CN100520917C - Media drive and control method for the same - Google Patents

Abstract

Embodiments in accordance with the present invention relate to improving error recovery process performance. A head slider in an embodiment of this invention includes a heater for adjusting a clearance between a head element section and a magnetic disk. During an error recovery process (ERP) for a reading error, if a particular environmental temperature is in a low-temperature region, a microprocessing unit (MPU) executes the ERP steps of increasing a heater power value of the heater (i.e., STEP X to STEP X+2), preferentially over the ERP steps of reducing the heater power (i.e., STEP X+3 to STEP X+5). In the low-temperature region, the possibility of error recovery in an earlier step can be raised by executing the heater power increasing ERP steps earlier than the heater power reducing ERP steps.

Description

Media drive and control method thereof

Technical field

The present invention relates to media drive and control the method for this media drive, relate more specifically to have the well heater control of the media drive of well heater, this well heater is used to adjust the gap between head element part and the recording medium.

Background technology

Be known in the art use all kinds medium device for example CD, tape and semiconductor memory as data storage device.In the middle of them, it is one of requisite memory storages of computer nowadays system to such degree so that they generally that hard disk drive (hereinafter being called HDD) becomes as the memory storage of computing machine.In addition, be not limited to aforesaid computing machine, HDD is more and more extended on using.For example, HDD is used for mobile picture record/transcriber, auto-navigation system, cell phone and is used in the removable memory of digital camera.

The disk that uses among the HDD has a plurality of data tracks that form with one heart.Write down many groups servo data and a plurality of data sector on each data track, each group servo data comprises address information, and each of a plurality of data sector comprises user data area.Between each group servo data, write down a more than data sector.The head element part of the head slider that the actuator that is waved supports can visit the expected data sector according to the address information of this servo data, therefore writes user data or read user data from this data sector on this data sector.

In order to improve the recording density of disk, importantly reduce disk and the gap between the head element part of floating on the surface of disk.In order to realize that this reduces, several mechanisms in this gap have been proposed to adjust.One of this mechanism is, by the head slider with well heater being provided and utilizing this heater heats head slider with adjusting play (for example referring to Patent Document 1).Hereinafter, this method is called as TFC (hot flying height control).In TFC, electric current is provided for well heater with the generation heat, and passes through the thermal expansion of this well heater, makes head element part 12 outstanding.Therefore can reduce the gap between disk and the head element part.

[patent documentation 1]

The Jap.P. spy number of opening 05-20635

Summary of the invention

The problem that invention solves

If during the inter-process of HDD, make a mistake, HDD execution error rejuvenation (ERP) so.HDD has several ERP, as is used for reading from disk the ERP of the read procedure of user data, is used for the ERP of the process of writing on the disk that user data is write on, and the ERP that is used for reading from disk the process of microcode.Each ERP comprises a plurality of ERP steps that are used to revise circuit parameter and target location.HDD realizes wrong the recovery by carrying out each ERP step, and ERP finishes from the step that mistake is recovered at HDD.

Importantly may realize wrong recovery and shorten the required processing time in the step the earliest among the ERP.Delay during mistake is recovered reduces performance.In addition, if the processing time is oversize, main frame will judge that HDD can not be accessed so, and the result will be disconnected as time-out error (overtime) to the connection of HDD.Therefore require to carry out suitable ERP step, and carry out each ERP step with suitable order.

About HDD, importantly suppress the instability of magnetic head performance.Instability shows as the variation in the read signal waveform of reading component.More particularly, instable damage increases the read signal noise, for example, causes the plus or minus amplitude of read signal to increase significantly and becomes asymmetric.These incidents hinder accurately reading of servo data or user data.This is the fact that does not have one-domain structure and partly comprise little magnetic domain owing to the free layer in the reading component, and little magnetic domain demonstrates and is different from other regional magnetic properties that form this layer.

Therefore, the asymmetric factor by the magnetic bias that applies such as the inadequate magnetic bias of biasing layer or from the hard bias layer in the formation of free layer both sides causes instable damage.Even when instability in the fabrication phase of HDD process does not show, if but in the fabrication phase process, forming the biasing layer by halves, Electrostatic Discharge, disk contact or other incidents will be damaged product delivery instability afterwards so.Therefore it is important suppressing instability when using HDD.

The method of dealing with problems

Media drive comprises: the slider that floats on the medium of rotation according to an embodiment of the invention; Be arranged in the head element part in the described slider; Be arranged in the well heater in the described slider, wherein said well heater impels described head element part outstanding and regulate gap between described medium and the head element part by thermal expansion; Store the storer of table, show to discern execution in step at this wrong error recovery procedure (ERP) by this when mistake takes place, described table comprises the step of the heater power that changes described well heater; Controller is used to carry out the execution control by the execution in step of described table identification; And Temperature Detector.Wherein, according to utilizing the detected temperature of described Temperature Detector, described driver changes the execution priority of the heater power change step in error recovery procedure (ERP).

Preferably, be used for the error recovery procedure (ERP) of read error,, should table identification increasing the step of heater power so as execution in step if be lower than reference temperature by the detected temperature of Temperature Detector.Therefore can improve the wrong reliability of recovering.In addition, the step that this table is preferably discerned the step of increase heater power and reduced heater power is as execution in step, and the execution priority that increases the step of heater power, preferably is higher than the execution priority of the step that reduces heater power.Therefore can carry out mistake earlier recovers.

Preferably, be used for the error recovery procedure (ERP) of read error, if be higher than reference temperature by the detected temperature of Temperature Detector, this table identification reduces the step of heater power as execution in step so.Therefore can increase the wrong reliability of recovering.

Preferably, the step that the identification of this table increases the step of heater power and reduces heater power is as execution in step, and the execution priority that reduces the step of heater power preferably is higher than the execution priority of the step that increases heater power.Therefore can carry out mistake earlier recovers.

Preferably change the heater power of carrying out in the error recovery procedure (ERP) and change step according to type of error.Therefore can increase the wrong reliability of recovering.

In addition, be used for writing in the media the error recovery procedure (ERP) of the write error during the data, this table preferably discern reduce heater power step as execution in step.Therefore can increase the wrong reliability of recovering.

In addition, its servo data read signal level is lower than the error recovery procedure (ERP) of the mistake of datum during being used for writing processing procedure, and this table preferably sign increases the step of heater power as execution in step.Therefore can increase the wrong reliability of recovering.In addition, preferably determine heater power in the execution in step according to servo data read signal level.Therefore can come control heater according to the specific flying height of magnetic head.

