Patent Application
20070253095
Embodiments in accordance with the present invention relate to a pattern write method to a magnetic recording surface, and a demagnetization state determination method on the magnetic recording surface.
An embodiment of the present invention is directed to a method of writing a pattern on a rotating magnetic recording surface using a head including a read element and a write element disposed at each different position in the radius direction. With this method, in a first area of the magnetic recording surface, in such a manner that a value to be calculated from a value derived by the read element reading a pattern written by the write element at a different radius position follows a first reference, the write element sequentially writes a new pattern while the pattern written by the write element is being read sequentially by the read element for positioning. Moreover, in a second area having a base magnetization state different from the first area, in such a manner that a value to be calculated from a value derived by the read element reading a pattern written by the write element at a different radius position follows a second reference being different from the first reference, the write element sequentially writes a new pattern while the pattern written by the write element is being read sequentially by the read element for positioning. Using each different reference for two areas enables the accurate application of head control in accordance with the base magnetization state.
Embodiments of the present invention are especially effective when the first area is erased by the write element, and when the second area is erased by an external magnetic field.
In the second area, a plurality of patterns each at a different radius position, may be written by the write element, and using a value derived by reading the patterns by the positioned read element, the second reference is calculated from the first reference. This enables the derivation of the second reference with ease and accuracy.
Preferably, a determination is made whether the base magnetization state is satisfactory or not based on an amount of change observed in the value to be calculated in the second area with respect to the value to be calculated in the first area. Alternatively, preferably, in the second area, a determination is made whether the base magnetization state is satisfactory or not based on a variation observed in the value to be calculated plurally for the same radius position. Still alternatively, in the second area, a determination is preferably made whether the base magnetization state is satisfactory or not based on a variation observed in the value to be calculated plurally for a different radius position. By making a determination to see satisfactory or not, it can prevent pattern write based on erroneous calculation of the second reference.
Another embodiment of the present invention is directed to a method of writing a pattern on a rotating magnetic recording surface using a head including a read element and a write element disposed at each different position in a radius direction. With the method, in a first area, a plurality of patterns written by the write element at each different radius position are read by the read element at a first radius position, and a target is determined based on a value calculated using values being reading results and a first reference corresponding to the first radius position. Moreover, the patterns written by the write element are read by the read element and the head is positioned at the target, and in the state with the head positioned, a new pattern is written by the write element. In a second area, a plurality of patterns written by the write element at each different radius position are read by the read element at a second radius position, a second reference is calculated from the first reference based on a value to be calculated using values being reading results, and a new target is determined in accordance with the second reference. Further, the patterns written by the write element are read by the read element and the head is positioned at the new target, and in the state with the head positioned, a new pattern is written by the write element. Using each different reference for two areas enables the accurate application of head control depending on which area.
Still another embodiment of the invention is directed to a method of making a determination about a demagnetization state on a magnetic recording surface. With this method, a plurality of patterns written by the write element at each different radius position are read by the read element after positioning, and using values being reading results, a first comparison value is calculated. Moreover, a plurality of patterns written by the write element at each different radius position are read by the read element after positioning, and using values being reading results, a second comparison value is calculated. Further, based on a difference between the first and second comparison values, a determination is made whether the erasing state is satisfactory or not.
For each of the plurality of different radius positions, the plurality of patterns written by the write element at each different radius position are read by the positioned read element, and using values being reading results, a comparison value is calculated, and based on a variation observed in the comparison values at the plurality of different radius positions, a determination can be made whether the erasing state is satisfactory or not.
For a plurality of different positions in the circumferential direction at the same radius position, the patterns written by the write element at each different radius position are read by the positioned read element, and using values being reading results, a comparison value is calculated, and based on a variation observed in the comparison value plurally calculated at the same radius position, a determination can be made whether the erasing state is satisfactory or not.
According to embodiments of the present invention, a pattern of any desired pitch can be written in a plurality of areas varying in magnetization state.
In the below, described is an embodiment to which the present invention is applicable. For explicit reference, the following description and the accompanying drawings are not fully made or entirely shown as appropriate. In the respective drawings, any similar component is provided with the same reference numeral, and for explicit reference, once-described matters are not described again as required. In the below, a preferred embodiment of the present invention is described with exemplary servo write of a hard disk drive (HDD) being an example of a magnetic disk drive device. The embodiment is characterized in the technique of, with servo write, writing a pattern to areas varying in base magnetization state.
