JP2814566B2 - Calibration disk enclosure creation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Table of Contents] Outline Industrial field of application Conventional technology Problems to be solved by the invention Means to solve the problem Action Embodiment Effects of the invention [Summary] Positions of missing pulse and extra pulse Servo means for positioning the head on the track and sending the clock, with the aim of accurate defect location and the ability to calibrate with the pulse of the desired level, with regard to the method of creating a disk enclosure for calibration with the level set quantitatively , Data pattern or DC on the head
Writing means for sending and writing the erase signal, reading means for reading the data, and counting the set value set by clocking by starting with the index signal, the writing means keeps the data pattern or DC erase signal constant. Counting means for sending time, offset generating means for sending an offset signal to the servo means, and instructing the writing means to send a data pattern or a DC erase signal,
Providing control means for setting the set value of the counting means and the magnitude of the offset signal of the offset generating means, positioning the head on the track and writing the data pattern,
The head is shifted from the track in accordance with the magnitude of the offset signal, a DC erase signal is written, and the head is positioned on a different track from the above, and an erasing operation is performed. The data pattern is written by shifting the head from above the track in accordance with.

[Industrial applications]

The present invention relates to a disk enclosure used for calibration of a disk medium defect inspection equipment and the like, and more particularly to a calibration disk enclosure creation method capable of quantitatively setting the position and level of a missing pulse and an extra pulse.

When a disk medium used in a magnetic disk device is manufactured, a test for detecting the presence or absence of a medium defect and detecting the state and position of the defect is performed. For this reason, media defect inspection facilities or functional test facilities are used. However, when evaluating whether these facilities are normal or at regular inspections, a disk enclosure for calibration (a part of the magnetic disk unit, Spindle, disk, access arm,
(A linear motor or the like) is used.

 FIG. 4 is a view for explaining a medium defect.

If the disk medium has a defect, when the data written on the disk medium is read, the amplitude of the read signal becomes small at the position of the medium defect as shown in FIG. As shown in FIG. 4 (b), if there is a defect in the area from which data has been erased, the data which should have been erased at this defect location remains without being erased, and a certain level of pseudo signal larger than noise is read out. There are cases.

If the amplitude of the signal in the portion shown in FIG. 4A becomes smaller than a certain value and a signal error occurs, the signal read from this portion is called a missing pulse, and FIG. When the amplitude of the pseudo signal read from the area from which the data shown in (1) is erased exceeds a certain value and a signal error occurs, this pseudo signal is called an extra pulse.

By the way, since the defect inspection equipment and the functional test equipment must detect the missing pulse and the extra pulse, and detect the generation position and level, etc., the disk medium mounted in the disk enclosure for calibration must It is necessary that missing pulses and extra pulses having various levels are recorded at predetermined positions.

[Conventional technology]

The position of a defect existing in the disk medium is represented by a distance from an index signal indicating the starting point of a track.
Therefore, in the test of the media defect position detection function of the conventional media defect inspection equipment or the like, a pulse generator is used, and an index signal extracted from the disk enclosure is used as a trigger to cause the pulse generator to transmit a pseudo error pulse delayed for a certain time. By detecting the pseudo error pulse by the medium defect inspection equipment, the distance from the index signal is measured, and it is checked whether the position of the medium defect is accurately detected.

Also, when testing the missing pulse detection function, it is necessary to check how much the level of the signal that has dropped from the normal signal level is read. It is necessary to check how high a pulse level is detected with respect to the erased level.

Therefore, in the test of the missing pulse detection function of the conventional medium defect inspection equipment and the like, the data pattern written on the disk medium at the maximum frequency of the modulation code is read by changing the threshold value by using the disk enclosure for calibration and detecting. In the test of the extra pulse detection function, the DC erased area is read by changing the threshold, and the determination is made based on the total number of detected errors.

[Problems to be solved by the invention]

As described above, in the test of the conventional medium defect position detection function, since the pulse generator is used, when a pseudo error pulse is transmitted with the index signal as a trigger, the detected medium defect position fluctuates every time. There is a problem that the results obtained at the time of evaluation and periodic inspection are different each time.

In the test of the missing pulse and extra pulse detection functions, the number of detected errors varies depending on the nature of the defect of the disk medium mounted in the disk enclosure for calibration. It is necessary to control the number, it is troublesome, it is not possible to create missing pulses and extra pulses of any level, and it is not possible to test with the desired level of missing pulses and extra pulses. is there.

