JPH06342345A - Disk drive and method for formatting magnetic disk - Google Patents

Abstract

PURPOSE:To enable accurate positioning and format sectors on a high speed magnetic disk by forming the sectors on the surface of the magnetic disk with servo burst pulses for embedding position information in tracks written. CONSTITUTION:The servo burst pulses are embedded on a hard disk first through a read/write head 36 under the control of, for example, a microcontroller 144. The controller 144 and a memory 146 operate on each other so as to perform formatting operation on the basis of a program stored in the memory. Further, the controller 144 detects the end of the servo burst and writes sector information to indicate the formatting of the disk 22 by the read/write head 36. When, however, all sectors are formed on a track, a control instruction is sent to an actuator control part 152 to move the head to the next track. The read/write head 36 moves to the next data track on the disk 22 and starts formatting the track.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to small form factor disk drives driven in computers and word processors, and more particularly by writing predetermined information and defining a user data area for each storage sector on the disk surface. And an improved disk drive for formatting a data sector of the same and a method of formatting a magnetic disk.

[0002]

Disk drive storage systems (disk drives) have long been used to store information in computers, word processors, computer control information retrieval systems and the like. In disk drives, information is typically recorded in the form of digital electrical signals on concentric storage tracks of magnetic disks. As is well known in the art, there are basically two
There are types. "Floppy" disk drive and "Her"
Disk drive. In both disc drives, the disc is rotatably mounted on a spindle. The read / write head is typically mounted on a pivot arm and moves radially across the surface of the disk to access different memory locations. There are more than 800 memory tracks per inch in the radial direction of the disk. Each track has, for example, 36-72 sectors.
, Each sector can store a plurality of digital data, typically 512 bytes or 1024 bytes.

In order to be able to read and write the proper information, the read / write head must be able to be precisely located in the proper track on the disk. The floppy disk drive holds information on a replaceable flexible magnetic disk. Hard disks hold information on rigid, non-replaceable (possibly replaceable) disks. Har
Disks are often made of magnetically coated aluminum. Hard disks have a greater amount of information retention density than floppy disks, and therefore hard disks.
The magnetic disk drive must be able to align the magnetic head more accurately than the floppy disk drive.

In particular, a disk drive such as a small-factor disk drive is installed in the housing of a computer and receives instructions from a host computer for reading and writing information on the disk. In order to increase the memory capacity of the small factor disk drive, a large number of hard disks may be stacked inside each other. The disc is, for example, 3600 rp
In order to read and write information on the disk quickly, such as m (number of revolutions per minute), the spindle motor rotates at high speed.

The advent of personal and portable computer devices called "laptop computers" or "notebook computers" has led to
It played a major role in promoting compact and lightweight disk drives. The relative size of a disk drive is commonly referred to as the form factor. Form factors of 2.5 inches (6.25 cm) and smaller ones are becoming relatively common.

In addition to reducing the size and weight of disk drives associated with laptop computers, it is also important to increase the storage density by precisely formatting a large number of storage sectors on the surface of a magnetic disk. As I touched on a little earlier, a sector is a small area on a magnetic disk for storing data. Each sector also contains areas for sector identification and data synchronization. "Formatting" is a procedure of forming sectors on each track of a disc for storing data therein and forming other information such as sector identification data and a sync signal. The formatting procedure (or disk initialization) is required for all disk drives to define the sectors on the disk. The formatting procedure is usually done by the manufacturer before putting the disk drive on the market or before it is built into the computer.

As is well known in the art, prior to the formatting procedure, a special signal called the "servo burst pulse" is embedded over the disk surface to define the position of the track with respect to the disk radius. During the formatting procedure, the magnetic head (the read / write head of the disk drive for reading and writing data in the disk) uses an electric signal on the data surface to define each sector based on the instruction from the controller of the disk drive. give. This procedure, for example,
Steps for determining the position of the sector on the data, writing the identification data, defining the data area within the sector, and writing other electrical signals such as error correction codes. including.

In the formatting procedure, the servo burst pulse is used as a reference to determine the position of a particular track on the disk surface by reading the servo burst pulse with a read / write head. The servo burst pulses are determined by the controller so that the feedback loop of the disk drive can control the position of the read / write head as is well known in the art.

A high-density hard disk can have, for example, 40,000 or more sectors on one surface of the disk. Further, one disk drive may include one or more magnetic disks, for example, two or three or more magnetic disks. Therefore, in the case of two disks, 160,000 or more sectors must be formed in the disk of the disk drive on a total of four data surfaces. The read / write heads provide different identification signals, each defining an area of 160,000 or more sectors. Therefore, formatting all surfaces is very time consuming, as is the technique required to precisely position the read / write head on the disk surface.

In conventional disk drives, the index pulse is used as a reference to define the position of a sector when the read / write head is located near the sector to be disk formatted. That is, in the typical conventional method of formatting a hard disk, the index pulse, which is usually embedded in the disk at the same time as embedding the servo burst pulse, is used to define the absolute position of the intended sector. In such conventional methods, index pulses are applied to the surface of the disk such that the index pulse is detected by the read / write head at each disk revolution. The index pulse is embedded at an arbitrary position on the data track of the disc. As an example, the index pulse is embedded at the beginning of each track on the same radial line of the disc.

In formatting the disc using the index pulse, the index pulse is used as a start timing of the formatting operation. Therefore, the sector is formed on each track in a temporally continuous manner based on a predetermined time interval controlled by the controller of the disk drive. That is, in this conventional method, an index pulse is generated on each track of the disk to initiate a write operation to format a sector of the track. The main factors in the time required to format a sector are:
Disk speed (eg 3,600 rpm), time required to write data required for sectors, or
There is the time required for servo control of the read / write head position on the disk, including the time for the read / write head to read the servo burst pulse.

