KR100263051B1 - Track address write and read method od magnetic disk - Google Patents

Abstract

PURPOSE: A method for recording and reading a track address is provided to improve recording capacity and an access speed without increasing the number of bits of the track address. CONSTITUTION: A storing area of a disk is divided into first and second areas having different numbers of tracks. Track address of a smaller area is included in a track address values of a larger area. In a standby mode, the track address is read from the disk for comparing with a maximum value in the track area of the smaller area. In case of the read track address larger than the maximum value, the read track address is decided as a present track address. Otherwise, a value formed by adding the read track address and a maximum address value of the larger area is decided as the present track address.

Description

A track address recording and reading method of a magnetic disk recording apparatus.

1 is a general servo information recording format

2 is a block diagram of a general hard disk drive

3 is a diagram illustrating track address recording according to an embodiment of the present invention.

4 is a flowchart of reading a track address in a ready mode according to an embodiment of the present invention.

5 is a flow chart of reading a track address in search mode according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk recording apparatus, and more particularly, to a method of recording and reading a track address, which is one of servo information, on a disk.

In general, in a disk recording device such as a hard disk drive (HDD) or a floppy disk drive (FDD), data is stored in tracks arranged concentrically on the disk and extending in the circumferential direction. These tracks are accessed by magnetic heads (or data transducers) for reading, writing, and erasing data on the disc. The head flies over the track on the disc. The head is moved in a radial direction on the disc by the control of a head position servo mechanism that can be accurately positioned on any one of the tracks. As such, to accurately position the head on a particular track, one must know the current head position relative to the tracks.

Servo information informing the head position relative to the tracks as described above is provided by using a particular servo pattern which is read from the disk by the head. This servo pattern is permanently recorded on the disk in advance by a servo writer when assembling the magnetic disk recording apparatus. This servo pattern is used as track position information by being detected by the head when accessing data on the disk. One example of a method for providing servo information is an embedded servo method. In the embedded servo method, the servo information areas are arranged between the data areas on the disc.

A typical recording format of such servo information is shown in FIG. 1 as an example of an embedded servo method. Figure 1 shows an example of one track and is not an accurate scale. As shown in FIG. 1, servo information consisting of a servo address mark (hereinafter referred to as "SAM"), an index, a track address, a burst, and the like is recorded in a servo feed which is a servo information area on a disk. . The SAM has a specific pattern that signals the start of the servo feed. The index is information for determining the criteria of each track. The track address is a track position information that gives a series of numbers to the tracks. The track address is different for each track and is also called a track ID (Identificatrion). This track address is used to control the head position by the magnetic disk recording apparatus reading it at a predetermined sampling period during track seek. Burst is generally recorded in four types, A, B, C, and D, as information for controlling the position of the head, and is used to accurately on-track the head to the track during track following.

The track address of the servo information is encoded in gray code, recorded on disk, and decoded again at read time, and has a unique data value as described above. Therefore, the number of bits of the gray code is determined in consideration of the number of tracks set on one disk, and the maximum number of tracks distinguishable by the gray code is determined by the number of bits of the gray code. That is, when the number of bits of the gray code is N, the maximum number of tracks and the number of gray code bits have a relationship as shown in the following formula (1).

Number of tracks available = 2 ^N -1. … (One)

As magnetic disk recording apparatuses become increasingly high and high in speed, the capacities occupied by track addresses recorded on the disk are also gradually increasing. For example, when one servo sampling period is 185 ms and one track address occupies 4.8 ms when accessing the disk, the track addresses occupy about 2.59% of all the information recorded on the disk. Even if this ratio is the same as before, the capacity occupied by the actual track address has increased with high capacity and speed, which has become an important obstacle to increasing recording capacity or improving access speed.

On the other hand, the magnetic disk recording apparatus has an ASIC (Application Specific Integrated Dircuit) circuit for decoding track addresses read from the disk. However, currently used ASIC circuits have a fixed number of track address bits that can be decoded, so the maximum number of tracks that can be set on a disk is fixed. Therefore, if you want to increase the number of tracks further, it is impossible to implement without changing the hardware of the ASIC circuit.

