JPH087509A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To shorten access time by a head driving control section which executes control for shortening seek time while referencing the position signal of multiheads. CONSTITUTION:The head driving control section 5 discretely control the respective magnetic heads 2A, 2B in accordance with the control information, such as position information, outputted from positioning control sections 4A, 4B when the head driving control section receives a reading instruction of a file from a host position. The control sections 4A, 4B position the magnetic heads 2A, 2B by controlling driving the respective plural carriages 3A, 3B and output the position information of the respective head to a control section 5. As a result, the control section 5 executes control for shortening the seek time while referencing the position signals of the respective heads, thereby shortening the access time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, and more particularly to a multi-head magnetic disk drive.

[0002]

2. Description of the Related Art In the case of a conventional magnetic disk drive (hard disk drive), as shown in FIG.
A single magnetic head 52 for storing / reproducing data to / from this magnetic disk 51 was provided with 1 as a storage medium.

FIG. 8 shows the disk structure of MS-DOS (registered trademark of Microsoft Corporation, USA). As shown in this figure, an IPL area (system area), a FAT area, and a directory area are provided from the top of the disk.

With reference to FIG. 9, how a file is actually accessed under such a structure will be described. First, on the magnetic disk device, FIG.
FILE A is stored as shown in FIG. When a conventional magnetic disk device reads a file, a single head first searches the directory area.

The directory area is shown in FIGS. 9B and 9C.
As shown by, the leading cluster number is stored. Here, it is found that the leading cluster number of FILE A is “1” and the leading cluster number of FILE B is “3”.

Then, the connection state of the data stored in the FAT area is checked, and actual access is performed.

For example, as shown in FIG. 9D, a cluster number 2 to be read next is stored in the FAT area of a cluster number 1. That is, it is understood that the data of FILE A is linked in the order of cluster numbers 1 → 2 → 8 → 9.

Here, when data is actually accessed, even if data is spread over a plurality of clusters due to the configuration of a single magnetic head, if reading of the currently accessed cluster is not completed, it is natural. I can't move to the next cluster and start reading.

[0009]

When a conventional hard disk reads a file, one head first searches the directory section and searches for the existence of the file. If the file exists, the connection status of the cluster stored on the FAT is checked to access the actual data.

However, at this time, the data stored far away from the FAT (data stored near the center of the magnetic disk) is the data in which the moving time of the magnetic head takes time and the clusters are discontinuously scattered. In the case of (1), the conventional configuration of a single magnetic head has a disadvantage that the magnetic head cannot be moved until the reading of the corresponding cluster is completed and the access time is extremely reduced.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the disadvantages of the prior art and, in particular, to provide a magnetic disk capable of shortening the access time.

[0012]

According to the present invention as set forth in claim 1, a magnetic disk, a plurality of magnetic heads for reading data recorded on the magnetic disk, and the heads are mounted and separate head positioning is performed. A plurality of carriages that are independently driven by the mechanism, a positioning control unit that positions the magnetic heads by controlling the drive of each of these carriages, and outputs position information of each magnetic head to the head drive control unit, and this positioning The head drive controller controls the operation of each magnetic head based on control information such as position information output from the controller.

According to the second aspect of the present invention, the magnetic head is provided with the carriage so as to move in the vicinity of the same diameter on the magnetic disk.

According to the third aspect of the present invention, the head drive control unit starts the positioning control of the head and then controls the first head control so that the magnetic head which has previously output the position signal of the target position is read. It is equipped with means.

According to the present invention of claim 4, the magnetic disk has an address table in which the recording positions of the data forming the file are described, and the head drive control unit sets the start position of the data forming the file. A configuration is provided in which a second seek control unit that controls the positioning of the other magnetic head to the start position of the data when one magnetic head is read from the address table is adopted.

According to a fifth aspect of the present invention, the head drive control unit controls so that one magnetic head is positioned in the cylinder and then the other magnetic head is positioned in the cylinder to which data consecutive to the read data belongs. The seek control means is provided.

[0017]

According to the present invention of claim 1, during the operation of the apparatus,
When the file read command is received from the host device, the head drive control unit individually controls each magnetic head based on control information such as position information output from the positioning control unit. This control is performed by transmitting a seek position signal to each positioning control unit and receiving a head position signal from each positioning control unit. The positioning control unit positions the magnetic heads by drivingly controlling the plurality of carriages, and outputs position information of each magnetic head to the control unit. A magnetic head is mounted on these carriages, and the magnetic head reads data recorded on a magnetic disk.

According to the second aspect of the present invention, when the head positioning mechanism is driven and controlled by the positioning controller, the magnetic head moves in the vicinity on the same diameter of the magnetic disk.