The next index pulse in the next track is used as a reference for positioning the storage sector on the next track. The read / write head initiates formatting on the track based on the index pulse to sequentially form, for example, 72 sectors. The time to format one sector is not exactly the same, and there are some time differences between them. Thus, the last sector position of one data track is not always on the same radial line as the last sector position of another data track. That is, the position of the read / write head at the end of the formatting of one data track will change with respect to the position of the last sector of another data track. As a result, the read / write head must wait until the next track index pulse is detected each time it has to move to the next track for a format operation. Therefore, since the read / write head has to wait,
There is a loss of time in the formatting operation, and in the worst case, a loss of time corresponding to one rotation of the data of each track.

When changing the read / write head from one track to another, a head settling time of 1-2 ms is typically required. This settling time corresponds to the time during which the three or four sectors scheduled for use pass the track. Therefore, when head settling is complete, the read / write head is positioned after the first sector formatted in the previous track, and three or four sectors scheduled for formatting. In this situation, the read / write head has overrun a sector length of 3 or 4 from the index pulse due to head settling time.
Therefore, the read / write head must wait for the disk to rotate until the next track index pulse is detected before formatting the next data track.

Furthermore, with this method, the index pulse is used as a reference for absolute positioning for all possible sectors on the track, so that position errors accumulate over the entire track. That is, in the conventional method, the sectors are formed based on a predetermined order after the track index pulse is detected. The position of each sector on the track is determined with respect to the position of the index pulse. Thus, when the position accuracy of each sector is compromised, a so-called "lack" occurs in which a sector is not formed due to such accumulated position errors.

[0015]

Therefore, there is a need for a small form factor disk that has the ability to format sectors on a magnetic disk with more accurate positioning and faster speeds. There is also a need for small form factor discs that can define each position of a sector on a track on the magnetic surface of the disc and that is capable of embedding the necessary information about the sector without lacking.

[0016]

According to the present invention, a hard disk is formatted by writing servo burst pulses for embedding position information in tracks and forming sectors on the entire surface of a magnetic disk at high speed and precise positioning. The present invention relates to a disk drive using a new method (initializing a disk).

The present invention is an improved small form factor disk that uses a new method to format a magnetic disk for increased accuracy in forming many data storage sectors in a small space in a short time. Provide a drive. The present invention eliminates the need for index pulses and is provided by index pulses during format and read / write operations.
Reduces the lack phenomenon experienced with conventional disk drives.

The present invention provides a technique by which a disk drive manufacturer can format a hard disk without using index pulses to determine the absolute position of a sector. In the present invention, the servo burst pulse is used to define the position of each sector. Since the servo burst pulse is embedded in the entire track of the disk drive, for example, in one track at an accurate interval at 72 locations, by using the servo burst pulse as a reference for a nearby sector, more accurate positioning can be achieved than the conventional method. It is possible.

The present invention utilizes the end timing of the servo burst pulse to determine the starting position of the sector to be formed. After the formation of a sector, the servo burst pulse immediately after the sector that has just been formatted is used as a reference for positioning the next sector. Thus, at a particular disk radius, the end signal of the servo burst pulse will be the reference for the next adjacent sector, and the end signal of the next servo burst pulse will be the "reference" for the next adjacent sector. . In this way, each servo burst serves as a reference for the next sector, so that the expected sector positioning error is not accumulated by the data track formatting operation.

The disk drive of the present invention embeds a servo burst pulse in the hard disk and defines a large number of data sectors in addition to the entire operation of the disk drive, thereby controlling the entire operation procedure for formatting the hard disk. A controller, a memory that stores a series of programs for disk drive operations including format operations, a read / write head that reads and writes data in normal operation in addition to servo burst pulses and data to be formatted, and read / Disk drive electronics for forming a feedback control loop that determines the position of the read / write head by determining the data determined by the write / write head, and the like.

The method of formatting a hard disk according to the present invention comprises: (1) writing servo burst pulses in the radial direction on the surface of the disk; (2) operating a read / write head for detecting the end signal of the servo burst pulse;
(3) Determine the position of the next sector with respect to the end signal of the servo burst pulse, and (4) write the other data, including the identification field and data field, or error correction code and gaps at the end of the sector. , (5) after formatting all the sectors on the track, move to the next data track to further format the sectors on the next track, and (6) for all sectors on the disk surface (2 )-(5) is repeated.

The method of the present invention for the formatting procedure can be performed by the manufacturer before putting the disk drive on the market. By using the present invention, the hard disk format time can be significantly reduced. The present invention can effectively reduce the total time required for the disk formatting procedure, especially the time required for the read / write head to move around the disk surface boundary (head skew).

According to one aspect of the invention, when changing the read / write head from one data track to another data track, the read / write head is provided with the servo burst that comes immediately after the head moves to the next track. Format a sector with the next data track, starting from one sector (sector zero) by detecting the end. The first three or four servo bursts are passed while the head is fixed, but the disk drive of the present invention can format these sectors at the final stage of formatting this data track. That is, the format of the new track begins after the settling time of 3, 4 servo bursts has passed, and thus the region between settling is considered to be the end of the track. Therefore, unlike the conventional method, in the disk drive of the present invention, the formatting operation is started without waiting for one revolution in the movement of the data track. Therefore, since one disc surface contains about 1000 data tracks, the format according to the present invention can significantly reduce the time required to format the entire disc surface.

According to another aspect of the present invention, when formatting a hard disk, if a servo burst occurs during the formatting of the data area, the data area of the sector of the inner track is divided into two or more data areas. . This situation occurs because the outer track is longer than the inner track and each sector must have a uniform, eg 512 byte, data area over the entire disk surface. Thus, in order to maintain the same storage density, the innermost data track can have only 36 sectors, while the outermost data track can have, for example, 72 sectors. The number of servo bursts in this example is 72 regardless of the position of the data track.
Is. Therefore, especially in the inner data track, the servo burst occurs within the length of the data area of the sector because the length of the data area is relatively large with respect to the interval of the servo burst. According to the present invention, the remaining data area is
It is formed by the end timing of the servo burst that comes during the formatting of the data area.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to facilitate a better understanding of the present invention, a hard disk in which the present invention is adopted will be described first. Disk Drive Overview A disk drive device including an improved power control circuit and method according to the present invention is used in computer systems, such as laptop computers and notebook computers. In the perspective view of FIG. 1, the disk drive device has a housing 20 having one or more hard disks 22 for accommodating disk drive hardware. Although not shown in FIG. 1, the lower part of the housing 20, for example, is provided with a printed circuit board for assembling electrical circuit components of the disk drive electronics. The disk 22 preferably has a radius of about 2.5 inches (6.25 cm) and the disk 2
Information can be recorded on each of the two sides. For example, about 20-40 megabytes of information can be recorded on the formatted disk 22. In the example of the disk drive device shown in FIG. 3, two hard disks 22a and 22b are supplied and information of 80 to 160 megabytes can be stored. However, this storage capacity is expected to increase further due to future expansion.

