WO2009076870A1 - 一种硬盘磁头的读写头偏移参数表的测量方法 - Google Patents

一种硬盘磁头的读写头偏移参数表的测量方法 Download PDF

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Publication number
WO2009076870A1
WO2009076870A1 PCT/CN2008/073366 CN2008073366W WO2009076870A1 WO 2009076870 A1 WO2009076870 A1 WO 2009076870A1 CN 2008073366 W CN2008073366 W CN 2008073366W WO 2009076870 A1 WO2009076870 A1 WO 2009076870A1
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Prior art keywords
head
hard disk
read
track
offset parameter
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PCT/CN2008/073366
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English (en)
French (fr)
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Yanxiang Sun
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Shenzhen Excelstor Technology Ltd.
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Publication of WO2009076870A1 publication Critical patent/WO2009076870A1/zh

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/596—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on disks
    • G11B5/59605—Circuits
    • G11B5/59611—Detection or processing of peak/envelop signals
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/596—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on disks
    • G11B5/59627—Aligning for runout, eccentricity or offset compensation

Definitions

  • the present invention relates to the field of hard disk manufacturing technology, and more particularly to a method for measuring a head offset parameter table of a hard disk head. Background technique
  • the structure of the hard disk read/write head is as shown in Fig. 1:
  • the top end of the head arm is provided with two parallel magnetic heads, which are a read head and a write head.
  • the magnetic head is moved by the magnetic head arm to move over the hard disk. Due to the physical distance X between the read head and the write head, there is a head offset in the radial direction between the read head and the write head.
  • the parameter (mroffset, denoted as ⁇ value) is different for each track of the hard disk.
  • the hard disk servo system of the hard disk Since the servo system of the hard disk is located according to the position information acquired by the read head, when the hard disk is read, the hard disk servo system controls the read head of the magnetic head to directly reach the designated track, and no adjustment is needed; When writing to a magnetic track of a hard disk, it means that the write head needs to be moved to that magnetic track, and the position of the read head of the magnetic head needs to be adjusted according to the value of the magnetic head ⁇ on the magnetic track, the hard disk servo system Then, the read/write head movement is controlled. When the read head is positioned at the adjusted position, the write head is naturally positioned to the designated track.
  • the ⁇ value of the track 30000 is 5, then the hard disk
  • the general trend of the distribution of the read/write head offset parameter ⁇ of the track on the hard disk in the entire track space is shown in Fig. 2. It can be seen that the value of ⁇ is nonlinear with the change of the track.
  • the arithmetic unit set in our hard disk is a DSP unit that does not support floating-point arithmetic. Its accuracy is not enough to meet the requirements of some nonlinear calculations. Therefore, when calculating the ⁇ value of each track, it needs to be The nonlinear calculation is linear calculation.
  • the current method is to divide the disk surface corresponding to each head into multiple linear regions, and then measure the ⁇ values of the start and end rails of different partitions and store them on the hard disk. Read-only memory. After dividing the hard disk into 4 ⁇ partitions, since the span of the tracks of each partition becomes smaller, the variation of the ⁇ value in each partition can be approximated as a linear distribution, so that linear interpolation can be used in each partition. The lambda value of each target track is calculated, and the accuracy of the operation result on the DSP unit can also be achieved.
  • each lambda value is as follows: First, the target track of the start rail is written. After the write, the head is fine-tuned, the write head slowly leaves the target track, and the read head slowly moves closer to the target track. When the read head is close to the target track that has written data, the signal on the read head is slowly stronger.
  • the signal intensity on the read head is the strongest, and the most Stable; record the distance that the head is fine-tuned at this time, which is the head offset parameter ⁇ .
  • the hard disk has to be read and written repeatedly for 2 times. Since the number of partitions of the hard disk is often large, and the read and write operations of the hard disk take a long time, the test of obtaining the ⁇ value is time consuming, and if the track of a certain partition is damaged, the partition ⁇ value The accuracy of the test data is often greatly affected. For example, it takes 90 minutes to test the ⁇ value of a normal 2.5-inch hard disk. The test speed is slow, and the production and test efficiency are low. Summary of the invention
  • the technical problem to be solved by the present invention is to provide a method for measuring the head offset parameter table of a hard disk head with a faster test speed and higher precision.
  • a method for measuring a head offset parameter table of a hard disk head includes the following steps: ⁇ : obtaining a head offset parameter of two tracks on the hard disk by measurement;
  • ⁇ According to the read/write head offset parameters of the two tracks, the head and end offset parameters of the start track and the end track of each hard disk segment are calculated, and the read/write head offset parameter table is obtained, which will be read and written. The header offset parameter table is written to the hard disk.
