 5: servo sector generator, 6: data sector generator, 7: data control circuit, 8: head read signal, 9: write signal, 10: servo sector signal, 11: read gate, 12: read data, 13:
Write gate, 14: write data, 15: data sector signal, 16: data sector generation circuit, 17: delay circuit, 18: selector, 19: write data sector signal,
20: read data sector signal, 21: write mode signal, 22: analog demodulation circuit, 23: read data synchronization control circuit, 24: data conversion circuit, 25: synchronization control start signal, 26: gate creation circuit.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Terumi Takashi 2880 Kozu, Kodahara City, Kanagawa Prefecture Inside the Hitachi, Ltd.Storage Systems Division (72) Inventor Tsuneo Hirose 2880 Kozu, Kozu, Odawara City, Kanagawa Prefecture Storage Corporation Hitachi, Ltd. F term in the system division (reference) 5D044 AB01 BC01 CC05 CC09 DE02 DE75 GM11

Claims (10)

[Claims] 1. A data recording / reproducing circuit for outputting recording data as a recording signal after an output delay time according to a control signal, wherein the control signal outputs recording data after activation as a recording signal after the reproduction delay time. And a data recording / reproducing circuit that continues outputting the recording signal after the control signal is deactivated. 2. A reproduction signal is reproduced according to a control signal.
A data control circuit which receives reproduced data obtained after an output delay time and continuously receives the reproduced data output even after the control signal is deactivated. 3. The data control circuit according to claim 2, wherein a period for continuously receiving said reproduction data is set by predictive control. 4. A recording data control circuit for generating recording data together with a first control signal, a data recording circuit for outputting the recording data as a recording signal after a first output delay time in accordance with the first control signal, A data reproduction circuit for outputting a reproduction signal as reproduction data after a second output delay time in accordance with a second control signal, generating the second control signal, and receiving the reproduction data based on the second control signal A data recording / reproducing circuit comprising a reproduced data control circuit. 5. The data recording / reproducing circuit according to claim 4, wherein timings of said first control signal and said second control signal are different. 6. The data recording / reproducing circuit according to claim 5, further comprising a data control circuit for generating said first control signal and said second control signal. 7. A data reproducing circuit for receiving a block signal composed of a phase synchronizing signal, a data synchronizing signal and a data signal and outputting it as reproduced data, wherein the data reproducing process of the block signal is performed according to a first control signal. And a second data reproduction circuit that reproduces data based on the output of the first data reproduction circuit according to a second control signal and outputs the reproduced data as reproduction data. Data recovery circuit provided. 8. The second data reproducing circuit continues reproducing data even after the first control signal is deactivated and outputs the data as reproduced data, and the second data reproducing circuit outputs the reproduced data during the output period of the reproduced data. 8. The data reproducing circuit according to claim 7, wherein the first data reproducing circuit starts a part of the data reproducing process of the block signal when one control signal is activated. 9. The data recovery circuit according to claim 1, wherein the first data recovery circuit controls a phase and an amplitude for reproducing the block signal based on the phase synchronization signal. 8. A data reproducing circuit according to claim 7, which reproduces a data signal. 10. A control signal generating circuit for generating the second control signal based on the first control signal.
A data reproduction circuit as described.