Each hard disk 22 is rotated by a spindle motor mechanism 24, which will be described in detail with reference to FIG. As shown in FIG. 1, since the rotary actuator 26 is used for reading and writing information on the surface of the disk 22,
It is supplied close to the disk 22. The actuator mechanism 26 includes an actuator coil 28 to which electric current is supplied to cause the actuator mechanism 26 to perform a rotational movement.

The actuator arm 30 is also a part of the actuator mechanism 26. Actuator arm 30 has a generally triangular actuator arm or rod beam 32. Near the free end of the rod beam 32 is a flexure 34 that is flexibly installed on the rod beam 32. A transducer or read / write head (not shown but below flexure 34) contacts flexure 34 and extends therefrom toward the surface of disk 22. Read / write head 36
An actuator pivot 38, which constitutes a pivot axis, is incorporated in the actuator arm 30 so that the actuator arm 30 can rotate in order to access the desired position on the disk surface.

FIG. 1 further shows the rear portion 40 of the actuator mechanism 26. The rear portion 40 includes a traveling or movable member 44. In the preferred embodiment, the rear portion 40 is constructed of a non-magnetic material such as plastic or fiber material. The non-magnetic rear portion functions to disconnect the current loop formed when the other portion of the actuator mechanism 26 is made of metal. The rear portion of the non-magnetic material is
As is well known for such disk drive actuator mechanisms, it provides the balancing function of the actuator mechanism 26 around the pivot 38. Also, this non-magnetic material rear portion does not obstruct the return path of the magnetic field associated with the coil and motor operation.

The rear portion 40 and the movable member 44 included therein provide a novel collision stopping mechanism, and function by the combination of the first stopping member 44 and the second stopping member 43. The rear portion further has a stop spring 44 and a hub 45. For more information on the rear portion 40 and its associated crash stop mechanism, see "Rotary Disc Drive Actuator" by U.S. patent application Ser. No. 07 / 975,386 filed on November 12, 1992 by the same applicant as the present invention. It is shown.

Further, an important part of the disk drive device is a flexible circuit 62, as shown in FIG. The flexible circuit 62 has a read / write head 62.
Constructed of flexible material with etched circuits to transfer information between. An end of the flexible circuit 62 is connected to the actuator arm 30, and a part of the flexible circuit 62 is attached to the housing 20.

The integrated circuit (IC) is a flexible circuit 62.
It is installed on top of. Moreover, the other end of the other flexible circuit 62 is also a flexible circuit 78 having a connection terminal for connecting to drive control electronics. When the actuator body 30 rotates,
The flexible circuit 62 is deformed by the actuator assembly 26 with zero torque.

The spindle motor is hidden under the spindle motor mechanism 24 of FIG. 1, but a sectional view is shown in FIG. 3 described later. In this configuration, as shown in FIG. 3, two disks 22a, 22b are stacked on a spindle motor, and a second actuator arm (not shown) is well known in the art. To
It is inserted between two discs for reading and writing from the lower disc. This configuration does not limit the scope of the present invention, and it is well known that two or more disks can be stacked in a small form factor disk drive.

In FIGS. 2A and 2B, the operation of the disk drive is performed as follows. In FIG. 2, the read / write head 36 on the load beam 32 is located on the outer track T1 of the disk 22. In FIG. 2B, the actuator 2 based on the instruction from the host computer.
By the operation of the disk drive 20 which activates 6,
The position of the read / write head 36 moves to the track T2 of the disk 22. As shown in FIG. 2A, it is assumed that the read / write head 36 is paused at the accessed track T1 after the previous read / write operation. The disk drive 20 is accessed within a predetermined time period,
It is assumed that the spindle motor 90 and actuator assembly 26 are not in the "sleep" state when a new instruction is given to move the read / write head to track T2.

The user of the host computer (eg, laptop computer) gives the disk 22 instructions for reading and writing. The host computer and the disk drive electronics, that is, the electric circuit and IC (FIG. 1) on the printed circuit board (not shown) are flexible to drive the actuator motor (not shown) through the actuator coil. Circuit 62
Send a signal from. Since the current levels for driving the spindle motor are relatively high, the spindle motor assembly 24 (FIG. 3) preferably provides the drive signal through a different line (not shown). The spindle motor assembly 24 rotates the disk 22 at a high speed, such as 3,600 rpm, and the actuator motor moves the actuator arm 30 radially over the rapidly rotating disk.

As is well known in the art,
The positioning operation from the information sector of a certain track to the information sector of another track is basically performed by a servo mechanism which is a feedback controller. In the servo mechanism, a predetermined signal including a servo burst is provided on the disk 22, and the servo coil and other signals of the disk are read by a read / write head to drive the actuator coil 28. The current is controlled so as to stop at the target sector of track T2 in FIG. 2 (b).

An example of the construction of the spindle motor assembly 24 is shown in the sectional view of FIG. 2 aluminum data
The discs 22a and 22b are disc clamp plates 128.
Is attached to the spindle motor housing 90. The center of the clamp plate 128 is fixed to the uppermost portion of the spindle motor housing 90 with a screw 132. The periphery of the clamp plate 128 has a downwardly curved circular elbow 130 that exerts a downward force when the screw 132 is secured to the surface of the upper disc 22a. The upper disc 22a is installed on a ring-shaped disc spacer-117 supported by the lower disc 22b.
Disc Spacer-117 is precision machined to determine the height at which a lower actuator arm (not shown) can move between discs. The downward clamping force is transmitted to the annular flange 80 of the hub of the housing 90 through the lower disc 22b.

