JPH036478A - Calibration disk enclosure preparing system - Google Patents

Abstract

PURPOSE:To always accurately perform the evaluation or periodical inspection of medium flaw inspection equipment by forming a missing or extra pulse of an arbitrary level on the disk medium of a calibration disk enclosure at an arbitrary position. CONSTITUTION:A servo head 3 reads the data recorded on a disk 2 to send the same to a servo means 5 which in turn positions the servo head 3 and a data head 4 on an objective track on the basis of the indication of a control means 10. The control means 10 sets offset quantity to an offset generating means 6 and sends out the signal corresponding to the magnitude of said offset quantity to the servo means 5 and, therefore, the heads 3, 4 follow the objective track at shifted positions corresponding to said signal. By this constitution, a missing or extra pulse having the amplitude corresponding to the offset quantity can formed at the position corresponding to the value set to a mount means 9 by the control means 10 from the starting point of the track and this position is not changed and the disk enclosure becoming the base of the accurate inspection of a medium can be prepared.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Application Fields Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems Action Examples Effects of the Invention [Summary] Positions of missing pulses and extra pulses Regarding the method of creating a disk enclosure for calibration in which the level is quantitatively set, the aim is to accurately locate the defect and calibrate using pulses at the desired level. and a data pattern or DC on the head.
A writing means that sends out an erase signal to write data, a reading means that does not read data, and a writing means that is activated by an index signal and sends a constant data pattern or DC erase signal to the writing means when the set value set by the clock is counted. A counting means for sending out a time signal, an offset generating means for sending an offset signal to the servo means, an instruction to the writing means whether to send a data pattern or a DC erase signal, and a set value of the counting means and an offset generating means for sending an offset signal to the servo means. A control means for setting the magnitude of the offset signal is provided, and after the head is positioned on the track and a data pattern is written, the head is shifted from the track according to the magnitude of the offset signal, and a DC erase signal is generated. At the same time, the head is positioned on a different track from the above to perform an erase operation, and then the head is shifted up the track according to the magnitude of the offset signal to write the data pattern. do.

[Industrial application field]

The present invention relates to a disk enclosure used for calibrating defect inspection equipment for disk media, and more particularly to a method for creating a disk enclosure for calibration that makes it possible to quantitatively set the positions and levels of missing pulses and extra pulses.

After disk media used in magnetic disk devices are manufactured, tests are conducted to detect the presence or absence of medium defects, as well as the state and position of the defects. For this reason, media defect inspection equipment or function test equipment is used, but when evaluating whether these equipment is normal or not, and during periodic inspections, a case enclosure enclosure (a part of the magnetic disk drive) for calibration is used. (composed of a spindle, disk, access arm, linear motor, etc.) is used.

FIG. 4 is a diagram illustrating medium defects.

If there is a defect in the disk medium, when data written on the disk medium is read, the amplitude of the read signal may become small at the position of the defect, as shown in the part shown in (■) in Figure 4(a). , if there is a defect in the area where data has been erased, as shown in (■) in Figure 4(b), the data that should have been erased at this defect location remains unerased, and a pseudo signal of a certain level greater than the noise is read out. There are cases where it is done.

If the amplitude of the signal in the part shown in (■) in FIG. 4(a) becomes less than a certain value and a signal error occurs, the signal read from this part is called a missing pulse, and the fourth
If the amplitude of the pseudo signal read from the area where the data has been erased, shown in (b), exceeds a certain value and results in a signal error, this pseudo signal is called an extra pulse.

By the way, defect inspection equipment and functional test equipment must detect these missing pulses and extra pulses, and detect their occurrence positions and levels, so the disk media installed in the disk enclosure for calibration must
It is necessary that missing pulses and extra pulses with various levels are recorded at predetermined positions.

[Conventional technology]

The position of a defect existing on the disk medium is expressed by the distance from the index signal indicating the start point of the track. Therefore, in testing the media defect position detection function of conventional media defect inspection equipment, etc., a pulse generator is used, and the index signal taken from the disk enclosure is used as a trigger to send out a pseudo error pulse delayed for a certain period of time from the pulse generator. By having the medium defect inspection equipment detect this pseudo error pulse, the distance from the index signal is measured to check whether the medium defect position is detected accurately.