This table preferably is used for changing the write current waveform so that the magnetic field intensity that reduces to produce, and be used for increasing heater power with compensation since the calorific capacity that wave form varies was caused reduce.The instable error recovery procedure (ERP) that therefore can be suitable for head element part.

This controller preferably is configured the instability of judging head element part and whether surpasses reference value, if judge above reference value, promotes the execution priority rank of the step that changes heater power so.Therefore, can realize the recovery early of the mistake from instable distress condition.In addition, the execution priority that preferably heater power reduced step of this controller promotes to being higher than heater power and increases the rank of the execution priority of step.Therefore, can realize recovery as early as possible, be used to increase the instable heater power of common damage from mistake.

Another embodiment of the present invention is a kind of method that is used to control media drive, this media drive comprises: the slider that floats on the medium of rotation, be arranged in the head element part in the described slider, and be arranged in well heater in the described slider, described well heater makes described head element part outstanding by thermal expansion, and regulates the gap between described medium and the head element part.This control method comprises: when mistake takes place, then with reference to the table that is used for discerning at the execution in step of this wrong error recovery procedure (ERP); And in described error recovery procedure (ERP), carry out step, the feasible heater power that changes described well heater by described table identification.Wherein, according to detected temperature, the heater power that change will be carried out in described error recovery procedure (ERP) changes the execution priority of step.

The effect of invention

According to the present invention, can improve the mistake that error recovery procedure (ERP) in the media drive maybe can suppress wherein and take place.

Description of drawings

Fig. 1 schematically shows the block diagram of the general structure of HDD according to a preferred embodiment of the present invention.

Fig. 2 shows the sectional view tool of the head slider structure of the well heater that is useful on TFC in the present embodiment.

Fig. 3 schematically shows the block diagram of logical organization, among this logical organization and this embodiment to read ERP relevant.

Fig. 4 is the view that schematically shows the example of reading ERP table, and it is relevant with normal temperature district among this embodiment that this reads the ERP table.

Fig. 5 is the view that schematically shows the example of reading the ERP table, and it is relevant with the low-temperature space in the present embodiment that this reads the ERP table.

Fig. 6 schematically shows the view that the example of ERP table is read in high-temperature region among the embodiment.

Fig. 7 be schematically show with this embodiment in the block diagram of writing the relevant logical organization of ERP.

Fig. 8 is the view that schematically shows the example of writing the ERP table of ' based on the termination of writing of the speed ' mistake that is used for this embodiment.

Fig. 9 is the view that schematically shows the example of writing the ERP table of ' the servo VGA ends ' mistake that is used for this embodiment.

Figure 10 is the topology view that schematically shows the magnetoresistive element among this embodiment.

Figure 11 (a) and 11 (b) show because the curve map of the damage that the instability of TFC causes.

Figure 12 is the view that schematically shows the write current waveform among this embodiment.

Figure 13 (a) and 13 (b) are the views that schematically shows the data layout of the servo figure among this embodiment.

Figure 14 shows the curve map of the performance quantity of the read signal waveform that is used for the instability judgement.

Embodiment

To describe below and can use embodiments of the invention.Clear for what describe, following description and accompanying drawing are omitted as one sees fit and are simplified.In addition, in each figure, identical reference number is assigned to identical composed component, and clear for what describe, omits the description that repeats as required.

One of characteristics factor of present embodiment is the TFC (the floating highly control of heat) that is used for the error recovery procedure (ERP) of media drive.TFC regulates the gap between head element part and the recording disc by means of the thermal expansion that is caused by the heat that produces on the slider.Hereinafter, will take hard disk drive (HDD) to describe embodiments of the invention as the example of media drive.For the ease of the understanding of the These characteristics of present embodiment, will at first summarize the general structure of HDD below.

Fig. 1 schematically shows the block diagram according to the general structure of the HDD 1 of present embodiment.As shown in Figure 1, HDD 1 is included in comprising in the shell 10 of gas-tight seal: disk 11 is examples of recording disc; Head slider 12; Arm electronic equipment (AE) 13; Spindle drive motor (SPM) 14; Voice coil motor (VCM) 15, and actuator 16.

HDD 1 also has the circuit board 20 that is fixed to shell 10 outsides.On circuit board 20, be furnished with: read/write channel (R/W passage) 21, electric-motor drive unit 22, comprise the hard disk controller (HDC) of combination and the integrated circuit 23 of microprocessing unit (MPU) (HDC/MPU 23 hereinafter), RAM 24 and other IC.The element of each circuit can be integrated among the IC or be installed among the IC of a plurality of separation.User data from external host 51 is received by HDC/MPU 23, is written on the disk 11 by head slider 12 via R/W passage 21 and AE 13 then.Therefore, the user data that is stored on the disk 11 is read by head slider 12, and exports these user data to external host 51 via AE 13 and R/W passage 21 from HDC/MPU 23.

Disk 11 is fixed to SPM 14.SPM 14 is with required angular velocity spinning disk 11.Electric-motor drive unit 22 drives SPM 14 according to the control data from HDC/MPU 23.Disk 11 in this example has the data recording surface on two sides, and with the form that is associated with this record surface head slider 12 is set.Each head slider 12 comprises the slider part of floating along the surface of disk on disk, and head element part, and it is fixed to this slider part, and changes between magnetic signal and electric signal.Head slider 12 in the present embodiment has by heating and impels head element part outstanding and carry out TFC to regulate the well heater in the gap (flying height) between head element part and the disk.To describe the structure of head slider 12 with reference to figure 2 in detail after a while.

Each head slider 12 is fixed to the front end of actuator 16.Actuator 16 is coupled to VCM 15, and pivots around rotating shaft, with the moving head slider 12 that makes progress in the footpath of spinning disk 11 on the surface of disk.Electric-motor drive unit 22 drives VCM 15 according to the control data (being called DACOUT) from HDC/MPU 23.The number of disk 11 can be one or more, and can form record surface on the one or both sides of disk 11.

AE 13 selects a head element part 12 from a plurality of head element part 12, with visit disk 11, amplifies the read signal that is reproduced by selected head element part 12 with certain gain stage then, and sends this read signal to R/W passage 21.Same, be sent to selected head element part 12 from the tracer signal of R/W passage 21.In addition, AE 13 provides electric current (electric power) to well heater, and is used as regulating circuit so that the magnitude of current that is provided to be provided.