The spindle motor housing 90 further has a shaft 86 extending downward as a center. The bearings 108, 110 are rotatably coupled between the shaft 86 of the spindle motor 90 and a hollow cylindrical flange 112 extending upwardly from the base 116. The annular magnet 98 is adhered to the outer surface of the base flange 112 which supplies electromagnetic drive, and at the same time, the stator.
It is glued inside the spindle motor 90 so that it rotates closely around 100. Current is starter-10
When flowing through 0, the base 116 is fixed to the disk drive housing 20 so that the spindle motor housing 90 rotates on the base 116.
(Appendix: Spindle motor, as used here
Since the housing 90 is a rotating portion of the spindle motor assembly 24, the spindle motor housing 90 is also referred to as a spindle motor 90 here. ) More details about the spindle motor, namely the structure of each of its components, the material of the parts, the process of assembly, etc., are assigned by the same applicant as the applicant of the present invention.
US Patent Application No. 07 / filed on Nov. 12, 2013
974, 986, "Disk Drive Spindle Motors". Electric Circuit Configuration FIG. 4 shows an example of the electric circuit configuration of the disk drive according to the present invention. In FIG. 4, the micro controller 14
4 and a minimum number of control support circuits direct all the functions of the disk drive 20. In the preferred embodiment of the invention, the micro-controller 144 may be of any type required in the market. Eg 3
Megahertz Crockate Motorola MC68HC1
1. An HCMOS single chip micro controller can be used.

Read Only Memory (ROM) 146
Is general purpose data, address, control bus 16
0 to the micro controller 144. The ROM 146 stores a control program for the micro controller that supports the main tasks required to execute all the functions of the disk drive 20.
These tasks include format control, access time vs. power consumption control according to the present invention, current control of the spindle motor, and host computer.
Interface control, actuator drive control, spindle motor drive control, read / write control, monitor control, and the like. The register-147 can be replaced with the ROM 146 in the microcontroller or the internal memory or the register, but it is preferable to use it as the storage information for the access time vs. power consumption table as described above.

An interface control circuit 148 is provided to support the microcontroller 144 in performing interface tasks with the host computer. A standardized interface control circuit is commercially available in the form of an integrated circuit, such as the CL-SH250 integrated SCSI disk controller by Irus Logic. Generally, the interface controller 148 provides a hardware interface between the disk drive 20 and the host computer through the communication bus 180. In this way, the interface controller 148 manages the bidirectional flow of data between the communication bus 180 and the bus 160.

The actuator controller 152 and the current limiter 153 are provided as an internal interface between the micro controller 144 and the actuator mechanism 26. Actuator controller 152 includes a digital-to-analog converter for converting the digital position control word to an analog voltage and providing that analog voltage on line 166. A digital position control word supplied by the microcontroller 144 via the bus 160 represents the desired actuator position. The current controller 153 is supplied by a digital current control word from the micro controller 144 via the line 175. This control word on line 175 determines the output current level supplied to the voice coil motor of actuator mechanism 26. As will be described in detail later, the digital current control word is determined by the seek profile in the program of the present invention. Further, the current limiter 153
The details of the seek profile will be described later. The enable to the actuator controller 152 is supplied from the control support circuit 150 via the control line 164. For this purpose, this control support circuit 15
0 serves as a parallel port expander for latching control data supplied from the microcontroller 144 via the bus 160.

The read / write controller 156 similarly functions as an internal interface between the bus 160 and the read / write head of the actuator assembly 26 via the data line 176. Read / write head controller 1
Reference numeral 56 fulfills the functions of serial and deserialization and the function of the data encoding / decoding data clock. The configuration and initialization of the read / write controller 156 is controlled by the bus 16 under the direct control of the microcontroller 144.
It is executed by transferring the control word and data word to the read / write controller 156 via 0.

Spindle motor controller 154 is provided to supply drive current to spindle motor 24 via current line 170 and current limiter 155. The drive current is selected by a digital word from the micro controller 144 to the control support circuit 150. This digital word is latched on line 168 and fed to spindle motor controller 154. The current limiter 155 is supplied with the digital current control word from the micro controller 144 via the line 173. This current control word determines the output current level supplied to the spindle motor 24. The digital current control word is determined by the starting current control program of the present invention. The internal structure of the current limiter 155 is similar to that of the current limiter 153. The start current control program will be described later in detail. Based on the instruction from the micro controller 144, the current limiter 15
The spindle motor controller 154 supplies drive current to the current limiter 155 via line 170 so that the drive current level 5 can be varied significantly. FIG. 5 shows the current controller 153 according to the invention of FIG.
It is an example of a detailed block diagram. The current controller 15 of the present invention for generating a spindle motor current.
5 can also have the same configuration. The circuit configuration of FIG. 5 is for illustrative purposes only, and it will be apparent to those having ordinary skill in the art that various other configurations are possible based on the essence of the present invention. The current limiter 153 driving the actuator assembly 26 includes a voltage divider 15
7, a voltage comparator 159, a power amplifier 161, and a buffer-163. Series resistor R is connected to the output of power amplifier 161, which provides drive current to actuator assembly 26.

The voltage divider 157 is supplied with the digital current control word from the micro controller 144. The digital current control word defines the drive current level, ie the current controller level (or gain) based on the process of the seek profile of the present invention. That is, as described above regarding the access time setting by the vendor unique command or seek command, the gain (that is, the current level) for driving the actuator assembly 26 is a seek profile based on the user setting. decide. The voltage divider 157 divides the reference voltage V based on the digital current control word and supplies the resultant voltage to the comparator 159.

