JPH04229468A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To eliminate the need for positioning at the time of selecting the head address larger by one address than a magnetic head selected by a host device by providing two sets of head positioning control means which controls two sets of head disk assemblies. CONSTITUTION:A head selecting circuit 6 also selects the head address larger by one address than the head address assigned by the host device. Respective one set within the respective magnetic heads housed in two sets of the HDAs 100, 101 are simultaneously selected in this way. Two sets of positioning control circuits 8 position and control the magnetic heads housed in the respective HDAs to a desired cylinder by the signal from a position error signal forming circuit 7 when the host device assigns the desired cylinder. The servo signals to be used by the respective control circuits 8 are the servo signals to be read out by the magnetic head assigned by the host device with the one HDA and are the servo signals to be read out by the magnetic head of the address larger by one address than the magnetic head assigned by the host device with the other HDA.

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 control of a head positioning operation associated with a head selection operation in a data surface servo type magnetic disk drive that positions the head using servo signals.

0002

[Prior Art] In a magnetic disk drive, a large number of data tracks are formed on an information recording surface.
In writing and reading operations, it is necessary to position the magnetic head on the target data track (cylinder). As a method for positioning the magnetic head, an information area (servo area) is used to position a part of each data track corresponding to the magnetic head of the magnetic disk device.
There is a data surface servo method used as a.

FIG. 3 is a circuit block diagram of a conventional data surface servo type magnetic disk device. In FIG. 3, a magnetic disk plate 31, a magnetic head 32, a spindle 33, a head positioning mechanism 34, and a drive motor 35 are housed in a head disk assembly (HDA). The magnetic disk plate 31 is a recording medium that actually stores data, and is fixed to a spindle 33 and driven to rotate at high speed.

FIG. 4 is a plan view showing how the recording surface of the magnetic disk plate in FIG. 3 is divided. In FIG. 4, a recordable area on the recording surface of the magnetic disk plate 31 is called a recording area 39. The recording area 39 is divided into a servo area 40, which is a servo signal recording area for head positioning, and a data area 41, where data is actually recorded. Although eight servo areas 40 are shown in this figure, the present invention is not limited to this. Further, a plurality of servo tracks are arranged in the servo area 40 and a plurality of data tracks are arranged in the data area 41 in a concentric manner.

In FIG. 3, the magnetic head 32 has a number of head positioning mechanisms 34 corresponding to the recording surfaces on which data is stored.
The head positioning mechanism 34 is driven for positioning by a drive motor 35. Head selection circuit 3
6 selects only one magnetic head 32 designated by the host device of the magnetic disk device. Of the information recorded on the magnetic disk plate 31 read from the magnetic head 31 selected by the head selection circuit 36, only servo information (servo signal) is separated and input to the position error signal generation circuit 37. The position error signal generation circuit 37 demodulates a position error signal from the input servo signal. The positioning control circuit 38 controls the current supplied to the drive motor 35 based on the position error signal and the feedback signal of the drive current flowing to the drive motor 35 .

[0006] Here, the position error signal will be explained using FIG. FIG. 5 is a configuration diagram of the servo area of the magnetic disk plate in FIG. 3. The data track 42 is divided into 1/2 tracks in the servo area 40 and servo signals are written therein. The first servo track 43a and the second servo track 43b in the servo area 40 are divided along the center line of the data track 42, and are magnetized so as to obtain signals of opposite polarity. If the magnetic head 32 is correctly located on the data track 42, the magnetic head 32 will be located on the boundary between the first servo track 43a and the second servo track 43b in the servo area 40, and the servo signal to be read will be demodulated. The position error signal 44 becomes zero. Position error signal 4
4 extracts a negative signal from the first servo track 43a and a positive signal from the second servo track 43b, and demodulates it as a signal proportional to the difference between the two signals. As a result, the position error signal 44 becomes a signal proportional to the displacement of the magnetic head 32, as shown in FIG. Since the position error signal 44 can only be obtained from the servo area 40, while the magnetic head 32 is in the data area 41, it holds the position error signal 44 demodulated in the previous servo area 40, and then The position error signal 44 is read out and newly demodulated.

FIG. 6 is a diagram showing a position error signal during movement of the magnetic head. The position error signal 44 obtained in this way is shown in FIG. 6(a) while the magnetic head 32 is moving for positioning.
The signal will be as shown in .

The magnetic disk device selects the magnetic head designated by the host device, and moves the magnetic head to the target cylinder designated by the host device in accordance with the position error signal obtained from the servo signal of the servo area read by the selected magnetic head. let Next, the positioning of the magnetic head is controlled so that the position error signal is maintained at zero level in the target cylinder.

[0009]

[Problems to be Solved by the Invention] In the head positioning operation in the above-mentioned conventional data surface servo type magnetic disk device, the position error signal demodulated from the servo signal of the servo area to be read by the magnetic head designated by the host device is The positioning of the magnetic head is controlled so that the level becomes zero level.

However, even if the position error signal obtained from the servo signal read by one magnetic head of the same cylinder is at zero level, the position error signal obtained from the servo signal read by other magnetic heads is not at zero level. . Therefore, there is a drawback that a magnetic head positioning operation is required for each magnetic head selection operation.