  • a method for measuring a head offset parameter table of a hard disk head includes the following steps: A: The head and head offset parameters of the two target tracks on the hard disk are obtained by measurement;
  • FIG. 1 is a schematic structural view of a magnetic head of a hard disk according to an embodiment of the present invention
  • FIG. 2 is a schematic diagram showing the variation of the head offset parameter with the radius of the track on the hard disk in the embodiment of the present invention. detailed description
  • the circle in the figure represents the track on which the read head of the disk is located; Oo represents the center of the disk of the hard disk; ( ⁇ represents the axis of the head arm; AB represents the head of the disk and the head of the disk)
  • Ri is the radius of the track
  • the read head is at the ith
  • the difference between the distance Wi between the write head and the center of the hard disk is the head offset parameter ( ⁇ value).
  • the head offset parameter is due to the existence of a physical distance X between the read and write heads, so that at the same time, the read head and the write head B are respectively located on different tracks; and since the distribution of the tracks on the disk is
  • the disk disc center Oo is a set of concentric circles of the center. Therefore, the read head offset parameters (ie, the ⁇ value) of the read head A and the write head B above different tracks are different, and the curve direction is as shown in FIG. 2 Show. Therefore, it is entirely possible to derive the ⁇ value of the track at other locations based on the lambda value of the track.
  • the geometric connection AB between the head A and the write head B is 0 with the read head and the center of the hard disk.
  • the distance between Ri when the read head is at the i-th track, the write head B and the center of the hard disk disc 0.
  • the physical distance X between the read head A and the write head B and the geometric connection between the read head A and the write head B and the head arm can be calculated geometrically.
  • the hard disk can be first On-chip measurement obtains the ⁇ value of the two tracks. The farther the distance between the two tracks is, the better; according to the current track and the center of the hard disk disk 0.
  • the distance between Ri and other related parameters can calculate the spacing X between the head A and the write head B in the hard disk head and the angle between the geometric connection between the head A and the write head B and the head arm. .
  • the ⁇ value of the start rail and the end rail of each partition on the disk can be calculated, the read/write head offset parameter table is obtained, and the head offset parameter table is recorded to the hard disk.
  • the method of measuring the lambda value of two tracks can use existing measurement methods.
  • W i the distance between the write head and the center of the hard disk disc when the read head is at the i-th track
  • Ro the distance between the read head and the center of the hard disk at the 0th track
  • d the distance between the center of the hard disk and the rotating shaft of the head arm
  • ⁇ the angle between the geometric connection between the read head and the write head and the head arm.
  • the i-th track and the zeroth track are the two tracks obtained by the aforementioned measurement of the ⁇ value.
  • R the distance between the read head at the target track (at the start or end track) and the center of the hard disk. Since R is the corresponding relationship with the target track, this R value can be given by the given target. Orbital calculation
  • d the distance between the center of the hard disk and the rotating shaft of the head arm; :: the angle between the read head and the center of the hard disk platter and the angle between the head arms;
  • ⁇ the angle between the geometric connection between the read head and the write head and the head arm
  • W the distance between the write head and the center of the hard disk when the read head is at the target track
  • ⁇ read/write head offset parameter
  • ⁇ The physical distance between the read head and the write head.
  • a method for measuring a head offset parameter table of a hard disk head includes the following steps:
  • ⁇ the physical distance X between the read head and the write head of the hard disk head and the angle between the geometric connection between the read head and the write head and the head arm are calculated. ⁇ ;
  • step C Calculate the head offset parameter of at least two tracks of each partition of the hard disk disc according to the physical distance X and the angle, thereby obtaining a head and head offset parameter table, and the head offset parameter Table is written to the hard disk.
  • step C it is preferable to calculate the head offset parameters of the start rail and the end rail of each partition.
  • the two target magnetic tracks are radially apart from the disk.
  • the head track offset parameter of the target track and the at least one track adjacent to the target track may be measured, and the average value of the obtained head offset parameter is used as the read of the target track.
  • Write header offset parameter is used as the read of the target track.
  • the ⁇ value of the two tracks is calculated, and the obtained X and the precision are the highest, and the head offset is improved.
  • the accuracy of the parameter table is improved.
  • the track on the hard disk platter we tested may have bad sectors, if only the ⁇ value of a track is measured, the wrong ⁇ value may be obtained. Even if the track being tested has no bad sectors, there are errors in our measurement process. Therefore, we select one or more tracks (such as 5 tracks) adjacent to the track to be measured, measure their ⁇ values separately, and average the ⁇ values of these tracks, which is recorded as the track we want to measure. The value of ⁇ . Since the ⁇ value of the bad track is very different from the normal ⁇ value, it is easy to find when there are bad tracks in the track measured in the hard disk, and the possibility that multiple tracks are bad sectors at the same time is very small, and will be measured.