An analog voltage is supplied to the power amplifier 161 from the actuator controller 152. The analog voltage from this actuator controller 152 corresponds to a digital position control word that defines the position of the read / write head 36 on the disk 22. The other input terminal of the power amplifier 161 is connected to the output terminal of the comparator 159. The power amplifier 161 supplies drive power to the actuator assembly through the resistor R. Buffer-163 detects the voltage drop across resistor R, which indicates the amount of current to actuator assembly 26, and supplies that voltage drop to comparator 159 for comparison with a reference voltage. Therefore, the power amplifier 161, the buffer-163, and the comparator 159 constitute a negative feedback loop, and the output current to the actuator assembly is output based on the digital current control word from the micro controller 144. To control. In this configuration, the current limiter 1
53 and 155 can generate actuator drive current and spindle motor drive current, respectively, the amount of which is controlled by the signal of the micro controller 144. For example, 400mA and 600m
A spindle motor starting current of 800 mA is selected and generated by the current limiter 155.

The switch S1 is provided for switching between the feedback loop including the comparator 159 and the feedback loop directly connected to the output of the buffer-163. In the latter feedback loop, the output current to the actuator is directly determined by the input signal from the actuator control 152 because the feedback loop functions as a unity gain buffer. The switch S1 is controlled by a command signal from the micro controller 144. Therefore, when the user does not need the current limiting function of the present invention (actuator power consumption control by access time or spindle motor current control), the switch S1 is operated to activate the current controller 153. You can disable 155.

For more details on the power saving operation, refer to US patent application Ser. No. 07 / 975,503, entitled “Disk Drive Power Control Circuit,” filed Nov. 12, 1992 by the same applicant as the present applicant. That method ”. Magnetic Disk Format FIG. 6 represents magnetic data with multiple data storage tracks for corresponding radii. The magnetic disk 22 includes a plurality of tracks T12, T14, T16, T18, and each track is located at a specific radius R12, R14, R16, R18 from the center of the disk 22. In modern disk drives, many data tracks, such as about 1000 tracks, are located on one surface of the disk. These data tracks are defined by "servo burst pulses" that are embedded throughout the disk surface. As is well known in the art,
A servo burst is a set of pulsed signals formed by several types of pulsed high frequency signals, such as shown in US Pat. No. 5,025,335, acquired by Stefansky. For example, as shown in FIG. 11, the servo burst pulse is embedded at 72 positions every disk rotation (track by track).

FIG. 7 is a schematic diagram showing several data sectors in one track of the disc. Sector ST
20, ST21, ST23 are successively formed on the track by the formatting process which is the subject of the present invention. Generally, the radius of the disc (length of the track) forms 36 to 72 sectors on one track of this type of small form factor disc drive. Each sector can store 512 bytes or 1024 bytes of digital data. Each sector consists of two parts, a header field that stores various identification information and a data field that stores user data (user area).

Ordinary header fields include variable frequency oscillation (VFO), address mark (AM), ID sync signal (ID SYNC), cylinder address, read / write head address, sector address, and cycle redundancy code (CRC). It consists of various types of information.
The data field includes variable frequency vibration (VFO), data synchronization signal, data area, error correction code (EC
C), end gap, etc. A more detailed description of the structure of the sector is given later with respect to FIG.

FIG. 8 shows a conventional method of disc formatting using index pulses. As described above, the "format" is a procedure for forming a sector on each track of the disc and storing the data therein together with other information such as sector identification data and a sync signal. The formatting process is typically performed by the disk drive manufacturer before putting the disk drive on the market or installing the disk drive in a computer. The index pulse is embedded in the disc for each data track, as described as "index" in FIG. Normally, the index pulse is embedded at the same time as the servo burst pulse is embedded in the disc, as described above. In conventional disk drives, the index pulse was used as a reference for the position of the read / write head when formatting a hard disk.

In the format process, the read / write head writes sector information to define each sector based on commands from the disk drive controller, as described above. The index pulse is
Used to determine the absolute position of a particular sector on the data track. Thus, once the index pulse is detected on the data track, the read / write head continues to write the information necessary to form the sector on the track one by one at a predetermined time interval between sectors. At the same time, the servo burst pulses are used as a reference to position each data track on the disk surface so that the read / write head is kept in track by reading the servo burst signal.
The servo burst signal is determined by the controller so that the servo operation of the disk drive (the feedback loop formed by the disk drive electronics) can control the position of the read / write head, as is well known in the art. It

In the example of FIG. 8, the index pulse is detected every time the disk rotates. When the read / write head detects the index pulse, the controller provides information about the order of sectors (sector table) so that the read / write head writes the sector information to form the sector on the track. Therefore, after the index pulse I1 is detected, the sector ST0
Sector ST0 is formed by writing the sector information of. After a predetermined time (or gap length) from the end of sector ST0, the read / write head is
Proceed to form sector ST1. Similarly, the read / write head proceeds to form sector ST2 after a predetermined time from the end of sector ST1. Sectors ST3, ST4. ． ． Are formed in the same way. This formatting operation is repeated until all sectors of the track have been formed.

After formatting one data track on the disk surface, the read / write head moves to the next track. The format operation starts when the read / write head detects the index pulse T2 of the next track. Sectors STk, STk + 1, ST
k + 2 and the like are formed by the same procedure as the previous data track. As such, the read / write head moves to the next data track and repeats the formatting operation for this track. This operation is repeated until all sectors are formed on all data tracks on the disk surface.

As described above, when the disk is formatted using the index pulse, the index pulse is used as the start timing of the formatting operation. Thus, the sectors are formed on each track in a time-sequential manner based on predetermined time intervals controlled by the disk drive controller. That is, in this conventional method, an index pulse is detected on each track on the disk to initialize the write operation to format the sector on the track. The time interval for formatting a sector depends on the rotation speed of the disk (eg, 3600r).
pm) or the time it takes to write the required data to the sector, or the time it takes to servo control the position of the read / write head on the disk, including the time it takes for the read / write head to read the servo burst pulses. , Determined by various time factors.

On the next track, the next index pulse is used as a reference to position the sector on the next track. Based on the index pulse, the read / write head initiates formatting to continuously form, for example, 72 sectors on the track.
The actual time to format one sector is not the same as the others, each with a slight time lag. This slight time difference of each sector is accumulated through the formatting operation of all sectors of each data track.