It is therefore an object of the present invention to provide a track address writing and reading method in which the recording capacity can improve the access speed without increasing the number of bits of the track address.

Another object of the present invention is to provide a track address recording and reading method which can increase the number of tracks without changing the hardware.

According to the present invention for achieving the above objects, a storage area on a disc is divided into first and second areas having different track numbers, and track addresses of a small area having a small number of tracks are assigned to track address values of a large area having a large number of tracks. Recording is performed continuously from the initial value to be included, and based on the track address read from the disc according to the operation mode, the maximum value of each track address in the large and small areas, the maximum movable distance of the head, and the previous track address value. And determining the current track address.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, it should be noted that like elements in the drawings represent like reference numerals wherever possible. Also, many specific details, such as specific process flows, are shown to provide a more general understanding of the present invention. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And a detailed description of known and possible configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

First, referring to FIG. 2 showing a block diagram of a HDD, which is one of magnetic disk recording apparatuses to which the present invention is applied, the configuration and operation of a HDD useful for understanding the present invention will be described as follows. Figure 2 shows an example with two disks and four heads corresponding to one of each side of the disk.

The preamplifier 14 connected to the head 12 preamplifies the signal picked up by the head 12 to apply an analog read signal to the read / write channel circuit 16. The write data according to the encoded write data applied from the write channel circuit 16 is applied to the head 12 so that the write data is written onto the disc 10.

The read / write channel circuit 16 detects and decodes a data pulse from a read signal applied from the preamplifier 14, applies the read data to the disk data controller (DDC) 18, and writes the write data applied from the DDC 18. Encode and apply to preamplifier 14.

The DDC 18 is controlled by the microcontroller 22 and transmits data received from a host such as a personal computer (PC) through the read / write channel circuit 16 and the preamplifier 14 to the disk 10. Or write data from the disk 10 to the host. The DDC 18 also interfaces the communication between the host and the microcontroller 22. A random access memory (RAM) 20 temporarily stores data transmitted between the host, the microcontroller 22 and the read / write channel circuit 16.

The microcontroller 22 controls the DDC 18 in response to a read or write command received from the host and controls track search and track following. The read only memory (ROM) 24 stores the execution program of the microcontroller 22 and various setting values.

The servo driver 26 generates a driving current for driving the actuator 28 by the signal for controlling the position of the head 12 generated from the microcontroller 22 and applies it to the actuator 28. The actuator 28 moves the head 12 on the disk 10 in response to the direction and level of the drive current applied from the western driver 26. The spindle motor driver 30 rotates the disk 10 by driving the spindle motor 32 in accordance with a control value for the rotation control of the disk 10 generated from the microcontroller 22. The disk signal controller 34 decodes servo information from the read data output from the read / write channel circuit 16 and applies it to the microcontroller 22, and applies various control signals necessary for read / write from the DDC 18. The signal is generated and controlled by the microcontroller 22 and applied to the preamplifier 14, the read / write channel circuit 16, the DDC 18, and the like. As the disk signal controller 34, an ASIC designed for each HDD is usually used.

According to the present invention applied to the HDD as described above, when the servo information is recorded on the disc 10 by the servo writer, the storage area on the disc 10 may be divided into first and second tracks having different numbers of tracks as shown in FIG. It is divided into second areas A1 and A2. 3 shows only one surface on the disk 10 for convenience, the first region A1 is allocated to a large area having a large number of tracks on the outer circumferential side, and the second region A2 is a small area having a small number of tracks on the inner circumferential side. Shows an example of assigning. This is set when the track address is sequentially set for each track from the outermost circumference on the disc 10 to the inside, and the parking area is set to the innermost circumference area on the disc 10. At this time, the track addresses of the second area A2 are continuously recorded from the initial value to be included in the track address values of the first area A1. Further, the track aberration between the first and second regions A1 and A2 is set to be larger than the maximum number of tracks (hereinafter, " K ") that the head 12 can move during one servo sampling period. When the track number difference between the first and second regions A1 and A2 is set smaller than the K value, the track address is changed when the head 12 moves between the first and second regions A1 and A2 during the track search. This is because it cannot be read correctly.