For manufacturing an HDD of the embodiment, first an external magnetic field is used to erase an area on the outer radius side of a magnetic disk, which is incorporated inside of a head disk assembly (HDA). Thereafter, through control over the internal mechanism inside of the HDA, pattern writing is performed to the magnetic disk inside of the HDA. Described first is erasing by the external magnetic field.
The external magnetic field generation device 9 is provided with permanent magnets 91 and 92, and a magnet support section 93 that supports the permanent magnets 91 and 92. The permanent magnets 91 and 92 are disposed to face each other with a space therebetween. In the space between the permanent magnets 91 and 92, a magnetic field is generated by the permanent magnets 91 and 92. Into this space, the HDA 1 is partially inserted, and in this state, the magnetic disk 11 is rotated using a spindle motor (SPM: not shown) so that the area on the outer radius side of the magnetic disk 11 is erased. The magnetic force of the magnetic field formed by the permanent magnets 91 and 92 is stronger than the force of retaining the magnetic disk 11. In this sense, this external magnetic field can erase the data recorded on the magnetic disk 11. By using the external magnetic field, erasing can be swiftly performed to the magnetic disk 11.
The magnetic field generated between the permanent magnets 91 and 91 is directed vertical or parallel with respect to the recording surface of the rotating magnetic disk 11. The direction of the external magnetic field can be changed depending on the recording method of the magnetic disk 11 to be incorporated inside of the HDA. In order not to affect the external magnetic field to the SPM, inside of the external magnetic field, only a part of the area on the outer radius side of the magnetic disk 11 is inserted. Therefore, the area on the inner radius side of the magnetic disk 11 is not erased to a full degree. In this sense, in the embodiment, by the servo write performed to the magnetic disk 11, the area on the inner radius side is erased by the head element section of the HDA 1.
Described next is the servo write in this embodiment.
The HDD is also provided with, in addition to the HDA 1, a circuit board fixed to the outside of the cabinet 10. On the circuit board, an IC is incorporated for execution of signal processing and control processing. With servo write in this embodiment, the circuit on this circuit board for control use is not used, and the servo write control device 2 exercises control over the servo write. With the servo write in this embodiment, the internal mechanism of the HDA 1 is directly controlled, and the magnetic disk 11 is written with servo data (servo patterns). The magnetic disk 11 is a nonvolatile storage disk that stores data by a magnetic layer being magnetized.
Such servo write is referred to as self servo write (SSW). With the SSW, using the components inside of the cabinet 10, the magnetic disk 11 is written with the servo data for use for writing and reading of user data. In the below, this servo data is referred to as product servo pattern. Note here that the servo write in this embodiment can be performed using the control circuit incorporated on the HDD.
The servo write control device 2 performs the SSW in this embodiment while exercising control thereover. The servo write control device 2 includes an SSW controller 22. This SSW controller 22 exercises control over the SSW in its entirety. The SSW controller 22 exercises control over positioning of the head slider 12, control over pattern generation, and others. The SSW controller 22 can be configured by a processor that operates in accordance with a micro code that is stored in advance. The SSW controller 22 executes control processing in accordance with a request coming from any external information processing device, and forwards any necessary information such as error information to the information processing device.
At the time of pattern writing to the magnetic disk 11, the SSW controller 22 issues a command to a pattern generator 21, and the pattern generator 21 generates any predetermined pattern. A read/write interface 23 goes through a conversion process for the pattern generated by the pattern generator 21, and forwards a pattern signal to the preamplifier IC 13. The preamplifier IC 13 amplifies the signal for transfer to the head slider 12, and the head slider 12 writes the pattern to the magnetic disk 11.
The SSW controller 22 exercises control over the actuator 16 using the signal read by the head slider 12, and moves and positions the head slider 12. To be specific, the signal read by the head slider 12 is input to an amplitude demodulator 27 via an RW interface 23. The read signal having been subjected to the demodulation process by the demodulator 27 is subjected to AD conversion by an AD converter 26, and the result is input to the SSW controller 22. The SSW controller 22 analyzes the resulting digital signal, and calculates a value control signal.