[0011]

[Means for Solving the Problems] A magnetic disk device of the present invention includes two sets of HDAs and two sets of head positioning control means for controlling the HDAs, and one of the HDA
An even numbered head address is assigned to A, and an odd numbered head address is assigned to the other HDA, and the two sets of head positioning control means perform a head positioning operation by the data surface servo at the head address specified by the host device, and at the same time the head address is one address larger. Head positioning operation is performed using the data surface servo at the head address.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a magnetic disk device of the present invention. This embodiment is basically the same as the conventional magnetic disk device shown in FIGS. 3 to 6. However, the magnetic disk device of this embodiment differs from the conventional example in that it has two sets of HDAs and two sets of positioning control circuits, and the head selection circuit.

First, in FIG. 1, two sets of HDA 100,
A magnetic disk plate 1, a magnetic head 2, a spindle 3, a head positioning mechanism 4, and a drive motor 5 are housed in the magnetic disk 101, respectively. The magnetic disk plate 1 is shown in Figure 4.
Like the conventional magnetic disk plate shown in FIG. 5, it is divided into a data area and a servo area, and this servo area also has a first servo track 4a and a second servo track, similar to the conventional servo area 40 shown in FIG. 4b, each of which has a servo signal written in it.

The servo signal read by the magnetic head 2 selected by the head selection circuit 6 is demodulated into a position error signal by the position error signal generation circuit 7. This position error signal is also similar to the position error signal 44 of the conventional example. The positioning control circuit 8 controls the current supplied to the drive motor 5 based on the position error signal and the feedback signal of the drive current flowing to the drive motor 5, and moves and positions the magnetic head 2 to a target cylinder designated by the host device.

FIG. 2 is a diagram showing head address assignment in the magnetic disk device of this embodiment. As shown in FIG. 2, the magnetic heads 2 housed in one HDA (for example, HDA 100) are assigned even addresses (#0, #2, #4, #6) and are housed in the other HDA 101. Odd addresses (#1, #3, #5, #7) are assigned to the magnetic heads 2.

The head selection circuit 6 selects the head address designated by the host device, and also selects a head address that is one address larger than the head address designated by the host device. As a result, one of the magnetic heads housed in the two sets of HDAs 100 and 101 is simultaneously selected. When the host device specifies a target cylinder, two sets of positioning control circuits 8 control the positioning of the magnetic heads housed in each HDA to the target cylinder using signals from the position error signal generation circuit 7. At this time, the servo signal used by each positioning control circuit 8 is a servo signal read by a magnetic head designated by the host device in one HDA, and a magnetic head at an address one address larger than the magnetic head designated by the host device in the other HDA. This is a servo signal read by the head.

[0017]

As explained above, the magnetic disk drive of the present invention includes two sets of HDAs and two sets of positioning control circuits, and even-numbered head addresses of the magnetic heads are assigned to one HDA.
Assign it to the magnetic head stored in A and the other HD
Allocate odd addresses to the magnetic heads stored in A, select the magnetic head with the head address specified by the host device, select the magnetic head with the head address one address higher, and select the target cylinder specified by the host device. to each HD
Since the positioning of the magnetic heads A is controlled at the same time, when the host device selects a magnetic head on the same cylinder whose head address is one address higher than the magnetic head selected by the host device, it is already selected and positioned. For,
This has the effect that there is no need to perform a positioning operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a magnetic disk device of the present invention.

FIG. 2 is a diagram showing head address assignment in the magnetic disk device of this embodiment.

FIG. 3 is a circuit block diagram of a conventional data servo type magnetic disk device.

FIG. 4 is a plan view showing how the recording surface of the magnetic disk plate in FIG. 3 is divided.

FIG. 5 is a configuration diagram of a servo area of the magnetic disk plate in FIG. 3;

FIG. 6 is a diagram showing a position error signal during movement of the magnetic head.

[Explanation of symbols] 1, 31 Magnetic disk plate 2, 32 Magnetic head 3, 33 Spindle 4, 34 Head positioning mechanism 5, 35 Drive motor 6, 36 Head selection circuit 7, 37 Position error signal generation circuit 8, 38
Positioning control circuit 39 Recording area 40 Servo area 41 Data area 42 Data track 43 Servo track 44 Position error signal 100, 101 HDA

Claims (4)

[Claims] 1. A data surface servo type magnetic disk device in which a servo area in which a servo signal is written in advance is provided in one or more parts of a data track, and a magnetic head is positioned using the servo signal of this servo area. , a magnetic disk drive comprising two sets of head disk assemblies and two sets of head positioning control means for controlling the head disk assemblies. 2. The magnetic disk device according to claim 1, wherein an even head address is assigned to one of the head disk assemblies, and an odd head address is assigned to the other head disk assembly. 3. The magnetic disk device according to claim 1, further comprising head selection means for selecting a head address that is one address larger at the same time as selecting the head address designated by the host device. 4. The two sets of head positioning control means perform a head positioning operation using the data surface servo at the head address designated by the host device and a head positioning operation using the data surface servo at the head address that is one address higher. A magnetic disk device according to claim 1.