In the example of FIG. 3, the number of tracks of the first area A1 is set to n + 1 and the number of tracks of the second area A2 is set to m. Then, the m value is set less than n-2k, and the track addresses of the first area A1 will be TAO to TAn, and the track addresses of the second area A2 will be TAO to TAm. Compared to this m value or n value, k value is usually very small.

By recording the track address as described above, the present invention enables the recording of n + m track addresses with only the number of bits required to record the n track addresses conventionally. In other words, the number of bits of the track address can be reduced as compared with the conventional art.

When the track address is read from the disc 10 on which the servo information is recorded as described above, the tracks having the same track address between the first and second areas A1 and A2, that is, the track addresses TAO to TAm, are the same. If the head 12 is located in the tracks, the actual current track address will not be known. Therefore, in order to read the actual current track address from the read track address, a reading process according to the flowchart of FIG. 4 or FIG. 5 as described later is required. The actual current address described above is the track address recorded in the track in the first area A1 plus n.

In addition, the above-described reading process can be performed simply when the operating mode of the HDD is in the ready mode, compared to the seek mode. The preparation mode refers to a mode in which the head 12, which is parked in the parking area on the disk 10, is unlatched when the power supply of the first HDD is "on" and then is in a ready state. The search mode is a track search state as described above, and refers to a mode in which the head 12 is moved to the target track in order to read or write data on the actual disk 10 in the state where the preparation state is completed as described above.

Accordingly, in the ready mode, since the head 12 is just out of the parking area, the head 12 may be located in the second area A2 or the inner circumferential side of the first area A1. In this case, therefore, the current track address can be known simply by comparing the track address read from the disk 10 by the head 12 with the m value. In contrast, in the search mode, the head 12 may be located in the entire first and second regions A1 and A2 on the disk 10, thereby making the reading process more complicated.

Referring first to FIG. 4 showing a track address reading flow chart in the ready mode according to the present invention, the microcontroller 22 reads the track address from the disc 10 in step 100. FIG. The microcontroller 22 then compares the read track address value with the m value in step 102. At this time, when the track address value read is larger than the m value, naturally, the head 12 is not only in the first area A1 on the disk 10 but also the track address larger than the m value does not overlap the second area A2. Because it does not. On the other hand, when the read track address value is smaller than m, the microcontroller 24 determines, as a current track address, the value obtained by adding n values to the read track address in step 106. This is because when the lead track address value is smaller than m, the head 12 is located in the second area A2 because the head 12 is just out of the parking area as described above.

Therefore, even when the track address is recorded as shown in FIG. 3, the actual current track address can be accurately read in the ready mode.

Next, referring to FIG. 5, which shows a flowchart for reading a track address in the search mode according to the present invention, the microcontroller 22 reads the track address from the disc 10 in step 200. FIG. The microcontroller 22 then compares the read track address value with the m value in step 202. If the lead track address value is larger than m, the microcontroller 24 determines the lead track address as the current track address in step 210. This means that if the lead track address value is larger than the m value, of course, the head 12 is not only in the first area A1 on the disk 10 but also the track address larger than the m value does not overlap the second area A2. Because.

On the other hand, when the lead track address value is not larger than m in step 202, the microcontroller 22 compares the previous track address value with the m + k value in step 204. The previous track address value refers to the track address read in the immediately preceding servo sampling period. If the previous track address value is not greater than m + k, the microcontroller 22 determines the read track address value as the current track address in step 210. This is because the previous track address is not larger than the m + k value, that is, the head 12 is on the outer circumferential side of the first area A1 and the movement of the head 12 is made within the k value. (12) This is because the position is also in the first area A1.