According to the third aspect of the present invention, when the file read command is received from the host device, the head drive control section first starts the head positioning control. In response to this, each positioning control unit controls the operation of the head positioning mechanism of the carriage to move the magnetic head to the target position. Each positioning control unit receives the position signal on the magnetic disk of each magnetic head, compares the received position signal with the position signal related to the positioning command, and if they match, drives a seek completion signal to drive the head. Output to the control unit. Subsequently, the head drive control unit controls the magnetic head that has previously output the position signal of the target position to start reading. On the other hand, the other magnetic heads are controlled so as to wait for the next operation.

According to the fourth aspect of the present invention, when a file read command is received from the host device, the head drive control section first positions one magnetic head in the cylinder in which the address table is recorded. Then, when the recording start position of the data forming the file related to the read command is read from the address table, the other magnetic head is positioned to the start position of the data without waiting for the end of reading of the addresses of all the data. To do.

According to the fifth aspect of the present invention, when a file read command is received from the host device, the head drive control section first positions one magnetic head in the cylinder.
Then, when the file is recorded discontinuously, the other magnetic head is controlled to be positioned at the cylinder to which the data continuous to the read data belongs.

[0022]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the present embodiment. In the magnetic disk drive, a magnetic disk 1, a plurality of magnetic heads 2A and 2B for reading data recorded on the magnetic disk 1, and these magnetic heads 2A and 2B are shown. 2B mounted and separate head positioning mechanisms 6A, 6B
A plurality of carriages 3A, 3A that are independently driven,
The magnetic heads 2A and 2B are positioned by controlling the drive of these carriages 3A and 3A, respectively, and the position information of the magnetic heads 2A and 2B is stored in the head drive controller 5.
Positioning control sections 4A and 4B that output the magnetic heads 2A and 4B, and a head drive control section 5 that individually controls the operations of the magnetic heads 2A and 2B based on the control information such as the position information output from the positioning control sections 4A and 4B. Is equipped with.

The carriages 3A and 3B are installed such that the magnetic heads 2A and 2B move near the same diameter of the magnetic disk 1.

This will be described in detail. Magnetic disk 1
Is a disk-shaped storage medium for recording data (information) created by a higher-level device. The disk-shaped storage medium is coated with a magnetic substance and records binary data by reversing the magnetism. Corresponding to this, the magnetic heads 2A, 2
B includes a head core wound with a coil, and a slider for floating the head core from the magnetic disk 1 while keeping a very small gap (spacing). It is supported by. To read data from the magnetic disk 1, first, the magnetic heads 2A and 2B are moved to a track position including a target block. Then, when the magnetic heads 2A and 2B pass over the target block due to the rotation of the magnetic disk 1, the head core is magnetized to the same magnetism as the passing magnetic domain. Further, an electric signal is generated by the coil wound around the head core according to the change in the polarity. By converting this electric signal to binary data, data recorded as magnetic on the magnetic disk 1 is reproduced.

The head positioning mechanisms 6A and 6B are classified into a direct drive type and a rotary type. In the direct-acting type, the magnetic head 2A is attached to the carriage 3A in a comb shape, and the rollers for the carriage are coupled with a load applied to the rail. In the case of the rotary type, the positioning is performed by rotating the carriage 3A about a rotation axis, and is driven by an actuator behind the carriage 3A. In the present embodiment, a rotary type is adopted, which is driven by a voice coil motor and positioned by a track servo.

As shown in FIG. 2, the magnetic disk device 6 has magnetic heads 2A and 2B, each of which has several magnetic disks 1 stacked thereon in order to obtain a necessary storage capacity. The carriage 3A for each magnetic disk 1
Are integrally attached to the same head positioning mechanism 6A. On the other hand, the carriage 3 for each magnetic disk 1
B is also integrally attached to the same head positioning mechanism 6B. In the present embodiment, a position signal (position signal) is written on one surface of a plurality of magnetic disks 1 and used as a servo disk, and the position is detected by the servo head to perform positioning.

The positioning control units 4A and 4B control the driving of the head positioning mechanisms 6A and 6B, respectively, to position the magnetic heads 2A and 2B, receive the position signals read by the servo heads, and compare the position signals with the target positions. To seek data. The target position for positioning is given to the head drive control unit 5, and the received position signal and seek completion signal are output to the head drive control unit 5.

Since this embodiment adopts such a configuration, the head drive controller 5 can perform various controls in order to speed up the data reading operation. In the current technology, the speed of positioning the magnetic heads 2A and 2B is lower than the speed at which data is transferred from the magnetic disk device to the higher-level device, and the head drive control unit 5 solves this throughput. The magnetic head, which can be independently driven and controlled, is fully utilized as described in detail below.