The SSW controller 22 forwards the value to a DA converter 25. The DA converter 25 subjects the acquired data to DA conversion, and provides a control signal to a VCM driver 24. Based on the control signal, the VCM driver 24 supplies a control current to the VCM 15, and moves and positions the head slider 12. In this specification, the device including the components except for the servo write control device 2 and the magnetic disk 11 of the HDA 1, is referred to as self servo track writer (SSTW). That is, the SSTW takes charge of servo pattern writing onto the recording surface of the magnetic disk 11.
As shown in
The head sliders 12a to 12f are all fixed to the actuator 16. Specifically, an actuator arm 162a supports the head slider 12a, an actuator arm 126b supports the head sliders 12b and 12c, an actuator arm 162c supports the head sliders 12d and 12e, and an actuator arm 162d supports the head slider 12f.
The actuator 16 is coupled to the VCM 15, and rotates about the circular axis 161, thereby moving the head sliders 12a to 12f in the radius direction on the recording surfaces of the magnetic disks 11a to 11c. The head sliders 12a to 12f are each provided with a slider, and a head element section (not shown) serving as a thin film element formed thereto. The head element section is provided with a write element that converts an electric signal into a magnetic field in accordance with write data, and a read element that converts the magnetic field from the magnetic disk 11 into an electric signal.
The preamplifier IC 13 selects any one head slider from the plurality of head sliders 12a to 12f for data reading, and amplifies (preamplifies) a reproduction signal reproduced by the selected head slider using a fixed gain. The result is output to the servo write control device 2. The preamplifier IC 13 amplifies the signal coming from the servo write control device 2, and outputs the result to the selected head slider. At the time of product servo pattern writing, all of the head sliders 12a to 12f are selected at the same time.
Referring back to
The burst pattern (BURST) is a signal that indicates the more precise position of the servo track indicated by the track ID. The burst pattern typically includes four amplitude signals of A, B, C, and D in a staggered format with a slight positional difference on an orbit for every servo track (refer to
With the SSTW, the pattern written for its own to the magnetic disk 11 is referred to, and using the temporal and spatial information derived from the signal, the next pattern is written to the position displaced by read/write offset in the radius direction while the head element section 120 is being controlled temporally (timing control in the circumferential direction) and spatially (position control in the radius direction).
The read/write offset (RWO) is a space in the head element section 120 in the radius direction between the write element 121 and the read element, and specifically, a distance between the center of the read element 122 and that of the write element 121 on the magnetic disk 11 in the radius direction. The read/write offset varies depending on the radius position on the magnetic disk 11. Note here that the write element 121 and the read element 122 show some position difference also in the circumferential direction, and the space in this direction is referred to as read/write separation.
With the SSTW in this embodiment, a selection is made from a plurality of head element sections 120 (e.g., the head element section of the head slider 12b in
In this embodiment, as shown in
More specifically, with the SSTW, the head element section 120 is positioned using the radial pattern 117, and with the timing pattern 116 used as a reference, the timing is measured for pattern writing. After a lapse of time predetermined by the timing at which the read element 122 of the propagation head reads the timing pattern, the write element 121 of each of the head element sections 120 writes the product servo pattern 115 (a part thereof). The timing pattern 116 for the next sector is written based on the reading of the timing pattern 116 of the preceding sector.
As shown in
The write element 121 writes a half of the product servo pattern with a cycle of the magnetic disk. In this specification, the track corresponding to the half of the product servo pattern is referred to as servo write track. The product servo pattern of one servo write track is denoted by 115. Moreover, the track of the product servo pattern is referred to as servo track. The track pitch of the servo write track is a half of the servo track pitch.
The timing pattern 117 in any one specific sector is formed at the position substantially the same in the circumferential direction. On the other hand, the radial patterns 117 are each formed at the position different from, in the circumferential direction, the radial pattern 117 adjacent thereto in the radius direction. That is, some position displacement is observed in the circumferential direction between any adjacent radial patterns 117. In the radius direction, some overlay is observed between any adjacent radial patterns 117. Note that, in
The SSW controller 22 performs head positioning using the read signal of the radial pattern 117. Specifically, by referring to
For positioning of the write element 121 at a target position 119, the SSW controller 22 moves the read element 122 from the target position 119 for positioning at the target position 118 located inner radius side of the read/write offset (RWO). The read element 122 reads radial patterns 117a, 117b, and 117c. The SSW controller 22 calculates a function value (in this specification, referred to as PES value) of the amplitudes (A, B, and C) of the respective radial patterns 117a, 117b, and 117c, and positions the read element 122 in such a manner that the value becomes the target value.