Receive during reading processing procedure after the read signal that AE 13 provides, R/W passage 21 amplifies this read signal, so that obtain constant amplitude.In addition, R/W passage 21 extracts data and these data of decoding from the read signal that obtains.The data of reading after decoded comprise user data and servo data.The user data and the servo data of decoding are provided for HDC/MPU 23.In addition, during writing processing procedure, R/W passage 21 is in the enterprising line code modulation of the write data that provides from HDC/MPU 23, and the write data with this code modulated further changes write signal into then, and provides this write signal to AE 13.

MPU among the HDC/MPU 23 is according to the microcode work that is loaded among the RAM 24.When HDD 1 starts working,, load the data that are used to control and be used for the data processing needs from disk 11 or ROM (not shown) except that the microcode of operating on the MPU.HDC/MPU 23 carries out the essential process relevant with data processing and is used for the overall control of HDD 1, as the positioning control based on servosignal (servocontrol), interface control, the defect management of read/write processes control, command execution priority management, head element part 12 and the ERP that is used for recovering from mistake HDD 1.HDC/MPU 23 also carries out the overall control of HDD 1.Particularly, the TFC among the 23 execution ERP of the HDC/MPU in the present embodiment.To TFC among the ERP will be described at this after a while.

Next, the structure of the TFC head slider 12 in the present embodiment is described below.Fig. 2 shows near the sectional view of the part-structure of the head slider 12 its air outflow edge (tail-lateral edges).Disk 11 rotates towards the right side from the left side of Fig. 2.Head slider 12 has head element part 122 and supports the slider part 123 of this head element part 122.The HDD that TFC in the present embodiment can be applied to adopting the HDD of perpendicular magnetic recording and adopt longitudinal magnetic recording.

Head element part 122 is carried out the magnetic data read/write processes on disk 11.This head element part 122 has the reading component 32 and the writing component 31 of the tail side that is positioned at head element part 122.Writing component 31 is sensing elements, and it flows through the electric current of writing coil block 311 and produce magnetic field between pole piece 312 by use, and writes down magnetic data thus on disk 11.Reading component 32 is magnetic resistance type elements, and it comprises the magnetoresistive element 32a with magnetic anisotropy, and passes through to use the magnetic data of the resistance value of element 32a from disk 11 playback records; Wherein resistance value changes according to the certain strength that is derived from the magnetic field of disk 11.

Form head element part 122 on the AlTiC substrate that constitutes slider part 123, this formation uses film to form technology such as plating, sputter or polishing are carried out.Magnetoresistive element 32a is sandwiched between magnetic shielding 33a, the 33b, and writes coil block 311 and centered on by deielectric-coating 313.And head element part 122 has the diaphragm that is formed by for example alumina around writing component 31 and reading component 32, and protects whole head element part 122 with this diaphragm 34.Near writing component 31 and reading component 32, use film to form the well heater 124 that technology forms the resistor that use forms by film.In the present example, well heater 124 is positioned in the diamagnetic end with respect to the head element part 122 of disk 11.Well heater 124 can form by being filled in the gap to permalloy base film resistor formation zigzag and with alumina.

When AE 13 provides current to well heater 124, impel head element part 122 outstanding and distortion in its vicinity from the heat of well heater 124.In non-heated condition, air-supported (ABS) of head slider 12 has the shape that is shown as S1, and the gap between head element part 122 and the disk is shown as C1.In Fig. 2, be schematically depicted as intermittent line by the outstanding surface configuration S2 of well heater between 124 periods of heating.Head element part 122 is near disk 11, and this moment clearance C 2 between the two less than clearance C 1.Fig. 2 is a synoptic diagram, and the size relationship in this view is not accurately.Protuberate shape S2 has for example nanometer scale (that is several nanometers) aspect overhang.The overhang of head element part 122 changes according to the heater power that offers well heater 124.

As mentioned above, in the present embodiment, the TFC among the ERP constitutes the principal feature of HDD 1.To be described in below in the read procedure and to carry out reading the ERP of user data from disk 11, and in writing process, carry out on disk 11, to write the ERP of user data.These processes can be applied to other ERP as the ERP the process of reading microcode from disk 11.

At first, ERP in the read procedure is described below.If make a mistake during read procedure, HDD 1 carries out relevant ERP (below, be called and read ERP) so.As shown in the block diagram of Fig. 3, MPU 232 reads ERP according to the ERP table 241 of reading of RAM 24 stored.In reading ERP table 241, deposited a plurality of steps, for example, 256 ERP steps, and MPU 232 sequentially carries out each ERP step.

Typical ERP step comprises, for example, changes the filtration coefficient of the waveform-wave filter such as grade in the R/W passage 21, and the magnetic track deviation value that changes head element part 122.Especially, the ERP table 241 of reading in the present embodiment comprises the ERP step that the heater power that is used for TFC is changed (comprising ON/OFF).Thus, in order to improve wrong restorability, change the resolution of read signal.This resolution increases with heater power.

MPU 232 can be by being provided with the coefficient that parameter changes waveform-wave filter such as grade in the register of R/W passage 21.By MPU 232, the servo circuit of use HDC 231 carries out the location of head element part 122.The read signal that R/W passage 21 provides from head slider 12 via AE 13 (among Fig. 3, being shown as read signal) extracts servo data.MPU 232 obtains servo data via the servo circuit of HDC 231, and carries out the positioning control of head element part 122.

MPU 232 can change the electric power (electric current) that offers well heater 124 by the heater power value is set in the register of AE 13.AE 13 provides electric current (power) to give the well heater 124 of head slider 12 according to above-mentioned setting value.The user data of having read from disk 11 during the ERP process is stored in the impact damper 242 via R/W passage 21 and HDC 231.

Reading among the ERP of present embodiment, change the execution sequence of the ERP step that is used for TFC according to environment temperature.The example that detected temperatures district wherein is divided into three humidity provinces (low-temperature space, normal temperature district and high-temperature region) and changes the execution sequence of the ERP step that is used for TFC according to the specific change of humidity province will be described below.The definition of each humidity province is based on the predetermined reference district.

The environment temperature detected according to Temperature Detector 25, MPU 232 determines to read the execution sequence of each step of depositing in the ERP table.In each humidity province, MPU 232 also skips specific ERP step and selects other ERP steps as execution in step.The execution in step of selecting is sequentially carried out, and ERP finishes in successfully carrying out the wrong step of recovering.

MPU 232 changes heater power according to Temperature Detector 25 detected environment temperatures.Typically, heater power increases continuously along with reducing of temperature, and in reference temperature or more low temperature place down, heater power is taked the maximum constant value.At last reference temperature or above place, heater power is set as zero.