Therefore, the last sector position of one data track is not always on the same radial line as the other data tracks. So the position of the read / write head at each end of the format of one data track is
Different for other tracks. The main cause of this fluctuation is
Differences in time (accumulated position errors) and changes in head skew from one track to another (read / read
Change in the mechanical position of the writing head). Moreover, the read / write head requires some time to move the position of the head from one track to another, as described below. As a result, each time the read / write head has to move to the next track for a format operation, the head must wait until the next track index pulse is detected. Therefore,
There is a loss of time in the formatting operation wasted by the read / write head, and in the worst case, a loss of time corresponding to the disk rotation of each track.

For example, in FIG. 8, the index pulse is arranged on the radial line Ri by the method of one index pulse for each track. The disk 22 rotates in the direction indicated by the arrow at the upper left of FIG. The read / write head 36 is shown on the left side of FIG. If the read / write head 36 comes to a position as shown at the end of the format of one track, that is, just to the left of the radial line Ri, the index pulse, as marked by A1, I2 immediately arrives on sectors Tk, STk + 1, STk + 2. ． ． And start formatting. However, the read / write head 36
However, in order to format the track T3, for example, A
If it is just to the right of the radial line Ri as marked by 2, the read / write head 36 has to wait approximately one revolution of the disk 22 until the index pulse I3 is detected.

Because of the time required for the read / write head to change its position from one track to another,
This situation happens easily. When moving the read / write head from one track to another, a 1-2 ms head settling time is required. This settling time is
Equal to the time it takes for three or four sectors to cross the track. Thus, when head settling is complete, the read / write head is positioned after the first sector formatted on the previous track, and three or four sectors expected to be used. Since the disk contains more than 800 data tracks on one surface, and the disk with two hard disks contains more than 3200 tracks, the conventional method has a considerable amount of time to complete the formatting operation. I need time.

Furthermore, with this method, the index pulse is used as a reference for absolute positioning for all possible sectors on the track, so that position errors accumulate over the entire track. That is, in the conventional method, the sectors are formed based on a predetermined order after the track index pulse is detected. The position of each sector is determined on the track with respect to the position of the index pulse. Thus, if the position accuracy of each sector is compromised, a so-called "lack" occurs in which a sector is not formed due to such accumulated position error.

In the present invention, the end of the servo burst pulse is used as a reference for the next sector format. FIG. 9 is a timing chart showing the timing relationship between the index pulse of the conventional method and the end of the servo burst pulse of the present invention regarding the sector format signal. FIG. 9A shows the index pulse I1 of the above-described conventional method for formatting a hard disk. In FIG. 9B, the end of each servo burst pulse is the sector ST1 of FIG. 9C.
The servo burst pulses SB1 to SB4, which serve as a trigger for starting the ST4 format, are shown. Note that this condition does not necessarily occur, as the number of servo bursts exceeds the number of sectors formed by the data tracks, as described below in FIG.

As shown in FIGS. 9B and 9C,
The end timing of each servo burst SB1 determines the start position of the first sector ST1 to be formed. After the first sector ST1 is formed, the servo burst SB2 immediately after the end of the first sector ST1 which has just been formatted is the next sector ST2.
Used as a reference for determining the starting position of the. The end timing of the servo bursts SB3 and SB4 is the sector ST.
3 and ST4 start timings are determined respectively. In this method, at a particular radius on the disk, the end signal of the servo burst becomes the reference for the next adjacent sector, and the end signal of the next servo burst pulse becomes the reference for the next adjacent sector. . as a result,
Position errors of sectors that are likely to be used do not accumulate due to data track formatting operations.

In operation, servo burst pulses are initially embedded in the hard disk through the read / write head 36, for example under the control of the microcontroller 144 of FIG. In the preferred embodiment of the invention, servo burst pulses are embedded in the disc, for example at 72 locations on each track. The structure of the servo burst of the present invention is the same as that of the conventional technique. A typical servo burst includes four types of pulsed signals such as servo burst A, servo burst B, servo burst C, and servo burst D. Each servo burst AD consists of 4 bytes, so a set of servo bursts contains 16 bytes as disclosed in US Pat. No. 5,025,335. In the preferred embodiment, these 16 byte servo bursts are embedded at 72 locations on each track of disk 22 so that they can be read in a fixed amount of time.

In FIG. 4, when formatting a disk, the controller 144 is instructed to start the formatting operation. The controller 144 and the memory 146 interact to perform a formatting operation based on a program stored in the memory 146. Prior to the formatting operation, the manufacturer inputs the necessary information on the disk to be formatted. Such information includes the number of data tracks, the number of sectors on the track, and so on. The read / write head 36 detects embedded servo bursts and directs them to the controller 144.
To the read / write control unit 156. As a result, the controller 144 sends control commands to the actuator control to maintain the precise position of the read / write head 36 on a particular data track of the disk 22.

The controller 144 detects the end of the servo burst and directs the read / write head to format the disk by writing sector information. The read / write head writes an identification (ID) field or data field, also called a header field. The ID field has a sector and data fields including a data track address and a 512-byte data area for the user. A typical sector total capacity is 561 bytes. The detailed structure of the ID and data fields is described in FIG. The read / write head 36 writes information for the next sector until the end timing of the next detected servo burst.

Sectors are formed by repeating this operation for a particular data track. If all sectors are formed on the track, the controller 144 sends a control command to the actuator controller 152 to move to the next track. The read / write head 36 moves its position to the next data track on the disk 22 and begins formatting this data track. Thus, each time the formatting for a data track is complete, the read / write head moves to the next data track to complete the formatting of all data tracks on the disk surface.