In the state that the read element 122 is positioned at the target position 118, the write element 122 writes the radial pattern 117d. Note that, in the pattern write process, typically, the target position of the read element 122 does not come to the center of the respective radial patterns 117, and is displaced in the radius direction.
As such, the SSTW sequentially performs pattern writing to the servo write tracks starting from the inner radius side. As described by referring to
By referring to
Specifically, by referring to
When the magnetic disk 11 is rotated once, and when the erase is completed for the track being the movement destination, the write element 121 is returned to the servo write track (write element position 121b) to which the pattern writing is performed immediately therebefore [2]. Moreover, the write element 121 is moved to the outwardly-adjacent servo write track for writing of a pattern including the next product servo pattern 115 [3], and at the write element position 121a, pattern writing is performed. The read element position at this time is denoted by 122a.
Thereafter, with the servo pattern write sequence in the inner radius side area 211, a seek process for any to-be-erased servo write track, an erase process for the seek destination, a seek process for position return before the seeking, another seek process for the outwardly-adjacent servo write track, and a servo pattern write process for the seek destination are repeated.
The servo pattern write sequence in the outer radius side area 212 is the one derived by eliminating the processes for erase from the servo pattern write sequence in the inner radius side area 211. To be specific, in
The SSW controller 22 in this embodiment sequentially moves the head sliders 12a to 12f in such a manner that a value referred to as APC matches a predetermined value that is previously set. In this manner, a product servo pattern of any desired pitch is written. The SSTW determines a target PES value in such a manner that the APC matches (gets closer to) the predetermined value, and in the state that a propagation head is positioned at the target position, pattern writing is performed at each corresponding servo write track.
The APC is calculated from reading amplitudes A, B, and C of the radial patterns 117 of three servo write tracks, which are adjacent to one another in the radius direction. Specifically, in the state that the propagation head is positioned at the center of one radial pattern 117, the reading amplitudes A, B, and C are acquired respectively for the radial patterns 117. The APC is calculated by (A+C/B).
As shown in
Using each different reference APC to the inner radius side area 211 and the outer radius area 212 is counted as one characteristic with the SSW of the embodiment. The magnetization state of the base before pattern writing of the to-be-self-erased inner radius side area 211 is different from that of the outer radius side area 212 to be erased by the external magnetic field. When the read element 122 measures the APC after reading the radial pattern 117, the read element 122 reads also the magnetization of the base portion in addition to the radial pattern 117. Therefore, in the inner radius side area 211 and the outer radius side area 212 each being different in demagnetization state, even if the radial pattern 117 of the same pitch is read, the resulting APCs will be different.
In consideration thereof, at the time of pattern writing in the outer radius side area 212, the reference APC used in the inner radius side area 211 is changed, and any new reference APC is set.
With pattern writing performed to the servo write tracks by using the reference APC as a target, control is exercised so as to derive any desired value for the servo write track pitch. Note here that the reference APC is determined in advance in the development stage. Specifically, to make such a determination, a rotary positioner is used to write any ideal pattern in an HDA of the same design, and the APC of the pattern is measured.
The SSTW of this embodiment is set in advance with, before starting the SSW, a reference APC curve corresponding to each of the servo write tracks of the inner radius side area 211 and the outer radius side area 211. That is, at the time when the SSW is started, the areas share the same reference APC curve. In the APC calibration sequence, the SSTW corrects the preset reference APC curve, and sets the APC curve 82 to the outer radius side area 212. Described first is this APC calibration sequence.
With the SSW of this embodiment, after pattern writing is performed for the number of any predetermined servo write tracks, the APC calibration is executed. That is, the SSW of this embodiment includes a plurality of sequences, i.e., includes a pattern write sequence of performing pattern writing sequentially to the servo write tracks on the recording surface, and an APC calibration sequence that is executed between the pattern write sequences.
In the APC calibration sequence, pattern writing is performed with a pitch in accordance with the design. Therefore, the APC of the written pattern is measured, and a PES value is determined for use as a target for the pattern writing thereafter. Such an APC calibration sequence is performed once for every several hundred servo write tracks.
