CN1317692C - Embedded servo-type disc writing operating method - Google Patents

Embedded servo-type disc writing operating method Download PDF

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Publication number
CN1317692C
CN1317692C CNB03126719XA CN03126719A CN1317692C CN 1317692 C CN1317692 C CN 1317692C CN B03126719X A CNB03126719X A CN B03126719XA CN 03126719 A CN03126719 A CN 03126719A CN 1317692 C CN1317692 C CN 1317692C
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disk
track
servo
magnetic track
virtual
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CN1553433A (en
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诺雷丁·克米齐
布鲁斯·伊莫
约翰·史概尔
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Shenzhen Excelstor Technology Co Ltd
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Shenzhen Excelstor Technology Co Ltd
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Abstract

The present invention relates to an embedded servo type magnetic disc writing operating method. Before a magnetic disc is installed on a central driving shaft, the servo information of the magnetic disc is already written in advance. Then, the magnetic disc is installed on the central driving shaft, and a series of concentric virtual magnetic tracks is defined according to servo magnetic tracks written in advance. When a drive is operated, the concentric virtual magnetic tracks can reduce the action amplitude of an actuator and increase the acceptable tolerance of position deviation. The writing operation in advance of the servo information of the magnetic disc can improve the running efficiency of the magnetic disc drive and can also reduce the pressure to an absolutely dust-free chamber.

Description

Embedded servo disk write operation method
[technical field]
The present invention is about a kind of servo disk write operation method, particularly a kind of embedded servo disk write operation method.
[background technology]
Hard disk drive is a kind of magnetic data memory storage, the data that the user creates can be carried out read-write operation.Typical hard disk drive comprises one or more disks, and disk can be around central shaft with high angular velocity (typical angular velocity is 3600rpm) rotation.Actuator arm is W head and is radially positioned at magnetic disk surface, and W head can be encoded to the data on the disc.Under desirable working environment, W head writes data that to form width be 2.5 microns narrow annular magnetic track, and this magnetic track is concentric with central shaft.Yet, in the operating process of disc driver, machinery concussion, bang and temperature variation all can cause the crooked of indivedual disks or depart from rotary middle spindle, if above situation takes place, and the actuator arm device will be positioned on the magnetic track by W head, still operate under the concentric with first front disk and central shaft, will can correctly not carry out for the read/write of data this moment.When disk its corresponding position of slipping away, will produce the new annular trace that a track with the magnetic track that had before write has overlapping.This concentric displacement is referred to as " position deviation ", when it takes place, W head wants the deviation of continuous trace location in order to avoid the new write operation of W head can cover the data that before write, briefly, if there is not existing additional information that read/write head is directed to correct track exactly on the disk, the accurate location of W head can't be realized.Realize accurate location, must the correction position deviation.It is servo-information that this additional information refers to impel servo control mechanism location in the driver element and the information of accurately locating, and it writes hard disk drive in advance before user data writes and after the driver element assembling.
About 1970, Winchester technology was released the Fixed disk that has the embedded servo system greatly.In the clean room of drive manufacturers, disk is assembled, disk is installed on the central shaft, magnetic head is installed on the driver, whole driver comprises the servo track Writing device interior, required servo-information is write by the W head of driver self, requirement to degree of accuracy is very high, and for example, the operation of write head must be to be realized by laser interferometry or the identical method of other degree of accuracy.As United States Patent (USP) the 5th, 315, provide a kind of method that makes up the servo track Writing device No. 372, this method is to utilize laser interferometry that one servo track registration arm is located.
Usually, the embedded servo data comprise a data field, and this data field is to define magnetic track; One servo bursts, the effect of this train of impulses are the reference positions of correctly arranging magnetic track; And some other zone, be used for read/write and system operation.The function of present W head by separately independently element realize that they require the difference that puts in order of read/write.United States Patent (USP) the 5th, 946 provides a kind of method that writes down the continuous servo pulse row of circumference for No. 157, and this spike train overlaps each other, and allows magnetoresistance to read head position in the linear width of a spike train.In addition, the accuracy of the write head of hard disk drive also requires to use " pusher locking device " to obtain needed degree of accuracy.In this, United States Patent (USP) the 5th, 774 provides a kind of synthetic method that has the pusher locking device of adjuster for No. 294, and the effect of this adjuster is to reduce when writing servo data, the erroneous effects that is produced by the sympathetic response of pusher locking device.