If the previous track address value is larger than m + k in step 204, the microcontroller 22 compares the read track address value with the n-k value in step 206. FIG. If the previous track address value is smaller than the n-k value, the microcontroller 22 determines the lead track address value as the current track address in step 210. This is because the head 12 is on the inner circumferential side of the first region A1 because the previous track address is larger than the m + k value but smaller than the nk value, but since the movement of the head 12 is within the k value, This is because the current head 12 position is also in the first area A1.

In contrast, when the previous track address value is not smaller than the n-k value in step 206, the microcontroller 22 determines the current track address by adding n to the read track address in step 208. This is a state where the head 12 was on the innermost circumference side of the first area A1 because the previous track address was larger than the nk value, and the head 12 was moved to the second area A2. This is because the position is in the second area A2.

Therefore, even when the track address is recorded as shown in FIG. 3, the actual current track address can be accurately read in the search mode.

Therefore, the number of tracks can be increased and set almost equal to one more bits without increasing the number of bits of the track address or changing the hardware. As a result, the number of bits in the track address for each track can be reduced by one bit, and the data can be used for data storage, thereby improving the recording capacity and access speed.

As described above, the present invention not only improves the recording capacity and access speed without changing the number of bits of the track address, but also increases the number of tracks without changing the hardware.

Meanwhile, in the above description of the present invention, specific embodiments have been described, but various modifications can be made without departing from the scope of the present invention. In particular, in the embodiment of the present invention has been applied to the HDD, the same applies to not only the HDD but also a magnetic disk recording apparatus such as an FDD. Therefore, the scope of the invention should not be defined by the described embodiments, but should be defined by the equivalents of the claims and the claims.

Claims (6)

A recording and reading method of a track address of a magnetic disk recording apparatus, When recording the servo device on the disc, the storage area on the disc is divided into first and second areas having different numbers of tracks, and the track address of a small area with a small number of tracks is a track of a large area with a large number of tracks. Writing continuously from the initial value to be included in the address values; Reading the track address from the disk in the ready mode and comparing a read track address value with a maximum value of the track addresses in the small area; Determining the lead track address as the current track address when the lead track address value is larger than the maximum value; And determining the read track address plus the maximum track address value of the large area as the current track address when the read address value is smaller than the maximum value. The track address recording and reading method according to claim 1, wherein the track aberration between the small area and the large area is set to be larger than the maximum number of tracks the head can move during a servo sampling period. 3. The track address recording and reading method according to claim 2, wherein the large area is allocated to the outer peripheral side on the disk and the small area is allocated to the inner peripheral side on the disk. In the track address recording and reading method of a magnetic disk recording apparatus, When recording servo information on the disc, the storage area on the disc is divided into first and second regions of the number of tracks having a difference greater than the maximum number of tracks the head can move during one servo sampling period. Continuously recording track addresses of the small area to a maximum value from the initial value so as to be included in the track address values of the large area having a large number of tracks; Reading the track address from the disk in the track search mode and comparing a read track address value with a first comparison value which is the maximum of the track addresses in the small area; Determining the lead track address as the current track address when the read track address value is larger than the first comparison value; Comparing the previous track address value with a second comparison value obtained by adding the maximum value and the maximum number of movable tracks when the read track address value is smaller than the first comparison value; Determining the lead track address value as a current track address when the previous track address value is larger than the second comparison value; Comparing the lead track address value with a third comparison value obtained by subtracting the maximum number of movable tracks from the maximum value among the track addresses of the large area when the previous track address value is not greater than the second comparison value; Determining the lead track address value as a current track address when the previous track address value is smaller than the third comparison value; And if the previous track address value is not smaller than the third comparison value, determining the current track address by adding the lead track address to the maximum track address value of the large area. And reading method. 5. The track address recording and reading method according to claim 4, wherein the track number difference between the small area and the large area is set larger than the maximum movable track number. 6. The track address recording and reading method according to claim 5, wherein the large area is allocated to the outer peripheral side on the disk and the small area is allocated to the inner peripheral side on the disk.