The SSW controller 22 of this embodiment sequentially moves the head element section 120 in such a manner as to derive a predetermined value for the APC. The issue here is that measuring the APC for every movement to the next servo write track requires a considerable amount of time, thereby greatly affecting the yield. In consideration thereof, with the SSW of this embodiment, an APC is measured for every hundreds of servo write tracks, and the resulting measurement value is used as a basis to determine a target PES for the next process.
In the APC calibration sequence, as shown in
The SSTW sets the APC curve 82 of the outer radius side area 212 in the APC calibration sequence at a predetermined radius position. Typically, at the ACP calibration position at the innermost side of the outer radius side area 212, the SSTW sets again the reference APC curve. As an example, considered here is a case where there is an area boundary at a 4900 servo write track position, and the SSTW performs ACP calibration at a 4800 servo write track position and at a 5000 servo write track position. In this case, the SSTW sets again the reference APC curve during the APC calibration at this 5000 servo write track position.
Specifically, in the APC calibration at the innermost side of the outer radius side area 212, the SSW controller 22 calculates an average value of the APCs for a plurality of servo write tracks (in the above example, four servo write tracks). That is, an APC average value calculated for each of the servo write tracks are added together, and the resulting value is divided by the number of servo write tracks. The SSW controller 22 uses this value to correct (adjust) the reference APC curve that is previously set.
Typically, the reference APC curve is set as a tertiary or quintic function with respect to a servo write track position. The SSW controller 22 compares an APC at the calibration position represented by the initially-set function with the actually-measured APC. Thereafter, a difference between these values is calculated, and the resulting difference is added to the function as an offset. The resulting new function serves as a function that represents the reference APC curve in the outer radius side area 212.
As such, using the APC actually measured in the outer radius side area 212, the function representing the reference APC curve used in the inner radius side area 211 is corrected so that the resulting reference APC curve can be suited to the base magnetization state of the outer radius side area 212. In this manner, the track pitch of the servo data can be controlled not to fluctuate that much.
In order to derive an accurate APC measurement value, as described above, it is preferable to measure a plurality of APCs, and use a value calculated from the resulting values. Moreover, as described above, it is preferable to measure the APC for a plurality of servo write tracks, and use an average value of the resulting values. Alternatively, a possible option is an average value of a plurality of APC values to be measured in one servo write track. Still alternatively, an APC measurement value of one servo write track or that being a part of a plurality of servo write tracks may be used.
As such, the reference APC curve is corrected by APC measurement actually performed in the outer radius side area 212. This APC measurement is thus required to be performed with accuracy. However, when the outer radius side area 212 is erased by the external magnetic field, there may be cases that some area closer to the inner radius side area 211 is not erased to a full degree. As such, APC measurement in an area of poor demagnetization state may result in noise mixture to the measured APC value, and vary a track pitch, which is key for accurate APC measurement.
Thus, there is a need to determine whether a measurement area for correction of a reference APC is satisfactorily demagnetized or not. In the APC calibration, the SSTW of this embodiment uses an APC measurement value being an exemplary comparison value to measure the base magnetization state in the area so that the demagnetization state is determined whether to be satisfactory or not. With the satisfactory demagnetization state, based on the reference APC that is newly set, the SSTW performs pattern writing in a row to the outer radius side area 212.
When the demagnetization state is determined as being not satisfactory, the SSTW stops servo write. For example, the HDA I is removed from the servo write control device, and is subjected again to the erase process using the external magnetic field. Alternatively, the SSTW uses the head element section 120 to subject, to self erase, the area including the area of poor demagnetization area. For example, the SSTW uses the head element section 120 to erase the entire surface of the recording surface. Alternatively, any predetermined area in the vicinity of the boundary is subjected to self erase using the head element section 120. Thereafter, the SSTW resumes pattern writing.
Described now is a method of determining the demagnetization state. The amount of change observed in an APC is counted as one preferable criterion for determining whether the demagnetization is satisfactory or not. The APC measurement value varies to some level depending on the track position; but the variation should never be large. Therefore, when the measurement APC value varies to a level exceeding a fixed value, a determination is made that an erroneous reference APC is about to be set.