The time required to position the magnetic heads 2A and 2B is the seek time required to move the carriages 3A and 3B to position the magnetic heads 2A and 2B in the target cylinder, and the positioning time in the target cylinder. After that, the target record is classified into the rotation waiting time until the target record reaches the magnetic heads 2A and 2B. In the present embodiment, the shortening of the seek time of the former is a major issue.

In the embodiment corresponding to claim 3, the head drive control section 5 controls the head position control so that after the head positioning control is started, the position signal of the target position is read by the previously output magnetic head. A seek control means is provided.
When the head drive control unit 5 receives a file read command from the host device, it first starts head positioning control. In response to this, each of the positioning control units 4A and 4B controls the operation of the head positioning mechanisms 6A and 6B of the carriages 3A and 3B so as to move the magnetic heads 2A and 2B to the target position. Each of the positioning control units 4A and 4B receives the position signal of each servo head on the magnetic disk 1, compares the received position signal with the position signal related to the positioning command, and completes seek if they match. The signal is output to the head drive controller 5. Then, the head drive controller 5
Controls to start reading with the magnetic head 2A that previously output the position signal of the target position.

Here, the waveform read by each of the magnetic heads 2A and 2B is converted into code data in the reproducing system. That is, the reproducing system firstly amplifies the waveform and compensates the waveform and then converts the pulse waveform into a pulse waveform. Then, the pulse waveform is converted into a binary digital value to demodulate the digital value into code data. ing. The switching of the input source to the reproduction system is performed based on an input switching signal transmitted from the head drive control unit 5. Therefore, the head drive control unit 5 outputs an input switching signal to the reproducing system so as to perform reproduction with the signal from the magnetic head 2A that previously output the position signal of the target position. At this time, the head drive controller 5 controls the other magnetic head 2B so that it waits for the next operation.

Since the first seek control means operates in this way, when the magnetic head 2A and the magnetic head 2B start seeking from different positions, reading is started by the magnetic head that reaches the target cylinder earlier. can do. Therefore, for example, when the home positions of the magnetic heads 2A and 2B are set on the inner peripheral side and the outer peripheral side of the magnetic disk 1, the seek time becomes 1/2 or less as compared with the conventional example in which such control is not performed. . Further, when the two magnetic heads 2A and 2B are positioned at the target cylinder at the same time or almost at the same time, the reading is started by the magnetic head that first reaches the register in which the data related to the read signal from the higher-level device is recorded. When set to 1, the rotation waiting time is halved
It can be:

In an embodiment corresponding to claim 4, the magnetic disk 1 is provided with an address table in which the recording position of the data which constitutes the file is described. Moreover, the head drive controller 5 reads the start position (cluster number) of the data forming the file to be read from one of the magnetic heads 2A from the address table by the other magnetic head 2B. The second seek control means for positioning control is provided.

Here, it is an object to shorten the seek time when the first cluster is far from the FAT area (close to the center of the magnetic disk). FIG.
It is a figure which shows the case where a cluster is distant from the FAT area. FIG. 4 is a flow chart showing the means for moving the magnetic head. The operation of this embodiment will be described in detail with reference to FIGS.

Here, the magnetic head positioned on the outer peripheral side is referred to as a magnetic head A, and the magnetic head positioned on the inner peripheral side is referred to as a magnetic head B. The magnetic head A first searches the directory area (step S1), and searches for the existence of the file. At the same time, the magnetic head B starts moving in the direction of the center of the circle assuming that the head cluster is far from the FAT area (step S4).

The head cluster number is stored in the directory area read by the magnetic head A as shown in FIGS. 9B and 9C. Therefore, the head drive control unit 5, which has received the head cluster number from the magnetic head A via one positioning control unit 4A, outputs the cluster number as a target position to the other positioning control unit 4B. The magnetic head B starts moving to the cluster without waiting for the end of the FAT area search of the magnetic head A (step S).
5). Here, even if the movement in the direction of the center of the circle has not been completed, the movement to the first cluster is started.

After completing the search of the directory area, the magnetic head A starts searching the FAT area to check the connection state of the clusters (step S2). After this is completed, the magnetic head A also starts moving to the head cluster (step S).
3). As described above, the head cluster is independently searched for from the position where the magnetic head B that has started moving earlier is relatively close to the center of the circle and the position where the magnetic head A is relatively close to the circumference.

Then, the magnetic head A or the magnetic head B
The one that finds the corresponding cluster starts reading the cluster (step S6). After that, the processing shown in FIG. 6 may be performed.