The read / write head 36 typically requires a settling time of 1.5 ms after track replacement (time the head is skewed). As described in FIG. 8, the time this head skews corresponds to sliding 3, 4 servo bursts into the next data track. This means that when the head settling for the next data track is complete, the read / write head 36 will be located 3-4 servo bursts after the first sector formatted in the previous track. In the present invention, the read / write head 36 formats the sector of the next data track, even in such a situation, by detecting the end of the servo burst immediately following head settling. The area corresponding to the first 3-4 servo bursts that have passed before head settling is formatted at the final stage of formatting this data track. Therefore, unlike the conventional method, the disk drive of the present invention can start the formatting operation without waiting for the rotation when exchanging data tracks. As described above, since the number of data tracks on one surface exceeds 800, the present invention can significantly reduce the time required for formatting.

As mentioned above, a fixed number, eg 72, of servo bursts occur at equal intervals in each data track. In the preferred embodiment, the number of servo bursts is
It is also unchanged for inner data tracks (smaller radius data tracks) which are much shorter in length than that of the tracks of the outer zone of the disc. In the inner data track, a relatively large number of servo bursts is preferred. Because the inner data track has a sharper curve than the outer data track, it requires precise positioning.

Since the outer track is longer than the inner track, and each sector must have an equal data area of, for example, 512 bytes on the entire disk surface, the outer track is more sized to maintain the same storage density as the hard disk. A large number of sectors can be formed. Thus, in the preferred embodiment, the innermost data track can have 36 sectors while the outermost data track can have 72 sectors. This is done by changing the storage frequency, eg higher frequencies for the outer data tracks and lower frequencies for the inner data tracks. The number of servo bursts in this example is 72 regardless of the position of the data track. Therefore, especially in the inner data track, the servo burst occurs within the length of the data area of the sector because the length of the data area is relatively large with respect to the interval of the servo burst.

FIG. 10 shows such a situation for servo bursts and sectors in the inner and outer data tracks. FIG. 10A shows the situation of the outer data track in which the servo bursts are spaced at intervals longer than the length of the sector. On the contrary, Fig. 10 (B)
Shows the situation on the inner data track where the servo bursts are spaced at intervals less than the length of the sector. In FIG. 10A, the read / write head 36
Formats the sector having the identification field ID1 and the data field D1 based on the end timing of the servo burst SB1. Similarly, the next sector with identification field ID2 and data field D2 is read / read immediately after the end of servo burst SB2.
It is formed by the writing head 36.

In FIG. 10B, the identification field I
While formatting the first sector with D1 and the data field D1 based on the servo burst SB1,
The next servo burst SB2 occurs in the data area. In this situation, controller 144 may
1 is divided into two data areas D1-1 and D1-2. The data area D1-1 is closed by detecting the servo burst SB2, and the remaining data area D1
-2 starts near the end of the servo burst SB2.
The next sector is formed at the end timing of the servo burst SB3.

FIG. 11 is a diagram showing a magnetic disk 22 formatted according to the method of the present invention. In FIG. 11, the radial line SB designates the position of the servo burst embedded in the disk 22 (all 72 locations are not shown in FIG. 11). As mentioned above, in the preferred embodiment, the radial line SB of 72, i.e. on the disk 22.
The 72 servo bursts represented by are provided on the data track. Therefore, servo bursts occur equally on the outer track and the inner track at the same radial position. The dot ID specifies the header (identification field) of each sector. Therefore, as shown in FIG. 10, the sector data field immediately follows the ID field. Since the length of the inner data track is shorter than that of the outer data track, servo burst placement (SB line) occurs on the inner track at shorter intervals. In such a situation, the inner track sector crosses the servo burst shown in FIG. 10B, as indicated by the ID dot spacing in FIG.

FIG. 12 is a diagram showing an example of the detailed structure of the sector of the present invention. Other formats are possible based on the intended use of the disk drive. For example, the data area is increased to 1024 bytes. The first part of the sector is the identification field, and the second part of the ID signal (header) and the sector is the data area (user area). Header fields typically consist of various types of information.

As shown in FIG. 12, in this example,
The header includes variable frequency vibration (VFO), address mark (AM), ID synchronization signal (ID SYNC), cylinder high (CYL-HIGH) and cylinder low (CY).
L-LOW), and read / write head address (HE
A cylinder address including AD), a sector address (SECTOR), a flag (FLAG), and a cycle redundancy code (CRC). Each sector contains a specified number of bytes as shown in FIG.
Each sector begins with a VFO, an all-zero 11-byte prefix field used by the read / write circuitry to lock the incoming data stream for read / write operations. AM and ID SYNC
Is used for synchronizing electrical circuits. CYL-HIGH and CYL-LOW indicate addresses on the surface of the disk provided in the disk drive and the data track. Since multiple read / write heads are used, HEAD is used to indicate the address of the read / write head. SE
CTOR indicates the address of each sector. The CRC is an error correction code such as CRC-CCITT, which consists of 16 bits.

A data field follows the 2-byte gap. The data field contains variable frequency vibration (V
FO), address mark (AM), data synchronization signal (D
ATA SYNC), data area (DATA), error correction code (ECC), and termination gap.
The data area is used by the user to write information.
It has 12 bytes. The error correction code ECC is provided to detect and correct errors in the data.
Each of the above signals is well known in the art and will not be discussed in further detail.

FIG. 13 is a schematic flow chart showing the operation of the disk formatting process according to the present invention. First, the formatting operation starts in step S1.
In step S2, the operator provides the controller (disk drive sequencer) with the information necessary for formatting. Such information includes the number of disks, the number of read / write heads, the number of sectors to be formed on a track, the number of servo bursts, etc. The formatting operation proceeds to step S3, which determines if a servo burst pulse should be detected by the read / write head. If the servo burst pulse is not detected, the operation repeats step S3 until the servo burst pulse is detected.