Fig. 4 shows the execution sequence of the ERP step in the normal temperature district.Classifying the step number of step X to step X+5 below the step number among Fig. 4 as, is the ERP step that is used for TFC.By the execution sequence (that is, sequence of steps) of each the ERP step shown in the example among Fig. 4, with the sequence consensus of step number.In the normal temperature district, MPU 232 carries out heater power in the mode that replaces increases and reduces the ERP step.In Fig. 4, X and " n " are positive integers.Although each the ERP step in this example is performed with the performance number that increases or reduce to limit, the present invention is not limited to the example of this performance number, and can limit for example rate of change of this performance number.

In the example of Fig. 4, after execution increased the step of 4mW with heater power, MPU 232 carried out the step that heater power is reduced 4mW.Selectively, after execution increased the step of 8mW with heater power, MPU 232 carried out the step that heater power is reduced 8mW.For the increase 12-mW of heater power with reduce 12-mW, MPU 232 also carries out similar procedure.The value that heater power is increased or decreased utilizes the independent design of each HDD to determine, and the value shown in top only is an example.

At normal temperatures, the change resolution according to the specific environment temperature does not trend towards becoming constant.Increase and reduce the ERP step by carry out heater power with aforesaid over-over mode, that is, alternately increasing and reduce operation by overhang head element part 122, the mistake that can be expected in the step is early recovered.

Fig. 5 shows the example of the ERP step execution sequence in the low-temperature space.In low-temperature space, MPU 232 is better than heater power not to be carried out heater power with reducing ERP step (step X+3 to incessantly X+5) and increases ERP step (step X is to step X+2).In Fig. 5, " k " and " m " is positive integer.Typically, resolution demonstrates the trend of reduction in low-temperature space.Therefore, in low-temperature space, increase the ERP step, can improve the possibility that the mistake in step is early recovered by reduce to carry out heater power before the ERP step at heater power.MPU 232, if so design can be skipped the ERP step that reduces heater power.

In addition, and compare, preferably increase the execution sequence of the ERP step of heater power in advance in the order of the ERP of normal temperature or above execution step.In the example of Figure 4 and 5, each ERP step of increase heater power has at low temperatures shifted to an earlier date " m " individual step.Since may be lower at aforesaid low-temperature space intermediate-resolution, by heater power being increased its priority higher in the humidity province that exceeds the normal temperature district of step distribution ratio, can realize mistake recovery early.

In addition, preferably to its lower priority in surpassing the humidity province in normal temperature district of the ERP step distribution ratio that reduces heater power.In other words, in surpassing the humidity province of normal temperature, the execution sequence that heater power reduces step preferably is delayed in its execution sequence back.This is to reduce the ERP step because the possibility that the mistake in other ERP steps is recovered is considered to be higher than heater power.

Fig. 6 illustrates the example of the execution sequence of the ERP step in the high-temperature region.In the high-temperature region, MPU 232 is better than heater power to be increased the ERP step and carries out heater power (step X is to step X+2) and reduce ERP step (step X+3 is to step X+5).In Fig. 6, " s " and " t " is positive integer.Typically, the resolution of read signal demonstrates the trend of increase in the high-temperature region.Therefore, in the high-temperature region, carry out heater power and reduce the ERP step, can improve the possibility that the mistake in higher level's step is early recovered by increase ERP step front at heater power.MPU 232, if so design can be skipped the ERP step that increases heater power.

In addition, and compare, preferably reduce the execution sequence of the ERP step of heater power in advance in the order of the ERP of normal temperature or following execution step.In the example of Fig. 4 and 6, each the ERP step that increases heater power has at low temperatures shifted to an earlier date " s " individual step.Since aforesaid may be high at the high-temperature region intermediate-resolution, by heater power being reduced step distribution ratio higher priority in normal temperature district or following zone, can realize that mistake early recovers.In the high-temperature region, if heater power is zero and well heater 124 is in the OFF state, MPU 232 skips each the ERP step that reduces heater power so.

In addition, the ERP step of increase heater power preferably is assigned with than priority lower in being lower than the temperature province of normal temperature.In other words, in being lower than the humidity province of normal temperature, the execution sequence that heater power increases step preferably is delayed in its execution sequence back.This is to increase the ERP step because the possibility that the mistake in other ERP steps is recovered is considered to be higher than heater power.In addition, MPU 232 preferably skips heater power according to detected temperature increases the ERP step.This makes it to be avoided owing to the outstanding head element part 122 that causes of head element part 122 and contacting of disk 11.

Next, ERP in the process of writing is described below.In writing process, in impact damper 242, store write data, and write data is sent to R/W passage 21 by HDC 231 from main frame 51.Write data is converted to write signal (write signal), sends to head slider 12 via AE13 then.

If make a mistake during writing process, HDD 1 carries out relevant ERP (hereinafter be called and write ERP) so.Shown in the block diagram among Fig. 7, MPU 272 writes ERP according to the ERP table 243 of writing of RAM 24 stored.In writing ERP table 243, deposited a plurality of steps, for example, 64 ERP steps, and MPU 232 sequentially carries out each ERP step.Write ERP table 243,, comprise the ERP step that changes the TFC heater power as reading the ERP table, and the ERP step of revising other circuit parameters.

During writing process, because the head element part 122 that causes owing to write current is outstanding, in surpassing the humidity province of normal temperature, well heater 124 typically is in the OFF attitude.But HDD 1 only can constitute that well heater 124 will be switched at once before write current flows, with ' difference rewrites ' during the starting stage that prevents to write.Selectively, this HDD 1 can be designed as at normal temperature or above place electric current and is provided for well heater 124.

In the present example, according to the error type of writing in the process, the ERP step of writing that MPU 232 selects to be performed also changes the execution sequence of writing the ERP step.The typical fault of writing in the process is ' writing termination '.If moving head componentry 12 from the target location away from predetermined reference level or more than, HDD 1 ends to write process so, carries out then and writes ERP.

Head element part 122 can be on both direction the wide position.One be disk 11 radially, and another is perpendicular to the direction of the record surface of disk 11.The mistake that causes data to be written into being different from the position of target location is moved in position diametrically, writes as offtrack or extruding, and/or the data that exist on the adjacent track are caused damage.If flying height is too big,, cause ' difference rewrites ' so owing to the abundant magnetic flux from writing component can not reach record surface.

HDD 1 uses the value of servo address, with moving radially the position of detecting head element part 122 from goal track.Servo address comprises servo track, servo sector and position error signal.If the servo address that detects moves at least one reference value from target, HDD 1 ends to write process so.This prevents that data are written into the position of moving from target.