The user data fields of embedded servo data field and adjacent concentricity magnetic track is arranged in radial wedge-shaped sectors.For guaranteeing to meet the requirements of degree of accuracy, writing of servo data is excircle along disk, writes a clock magnetic track earlier.The magnetic conversion that writes clock track is divided into predetermined a few part with disk, and write and the writing of clock track information of servo-information are synchronous, and servo wedge area is to be determined by the angle that clock track produces.In this, United States Patent (USP) the 5th, 796 provides a kind of method of writing clock track No. 541, and this clock track is independently, and irrelevant with the speed of central shaft.
At present, the effect of servo track be the seventies the same, servo control mechanism is as much as possible near by the servo track write.The servo-drive system of standard can be eliminated about 90% the track error that is run into.Excessive if misplace, driver is subjected to machinery concussion or temperature change, and the position deviation compensator will be got rid of nearly 90% mistake.United States Patent (USP) the 5th, 539 provides a kind of method of design one position deviation compensator for No. 714, and this compensator can provide online real-Time Compensation to the disk dislocation.According to this method, the rule rotation of centrifugal magnetic track (magnetic track of dislocation promptly takes place) produces the one-period signal, and the hamonic function of this signal is indicated by the magnetic track eccentricity.In the swing circle of predefined disk, compensator has compiled a certain harmonic constant of giving the signal of determined number.The compensation of these coefficients or Fourier is used for to the W head actuator signal that affords redress.At United States Patent (USP) the 5th, 930, in 067, a kind of multiple-harmonic compensation method that is used for trajectory track is provided, this method on principle with United States Patent (USP) the 5th, 539, No. 714 very close, and but, the harmonic compensation of high-order has improved the degree of accuracy of compensation thereby the latter has designed more.
Whether integrated compensator in disc driver no matter, the write operation of servo-information all be a loss greatly and extremely time taking process.Be about 20 in track density, 000TPI (magnetic track/inch), data capacity are about in 2.5 cun disks of 10GB (GB), and the time of writing servo information is approximately one hour.The complicacy of above patented technology of quoting and design makes the cost of servo track recorder writing servo information on disk very high, greatly between 50,000 to 250,000 dollars.In a word, servo recorder is very expensive device, and the handling capacity of its operation is very low, and this action need carries out in a clean dustless environment, and very difficult automation mechanized operation, needs the operator that suitable level professional technology is arranged.
[summary of the invention]
The invention provides a kind of embedded disk servo information write operation method.After having had servo-information on the disk, they just are installed to and drive on the central shaft, and W head and actuating device also can be worked.This method has reduced the device operation greatly and has reduced requirement to the space cleanliness.In addition, with respect to the present employed servo track recorder that is installed on the magnetic head, this magnetic disk servo magnetic track recorder that is not installed in the driver is a simpler and cheaper mechanical hook-up of price.This recorder is relatively easy a maintenance and the automatic device of operating of suitable disk.Not hard to imagine, this recorder can move automatically, work in 24 hours of no worker monitor.The magnetic disk servo magnetic track recorder that is not installed in the driver of an excellent in design can also be inscribed a folded disk simultaneously at a high speed.
Therefore, first purpose of the present invention is to realize under the pinpoint prerequisite of data track need not to sacrifice data capacity, simplifies and improve the efficient of servo data imprinting, and reduces the imprinting expense.
Second purpose of the present invention provides a kind of method with servo data guiding read/write data magnetic track, and it is static that this method allows the actuating magnetic head of standard configuration, rather than follows the trail of the rotating centrifugal track that has position deviation through regular meeting.