Also, when testing the missing pulse detection function,
It is necessary to check how low the signal was read compared to the normal signal level, and when testing the extra pulse detection function, it is necessary to check how high the level of the pulse was read compared to the DC erased level. I need to find out if it was done.

Therefore, in testing the missing pulse detection function of conventional media defect inspection equipment, a calibration disk enclosure is used, and a data pattern written on the disk medium at the maximum frequency of the modulation code is read by changing the dark value. Judgment is made based on the total number of errors detected, and in the test of the Extra Lavalse detection function, the DC erased area is read by changing the darkness value, and judgment is made based on the total number of errors detected.

[Problem to be solved by the invention]

As mentioned above, in the conventional media defect position detection function test,
Since a pulse generator is used, when a pseudo error pulse is sent out using the index signal as a trigger,
There is a problem that the detected media defect position varies each time, and the results obtained during evaluation and periodic inspection are different each time.

In addition, when testing the missing pulse and extra pulse detection functions, the number of errors detected varies depending on the nature of defects in the disk media installed in the calibration disk enclosure. There is a problem in that it is necessary to manage the number, which is time-consuming, and it is impossible to create missing pulses or extra pulses of any level, making it impossible to test with missing pulses or extra pulses of the desired level. be.

In view of these problems, the present invention makes it possible to create missing pulses and extra pulses of any level at any position on the disk medium of a disk enclosure for calibration, thereby improving media defect inspection equipment and function testing. The purpose of the present invention is to enable equipment evaluation and periodic inspection to be performed with always accurate media defect locations and desired levels of missing pulses and extra pulses.

[Means to solve the problem]

FIG. 1 is a diagram illustrating the present invention in detail.

The disk enclosure 1 is composed of a disk 2, a servo head 3, a data head 4, a carriage (not shown), a motor that drives the carriage, and a spindle motor that rotates the disk 2.

The servo head 3 reads servo information recorded on the disk 2 and sends this servo information to the servo means 5. Based on the servo information, the servo means 5 moves the carriage and positions the servo head 3 and data head 4 on the target track according to instructions from the control means 10.

When the data head 4 is positioned at the target track and the reading means 8 reads an index signal indicating the starting point of the track, the control means 10 causes the writing means 7 to send a data pattern of the maximum frequency of the modulation code to the data head 4,
Write to the entire area of the corresponding track.

When the writing of the data pattern is completed, the control means 10
An offset amount is set in the offset generating means 6, and the servo means 5 is caused to send an offset signal having a magnitude corresponding to this offset amount. Therefore, the servo head 3 and the data head 4 follow the target track at positions shifted from the center of the target track in accordance with the magnitude of the offset signal.

Here, the control means 10 sets a set value in the counting means 9 and then enables the counting means 9.

The enabled counting means 9 is activated when notified from the reading means 8 that the index signal has been read out,
Based on a clock synchronized with the servo information sent by the servo means 5, the control means 1o starts counting the set value.

When the set value has been counted, the control means 1o instructs the writing means 7 to do the D
A C erase signal is sent to the data head 4. Therefore, since DC erase was performed on a part of the area in which the data pattern of the target track followed by the data head 4 was shifted in accordance with the offset amount, the amplitude was changed in accordance with the offset amount. A smaller part is created. In other words, a missing pulse is created in this small amplitude portion.

When the control means 10 completes the generation of the missing pulse as described above, it instructs the servo means 5 to position the servo head 3 and data head 4 to a new trunk different from the target track.

Then, when the data head 4 is positioned at a new position of 1 to rack and the successive output means 8 reads the index signal indicating the starting point of the track, the writing means 7 is caused to send a DC erase signal to the data head 4, Erase the entire area.