In the present embodiment, because the write error that moves radially in the position of head element part 12 is known as ' write to follow the tracks of and end '.Specifically, " write follow the tracks of end " is due to the fact that: since before data are write or data write during head position move position error signal reference levels at least from the center of goal track, " write to follow the tracks of and end " is known as ' location-based termination '.And because " writing magnetic track ends " of the following fact become " based on the termination of speed ":, because even ' location-based termination ' do not take place, during the process that writes data on the disk 11, depart from-the magnetic track attitude, and make that position error signal changes its reference levels at least suddenly in the unit interval.

HDD 1 uses the yield value of servo VGA (variable gain amplifier), detects the displacement of its unsteady direction (vertical direction) upper magnetic head componentry 122 from the target location.Servo VGA gain changes on the contrary with respect to the amplitude of reading of servosignal.Therefore, when head element part 12 is left record surface, servosignal read that amplitude reduces and servo VGA gain increases.If during data write, servo VGA gain surpasses with reference to rank, and HDD 1 ends to write process so.This prevents ' difference rewrites '.In the present embodiment,, the flying height of magnetic head is known as ' writing VGA ends ' owing to increasing the above-mentioned mistake that causes.

Fig. 8 shows the chart of the execution sequence of the ERP step in ' based on the termination of speed ' incident.In each of chart,, revise each controlled variable of HDD1 in order to rewrite (rewriting).The ERP table 243 of writing shown in Fig. 8 comprises: as the ERP step relevant with TFC, increase/reduce the ERP step (step Y is to step Y+5) of heater power and the ERP step (step Y+6 is to step Y+8) that intention increases write current and increases heater power.

According to the type of write error, MPU 232 determines to write in the ERP table 243 the ERP step that is performed, and the execution sequence of determining the ERP step that is determined.For example, write ERP table 243 and have 64 ERP steps of depositing in advance, and MPU 232 selects the part of 64 ERP steps according to specific type of error, and change the execution sequence of selected ERP step.

As shown in Figure 7, if during writing process, make a mistake, notify this type of error as type of error (ERROR TYPE) from HDC 231 to MPU 232 so.This type of error is for example above-mentioned ' location-based termination ', ' based on the termination of speed ', ' writing VGA ends ' or the like.Other type of errors for example comprise the type of error that the temperature owing to AE 13 rises and causes.

After the notice that receives from HDC 231 ' based on the termination of speed ', MPU 232 carries out each ERP step according to ERP step execution priority shown in Figure 8.If generation between the second half that writes data on the disk 11 ' is write to follow the tracks of and is ended ' that is ' based on the termination of speed ', so because giving prominence to of the head element part 122 of write current makes magnetic head-disk contact probably.Therefore, MPU 232 selects heater power to reduce ERP step (step Y is to step Y+2) as execution in step.

After the notice that receives from HDC 231 ' location-based termination ', MPU 232 preferably skips heater power and regulates ERP step (STEP Y to STEPY+5) or carry out other ERP steps, as revise controlled variable, these other ERP steps are preferably regulated on the ERP step or were carried out before it at heater power.This is that it doesn't matter because ' location-based termination ' is considered to contact with magnetic head-disk.

But the ERP step (that is, step Y+3 is to step Y+8) that increases heater power is skipped.This prevents magnetic head-disk contact.For the mistake among the AE 13, for example, be unnecessary owing to be used for the ERP step of TFC, MPU 232 also skips the ERP step of TFC.

The write ERP relevant with ' servo VGA ends ' is described below.After the notice that receives from HDC 231 ' servo VGA end ', MPU 232 carries out each ERP step according to ERP step execution priority shown in Figure 9.Because ' servo VGA end ' also because the increase of the flying height of magnetic head causes, therefore can reduce gap between head element part 122 and the disk 11 by the increase heater power.Can realize wrong the recovery thus.Therefore, MPU 232 selects to increase the ERP step (that is, step Y+3 is to step Y+5) of heater power as execution in step.The ERP step (that is, step Y is to step Y+2) that reduces heater power is skipped.

If ' servo VGA ends ' takes place, MPU 232 carries out head slider load/unload ERP step (step Y+10) so.For ' servo VGA ends ' mistake,, preferably increase the ERP step of heater power early than load/unload ERP step ground owing to the adjusting based on TFC is than the more reliable error recovery method of head slider load/unload.

In addition, MPU 232 selects to increase the ERP step (that is, step Y+6 is to step Y+8) of write current and heater power together as execution in step.Increase heater power and write current together and can further improve write performance, realize thus recovering from the mistake of ' difference rewrites '.For fear of magnetic head-disk contact, preferably carrying out after a while than the step that only increases heater power increases the ERP of write current and heater power step together.

As another preferred example, the gain stage of the servo VGA of MPU 232 from mistake is determined the heater power value.For example, during the manufacturing test process of HDD 1, common servo VGA value is identified, and this value is recorded conduct with reference to gain stage.If MPU 232 is from the reference gain level of depositing and difference between the actual servo VGA gain stage that ' servo VGA ends ' obtain takes place, determine heater power value (increment in the heater power).More particularly, MPU 232 usefulness arithmetic are determined the heater power value or are determined according to the tables of data of depositing.The heater power value is determined to eliminate flying height and the normally variation between the flying height in ' termination ' error condition.

Although some ERP steps that above-mentioned example is used for depositing in advance by skip-table are selected execution in step, can be each ERP process and set up the independent ERP table that only comprises the ERP step that to be performed.

Next, the ERP relevant with the instability of head element part 122 is described below.MPU 232 judges whether instability damages the limit that exceeds standard.If instability is judged to be outside the limit of this standard, MPU 232 promotes the execution priority of the heater power change step in the relevant ERP table to the effective rank that is higher than when this standard is not exceeded so.Although preferably the institute that changes heater power is carried out in steps the change of execution priority, can only change partly changing step.This makes the early wrong recovery among the ERP become possibility.

Instability shows as the variation in the read signal waveform of reading component 32.More particularly, instable infringement increases the read signal noise, or causes the plus or minus amplitude of read signal to increase significantly and become asymmetric.These incidents hinder accurately reading of servo data or user data.This is due to the fact that: the free layer in the magnetoresistive element 32a does not have one-domain structure and partly comprises little magnetic domain, and this little magnetic domain demonstrates and is different from other regional magnetic behaviors that form this layer.