Two purposes of the present invention are to realize by following technical scheme: the present invention need introduce in a new notion " virtual magnetic track ", and its definition is the magnetic track of being followed by W head, and this magnetic track is not the track of the storage data of reality on the disk.Virtual magnetic track is that the rotating shaft with actual disk is the imaginary annular trace in center, arranges and memory address definition " virtual " this notion of writing servo information pattern intersection point in advance by magnetic track.Because the concentric virtual magnetic track of rotation is the constant characteristic that disk has been installed, they can allow servo data to write another servo track recorder unit.Because servo data is used for the defining virtual magnetic track at first, activate magnetic head the sleep mode terminal check its degree of accuracy.
The address that is used for the defining virtual magnetic track can be understood as and comprises array a: XXX.yyy, and wherein, XXX represents the servo identified code that writes in advance of particular track, and yyy represents the position deviation of intersection point, and this intersection point comes from institute's canned data in the servo pulse row.Because virtual magnetic track can guide W head, W head also can need not to follow the trail of the magnetic track of dislocation.The normal condition of magnetic-head actuator is static, follows the trail of virtual magnetic track by the next track address of loading and look for storage sequence.In fact, the stationary state of actuator is the standard of measurement of virtual magnetic track premium properties.
At first, a virtual magnetic track is respectively internal diameter (ID) part, middle footpath (MD) part and external diameter (OD) part by three radial component definition on the disk.These all are by locking a magnetic track that writes in advance and utilizing the position deviation compensator to decide the humorous wave component of position deviation motion to realize.Intermediate quantity is produced by linear interpolation method.
Compared with prior art, advantage of the present invention not only is embodied in the process of disk being inscribed servo-information, also is embodied in to install in the operation of back to driver.Just as mentioned above, the process of inscribing servo-information has been simplified, and can carry out automatically, and required servo track CD writer is than employed usually cheap a lot of now.In the course of normal operation to driver, the configuration of actuator is to reduce action as far as possible, rather than often follows the trail of the position deviation of physical track.The static state of standard means that actuator is subjected to minimum external force and acceleration, utilizes the inertia of mechanism to minimize the deviation of track.In a word, driver is to be limited by its optimum trajectory.Minimize trajector deviation and mainly be to follow track often, effectively reduce and to accept misalignment tolerances, thereby deviation leaves bigger deviation surplus in system with offset deviation.
[description of drawings]
With reference to the accompanying drawings, in conjunction with the embodiments the present invention is further described.
Fig. 1 is the typical disk vertical view of installing with the inventive method.
Fig. 2 is the workflow diagram of the hard disk drive assembling of employing usually.
Fig. 3 adopts the inventive method that the workflow diagram of magnetic head assembly is installed.
Fig. 4 is the Bode diagram of first, second and third harmonic crest of open-loop transfer function.
[embodiment]
The present invention relates to a kind of embedded servo disk write operation method.The servo-information of this disk is finished writing in advance, disk is installed to define a series of " virtual magnetic tracks " with one heart on the driving central shaft and on disk to be used for tracking and tracking subsequently.The concentric effect of virtual magnetic track and the rotary middle spindle of disk is put unlike the prior art and is can keep the magnetic head actuating device to be in still-mode when driver is operated, and in the prior art, after disk is installed on the driver, magnetic head and actuating device can constantly be followed the trail of the magnetic track deviation that produces when the servo data write operation, this magnetic track deviation be the change owing to the central shaft position cause or since the mechanical motion (for example carrying mistake, vibrations) during write operation and the non-annular that causes write and caused.The present invention has not only simplified the process of servo data write operation, has reduced the cost of servo data write operation, and has improved the tracking ability of hard disk drive.