  • Target track and nearby tracks The ⁇ value is averaged, which greatly reduces the possibility of ⁇ value error. Since the pitch of the tracks is small, our measurement error is much larger than the difference between the ⁇ values of adjacent tracks. Therefore, the ⁇ value of the track to be measured and the track in the vicinity is averaged. This makes the ⁇ value obtained more accurate, reduces the measurement error, and improves the accuracy of the obtained head offset parameter table.
  • the arithmetic unit in the hard disk is often a DSP unit that does not support floating-point operations, the values of ⁇ , ⁇ , and ⁇ are small, and slight errors can cause the hard disk to fail to read normally. It is required to use a floating point with high calculation accuracy.
  • the calculation therefore, the calculation of the parameter values X and ⁇ and the calculation of the ⁇ value are performed in an external computer. Firstly, the measured lambda values of several tracks are exported to an external computer, and the read and write head offset parameters of the start rail and the end rail of each partition are obtained by the iterative and recursive operations according to the above equations, and the hard disk is filled in.
  • the head and head offset parameter table is often a DSP unit that does not support floating-point operations, the values of ⁇ , ⁇ , and ⁇ are small, and slight errors can cause the hard disk to fail to read normally. It is required to use a floating point with high calculation accuracy. The calculation, therefore, the calculation of the parameter values X and ⁇ and the
  • the arithmetic unit in the hard disk is set to an FPU (Float Point Unit) unit that supports the floating point unit, the calculation process can be directly performed in the hard disk.
  • FPU Float Point Unit
  • the current FPU unit is more expensive, and the servo system of the matching hard disk is more complicated. This floating point operation is only needed during the test. Normal use of the hard disk is not required, so we still use the DSP unit. , does not change the structure of the hard disk # ⁇ , the test uses a computer that supports floating-point operations externally to calculate the read-write head offset parameters and then write to the hard disk.