If the servo burst pulse is step S4
If it is detected in, the format starts. As described above, when the formatting of the sector is completed, the next sector is formatted by detecting the next servo burst pulse. In step S5 it is determined whether the sector is the last sector of the data track. If the sector just formatted is not the last sector of the data track, step S6.
Formatting operations for all other sectors on the data track at are continued. If the last sector is detected in step S5, the formatting process stops in step S7 and proceeds to step S8 which determines whether another data track should be formatted (whether it is the last track). If there are no data tracks to format, the formatting operation ends at step S9. If there are other data tracks remaining to be formatted, the process returns to step S3 to continue the formatting process of the other data tracks. In this track exchange, the read / write head changes its position to the next track. Formatting of the next track is started by detecting a servo pulse in step S3 without waiting for the rotation of the disk as described above. The present invention regarding the formatting procedure is performed by the manufacturer prior to marketing the disk drive. With the present invention, the manufacturer does not have to wait for the disk to rotate each time the read / write head moves to the next data track, so the manufacturer uses the present invention to significantly reduce the time to format a hard disk. be able to. Thus, the present invention provides the total time required for the disk formatting procedure, and in particular the read / write head to cross the track boundary on the disk surface and move to the next data track (head skew).
The time required for this can be effectively reduced.

According to the present invention, the disk drive can provide an improved means for formatting the hard disk by detecting the end of the servo burst for the format start of the next sector as described above. Due to this capability, the disk drive of the present invention can reduce the time to format a disk and also eliminate the possibility of lack of sectors that existed in conventional disk drives.

While the preferred embodiment of the invention has been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. .

[Brief description of drawings]

FIG. 1 is a perspective view of a small form factor disk drive using a disk drive control circuit of the present invention and a method thereof.

FIG. 2A is a plan view of a disk drive showing an example in which a magnetic head and an actuator are in a rest state on a track outside the disk, and FIG. 2B is a magnetic head and an actuator, but the disk is not accessed. FIG. 8 is a plan view of the disc drive showing an example of another hibernation state inside the hour disc.

FIG. 3 is a sectional view of a spindle motor used in the present invention.

FIG. 4 is a block diagram of an electric circuit of the disk drive of the present invention.

5 is a block diagram showing an electric circuit of a current controller used in the electric circuit of FIG. 4. FIG.

FIG. 6 is a schematic diagram illustrating a magnetic head having multiple data storage tracks for corresponding radii.

FIG. 7 is a schematic diagram showing several sectors in one track of a disc.

FIG. 8 is a diagram illustrating a conventional method for formatting a disc using an index pulse.

FIG. 9 is a timing chart showing a timing relationship between an index pulse or servo burst pulse of the present invention and a signal forming a sector.

FIG. 10 is a timing chart showing a timing relationship between servo burst pulses and sector organization according to the present invention.

FIG. 11 is a diagram showing a magnetic disk formatted by the procedure of the present invention.

FIG. 12 is a diagram showing a detailed structure of a sector of the present invention.

FIG. 13 is a schematic flowchart showing an operation of a disk formatting process according to the present invention.

[Explanation of symbols]

 22 Disk 24 Spindle Motor Assembly 30 Actuator Arm 32 Load Beam 36 Read / Write Head 144 Microcontroller 146 Read Only Memory (ROM) 147 Register 148 Interface Control Circuit 150 Control Support Circuit 152 Actuator Controller 153, 155 Current Limiter 154 Spindle Motor Controller 156 Read / write controller 160 Bus 164 Control line 166, 168, 173, 175 line 170 Current line 176 Data line 180 Communication bus

Claims (11)

[Claims] 1. A disk drive used in a host computer, for storing information, a magnetic disk, an actuator assembly for positioning a read / write head on a magnetic disk surface, and a spindle motor for rotating the magnetic disk. The apparatus is a memory that stores a series of operation programs for formatting the magnetic disk, and the memory includes a series of information regarding operating conditions necessary for formatting the magnetic disk. A microcontroller to control the overall operating procedure for
The microcontroller determines the operating conditions,
By determining the timing of formatting each storage sector on each data track based on the end of the corresponding servo pulse detected by the read / write head, and determining the data detected by the read / write head. A disk drive device comprising: an electric circuit forming a feedback control loop for determining the position of the read / write head, the feedback control loop further including a microcontroller for the feedback control operation. 2. The disk drive device according to claim 1, wherein each of the storage sectors is formed by detecting an end of the servo burst pulse immediately before the storage sector. 3. The magnetic disk is provided with the embedded servo burst pulses having a predetermined spacing on the data tracks before the formatting operation,
The servo pulse is read / read on the data track.
The disk drive apparatus according to claim 1, wherein the disk drive apparatus is read by the read / write head to determine the position of the write head. 4. The servo burst pulse of the same number is embedded on each of the data tracks of the magnetic disk regardless of the position inside or outside the magnetic disk. Disk drive device. 5. The method of claim 4, wherein a smaller number of the storage sectors are formatted with the data tracks inside the magnetic disk rather than the data tracks outside the magnetic disk. Disk drive device. 6. The disk drive apparatus as claimed in claim 1, wherein the storage sector comprises a header field including identification data for the sector and a data field for storing data for a user. . 7. The data field according to claim 6, wherein the servo burst pulse is divided into a plurality of fields in which the data field having a predetermined length is detected during formatting. The described disk drive device. 8. The controller commands the actuator assembly to move from one data track to another after formatting a predetermined number of storage sectors for one data track. The disk drive device according to claim 1, wherein: 9. The format of the other track begins with the end of the servo burst pulse detected immediately after the read / write head settles from the one track to the other track. The disk drive device according to claim 8. 10. A method for formatting the magnetic disk by forming a number of storage sectors on the disk in a disk drive device for a host computer, the disk drive device comprising a magnetic disk for storing information. Read on disk, magnetic disk surface /
An actuator assembly for positioning a write head, a spindle motor for rotating a magnetic disk, writing a servo burst pulse on the surface of the magnetic disk, and detecting the end signal of the servo burst pulse. Determining the position of the next sector with respect to the end of the servo burst pulse and writing the header field including identification data of the storage sector and a data field for storing data for a user of the computer. A method of formatting a magnetic disk, comprising: defining a sector and repeating the above steps for all the storage sectors on the surface of the magnetic disk. 11. The formatting procedure further comprises the step of moving the read / write head from one data track of the magnetic disk to another data track when the formatting of the one data track is completed. 11. The magnetic disk formatting method according to claim 10.