Seeing also Fig. 1, is the vertical view that adopts the typical disk 10 of the inventive method installation.Servo-information at initialization servo data write operation stage disk central shaft 11 is positioned at magnetic disk servo magnetic track recorder.A plurality of typical servo tracks 12 are concentric annulus with this turning axle.In the disk of reality, write above 20000 such magnetic tracks.These servo tracks that write in advance are " physical track " hereinafter referred to as.Also demonstrated a plurality of embedded servo sectors 13 that typically comprise magnetic track definition information among Fig. 1, this sector and servo clock magnetic track form synchronously.There are 30 to 120 embedded servo sectors 8 sectors of only having drawn among Fig. 1 in actual disk.When disk being installed on the final disc driver, suppose that disk has obtained a new turning axle 14, this causes because of lack accurate adjustment capability in the track pitch program.In this new construction, use the inventive method and formed a series of new magnetic tracks, be called " virtual magnetic track ", it is donut with respect to new turning axle.The so virtual magnetic track 15 that only drawn among the figure, but the quantity of the quantity of virtual magnetic track 15 and physical track equates, and the quantity of per inch magnetic track (TPI) also equates.Virtual magnetic track with finish writing in advance but the servo pulse row 16a-16f that departs from the physical track of rotation center has formed a plurality of point of crossing, these point of crossing form unique address array, the form of each array is XXX.yyy.The track of virtual track address is to be the annulus at center with new turning axle 14.
Consult Fig. 2, the process flow diagram of the hard disk drive installation procedure that adopts for prior art.Although the manufacturer of disk will survey formula disk 20, the disk manufacturer can't carry out servo write operation to disk.Magnetic head assembling 21, disk installs 22, and the servo write operation 23 of disk and the steps such as encapsulation 24 of driver all are to finish in the clean room of drive manufacturers.In the outside of clean room, driver element is installed on the printed circuit board (PCB) (PCB) 25, test again 26 and the encapsulation.
Fig. 3 be adopt the inventive method to magnetic head assembly install workflow diagram.Disc drive manufacturers is tested disk 30 in its dust free room.Disc drive manufacturers or drive manufacturers are carried out servo write operation to disk earlier now, produce a free disk or a plurality of disk pack unit that is stacked 31.
Next the magnetic head assembly package program continues installing mechanism and magnetic head 32 with method well known in the prior art in the clean room of drive manufacturers, and disk 33 and the whole magnetic head assembly 34 of encapsulation finished writing in advance are installed, and withdraws from clean room then.Carry out the installation 35 of printed circuit board (PCB) (PCB) and the test 36 of device again.At last test phase, virtual magnetic track has been calibrated and defined to disk.Compare with whole test durations (needing some hrs) of device, the time that this program takies is very short, about about 1 minute.
Fundamental purpose of the present invention is that the tracking process is transformed into virtual field from physical field, and like this, magnetic head assembly is followed the tracks of is virtual magnetic track rather than the physical track finished writing in advance.Generally speaking, after disk is installed on the central shaft, can keep the position deviation of 0 to 200 inter-track.As the part of device to test program, the task of this calibration procedure is to use from the information of physical track position deviation acquisition comes the defining virtual magnetic track.Here with reference to William Messner and Marc Bodson " internal schema principle " (IMP) (" Design of Adaptive Feedforward Algorithms Using Internal ModelEquivalence; " International Journal of Adaptive Control and SignalProcessing, Vol.9,119-212 (1995)) method, in the present invention, the position deviation compensator is (with reference to United States Patent (USP) the 5th, 539, No. 714 and United States Patent (USP) the 5th, 930, No. 067) promptly use this principle.The harmonic wave that this compensator can obtain to be offset (the first, the second and third harmonic, or more) content.This IPM transfer function to the expression mode of each harmonic wave is As s=± j ω 0The time, the value of this formula is infinitely great.Fig. 4 is that first, second and third harmonic crest of open-loop transfer function is 70Hz in frequency, the Bode diagram of 140Hz relative not penalty function during with 210Hz.
Details are as follows for the step of calibration procedure:
1. enter magnetic track internal diameter (ID) part and will write the magnetic track locking.
2. enable position deviation compensator
3. position error signal is defined as in the position deviation compensator:
PES=PES (physical)+1F(t)
Wherein, 1F (t) is a first harmonic offset penalty function (being similar to the sinusoidal curve of known amplitude and phase place).