Figure 10 schematically shows the part-structure as the magnetoresistive element 32a when the record surface direction of disk 11 is observed element 32a.Magnetoresistive element 32a is the multilayer laminated structure that is formed by antiferromagnet layer 324, pinning layer 322, nonmagnetic layer 323, free layer 321 and protective seam 327.Pinning layer 322 and free layer 321 are ferromagnetic materials.The direction of magnetization of free layer 321 changes according to the record magnetization of disk, and the resistance of magnetoresistive element 32a correspondingly changes.Electric current flows between electrode film 325a and 325b.

The direction of magnetization of pinning layer 322 is fixed on it and limits direction by the reciprocation of itself and inverse ferric magnetosphere 324.The direction of magnetization of free layer 321 changes according to the record magnetization of record surface, but the inclined to one side field by producing between hard bias layer 326a and the 326b applies bias voltage on fixed-direction.If hard bias layer 326a, 326b are too thin, and the magnetic biasing pressure is not enough, and instability will be damaged so.The asymmetry that the magnetic biasing that instable damage is also applied by the hard bias layer 326a that forms from the both sides at free layer 321,326b is pressed and causing.

The floating highly control (TFC) of heat causes the deformation of head element part 122, and together changes the bias-field that produces by its expansion or temperature rising or these two incidents of well heater 124 between hard bias layer 326a, 326b.Thus, head instability changes according to the particular value of heater power.The thermal expansion of head element part also causes inverse ferric magnetosphere 324, pinning layer 322, nonmagnetic layer 323, free layer 321 and protects interactive variation between 327, changes head instability thus.Typically, head instability increases along with heater power and is compromised.Figure 11 A and 11B show the example of the read signal waveform of reading component 32 during the OFF state of well heater 124 and the ON state procedure respectively.

Figure 11 (a) shows the signal waveform that produces when well heater 124 is in the OFF state, and Figure 11 (b) shows the signal waveform that produces when well heater 124 is in the ON state.Heater power in two kinds of situations all is 17mW.And, Figure 11 (a) and a plurality of curve maps shown in 11 (b) show in the different signal waveforms that form under the bias voltage read, and equal 125mV, 145mV, 165mV, 185mV and 205mV respectively from the curve map A at top to the curve of bottom signal level shown in Figure 2.

As being appreciated that the expansion that is used for head element part 122 by conducting well heater 124, change the read signal waveform significantly by comparison diagram 11A and 11B.More particularly, noise increases amplitude significantly and makes amplitude asymmetric significantly.The thermal expansion of this expression head element part 122 has damaged the instability of magnetic head.

Although typically damage instability by heater 124, in the part of the head slider 12 of all tests, instability is suppressed by conducting well heater 124.This is considered to due to the fact that causing: heater 124 makes head element part 122 distortion, so that improves the inclined to one side field in the OFF state, or changes the temperature of magnetic head element so that improve field partially.But, in the part of the head slider 12 of all tests, observe these incidents.

23 pairs of head instabilities of HDC/MPU in the present embodiment are judged and are changed the execution priority of ERP step according to judged result.In the present embodiment, judge the step execution priority that the MPU 232 of instability operation determines among the ERP according to microcode.To describe subsequently by the instability of MPU 232 and judge.Be judged to be outside its criterion with the process that takes place if will at first describe instability below.Because head instability changes between the different head sliders, MPU 232 carries out independently instability judgement and independently ERP control for each head slider 12.This head slider can be from LBA (Logical Block Addressing) (LBA) identification of main frame 51 predetermined data.

11B is described with reference to figure 11A as top, and instable rank changes with the duty of well heater 124.Therefore, when MPU 232 judged that instability has exceeded required standard, MPU 232 increased the execution priority of the heater power change step among the ERP.For example, MPU promotes the execution priority of the step from step X to step X+5, and these steps are deposited with reading in the ERP table of Fig. 4 in advance.

In another situation, instability is typically damaged with the increase of heater power.Therefore, preferably before the step that increases heater power, carry out the step that reduces heater power.In the example that the Fig. 4 that reads the ERP table is shown, the execution priority of the step from step X to step X+5 is set as the execution priority that is higher than the step from step X to step X+2.

If the relation between the increase of regulation heater power/reduce and the instable damage determines that preferably heater power increases the execution priority that step and heater power reduce step.For example, for wherein suppressing instable head slider by increasing heater power, the priority that heater power increases step is set as above the priority that reduces the heater power step.

Above-mentionedly also be applied to write ERP table.After judging that instability has exceeded required standard, MPU 232 promotes the execution priority that heater power changes step.This writes that ERP table preferably not only comprises the waveform distortion that makes write current so that the step of the magnetic field intensity that reduces to be produced by write current, and comprises and change (increases) heater power simultaneously so that the step of the variation of the calorific capacity that compensation causes owing to the heater power variation.The representative value that limits the write current waveform comprises write current value, kick (kick) amplifier value and kick (kick) length.

As shown in figure 12, kick (kick) amplifier value KA represents the peak value output level of write current waveform, and uses big value in order to improve initial write performance.Kick (Kick) length K L is the length of peak value output.The write current value is the mean value of the write current that applies after obtaining kick (kick) amplifier value.Reduce write current value, kick (kick) amplifier value or kick (kick) length, reduce intensity by the magnetic field of write current generation.Can improve the instability of the reading component 32 during writing thus.Simultaneously, the calorific capacity of writing component 33 reduces, so in order to reduce the variation of temperature conditions, heater power preferably is increased, so that the reducing of calorific capacity of compensation writing component 33.Although preferably should decay almost by full remuneration, heater power can be set to the part of compensate for attenuation.

The instability deterministic process of being undertaken by MPU 232 is described below.Present embodiment uses four projects as the instability criterion.One is the read error rate of user data, and one is the implementation rate of the ERP during user data reads, and one is the read error rate of servo data, and one is the variation of the read signal waveform of user data.

MPU 232 in the present embodiment judge four standards each whether be exceeded.If any one standard is exceeded, MPU 232 is provided with the mark that expression exceeds this standard so.If for two or more standards are set up mark, MPU 232 changes the execution priority of the TFC step in the ERP table so, as mentioned above.When a plurality of standards are exceeded, can make MPU judges more reliably whether instability is damaged to such an extent that exceed standard, and more effectively carry out ERP by changing the execution priority of TFC step.

When design like this, if three of standard or above or all standards are exceeded, MPU 232 can change the execution priority of step so, if or a certain criteria be exceeded, also can change the execution priority of this step.Selectively, even any one standard is exceeded, also can change the execution priority of this step.