In the embodiment corresponding to claim 4, even when the first sector is far from the FAT area, the moving distance of the magnetic head A or the magnetic head B for finding the first cluster is reduced. , The access time can be effectively shortened.

In the embodiment corresponding to claim 5, the head drive control unit 5 positions the one magnetic head 2A in the cylinder and then positions the other magnetic head 2B in the cylinder to which the data continuous to the read data belongs. A third seek control means for controlling is provided. here,
The problem is to eliminate the increase in seek time that occurs when one file is recorded in discontinuous locations.

FIG. 5 is a diagram showing data in which clusters are discontinuously scattered. FIG. 6 is a flowchart showing the operation of moving the magnetic head. Here, in FIG. 6, the magnetic head X refers to a magnetic head performing a reading operation, and the magnetic head Y refers to a magnetic head whose positioning is controlled during the reading operation of the magnetic head X. Therefore, the same magnetic head 2A serves as the magnetic head X during the reading operation and serves as the magnetic head Y during the positioning operation.

When a cluster in the FAT area is read, a cylinder number, a head number, and a sector number corresponding to the cluster are determined. In the control shown in FIG. 6, it is assumed that each cluster number of the file related to the read command has already been read. When the magnetic head X is reading data (steps S11 to S12), the head drive control unit 5 compares whether the cluster being read and the cluster to be read next exist on the same cylinder. (Step S14). Here, in order to avoid mutual interference between the two magnetic heads on the same cylinder and realize efficient access, the magnetic heads 2 are mounted on the same cylinder.
A and 2B control not to perform reading simultaneously.

As a result of the comparison in step S14, if the cluster to be read next exists on the same cylinder, the magnetic head X continues reading (steps S11 to S12). Each time the reading of one cluster is completed, it is determined whether or not the read cluster is the last cluster constituting the file according to the read command (step S13).
The head drive control unit 5 ends the control of the reading operation.
On the other hand, as a result of the comparison in step S14, if the cluster to be read next does not exist on the same cylinder, the head drive control unit 5 proceeds to the positioning control of the magnetic head Y (steps S15 to S18). here,
Since the cluster number has already been read, the magnetic head Y that has not been read is positioned and controlled in that cluster (step S16), and the magnetic head Y waits for the end of reading of the magnetic head X that is currently being read (step S16). Step S18).

When the magnetic head Y has finished reading while the magnetic head Y is waiting for reading (step S12), it is compared whether the next cluster for which reading has just finished is the same cylinder (step S17). .

As a result, if they are the same, the head is not moved, and the magnetic head X continues to read the clusters on the same cylinder (steps S11 to S12). If they are not the same, the next cylinder is searched for,
At the same time, reading by the magnetic head that has been waiting is started (steps S18 and S11). Thereafter, the processing is performed by using the magnetic head Y that has been waiting as the magnetic head X that is performing the reading operation.

This will be described again by taking the case of FIG. 9 as an example. It is assumed that FILE A exists as shown in FIG. 9A, and that cluster numbers 1 and 2 exist in the same cylinder, and cluster numbers 8 and 9 exist in different cylinders. Assuming that the first cluster is found by the magnetic head 2A, the magnetic head 2B at this time indicates to which cluster to move next. When the magnetic head 2A is reading the cluster number 1, the magnetic head 2B first moves to the cylinder where the cluster number 8 exists. This is because cluster number 2 is the same cylinder as cluster number 1.

Thereafter, the magnetic head 2A sets the cluster number 1,
At the point in time when the reading of cluster No. 2 is completed, the magnetic head 2B starts reading of cluster number 8. Thereafter, similarly, the cluster number 9 is read by the magnetic head 2B, and the access ends.

As described above, in the embodiment corresponding to claim 5, even if a file in which clusters are discontinuous and scattered, when one magnetic head is reading the other magnetic head, It is possible to move to the next cluster, which can dramatically improve the access time.

[0049]

Since the present invention is constructed and functions as described above, according to this, when the file read command is received from the host device, the head drive control unit outputs the position information and the like output from the positioning control unit. Each magnetic head is individually controlled based on the control information. Therefore, various seek controls can be performed to shorten the seek time. Moreover, since this control is performed by transmitting the seek position signal to each positioning control unit and receiving the head position signal from each positioning control unit, the head drive control unit refers to the position signal of each head. Control can be performed to reduce the seek time. As described above, it is possible to provide an excellent magnetic disk device which has not been heretofore capable of dramatically shortening the access time by shortening the seek time.