  • the relationship between the ⁇ value of the track on the disk and the ⁇ value of the start track and the end track of each partition of the hard disk can be calculated by geometric relationship, only two targets need to be measured when testing the hard disk.
  • the ⁇ value of the track that is, only need to be read and written twice separately, after calculation, the ⁇ value of the start rail and the end rail of each partition can be obtained, and the measurement method of the read/write head offset parameter table of the hard disk is used only A small amount of read and write operations on the hard disk are required, which greatly saves test time.
  • the calculation time in the external computer is much smaller than the time during which the head reads and writes. For example, it takes only about 10 minutes to test the ⁇ value of an ordinary 2.5-inch hard disk, which greatly improves the production and testing efficiency.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Moving Of The Head To Find And Align With The Track (AREA)
  • Digital Magnetic Recording (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)

Description

一种硬盘磁头的读写头偏移参数表的测量方法 技术领域
本发明涉及硬盘制造技术领域， 更具体的说， 涉及一种硬盘磁头的 读写头偏移参数表的测量方法。 背景技术
硬盘读写磁头的结构如图 1所示： 磁头臂的顶端设有并列的两个磁 头， 分别为读头和写头。 读头和写头之间有微小的物理距离 X , 读头和 写头之间的几何连线与磁头臂之间具有固定的夹角 Φ (图中未示出）。 磁 头由磁头臂带动呈弧形在硬盘盘片上方移动， 由于读头和写头之间的物 理距离 X的存在， 读头和写头之间存在一个在盘片径向的读写头偏移参 数 (mroffset, 记为 λ值)， 针对硬盘的每条磁轨， 这个读写头偏移参数 λ 值都是不同的。 由于硬盘的伺服系统是根据读头获取的位置信息来定位 的， 因此， 在对硬盘进行读操作时， 硬盘伺服系统控制磁头的读头直接 到达指定的磁轨即可， 不需要作任何调整； 在对硬盘的某条磁轨进行写 操作时， 意味着写头需要移动到那条磁轨上， 磁头的读头的位置需要根 据那条磁轨上磁头 λ值作相应的调整， 硬盘伺服系统则控制读写磁头移 动， 当读头定位在调整的位置后， 写头就自然定位到指定的磁轨， 例如， 要对磁轨 30000进行写操作， 磁轨 30000的 λ值为 5 , 那么硬盘伺服系 统使读头定位在磁轨 29995(29995=30000-5)处， 写头自然就定位在磁轨 30000处， 就可以对磁轨 30000进行写操作了。
硬盘上磁轨的读写磁头偏移参数 λ值在整条磁轨空间的分布大致趋 势如图 2所示， 图中可见， λ值随着磁轨变化是非线性的。 为了得到每 条磁轨的读写磁头偏移参数 λ值， 在硬盘出厂前进行测试时， 对每条磁 轨的 λ值进行测量是不可能的， 只能通过计算得到。 而我们的硬盘内设 置的运算单元为不支持浮点运算的 DSP单元， 其精度是不足以达到一些 非线性计算的要求的， 因此， 在要计算得到每条磁轨的 λ值时， 需要化 非线性计算为线性计算， 目前的办法是将每个磁头对应的盘面分成多个 线性区， 然后测量不同分区的起始轨和结束轨的 λ值， 并储存在硬盘的 只读存储器中。 在将硬盘盘片分成 4艮多分区后， 由于每个分区的磁轨的 跨度变小， 每个分区内的 λ值的变化可近似为线性分布， 因而在每个分 区可以用线性插值的方法计算出每个目标磁轨的 λ值， 而其在 DSP单元 上运算结果的精度也是能达到要求的。