The read error rate of user data at first, is described below.After disk 11 is read user data, 23 pairs of these user data execution errors of having read of HDC/MPU are checked and (ECC) process of correction.Typically, (OTF) carry out error recovery in pattern or the loss correction mode at " high speed rotating (On The Fly) ", the OTF pattern is the on-line correction process, and the loss correction mode is the off line trimming process.The OTF pattern is set at first, and if the OTF error recovery impossible, this pattern changes the loss correction mode into so.The OTF pattern is different on disposal route with the loss correction mode, and the number of times that the error recovery in the loss correction mode can error recovery is the twice of OTF pattern.If by the change in the instability increase signal waveform, error rate increases significantly.Therefore, error rate can be used as the instability criterion.

In the OTF pattern, the coded word in the data sector is read continuously, and mistake is corrected arbitrarily simultaneously, and user data is continuously delivered to main frame 51.In the loss correction mode, if coded word is loaded (reading in), this coded word can not obtain error recovery in the OTF pattern, and the loading of coded word and the transmission of user data are temporarily stopped, and the mistake in the coded word is corrected.After proofreading and correct, restart the loading of coded word and the transmission of user data.

In OTF pattern and loss correction mode, transmitting CRC (CRCC) and error correction code (ECC) afterwards from R/W passage 21, these codes are used for carrying out error recovery procedure.ECC and CRCC for example can use can go up the Reed-Solomon code that calculates at Galois Field (Galois field) GF (28).During this loss trimming process, most probable exists wrong position to be estimated as the loss position probably, then based on this, calculates the data that comprise mistake.Error recovery procedure is the technology of common general knowledge, omits detailed description at this.

In OTF pattern and loss correction mode, HDC 231 at first execution error trimming processes and miscount rate.Irrelevant with correction mode, MPU 232 obtains error rate the error recovery procedure from HDC 231.If this error rate exceeds in advance the standard of setting up, MPU 232 sets up mark and is exceeded to represent this standard so.

Next, the implementation rate of the ERP of user data in reading is described below.In this example, be used as the reference value of implementation rate with respect to (with respect to) actual figure of reading ERP of data conveying capacity.If by the variation of instability increase signal waveform, read error suddenly increases and reads the implementation rate increase of ERP so.Therefore, the implementation rate of reading ERP becomes unstable criterion.Except the implementation rate of all reading ERP, the implementation rate of the particular step that sets in advance in the ERP table can be used as criterion.Can use two of these standards or any one.

By using the order that sends from main frame 51, MPU 232 can measure from disk 11 data volume that transmits and the actual figure of reading ERP.For each head slider 12, MPU232 calculates the data conveying capacity of time per unit and reads the ERP actual figure from these values.If MPU judges that reading the ERP actual figure surpasses aforesaid standards (reading the implementation rate of ERP) with respect to the data conveying capacity, MPU sets up mark to represent to have exceeded this standard so.If exceed required standard, then also use this process for the particular step in the ERP table.Read the designator that the ERP implementation rate becomes the user data error rate indirectly.And, can use the value that is different from the data conveying capacity to calculate the implementation rate of ERP or particular step.

Next, the read error rate of servo data is described below.In the read and write process, the servo data that HDC/MPU 23 reads from disk 11 according to head slider 12 is determined the position of head slider 12.If the variation in the signal waveform is increased by instability, the servo data read error increases suddenly so.Therefore, the read error rate of servo data becomes the instability criterion.

The servo data read error that several types is arranged.Figure 13 (a) shows the data layout of servo pattern.Figure 13 (b) shows how to write down servo pattern on record surface, and the relation of the position between writing component 31 and the reading component 32.Servo pattern by preamble (PREAMBLE), servo data mark (SERVO ADDRESS MARK) (SAM), magnetic track ID (Gray code: GRAY), physics servo sector number (PHSN) and pulse pattern (BURST) constitute.

Preamble (PREAMBLE) comprises the pattern of the amplification coefficient of the phase place that is used to detect read signal and conditioning signal amplifier.Servo address mark (SERVO ADDRESSMARK) (SAM) is represented the beginning of servo data.Magnetic track ID (Gray code (GRAY)) identifies on it track number with the magnetic track of final entry user data.Many servo sectors in magnetic track of physics servo sector numbering (PHSN) expression.At last, pulse pattern (BURST) is made of four kinds of figure A, B, C, D, and expression is by the detail location of the reading component 32 (head element part 122) in the magnetic track of magnetic track ID regulation.Reading component 32 is read servo figure, and MPU 232 carries out head position based on this graph data.

If reading component 32 can not read arbitrary sector of servo figure, servo data reads erroneous results so.This read error is (SAM) read error, magnetic track ID (GRAY) read error or physics servo sector numbering (PHSN) read error of preamble (PREAMBLE)/servo address mark (SERVO ADDRESS MARK).Therefore, if any one generation of these mistakes this means so the servo data read error has taken place.The R/W passage 21 of decoding servo data detects above mistake.

MPU 232 can know the generation of servo data read error by the register of visit R/W passage 21.For example, exceed the standard that has been set in advance if read several read error numbers with respect to servo data, MPU 232 sets up mark so, is exceeded to represent this standard.MPU 232 can measure each servo wrong number of reading reference count, because MPU obtains servo-information from R/W passage 21, so that positioning head.

If per 30,000 group servo data has the wrong number above 100 to be suggested as an example, MPU 232 sets up the mark that the expression relevant criterion is exceeded so, if or, during writing process, cause writing break event owing to the servo data read error recurs continuously above suitable reference count, MPU 232 sets up mark so.Take place if write break event, MPU 232 begins to write ERP so.Recur continuously if write break event after this, MPU 232 changes the execution priority of writing the TFC step in the ERP table so.

Next, the variation of the signal waveform of user data read signal is described below.If instability is decreased also, this causes the plus or minus amplitude of increase of read signal noise or read signal to increase significantly and the asymmetric incident that becomes so.Can discern unstable rank by measuring these incidents.More particularly, MPU 232 carries out the instability judgement based on the amplitude and the symmetry of signal waveform.Figure 14 schematically shows the example of signal waveform.The amplitude of this signal waveform is represented as L.And, being represented as A with respect to the amplitude forward of baseline, the amplitude on the negative sense is represented as B.The symmetry of signal waveform for example can be defined as (A-B)/(A+B).

The amplitude and the symmetry of the standard of measuring during becoming the fabrication phase are set in HDD 1.These values are stored on ROM or the disk 11.Use product after delivery during, R/W passage 21 is measured amplitude and symmetry and MPU 232 and is obtained this measured value from R/W passage 21.For example, MPU 232 obtains amplitude and symmetry Preset Time such as per 12 hours or when 10 GB information are transmitted from R/W passage 21, with the value obtained and each standard relatively, and judges the instability rank.