When the erasing operation is completed, the control means 10 sets an offset amount in the offset generation means 6, and causes the servo means 5 to send an offset signal of a magnitude corresponding to this offset amount. Therefore, the servo head 3 and the data head 4 follow the new track at a position shifted from the center of the new track in accordance with the magnitude of the offset signal.

Here, the control means 10 sets a set value in the counting means 9 and then enables the counting means 9. The enabled counting means 9 is activated when notified by the reading means 8 that the index signal has been read out, and is set to a set value set by the control means 10 based on a clock synchronized with the servo information sent by the servo means 5. Start counting.

When the set value has been counted, the control means 10 causes the writing means 7 to send out the instructed data pattern to the data head 4 for a predetermined period of time. Therefore,
Since a data pattern is written in a part of the DC erased area of the new track followed by the data head 4 at a position shifted according to the offset amount, a data pattern with an amplitude larger than the noise level is written. The inserted part will be created. That is, an extra pulse is formed in a portion having an amplitude larger than the amplitude of this noise.

[Effect]

By configuring as above, from the starting point of the track,
A missing pulse or an extra pulse having an amplitude corresponding to the offset amount set in the offset generating means 6 by the control means 10 can be created at a position corresponding to the set value set in the counting means 9 by the control means 10.

The position of the missing pulse or extra pulse created in this way is based on the index signal.
It is created at a position determined by a set value set by the control means 10, which is counted by a clock that cancels fluctuations in the rotational speed of the disk 2, and the position does not change each time it is read.

Furthermore, since the missing pulse or extra pulse is created with an amplitude corresponding to the offset amount set by the control means 10, the missing pulse and the extra pulse can be created at any level.

〔Example〕

FIG. 2 is a block diagram of a circuit showing one embodiment of the present invention.

The servo head 3 reads servo information recorded on the servo surface of the disk 2 and sends it to the demodulation circuit 12 via the amplifier circuit 11 3 4 . The servo information demodulated by the demodulation circuit 12 is sent to the position and speed side '41U circuit 13, where the current position of the servo head 3 is detected and sent to the control circuit 23.

In order to position the servo head 3 on a predetermined 1-rack, the control circuit 23 calculates the distance to the target track and notifies the position and speed control circuit 13 of the distance.

The position and speed control circuit 13 determines the target moving speed of the head from this distance, and outputs it to the motor 1 via the power amplifier circuit 14.
Coarse control for moving the servo head 3 and data head 4 by supplying current to the servo head 6 and driving the carriage 17 is started.

A servo head 3 and a data head 4 are attached to the arm of the carriage 17, and as the carriage 17 moves,
At the same time, they are transported to the destination truck position.

The position and speed control circuit 13 detects the moving speed of the servo head 3 from the inclination angle of the servo signal detected when the servo head 3 crosses the servo track.
The power amplifier circuit 14 is controlled to adjust the current supplied to the motor 16 so that the moving speed of the motor 16 becomes the same as the previously determined target speed.

When the servo head 3 reaches the vicinity of the target track, the position and speed control circuit 13 switches coarse control to fine control, positions the servo head 3 precisely on the target track, and thereafter follows the target track. control.

When the position and speed control circuit 13 switches to fine control,
The control circuit 23 is notified that the head positioning is completed, and the control circuit 23 enables the amplifier circuit 18.

Then, the data head 4 reads the index of the positioned target track and sends it to the amplifier circuit 18.

The index signal amplified by the amplifier circuit 18 enabled by the control circuit 23 is amplified to a predetermined level by the AGC amplifier circuit (automatic gain adjustment amplifier circuit) 19, and then formed into a pulse by the pulse generator 20. The signal is sent to the phase synchronization circuit 21.

The phase synchronization circuit 21 creates a clock for converting the pulsed index signal into a binary code, and distinguishes between this clock and the pulsed index signal by the discrimination circuit 2.
Send to 2.

Therefore, the discrimination circuit 22 reproduces the pulsed index signal into a binary code based on the clock sent out by the phase synchronization circuit 21 and sends it to the byte counter 24 and the control circuit 23.