传统的硬盘为了得到硬盘磁头的读写头偏移参数表的数据， 即盘片 上每个分区的起始轨和结束轨的读写头偏移参数 λ值， 就需要分别对盘 片上的每个分区的起始轨和结束轨进行读写测试， 以获得 λ值。 其中， 每个 λ值的测试过程如下： 先对起始轨的目标磁轨进行写操作， 写完后， 磁头微调， 写头慢慢离开目标磁轨， 读头慢慢移近目标磁轨。 读头由远 及近的靠近已写入数据的目标磁轨时， 读头上的信号感应慢慢变强， 当 到达目标磁轨正上方时， 读头上感应的信号强度最强， 且最稳定； 纪录 此时磁头微调行进的距离， 即为读写头偏移参数 λ。 设硬盘的一个盘片 上有 Ν个分区， 每个分区为了得到其起始轨和结束轨处的 λ值需要分别 进行读写操作各两次， 则要获得一个盘片上所有分区的 λ值， 对硬盘要 进行 2Ν次反复的读写操作。 由于硬盘的分区数 Ν常常很大， 且硬盘的 读写操作耗时较长， 这种得到 λ值的测试很耗费时间， 并且如果某个分 区被测试的磁轨有损坏，则该分区 λ值的测试数据精度往往受很大影响。 如对普通的 2.5寸硬盘进行得到 λ值的测试通常需要 90分钟的时间， 测 试速度慢， 生产、 测试效率较低。 发明内容
为克服上述缺陷， 本发明所要解决的技术问题是提供一种测试速度 更快， 精度较高的硬盘磁头的读写头偏移参数表的测量方法。
本发明的目的是通过以下技术方案来实现的：
一种硬盘磁头的读写头偏移参数表的测量方法， 包括以下步骤： Α: 通过测量得到硬盘盘片上两处磁轨的读写头偏移参数；
Β:根据此两处磁轨的读写头偏移参数，计算得到各个硬盘盘片分区 的起始轨、 结束轨的读写头偏移参数， 得到读写头偏移参数表， 将读写 头偏移参数表写入硬盘。
一种硬盘磁头的读写头偏移参数表的测量方法， 包括以下步骤： A: 通过测量得到硬盘盘片上两个目标磁轨的读写头偏移参数；
B:根据该两个读写头偏移参数，计算得到硬盘磁头的读头和写头之 间的物理距离 X , 以及读头和写头之间的几何连线与磁头臂之间的夹角 φ ;
C: 根据该物理距离 X和夹角 计算得到硬盘盘片各个分区的起始 轨、 结束轨的读写头偏移参数， 从而得到读写头偏移参数表， 并将读写 头偏移参数表写入硬盘。 附图说明
图 1是本发明实施方式中硬盘磁头的结构示意图； 以及
图 2是本发明实施方式中读写头偏移参数随硬盘盘片上磁轨的半径 变化的曲线示意图。 具体实施方式
下面结合附图和较佳的实施方式对本发明作进一步说明。
如图 1所示， 图中的圓形代表硬盘中盘片的读头 Α所在的磁轨； Oo 代表硬盘盘片圓心； （^代表磁头臂的转轴； AB代表硬盘磁头读头 A与 写头 B之间的几何连线； 其中， 读头在第 i条磁轨处与硬盘盘片圓心 0。 之间的距离 Ri(Ri即该条磁轨的半径)与当读头在第 i条磁轨处时， 写头 与硬盘盘片圓心之间的距离 Wi之差即为读写头偏移参数（λ值）。
读写头偏移参数是由于读、 写头之间存在有一物理距离 X , 导致在 同一时刻， 读头 Α和写头 B分别位于不同的磁轨上； 而由于磁盘上磁轨 的分布是以硬盘盘片圓心 Oo为圓心的一组同心圓， 因此，读头 A和写头 B在不同磁轨上方的读写头偏移参数 (即 λ值)是不同的，其曲线走向如图 2所示。 因此， 完全可以根据某处磁轨的 λ值推导出其它位置磁轨的 λ 值。
如： 我们可以通过硬盘磁头的读头 Α和写头 Β之间的物理距离 X , 和读头 A与写头 B之间的几何连线与磁头臂之间的夹角 Φ , 推算出磁头 在不同的磁轨处的 λ值； 可由于硬盘磁头的读头 Α和写头 B之间的物理 距离 X , 和读头 A与写头 B之间的几何连线与磁头臂之间的夹角 Φ的值 都是很小的， 是不能直接测得其精确值的， 因而， 根据磁头臂的转轴 与读头 Α之间的距离 1、硬盘盘片圓心 Oo与磁头臂的转轴 之间的距离 d、 读头 A和写头 B之间的几何连线 AB与读头与硬盘盘片圓心 0。的连 线的夹角 θ、读头 Α与硬盘盘片圓心 Oo的连线和磁头臂 AO之间的夹角 β、读头 Α在第 i条磁轨处与硬盘盘片圓心 0。之间的距离 Ri、 当读头在 第 i条磁轨处时， 写头 B与硬盘盘片圓心 0。之间的距离 Wi等可以测得 的参数，可以通过几何计算得出读头 A和写头 B之间的物理距离 X和读 头 A和写头 B之间的几何连线与磁头臂之间的夹角 。
为了得到通过直接测量难以得到的读头 A和写头 B之间的物理距离 X和读头 A和写头 B之间的几何连线与磁头臂之间的夹角 Φ , 可以先在 硬盘盘片上测量得到两条磁轨的 λ值， 这两条磁轨的间距越远越好； 根 据当前磁轨与硬盘盘片圓心 0。之间的距离 Ri等相关参数， 可以计算出 硬盘磁头中读头 A和写头 B之间的间距 X和读头 A和写头 B之间的几 何连线与磁头臂之间的夹角 Φ。再根据计算得到的 X和 Φ ,可以计算得到 磁盘上每个分区的起始轨和结束轨的 λ值， 得到读写头偏移参数表， 并 将读写头偏移参数表记录到硬盘中。 测量两条磁轨的 λ值的方法可以采 用现有的测量方法。
其中： 在测得两条磁轨的 λ值后， 根据如下方程组（1 ), 可以得到 硬盘磁头的读头和写头之间的物理距离 X和读头和写头之间的几何连线 与磁头臂之间的夹角
R i = W { + λ
W。 = W。 + λ
x2 + W,2 - R
c o s θί =
2 xWi
x2 + Wa 2 - R - c o s 6^ =
Figure imgf000006_0001
l 2 + R0 2 - d 2
co s β ο =
21R φ = π — β ; — Θ ; = 7Ι — β。 一 θ
( 1 ) 其中， 上述方程组（1 ) 中：
Ri: 读头在第 i条磁轨处与硬盘盘片圓心之间的距离；
Wi: 当读头在第 i条磁轨处时， 写头与硬盘盘片圓心之间的距离；
Ro: 读头在第 0条磁轨处与硬盘盘片圓心之间的距离；