In view of such problems, the present invention makes it possible to create a missing pulse and an extra pulse of an arbitrary level at an arbitrary position on a disk medium of a disk enclosure for calibration, thereby enabling a medium defect inspection facility and a functional test. It is an object of the present invention to enable the evaluation and the periodic inspection of the equipment to be always carried out with the accurate defect position of the medium and the desired level of the missing pulse and the extra pulse.

[Means for solving the problem]

 FIG. 1 is a diagram for explaining the principle of the present invention.

The disk enclosure 1 includes a disk 2, a servo head 3, a data head 4, a carriage (not shown), a motor for driving the carriage, and a spindle motor for rotating the disk 2.

The servo head 3 reads the servo information recorded on the disk 2 and sends the servo information to the servo means 5.
The servo unit 5 moves the carriage and positions the servo head 3 and the data head 4 on the target track based on the servo information according to an instruction from the control unit 10.

When the data head 4 is positioned at the target track and the reading means 8 reads the index signal indicating the starting point of the track, the control means 10 causes the writing means 7 to transmit the data pattern of the maximum frequency of the modulation code to the data head 4,
Write all areas of the 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 an offset signal having a magnitude corresponding to the offset amount is transmitted to the servo means 5. 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 the set value in the counting means 9 and then enables the counting means 9. The enabled counting means 9 is activated upon being notified that the index signal has been read from the reading means 8, and sets the set value set by the control means 10 based on the clock synchronized with the servo information transmitted by the servo means 5. Start counting.

When the counting of the set value is completed, the control unit 10 instructs the writing unit 7 for the time determined by the writing unit 7.
An erase signal is sent to the data head 4. Therefore,
Since the DC erase is executed at a position shifted according to the offset amount in a part of the area where the data pattern of the target track to be followed by the data head 4 is written, the amplitude becomes smaller corresponding to the offset amount. Part is created. That is, a missing pulse is created in the portion where the amplitude is small.

As described above, upon completing the missing pulse generation, the control means 10 instructs the servo means 5 to position the servo head 3 and the data head 4 on a new track different from the target track. Then, when the data head 4 is positioned on a new track and the reading means 8 reads the index signal indicating the starting point of the track, the writing means 7 sends a DC erase signal to the data head 4, and the entire area of the track is read. Let it be erased.

When the erasing operation is completed, the control means 10 sets an offset amount in the offset generating means 6 and causes the servo means 5 to transmit an offset signal having a magnitude corresponding to the 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 the set value in the counting means 9 and then enables the counting means 9. The enabled counting means 9 is activated when it is notified that the index signal has been read from the reading means 8, and sets the set value set by the control means 10 based on a clock synchronized with the servo information transmitted by the servo means 5. Start counting.

Then, when the counting of the set values is completed, the control unit 10 causes the data head 4 to transmit the data pattern instructed to the writing unit 7 for a time determined by the writing unit 7. Therefore,
Since a data pattern is written at a position shifted according to the offset amount in a part of a DC erased area of a new track followed by the data head 4, a data pattern having an amplitude larger than the noise level is written. The embedded part is created. That is, an extra pulse is formed in a portion having an amplitude larger than the amplitude of the noise.

[Action]

With the above configuration, the amplitude missing corresponding to the offset amount set by the control means 10 to the offset generating means 6 is provided from the starting point of the track to a position corresponding to the set value set by the control means 10 to the counting means 9. Pulses or extra pulses can be created.

The position of the missing pulse or extra pulse created in this way is created at a position determined by the set value set by the control means 10 which is counted by a clock for canceling the fluctuation of the rotation speed of the disk 2 based on the index signal. Therefore, the position does not change every time reading is performed.

Further, since a missing pulse or an extra pulse having an amplitude corresponding to the offset amount set by the control means 10 is created, the levels of the missing pulse and the extra pulse can be set to arbitrary levels.

〔Example〕

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

The servo head 3 reads the servo information recorded on the servo surface of the disk 2 and passes through the amplifier 11 to the demodulator 12
To send to. The servo information demodulated by the demodulation circuit 12 is sent to the position and speed control circuit 13, where the current position of the servo head 3 is detected and sent to the control circuit 23.

The control circuit 23 calculates the distance to the target track and notifies the position and speed control circuit 13 to position the servo head 3 on a predetermined track.