According to the present invention, when the head positioning mechanism is driven and controlled by the positioning controller, the magnetic heads move in the vicinity on the same diameter of the magnetic disk. The head drive control unit can shorten the seek time to ½ or less by keeping it on standby on both the outer side and the outer peripheral side. Therefore, it is possible to dramatically reduce the access time, which is unprecedented. It is possible to provide a magnetic disk device.

According to the third aspect of the present invention, when the file read command is received from the host device, the head drive control unit starts the head positioning control, and in response to this, each positioning control unit causes the magnetic head to move. Since the operation of the head positioning mechanism of the carriage is controlled so as to move the target position to the target position, it is possible to start seeking the target position with a plurality of magnetic heads. Further, each positioning control unit receives the position signal on the magnetic disk of each magnetic head, compares the received position signal with the position signal related to the positioning command, and when they match, a seek completion signal is sent. Since it is output to the head drive control unit, the head drive control unit can control the position signal of the target position to start reading by the magnetic head that has output first. Therefore, the positioning start position of the magnetic head And the target position for positioning, the reading can be started by the magnetic head which has reached the target position faster. Therefore, the seek time can be shortened as much as possible, and further, it is possible to provide an unprecedented excellent magnetic disk device capable of significantly shortening the access time.

According to the fourth aspect of the present invention, when the file read command is received from the host device, the head drive control unit positions one magnetic head in the cylinder in which the address table is recorded. Then, when the recording start position of the data forming the file related to the read command is read from the address table, the other magnetic head is positioned to the start position of the data without waiting for the end of reading of the addresses of all the data. Therefore, even if the start position of the target data is far from the address table, it is possible to significantly speed up the start of reading the data.
Therefore, it is possible to provide an unprecedented excellent magnetic disk device which can improve the access time.

According to the fifth aspect of the present invention, when a file read command is received from the host device, the head drive control section first positions and controls one magnetic head in the cylinder, and then the file is discontinuous. In the case where one file is separated and recorded discontinuously in order to control the other magnetic head to be positioned in the cylinder to which the data continuous to the read data belongs, While one magnetic head is reading, the other magnetic head can move to the next cluster, which can greatly reduce the seek time and therefore the access time. It is possible to provide an excellent magnetic disk device that does not exist in the past.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a front view showing a relationship between a plurality of magnetic heads and a carriage.

FIG. 3 is an explanatory diagram showing a magnetic disk when data is separated from a FAT area.

FIG. 4 is a flowchart showing processing steps of a second seek unit.

FIG. 5 is an explanatory diagram showing a magnetic disk when clusters are scattered discontinuously.

FIG. 6 is a flowchart showing the processing steps of a third seek means.

FIG. 7 is a front view showing the configuration of a conventional magnetic disk drive.

FIG. 8 is an explanatory diagram showing a logical disk structure of a magnetic disk.

FIG. 9 is a diagram illustrating a directory area and a FAT area. FIG. 4A is a diagram for explaining the state of files stored on the magnetic disk, FIG. 4B is a schematic diagram for explaining the directory area, and FIG. 4C is a detailed diagram for explaining the directory area. 4D is a diagram for explaining the FAT area.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 magnetic disk 2A one magnetic head 2B another magnetic head 3A one carriage 3B one carriage 4A one positioning control section 4B another positioning control section 5 head drive control section 6A one head positioning mechanism 6B another head positioning mechanism

Claims (5)

[Claims] 1. A magnetic disk, a plurality of magnetic heads for reading data recorded on the magnetic disk, a plurality of carriages to which the magnetic heads are mounted and which are independently driven by different head positioning mechanisms, A positioning control unit that positions the magnetic heads by driving and controlling each of these carriages and outputs position information of each magnetic head to the head drive control unit, and control information such as position information output from the positioning control unit. And a head drive control unit for controlling the operation of each magnetic head based on the above. 2. The magnetic disk drive according to claim 1, wherein the carriage is installed so that the magnetic heads move in the vicinity of the same diameter of the magnetic disk. 3. The head drive control unit includes first seek control means for controlling the head position control so that the head signal is read by the previously output magnetic head after starting the head positioning control. The magnetic disk drive according to claim 1 or 2, characterized in that: 4. The magnetic disk has an address table in which a recording position of data forming a file is described, and the head drive control unit determines a start position of data forming the file from the address table. 3. The magnetic disk drive according to claim 1, further comprising second seek control means for positioning and controlling the other magnetic head at the start position of the data when the other magnetic head reads. 5. The head drive control unit further comprises third seek control means for controlling one magnetic head to be positioned on a cylinder and then the other magnetic head to be positioned on a cylinder to which data consecutive to the read data belongs. The magnetic disk drive according to claim 1 or 2, wherein