When the control circuit 23 recognizes the detection of the index signal,
Disabling the amplifier circuit 18 and disabling the amplifier circuit 27
is enabled and instructs the modulation circuit 26 to send out the data pattern of the maximum frequency of the modulation code.

Therefore, the data head 4 is placed on the positioned track.
The data pattern is written following the index.

When the control circuit 23 causes one track worth of data to be written, it sets an offset amount in the offset generation circuit 15 and causes the position and speed control circuit 13 to send an offset signal. Therefore, the position and speed control circuit 13 performs control to shift the servo head 3 from the track it is following in response to the magnitude of this offset signal. Therefore, the data head 4 also moves to a position shifted from the center of the track being followed in accordance with the offset amount.

Here, the control circuit 23 disables the amplifier circuit 27, enables the amplifier circuit 18 and the byte counter 24, and then instructs the modulation circuit 26 to send out a DC erase signal. The enabled byte counter 24 is activated when the discrimination circuit 22 sends out an index signal, and based on the clock sent out by the phase synchronization circuit 28 that creates a clock synchronized with the servo information sent out by the demodulation circuit 12.
The control circuit 23 starts counting the set number of bytes. When counting of the set number of bytes is completed, the amplifier circuit 27 is enabled for a predetermined time, that is, the time for forming a missing pulse, and a signal is sent to disable the amplifier circuit 18.

Therefore, the data head 4 erases part of the data pattern written on the track in accordance with the offset amount by the DC erase 7 signal sent by the modulation circuit 26.

FIG. 3 is a diagram illustrating the operation of FIG. 2.

FIG. 3(a) shows a state in which DC erase is performed after writing a data pattern to the target track as described above. If the width of the data head 4 is CW, the data pattern is are written in center distribution in 1/2 CW increments. If the offset amount is 1/2 CW, as shown in
An erased area of size /2CW is created.

By stopping the sending of the offset signal sent by the offset generating circuit 15 to the track on which the data pattern has been written in this way, the data head 4 is again precisely positioned and read, as shown in FIG. As shown in b), a data pattern having a portion where the level has decreased by 50% is read at a position separated by the number of bytes counted by the hide counter 24 from the index. Therefore, a data pattern has been formed in which the detection position is accurate and there are missing pulses at the desired level.

When the missing pulse creation is completed, the control circuit 23 instructs the position and speed control circuit 13 to position the servo head 3 on the track where the extra pulse is to be created, and in the same manner as described above, positions the data head 4 on the new track.
is positioned, the control circuit 23 operates in the same manner as described above.
When the data controller 4 recognizes the read index signal, it disables the amplifier circuit 18, enables the amplifier circuit 27, and instructs the modulation circuit 26 to send out a DC erase signal.

Therefore, the data head 4 erases data from the positioned track following indexing.

When the control circuit 23 erases data for one track, it sets an offset amount in the offset generation circuit 15, and
The position and speed control circuit 13 is caused to send an offset signal. Therefore, the position and speed control circuit 13 performs control to shift the servo head 3 from the track it is following in response to the magnitude of this offset signal. Therefore, the data head 4 also moves to a position shifted from the center of the track being followed in accordance with the offset amount.

Here, the control circuit 23 disables the amplifier circuit 27, enables the amplifier circuit 18 and the byte counter 24, and then instructs the modulation circuit 26 to send out a data pattern. The enabled byte counter 24 is activated when the discrimination circuit 22 sends out an index signal, and based on the clock sent out by the phase synchronization circuit 28, the byte counter 24 is activated by the control circuit 24.
starts counting the number of bytes set by . When counting of the set Hyde number is completed, the amplifier circuit 27 is operated for a predetermined time, that is, the time to form an extra pulse.
A signal is sent to enable the amplifier circuit 18 and disable the amplifier circuit 18.

Therefore, depending on the data pattern sent out by the modulation circuit 26, the data head 4 writes the data pattern on the DC erased track at a position shifted in accordance with the offset amount.