In addition, for example, if the amplitude of measuring (for example surpasses reference value with respect to the rate of change of its reference value (standard), aspect rate of growth, 20%), MPU 232 sets up suitable mark so, if or the symmetry value of measuring (for example surpass reference value with respect to the rate of change of its reference value (standard), +/-30%), MPU 232 sets up suitable mark so.The value that reference value and measured value are preferably measured under the same conditions.For example, in the normal temperature district, can use the signal waveform that under well heater OFF/ unloaded state, obtains.

After any one mark that has kept of setting up the above-mentioned condition of expression, if those condition changings afterwards, MPU 232 can discharge this mark and it is returned its original state.In preferred example, MPU 232, in case it sets up the mark that relates to waveform change, then it keeps the specific markers state, and for other marks, reducing of MPU 232 response error rates returns the mark of setting up to original state.Can judge more accurately thus.The maintenance of mark that relates to signal waveform is based on such experimental fact: in case waveform is changed by instability, then should the change incident continue.

Although in above-mentioned example, MPU 232 changes the execution priority of ERP step based on the instability judged result, MPU 232 can use these judged results, is used for the process except that ERP.In preferred example, after judging that instability exceeds this standard, MPU 232 regulates the heater power during normal read is crossed.If instability exceeds standard, under identical condition, MPU 232 typically reduces heater power so.

Different with the operation in the normal read processing procedure, MPU 232 can judge the instability rank under the idle condition.MPU does not use being recorded in the directorial area of the user data that provides on the disk 11 by expecting that test data writes, and reads this test data, can measure error rate and other judgement projects.And MPU can know heater power adjusting result by carry out read/write processes in directorial area after regulating heater power.Therefore, MPU 232 can increase/reduce heater power and determine its adjustment level.

MPU 232 can use the part of above-mentioned judgement project or other judgement projects to judge instability.After concluding that instability exceeds standard, MPU 232 can report that also these results give main frame 51.

Although described the preferred embodiments of the present invention by example above, the present invention is not limited to the foregoing description or is limited by the foregoing description.The those skilled in the art within the scope of the invention can be easily changes, increases and/or replace each composed component of the foregoing description.For example, any one of the above-mentioned example of TFC can be applied to being equipped with the HDD of head slider, and this head slider only has reading component or writing component, or is applied to the media drive except that HDD.

The description of reference symbol

1 hard disk drive, 10 shells, 11 disks, 12 head sliders; 14 spindle motors, 15 voice coil motors, 16 actuators, 17 Temperature Detectors; 20 circuit boards, 21 read/write channel, 22 electric-motor drive units; 23 hard disk controllers/MPU, 24 RAM, 31 writing components; 32 reading components, 32a magnetoresistive element, 33a; the 33b shielding part, 34 diaphragms, 51 main frames; 121 tail lateral edges, 122 head element part, 123 slider parts; 124 heaters, 231 hard disk controllers, 232 MPU; 241 read the ERP table, 242 buffers, and 243 write the ERP table; 311 write coil block, 312 pole pieces, 313 deielectric-coating

Claims (14)

1, a kind of media drive comprises:

Slider floats on the medium of rotation;

Head element part is arranged in the described slider;

Well heater is arranged in the described slider, and wherein said well heater impels described head element part outstanding and regulate gap between described medium and the head element part by thermal expansion;

Storer, storage list in this storer shows to discern execution in step at the error recovery procedure (ERP) of described mistake by this when mistake takes place, and wherein said table comprises the step of the heater power that changes described well heater;

Controller is used to carry out the execution control by the execution in step of described table identification; And

Temperature Detector,

Wherein, according to utilizing the detected temperature of described Temperature Detector, described driver changes the execution priority of the heater power change step in error recovery procedure (ERP).

2, media drive according to claim 1,

Wherein, in the error recovery procedure (ERP) at read error, if utilize the detected temperature of described Temperature Detector to be lower than reference temperature, so described table is identified as execution in step to the step that increases heater power.

3, media drive according to claim 2, wherein,

Described table is identified as execution in step to step that increases heater power and the step that reduces heater power; And

The execution priority of the step of described increase heater power is higher than the described execution priority that reduces the step of heater power.

4, media drive according to claim 1,

Wherein, in the error recovery procedure (ERP) at read error, if utilize the detected temperature of described Temperature Detector to be higher than reference temperature, so described table is identified as execution in step to the step that reduces heater power.

5, media drive according to claim 4, wherein,

Described table is identified as execution in step to step that increases heater power and the step that reduces heater power; And

The described execution priority that reduces the step of heater power is higher than the execution priority of the step of described increase heater power.

6, media drive according to claim 1, wherein,

According to type of error, described driver changes in described error recovery procedure (ERP) the heater power that is performed is changed step.

7, media drive according to claim 6, wherein,

In the error recovery procedure (ERP) at the write error during writing data in the media, described table is identified as execution in step to the step that reduces heater power.

8, media drive according to claim 6, wherein,

For writing in the error recovery procedure (ERP) of mistake that servo data read signal level during the process is lower than datum, described table is identified as execution in step to a step that increases heater power.

9, media drive according to claim 8, wherein,

According to described servo data read signal level, described driver is determined the heater power in the execution in step.

10, media drive according to claim 1, wherein, described table changes the write current waveform, the feasible intensity that reduces the magnetic field that produces, and increase heater power, thus compensation is owing to the calorific capacity that waveform change causes reduces.

11, media drive according to claim 1, wherein, described controller judges whether the instability of described head element part surpasses reference value, surpasses reference value when judging, then promotes the execution priority of the step that changes heater power.

12, media drive according to claim 11, wherein, described controller increases the rank of the execution priority of step with the execution priority lifting that heater power reduces step for being higher than heater power.

13, a kind of method of controlling media drive, this media drive comprises: the slider that floats on the medium of rotation, be arranged in the head element part in the described slider, and be arranged in well heater in the described slider, described well heater makes described head element part outstanding by thermal expansion, and regulate gap between described medium and the head element part, this control method comprises:

When mistake takes place, then with reference to the table that is used for discerning at the execution in step of this wrong error recovery procedure (ERP); And

In described error recovery procedure (ERP), carry out step by described table identification, the feasible heater power that changes described well heater,

Wherein, according to detected temperature, the heater power that change will be carried out in described error recovery procedure (ERP) changes the execution priority of step.

14, method according to claim 13 also comprises,

According to type of error, the heater power that change will be carried out in described error recovery procedure (ERP) changes step.

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