Wo: 当读头在第。条磁轨处时， 写头与硬盘盘片圓心之间的距离 读写头偏移参数；
读头和写头之间的物理距离；
读头和写头之间的几何连线与读头与硬盘盘片圓心的连线的夹 β： 读头与硬盘盘片圓心的连线和磁头臂之间的夹角；
1: 磁头臂的转轴与读头之间的距离；
d: 硬盘盘片圓心与磁头臂的转轴之间的距离；
φ : 读头与写头之间的几何连线与磁头臂之间的夹角。
该第 i条磁轨和第 0条磁轨即为前述测量得出 λ值的两条磁轨。 得到硬盘磁头的读头和写头之间的物理距离 X和读头和写头之间的 几何连线与磁头臂之间的夹角 可以根据如下方程组（2 )得到各个分 区的起始轨、 结束轨的读写头偏移参数， 得到读写头偏移参数表： p = arccosi )
21R
θ = π - β - φ ( 2 )
Figure imgf000007_0001
λ = R - W
其中， 上述方程组（2 ) 中：
R: 读头在目标磁轨处 (起始轨或结束轨处)与硬盘盘片圓心之间的距 离， 由于 R与目标磁轨是——对应的关系， 因此这个 R值可由给定目标 磁轨推算出来；
1: 磁头臂的转轴与读头之间的距离；
d: 硬盘盘片圓心与磁头臂的转轴之间的距离； β： 读头与硬盘盘片圓心的连线和磁头臂之间的夹角；
9： 读头和写头之间的几何连线与读头与硬盘盘片圓心的连线的夹 角；
φ : 读头与写头之间的几何连线与磁头臂之间的夹角；
W: 当读头位于目标磁轨处时， 写头与硬盘盘片圓心之间的距离； λ: 读写头偏移参数；
χ: 读头和写头之间的物理距离。
一种硬盘磁头的读写头偏移参数表的测量方法， 包括以下步骤：
Α: 通过测量得到硬盘盘片上两个目标磁轨的读写头偏移参数；
Β:根据该两个读写头偏移参数，计算得到硬盘磁头的读头和写头之 间的物理距离 X , 以及读头和写头之间的几何连线与磁头臂之间的夹角 φ ;
C: 根据该物理距离 X和夹角 计算得到硬盘盘片每个分区的至少 两个磁轨的读写头偏移参数， 从而得到读写头偏移参数表， 并将读写头 偏移参数表写入硬盘。 所述步骤 C中， 较佳的是计算得到每个分区的起 始轨和结束轨的读写头偏移参数。 所述步骤 Α中： 较佳的是两条目标磁 轨在盘片径向上远离。 所述步骤 A中： 可以测量目标磁轨及与目标磁轨 相邻的至少一个磁轨的读写头偏移参数， 将得到的读写头偏移参数的平 均值作为该目标磁轨的读写头偏移参数。
其中， 选择来测量的两处磁轨之间的间距越大， 测得的 λ值的差距 也就越大， 则计算后得到的精度就越高。 尤其以硬盘盘片的最小磁轨处 ( Rid )和最大磁轨处（Rod )最好， 采用这两处磁轨的 λ值计算， 得到 的 X和 的精度最高， 提高了读写头偏移参数表的精度。
另外， 由于我们测试的硬盘盘片上的磁轨有可能有坏道， 若只是测 一条磁轨的 λ值， 则可能得到的是错误的 λ值。 即使测试的磁轨没有坏 道， 我们的测量过程中也是存在误差的。 因此我们在要测量的磁轨相邻 处多选择一条或几条磁轨 (比如 5条磁轨）， 分别测量其 λ值， 再将这些 磁轨的 λ值平均， 记作我们要测量磁轨的 λ值。 由于坏道的 λ值与正常 的 λ值差距很大， 当硬盘中测量的磁轨中有坏道时是很容易发现的， 而 多条磁轨同时是坏道的可能性极小， 将要测量的目标磁轨及附近的磁轨 的 λ值进行平均， 大大减小了 λ值出错的可能。 由于磁轨的间距很小， 我们的测量误差是远远大于相邻磁轨之间的 λ值之差的， 因此， 对要测 量的磁轨及其附近的磁轨的 λ值进行平均， 能使得我们得到的 λ值更加 精确， 减少了测量误差， 提高了得到的读写头偏移参数表的精确度。
由于硬盘中的运算单元常为不支持浮点运算的 DSP单元，而 χ、 Φ和 λ值都是很小的， 细微的误差都会导致硬盘不能正常读取， 要求必须采 用计算精度高的浮点运算， 因此， 对参数值 X和 Θ的计算及 λ值的计算， 是在外部的计算机中进行的。 先将测得的若干磁轨的 λ值导出至外部计 算机中， 根据上述方程组通过迭代、 递归等运算， 得到各个分区的起始 轨、 结束轨的读写头偏移参数， 填入硬盘的读写头偏移参数表中。 而若 将硬盘中的运算单元设置成为支持浮点运算单元的 FPU(Float Point Unit, 浮点运算单元)单元， 则这种计算过程可以直接在硬盘内完成。 不 过， 现阶段 FPU单元的价格较贵， 而且与其相匹配的硬盘的伺服系统也 更复杂， 而这种浮点运算仅在测试时需要， 正常使用硬盘是不需要的， 因而我们仍采用 DSP单元， 不对硬盘的结构#文任何的改变， 测试时采用 由外部支持浮点运算的计算机计算后得到读写头偏移参数再写入硬盘的 方式。
由于磁盘上磁轨的 λ值与硬盘盘片各个分区的起始轨、 结束轨的 λ 值之间的关系可以通过几何关系计算得出， 因而在对硬盘进行测试时， 只需要测两处目标磁轨的 λ值， 即只需要分别读写两次， 计算后即可得 到各个分区的起始轨、 结束轨的 λ值， 使用这种硬盘的读写磁头偏移参 数表的测量方法， 只需要对硬盘进行少量的读写操作即可， 因此大大节 省了测试时间。 而且， 在外部计算机中进行计算的时间会比磁头的读写 操作的时间小得多。 如对普通的 2.5寸硬盘进行得到 λ值的测试仅需要 10分钟左右的时间， 大大提高了生产、 测试效率。
以上内容是结合具体的优选实施方式对本发明所作的进一步详细说 明， 不能认定本发明的具体实施只局限于这些说明。 对于本发明所属技 术领域的普通技术人员来说， 在不脱离本发明构思的前提下， 还可以做 出若干筒单推演或替换， 都应当视为属于本发明的保护范围。