To be specific, by using the measurement APC value in the inner radius side area 211 as a basis, the SSW controller 22 makes a comparison with the APC value measured in the outer radius side area 212 when the reference APC is set again. When an amount of value change observed in these comparison values is exceeding an allowable reference range, the SSW controller 22 determines that the demagnetization is not satisfactory.
In accordance with the above example, the SSW controller 22 stores the APC average value derived by the APC calibration at the 4800 track. Then, the APC average value acquired in the APC calibration at the 5000 track is compared with the APC average value in storage. When the difference therebetween falls in the reference range, the SSW controller 22 determines that the demagnetization state is satisfactory. Note here that the APC value for use for such a determination is preferably an average value of a plurality of APC values.
This is not restrictive, and as described above by referring to in the description about re-setting of a reference APC, any other APC values may be used such as an average value in one servo write track. Moreover, using an average value of a plurality of APC values is substantially the same as using the sum of the plurality of APC values. This is similarly applicable also to the description below.
Other preferable determination references use variations observed in the APC values. As one specific technique, in the outer radius side area 212, in the APC calibration, a determination is made based on the variations observed in the APC values in a plurality of servo write tracks. As one preferable example, utilized is dispersion of the APC average value for each of the servo write tracks. In the example described by referring to
The SSW controller 22 uses an APC value for each of the sectors in one servo write track to calculate an APC average value of the servo write track. Similarly to each of other servo write tracks, the SSW controller 22 calculates an APC average value. The SSW controller 22 also uses an APC average value for each of the servo write tracks to calculate dispersion that denotes the variations of the resulting values.
The SSW controller 22 has a reference range that is set in advance, and compares the acquired dispersion with this reference range. When the dispersion is in the reference range, the SSW controller 22 determines that the demagnetization state has no problem (satisfactory state). On the other hand, when the dispersion is not in the reference range, the SSW controller 22 determines that the demagnetization is not satisfactory. Note here that, for accurate measurement, it is preferable to calculate dispersion from the larger number of servo write tracks.
Another preferable technique of using the APC value variation is to use the variation observed in the APC values for each of the sectors in one servo write track. In the APC calibration in the outer radius side area 212, the SSW controller 22 performs APC value measurement for each of the sectors in the selected servo write track. The SSW controller 22 calculates the dispersion of each of the APC values for the sectors.
The SSW controller 22 has a reference range that is set in advance, and compares the acquired dispersion with this reference range. When the dispersion is in the reference range, the SSW controller 22 determines that the demagnetization state has no problem (satisfactory state). On the other hand, when the dispersion is not in the reference range, the SSW controller 22 determines that the demagnetization is not satisfactory. Alternatively, the SSW controller 22 may calculate the dispersion for a plurality of the servo write tracks, and using a plurality of dispersions, determine whether the demagnetization state is satisfactory or not.
As such, three determination criteria are described. Preferably, the SSW controller 22 makes a determination about all of these criteria. After such determination making, when at least one determination criterion out of these is not satisfied, the SSW 22 controller determines that the base is in the poor magnetization state. Note here that the SSW controller 22 is not required to use all of the three determination criteria, and may use one or two determination criteria. Alternatively, when the two or three determination criteria are not satisfied, the SSW controller 22 may determine that the demagnetization state is not satisfactory.
In the above description, the dispersion of APC values in the radius direction (APC dispersion in a plurality of servo write tracks) is used separately from the dispersion of APC values in the circumferential direction (APC dispersion in one servo track). This is not restrictive, and these may be used together. That is, the SSW controller 22 performs APC value measurement for each of the sectors in a plurality of servo write tracks, and calculates the dispersion of the APC values being the measurement results. Utilizing such dispersion, the demagnetization state may be determined as being not satisfactory. Note here that, as a value denoting variation of APC values, a function other than the dispersion may be used.
As such, the present invention is described with exemplary embodiments, but the present invention is not restrictive to the above-described embodiments. Those skilled in the art can devise modifications, additions, and variations for the components of the above-described embodiment without departing from the scope of the present invention with ease. For example, a servo write control function can be provided to a control circuit of an HDD. The determination about the base demagnetization state may be used not only to SSW but also to determine which area to be self-erased in the development stage for HDDs, for example. The re-setting of the reference APC or the determination about the base demagnetization state may not be performed in the APC calibration but may be executed as other independent sequences.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-122744 | Apr 2006 | JP | national |