The position and speed control circuit 13 determines the target moving speed of the head from this distance, supplies current to the motor 16 via the power amplifier circuit 14, drives the carriage 17, and moves the servo head 3 and the data head 4. Start coarse control.

The servo head 3 and the data head 4 are attached to the arm of the carriage 17, and are conveyed to the target track at the same time by the movement of the carriage 17.

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 so as to be the same, and the current supplied to the motor 16 is adjusted.

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

When the position and speed control circuit 13 switches to fine control,
The control circuit 23 is notified that the positioning of the head has been completed, and the control circuit 23 enables the amplifier circuit 18. When the data head 4 reads the index of the positioned target track, it sends it to the amplifier circuit 18.

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

The phase synchronization circuit 21 creates a clock for converting the pulsed index signal into a binary code, and discriminates this clock from the pulsed index signal.
To send to.

Therefore, the discriminating circuit 22 reproduces the pulsed index signal into a binary code based on the clock sent from 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,
The amplifier circuit 18 is disabled and the amplifier circuit 27 is enabled, and the modulation circuit 26 is instructed to transmit a data pattern having the maximum frequency of the modulation code.

Therefore, the data head 4 writes the data pattern on the positioned track following the index.

When the control circuit 23 causes one track of data to be written, the control circuit 23 sets an offset amount in the offset generation circuit 15 and
The position and speed control circuit 13 sends an offset signal. Therefore, the position and speed control circuit 13 performs control to shift the servo head 3 from the track being followed according to the magnitude of the offset signal. For this reason, the data head 4 also moves to a position shifted from the center of the track being followed according to the offset amount.

Here, the control circuit 23 disables the amplification circuit 27, enables the amplification circuit 18 and the byte counter 24, and then instructs the modulation circuit 26 to transmit a DC erase signal. The enabled byte counter 24 is activated when the index signal is transmitted from the discrimination circuit 22, and is controlled by the control circuit 23 based on the clock transmitted by the phase synchronization circuit 28 that creates a clock synchronized with the servo information transmitted by the demodulation circuit 12. Start counting the number of bytes set by. When the counting of the set number of bytes is completed, a predetermined time, that is,
A signal for enabling the amplifier circuit 27 and disabling the amplifier circuit 18 for a time period for forming the missing pulse is transmitted.

Therefore, the data head 4 erases a part of the data pattern written on the track according to the offset amount by the DC erase signal sent from the modulation circuit 26.

 FIG. 3 is a diagram for explaining the operation of FIG.

FIG. 3A shows a state in which a data pattern is written on the target track as described above and then DC erase is performed. If the width of the data head 4 is CW, the data pattern is It is written in 1 / 2CW by center distribution. Assuming that the offset amount is 1/2 CW, an erased area having a size of 1/2 CW is created in a part of the data pattern as shown in FIG.

By stopping the sending of the offset signal sent by the offset generating circuit 15 to the track on which the data pattern is written in this manner, the data head 4 is accurately positioned and read again. As shown in (b), a data pattern having a portion whose level is reduced by 50% is read at a position apart from the index by the number of bytes counted by the byte counter 24. Therefore, a data pattern in which the detection position is accurate and a missing pulse of a desired level exists is formed.

When the generation of the missing pulse is completed, the control circuit 23 instructs the position and speed control circuit 13 to position the servo head 3 on the track on which the extra pulse is to be generated.
When the control circuit 23 recognizes the index signal read by the data head 4 in the same manner as described above, the control circuit 23 disables the amplifier circuit 18 and controls the amplifier circuit 27.
Is enabled, and the modulation circuit 26 is instructed to transmit a DC erase signal.

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

When the control circuit 23 erases data for one track, the control circuit 23 sets an offset amount in the offset generation circuit 15 and
The position and speed control circuit 13 sends an offset signal. Therefore, the position and speed control circuit 13 performs control to shift the servo head 3 from the track being followed according to the magnitude of the offset signal. For this reason, the data head 4 also moves to a position shifted from the center of the track being followed according to the offset amount.

Here, the control circuit 23 disables the amplification circuit 27, enables the amplification circuit 18 and the byte counter 24, and then instructs the modulation circuit 26 to transmit a data pattern. The enabled byte counter 24 starts when the discrimination circuit 22 sends out the index signal, and starts counting the number of bytes set by the control circuit 23 based on the clock sent out by the phase synchronization circuit 28. Then, when the counting of the set number of bytes is completed, a signal for enabling the amplifier circuit 27 and disabling the amplifier circuit 18 for a predetermined time, that is, a time for forming an extra pulse, is transmitted.