Claims

权利要求:
1、 一种硬盘磁头的读写头偏移参数表的测量方法， 其特征在于： 包 括以下步骤：
A: 通过测量得到硬盘盘片上两处磁轨的读写头偏移参数；
B:根据此两处磁轨的读写头偏移参数，计算得到各个硬盘盘片分区 的起始轨、 结束轨的读写头偏移参数， 得到读写头偏移参数表， 将读写 头偏移参数表写入硬盘。
2、如权利要求 1所述的一种硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述的步骤 A中， 分别测量硬盘盘片的最小磁轨处的 读写头偏移参数和最大磁轨处的读写头偏移参数。
3、如权利要求 1所述的一种硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述的步骤 A中： 测量目标磁轨及与目标磁轨相邻的 至少两个磁轨的读写头偏移参数， 将得到的读写头偏移参数的平均值作 为该目标磁轨的读写头偏移参数。
4、如权利要求 1所述的一种硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述的步骤 B中： 先根据得到的两处磁轨的 λ值， 通 过计算得到硬盘磁头的读头和写头之间的物理距离 X , 以及读头和写头 之间的几何连线与磁头臂之间的夹角 Φ , 再根据该物理距离 X和夹角 计算得到各个分区的起始轨、 结束轨的读写头偏移参数。
5、如权利要求 4所述的一种硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述的步骤 Β中， 根据如下方程组（1 ), 得到硬盘磁 头的读头和写头之间的物理距离 X和读头和写头之间的几何连线与磁头 臂之间的夹角 Ri = Wt + λ
R = W +
xl + W: ― R;
cos θ{
2xWi
x2 +Wa 2 - cos Θ o
Figure imgf000011_0001
■ I2 + R o2 - d2
cosP0
21R o φ = π Θ
(1) 其中， 上述方程组（1) 中：
Ri: 读头在第 i条磁轨处与硬盘盘片圓心之间的距离；
Wi: 当读头位于在第 i条磁轨处时， 写头与硬盘盘片圓心之间的距 离；
Ro: 读头在第。条磁轨处与硬盘盘片圓心之间的距离；
Wo: 当读头位于在第。条磁轨处时， 写头与硬盘盘片圓心之间的距 离；
λ: 读写头偏移参数；
X： 读头和写头之间的物理距离；
9： 读头和写头之间的几何连线与读头与硬盘盘片圓心的连线的夹 角；
β： 读头与硬盘盘片圓心的连线和磁头臂之间的夹角；
1: 磁头臂的转轴与读头之间的距离；
d: 硬盘盘片圓心与磁头臂的转轴之间的距离；
φ: 读头与写头之间的几何连线与磁头臂之间的夹角。
6、如权利要求 5所述的一种硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述的步骤 B中， 根据如下方程组（2 )得到各个分区 的起始轨、 结束轨的读写头偏移参数： p = arccosi )
21R
θ = π - β - φ
Figure imgf000012_0001
λ = ^ - W ( 2 ) 其中， 上述方程组（2 ) 中：
R: 读头在目标磁轨处与硬盘盘片圓心之间的距离；
1: 磁头臂的转轴与读头之间的距离；
d: 硬盘盘片圓心与磁头臂的转轴之间的距离；
β： 读头与硬盘盘片圓心的连线和磁头臂之间的夹角；
Θ: 读头和写头之间的几何连线与读头与硬盘盘片圓心的连线的夹 φ : 读头与写头之间的几何连线与磁头臂之间的夹角；
W: 当读头位于目标磁轨处时， 写头与硬盘盘片圓心之间的距离; λ: 读写头偏移参数；
χ: 读头和写头之间的物理距离。
7、如权利要求 6所述的一种硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述的步骤 Β中： 测量得到的读写头偏移参数发送到 外部的计算机中根据方程组 (1)和方程组 (2)进行计算， 计算得到各个分区 的读写头偏移参数后， 再由该计算机将读写头偏移参数写入硬盘中。
8、如权利要求 6所述的一种硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述的步骤 Β中： 根据测量得到的读写头偏移参数计 算得到各个分区的读写头偏移参数的运算过程在硬盘中的 FPU运算单元 中进行。
9、 一种硬盘磁头的读写头偏移参数表的测量方法， 其特征在于： 包 括以下步骤：
A: 通过测量得到硬盘盘片上两个目标磁轨的读写头偏移参数；
B:根据该两个读写头偏移参数，计算得到硬盘磁头的读头和写头之 间的物理距离 X , 以及读头和写头之间的几何连线与磁头臂之间的夹角 φ ;
C: 根据该物理距离 X和夹角 计算得到硬盘盘片每个分区的至少 两个磁轨的读写头偏移参数， 从而得到读写头偏移参数表， 并将读写头 偏移参数表写入硬盘。
10、如权利要求 9所述的硬盘磁头的读写头偏移参数表的测量方法， 其特征在于： 所述步骤 C中， 计算得到每个分区的起始轨和结束轨的读 写头偏移参数。
11、 如权利要求 10 所述的硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述步骤 Α中： 两条目标磁轨在盘片径向上远离。