4. multiplicative model to the Virtualization Mode conversion formula is:
PES=PES (physical)-k 1(n)cos(ω rt)-k 2(n)sin(ω rt)
Wherein, ω rBe rotational frequency; T is the time;
Constant k 1And k 2The calculation formula be:
k 1(n)=k 1(n-1)+ε1F(t)sin(ω rt)
k 2(n)=k 2(n-1)+ε1F(t)cos(ω rt)
Wherein, n is the track number of disk, and conversion ratio ε is the less constant of a numerical value, and choosing of its numerical value can guarantee from the level and smooth conversion of physical track pattern to virtual magnetic track pattern.k 1And k 2The corresponding same virtual magnetic track of numerical value, the circular track that servo tracking increases, when magnetic track becomes when circular completely, the value of function 1F (t) is reduced to 0.
5. be positioned at now under the virtual magnetic track pattern, at this moment, position signalling is defined as:
PES (virtual)=PES (physical)-k 1sin(ω rt)-k 2cos(ω rt)
6. identical method also is applicable to high-order harmonic wave.
7. actuator moves to the next position (path portion in the disk (MD)), repeats for the 1st to 7 step.
8. transfer arm moves to disk outer radius portion (OD), and above program repeats once again.
9. use linear interpolation legal system one form, determine the k of all magnetic tracks 1And k 2Value.This table is stored in the Nonvolatile storage array.
10. drive and be transformed into virtual magnetic track field, and other each objects do not change." be transformed into virtual magnetic track field " in the present invention the meaning is that " physics " magnetic track 12 (as shown in Figure 1) with unique address that magnetic track defines during no longer by servo write operation defines, but by calculating the annulus around real turning axle rotation of intercept definition with the servo pulse row point of crossing of finishing writing in advance (16a-16h among Fig. 1).The form of each intercept is reduced to the combination of a track address (XXX) and a magnetic track deviate (yyy), and still, previous track address is always identical, and the magnetic track deviate is position error signal (PES).Must use physical track when the magnetic head width is calibrated in test procedure with position deviation compensation.
Details are as follows for tracking pattern (navigating to goal track from current given virtual track location): the tracking pattern, each distance is that position rub-out signal (PES) all is reference object magnetic track definition, and draws velocity across (speed of the best of using in the tracking stage and the tabulation of acceleration) based on this signal.
The strict difinition of goal track distance is as follows relatively:
PES (goal track distance relatively)=(virtual target magnetic track)-(virtual current track).
Wherein, virtual magnetic track definition is the same:
PES (virtual)=PES (physical)-k 1sin(ω rt)-k 2cos(ω rt)
Because it is very little that the sine function of current track is compared with distance, be the effective processing time because of what calculate use again, we will think apart from approximate:
PES (goal track is apart from distance relatively)=(virtual target magnetic track)-(physics current track).
Just
PES (goal track distance relatively)=PES (virtual target magnetic track)-PES (physics current track)
Or
PES (goal track distance relatively)=PES (physical target disk)-k 1Sin (ω rT)-k 2Cos (ω rT)-PES (physics is worked as front disk)
The slope of physical track and virtual magnetic track is identical, so need not different slopes is revised.

Claims (7)

1. embedded servo disk write operation method, it is characterized in that: the servo-information of disk had been write on servo physical track be installed to the driving central shaft of hard disk at disk before in advance, after being installed to disk on the driving central shaft, define concentric " the virtual magnetic track " of a series of rotations according to the servo physical track of finishing writing in advance, this method comprises:
(1) provides a hard disk drive;
(2) this disk is installed on the servo track Writing device, this Writing device carries out write operation to servo track;
(3) writing servo information forms servo physical track on this disk;
(4) disk that this servo-information is finished writing is sent on the hard disk drive that comprises a central shaft, a W head, a magnetic head actuating device and a position deviation compensator;
(5) this disk is installed on the central shaft of this drive unit;
(6) be assembled on the printed circuit board (PCB) with this hard disk drive encapsulation, and with it;
(7) test this hard disk drive;
At this test phase, the a series of virtual magnetic tracks of definition on this disk, this virtual magnetic track defines according to the point of crossing in the actual cycle path of this servo physical track of finishing writing in advance and this read/write head, and this point of crossing is to obtain by a calibration procedure, and this program comprises:
(a) select a plurality of different radial positions on this disk, at first enter the magnetic track inner-diameter portion whose and will write the magnetic track locking;
(b) the servo physical track that will finish writing is latched into corresponding radial position place;
(c) enable position deviation compensator;
(d) compensator obtains a position error signal;
(e) selected one guarantee from physical track to the smoothly stable conversion coefficient of changing of virtual magnetic track;
(f) the record harmonic constant can obtain a large amount of harmonic waves according to harmonic constant;
(g) in virtual magnetic track scope to virtual magnetic track definition position deviation signal;
(h) detent moves to the next position, and promptly path portion in the disk repeats (b)-(g) step;
(i) transfer arm moves to the disk outer radius portion, repeats (b)-(g) step again;
(j) use linear interpolation to set up a chart, defined every other virtual magnetic track in the table;
(k) this table is stored in the Nonvolatile storage array;
(8) the disk drive mode is transformed under the virtual magnetic track pattern.