Therefore, the data pattern written by the modulation circuit 26 causes the data head 4 to write the data pattern on the DC erased track at a position shifted according to the offset amount.

FIG. 3 (c) shows a state where the data pattern is written after the new track is DC-erased as described above. If the offset amount is 1/2 CW, the DC erase is performed as shown in FIG. A data pattern having a CW size from the center of the track is written in 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 manner, the data head 4 is accurately positioned and read again. Since half of the data pattern shown in c) is read, FIG.
As shown in (2), a data pattern whose level is 50% of a normal data pattern is read at a position away from the index by the number of bytes counted by the byte counter 24. Accordingly, a DC-erased track in which a detection position is accurate and an extra pulse of a desired level exists is formed.

The error detection circuit 25 is provided to check whether the levels of the generated missing pulse and extra pulse are generated at desired levels, and is input through the detection level set by the control circuit 23 and the amplification circuit 18. The level of the missing pulse or the extra pulse is compared by a comparison circuit, and when a missing pulse having a level lower than the set level is detected, a detection signal is sent to a terminal A, and when an extra pulse having a level higher than the set level is detected, A detection signal is sent to terminal B.

〔The invention's effect〕

As described above, according to the present invention, it is possible to generate an extra pulse and a missing pulse indicating an accurate medium defect position and to generate a missing pulse and an extra pulse of an arbitrary level. When calibrating test equipment, it is possible to create a standard disk enclosure that can always be implemented with accurate media defect locations and desired levels of missing and extra pulses.

[Brief description of the drawings]

 FIG. 1 is a block diagram for explaining the principle of the present invention, FIG. 2 is a block diagram of a circuit showing one embodiment of the present invention, FIG. 3 is a diagram for explaining the operation of FIG. 2, and FIG. 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 servo means, 6 is offset generating means, 7 is writing means, 8 reading means, 9 is counting means, and 10 is control. Means, 11, 18, 27 are amplification circuits, 12 is demodulation circuit, 13 is position and speed control circuit, 14 is power amplification circuit, 15 is offset generation circuit, 16 is motor, 17 is carriage, 19 is AGC amplification circuit, Reference numeral 20 denotes a pulsating circuit, reference numerals 21 and 28 denote phase synchronization circuits, reference numeral 22 denotes a discrimination circuit, reference numeral 23 denotes a control circuit, reference numeral 24 denotes a byte counter, and reference numeral 25 denotes an error detection circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 5/00 G01R 33/12

Claims (1)

(57) [Claims] A head (3) (4) is positioned on a track provided on a disk (2) of a disk enclosure (1), and a clock synchronized with servo information read by the head (3) is transmitted. Servo means (5) for performing a data pattern having a maximum frequency of a modulation code or a DC erase signal to the head (4) to write the data pattern on the track on which the head (4) is positioned (7) reading means for reading data written on the track (8)
Starting by the index signal indicating the starting point of the track read by the read means (8), and the servo means (5)
A counting means (9) for instructing the writing means (7) to send a data pattern or a DC erase signal for a predetermined time when counting a preset value based on a clock transmitted by the servo; An offset generating means (6) for transmitting an offset signal of a preset size to the means (5), and an instruction as to whether a data pattern or a DC erase signal is to be transmitted to the writing means (7). At the same time, a setting value is set in the counting means (9), and a control means (10) for setting the magnitude of the offset signal is provided in the offset generating means (6). Position it on the track,
After writing the data pattern sent by the writing means (7), the heads (3) and (4) are shifted from the track in accordance with the magnitude of the offset signal sent by the offset generating means (6). Thereafter, based on the instruction from the counting means (9), the DC erase signal sent from the writing means (7) is written, and the heads (3) and (4) are positioned on different tracks from the above. After the writing means (7) sends a DC erase signal to perform an erasing operation, the heads (3) and (4) are moved according to the magnitude of the offset signal sent from the offset generating means (6). After shifting from the track,
Based on the instruction of the counting means (9), the writing means (7)
A method for creating a disk enclosure for calibration, characterized by writing a data pattern to be sent out by a computer.