12、 如权利要求 11 所述的硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述步骤 A中： 两个目标磁轨分别为硬盘盘片的最小 磁轨和最大磁轨。
13、 如权利要求 10 所述的硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述步骤 A中： 测量目标磁轨及与目标磁轨相邻的至 少一个磁轨的读写头偏移参数， 将得到的读写头偏移参数的平均值作为 该目标磁轨的读写头偏移参数。
14、 如权利要求 13 所述的硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述步骤 A中： 测量目标磁轨及与目标磁轨相邻的至 少两个磁轨的读写头偏移参数。
15、 如权利要求 10 所述的硬盘磁头的读写头偏移参数表的测量方 法， 其特征在于： 所述步骤 B中， 根据方程组 (1)计算物理距离 X和夹角
Ri = + λ
R = W +
X2 +Wi 2 - cos θί =
2xWt
X2 +Wo 2 - R
cos o2
θο =
Figure imgf000014_0001
I2 + R
cos β0 = o2 - d2
LK 一 β ; - Θ i θ。 （1) 所述步骤 C中， 根据方程组 (2)计算各分区的起始轨、 结束轨的读写 头偏移参数： p = arccosi )
21R
θ = π - β - φ
Figure imgf000014_0002
λ = ^ - W (2) Ri: 读头在第 i条磁轨处与硬盘盘片圓心之间的距离；
Wi: 当读头位于在第 i条磁轨处时， 写头与硬盘盘片圓心之间的距
Ro: 读头在第 0条磁轨处与硬盘盘片圓心之间的距离；
Wo: 当读头位于在第。条磁轨处时， 写头与硬盘盘片圓心之间的距 X： 读头和写头之间的物理距离；
9： 读头和写头之间的几何连线与读头与硬盘盘片圓心的连线的夹 β： 读头与硬盘盘片圓心的连线和磁头臂之间的夹角；
1: 磁头臂的转轴与读头之间的距离；
d: 硬盘盘片圓心与磁头臂的转轴之间的距离；
φ : 读头与写头之间的几何连线与磁头臂之间的夹角。
R: 读头在各分区的起始轨或结束轨处与硬盘盘片圓心之间的距离； W: 当读头位于起始轨或结束轨时， 写头与硬盘盘片圓心之间的距
PCT/CN2008/073366 2007-12-06 2008-12-08 一种硬盘磁头的读写头偏移参数表的测量方法 WO2009076870A1 (zh)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07326032A (ja) * 1994-05-31 1995-12-12 Nec Corp 磁気ディスク装置
US20030156347A1 (en) * 2002-02-21 2003-08-21 Fujitsu Limited Magnetic disk drive system
US20050002121A1 (en) * 2003-07-01 2005-01-06 Allen Gregory M. Method and apparatus for writing with head having spaced read and write elements
CN1652209A (zh) * 2004-01-29 2005-08-10 株式会社东芝 用于磁盘驱动器中磁头定位控制的方法与设备
CN1988003A (zh) * 2005-12-21 2007-06-27 株式会社东芝 磁盘驱动器中用于磁头定位控制的方法和装置
US20070258165A1 (en) * 2006-03-13 2007-11-08 Samsung Electronics Co., Ltd. Third order curve fit for head skew in a hard disk drive

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07326032A (ja) * 1994-05-31 1995-12-12 Nec Corp 磁気ディスク装置
US20030156347A1 (en) * 2002-02-21 2003-08-21 Fujitsu Limited Magnetic disk drive system
US20050002121A1 (en) * 2003-07-01 2005-01-06 Allen Gregory M. Method and apparatus for writing with head having spaced read and write elements
CN1652209A (zh) * 2004-01-29 2005-08-10 株式会社东芝 用于磁盘驱动器中磁头定位控制的方法与设备
CN1988003A (zh) * 2005-12-21 2007-06-27 株式会社东芝 磁盘驱动器中用于磁头定位控制的方法和装置
US20070258165A1 (en) * 2006-03-13 2007-11-08 Samsung Electronics Co., Ltd. Third order curve fit for head skew in a hard disk drive

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