2. embedded servo disk write operation method as claimed in claim 1 is characterized in that: a plurality of radial positions on the disk are the inner-diameter portion whose by disk, and middle path portion and outer radius portion are formed.
3. embedded servo disk write operation method as claimed in claim 1 is characterized in that: this chart is to use linear interpolation to draw according to the harmonic constant of a plurality of radial positions acquisitions of disk.
4. embedded servo disk write operation method as claimed in claim 1 is characterized in that: the position deviation compensator produces high-order harmonic wave, and high-order harmonic wave can make virtual magnetic track obtain higher accuracy.
5. embedded servo disk write operation method as claimed in claim 1, it is characterized in that: in virtual magnetic track, further comprise a tracking pattern, it is goal track that this pattern is positioned at tracked virtual magnetic track, this virtual target track location that to be sought according to the position calculation of current virtual magnetic track and the distance of current virtual track location, the position error signal of this position error signal, physics current track and their sine function and determine apart from foundation physical target magnetic track.
6. embedded servo disk write operation method as claimed in claim 1 is characterized in that: this disk drive can carry out operations such as read/write and magnetic track tracking to several disks that are installed on this driver.
7. embedded servo disk write operation method as claimed in claim 6 is characterized in that: these several disks all pass through similarly calibration, and each disk all has the virtual magnetic track of oneself.
CNB03126719XA 2003-05-26 2003-05-26 Embedded servo-type disc writing operating method Expired - Fee Related CN1317692C (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5124987A (en) * 1990-04-16 1992-06-23 Storage Technology Corporation Logical track write scheduling system for a parallel disk drive array data storage subsystem
CN1167982A (en) * 1996-06-10 1997-12-17 富士通株式会社 Head position control for disk drive which performs recording about rotational center even if recorded servo information is eccentric
US5926336A (en) * 1996-09-13 1999-07-20 Samsung Electronics Co., Ltd. Method and apparatus for rewriting servo information on a disk in a hard disk assembly
US6411459B1 (en) * 1999-02-22 2002-06-25 Seagate Technology Llc Advanced servo writing method for hard disc drives
US6549360B1 (en) * 1998-05-19 2003-04-15 Seagate Technology Llc Magnetic recording medium with laser-formed servo-marks

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5124987A (en) * 1990-04-16 1992-06-23 Storage Technology Corporation Logical track write scheduling system for a parallel disk drive array data storage subsystem
CN1167982A (en) * 1996-06-10 1997-12-17 富士通株式会社 Head position control for disk drive which performs recording about rotational center even if recorded servo information is eccentric
US5926336A (en) * 1996-09-13 1999-07-20 Samsung Electronics Co., Ltd. Method and apparatus for rewriting servo information on a disk in a hard disk assembly
US6549360B1 (en) * 1998-05-19 2003-04-15 Seagate Technology Llc Magnetic recording medium with laser-formed servo-marks
US6411459B1 (en) * 1999-02-22 2002-06-25 Seagate Technology Llc Advanced servo writing method for hard disc drives

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