FIG. 3(C) shows a state in which a data pattern is written after DC erasing a new track as described above. If the offset amount is 1/2 CW, the DC erase is performed as shown in ■. A data pattern having a size of CW is written from the center 2 of the track to a part of the track.

By stopping the sending of the offset signal sent by the offset generating circuit 15 to the track on which the data pattern has been written in this way, the data head 4 is again precisely positioned and read, as shown in FIG. Since 1/2 of the data pattern shown in ■ in C) is read, the
), a data pattern with a level of 50% of the normal data pattern is read at a position separated by the number of bytes counted by the byte counter 24 from the index.

Therefore, a DC erased track is formed in which the detection position is accurate and the extra pulse of the desired level is present.

The error detection circuit 25 is provided to check whether the levels of the created missing pulses and extra pulses are at the desired level. The comparator circuit compares the levels of input missing pulses or extra pulses, and if a missing pulse with a level lower than the set level is detected, a detection signal is sent to terminal A, and an extra pulse higher than the set level is detected. When this occurs, a detection signal is sent to terminal B.

〔Effect of the invention〕

As explained above, the present invention is capable of creating extract 1 to Lavals and missing pulses that indicate the exact location of media defects, as well as creating missing pulses and extra pulses of arbitrary levels. When calibrating or functional test equipment, a standard disk enclosure can be created that can always be performed with accurate media defect locations and desired levels of missing and extra pulses.

[Brief explanation of drawings]

FIG. 1 is a block diagram explaining the present invention in detail, FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention, FIG. 3 is a diagram explaining the operation of FIG. 2, and FIG. 4 is a medium It is a figure explaining a defect. In the figure, 1 is a disk enclosure, 2 is a disk, 3 is a servo head, 4 is a data head, 5 is a servo means, 6 is an offset generation means, 7 is a writing means, 8 is a continuous output means, 9 is a counting means, 10 is a counting means Control means, ICl3.27
12 is an amplifier circuit, 12 is a demodulation circuit, 13 is a position and speed control circuit, 14 is a power amplifier circuit, 15 is an offset generation circuit, 1
6 is motor, 17 is carriage, 19 is AG
C amplifier circuit, 20 is a pulse generator, 21.28 is a phase synchronization circuit, 22 is a discrimination circuit, 23 is a control circuit, 24 is a byte counter, and 25 is an error detection circuit. 5 <a> (1,) (d-) Operation shown in Figure 2? Explanatory diagram Figure 79 (a) (L) Women's collection Illustrated diagram of deficiencies covered by government funds

Claims (1)

[Claims] The heads (3) and (4) are positioned on the tracks provided on the disk (2) of the disk enclosure (1), and a clock synchronized with the servo information read by the head (3) is provided. servo means (5) for sending out a data pattern of the maximum frequency of the modulation code or a DC erase signal to the head (4) to cause the head (4) to write on the track in which it is positioned; means (7); and reading means (8) for reading data written on the track.
and the servo means (5) is activated by an index signal indicating the starting point of the track read by the reading means (8).
a counting means (9) that instructs the writing means (7) to send out a data pattern or a DC erase signal for a predetermined time when counting a preset value based on a clock sent by the servo; Instructing the means (5) to send out a data pattern or a DC erase signal to the offset generating means (6) for sending out an offset signal of a preset size, and to the writing means (7). and a control means (10) for setting a set value in the counting means (9) and a magnitude of an offset signal in the offset generating means (6), and controlling the heads (3) and (4). position on the track,
After writing the data pattern sent out by the writing means (7), the heads (3) and (4) were shifted from the track in accordance with the magnitude of the offset signal sent out by the offset generating means (6). Thereafter, based on the instructions of the counting means (9), the writing means (7) writes a DC erase signal sent out, and the heads (3) and (4) are positioned on a different track from the above. , the writing means (7
) to send out a DC erase signal to perform an erase operation, and then the heads (3) and (4) were shifted from above the track in accordance with the magnitude of the offset signal sent by the offset generating means (6). After that, the writing means (7) writes a data pattern sent out based on the instructions of the counting means (9).