JPS5956214A - Servo track writer for magnetic disc device - Google Patents

Abstract

PURPOSE:To shorten the servo information recording time and reduce the production cost, by connecting servo signal recording circuits and magnetic heads for servo whose number corresponds to the number of magnetic double layer disc faces and recording servo information simultaneously. CONSTITUTION:A head disc assembly constituted with magnetic double layer discs 22-26 and magnetic heads 41-50 is set onto a mechanism part 57 for index and reference clocks consisting of a single layer magnetic disc 27, heads 29 and 30 for reference clock, and a head 40 for index, and they are connected to the same revolving shaft 28. Low-frequency reference clock signals of even and odd tracks are reproduced by heads 29 and 30 for reference clock. These reference clock signals are used, and servo information is recorded simultaneously by servo signal recording circuits and servo signal recording magnetic heads which correspond to magnetic double layer disc faces of the head disc assembly respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a servo trunk writer for a magnetic disk device. Currently, most of the magnetic head positioning methods in magnetic disk drives are servo surface servo methods.

In the servo surface servo system, errors in positioning accuracy occur due to the difference in 'thAS between the servo disk and the data disk4.! As the trunk density increases, the positioning error of the magnetic head increases, making it impossible to achieve a high areal density. Therefore, various data surface servo methods are being considered in order to increase positioning accuracy. Among the data surface servo methods, the buried servo method using a magnetic double-layer disk is considered to have the highest accuracy. In order to realize a magnetic disk device, a servo track writer is required to record servo information for head positioning on the servo medium below the magnetic disk.In the conventional servo track writer for the servo surface servo system,・Select one disk in the disk assembly, record index information and reference clock information on that disk, reproduce the recorded information, convert it into a signal, and use the reference clock signal to drive the servo disk. Record the servo information of the odd and even tracks.

This method is applied to a data servo using a magnetic double layer disk (
When applied to a head-disk assembly for buried servo, it is necessary to record servo information on all surfaces of the disk. Compared to the servo recording time, the number of disk surfaces is N times larger, and the magnetic
This has the disadvantage of significantly increasing the cost of the multilayer disc.

SUMMARY OF THE INVENTION An object of the present invention is to improve these disadvantages and provide a servo trunk tractor for a buried engine.

A servo track writer for a magnetic disk device according to the present invention, a reference clock magnetic head connected thereto, a reference clock recording and reproducing circuit connected thereto, an indexing magnetic head and an index recording and reproducing circuit connected thereto, and these connected. A servo track writer for a magnetic disk device having a servo trunk writer control section, a servo signal recording circuit, and a head positioning control section includes a single-layer magnetic disk coupled to the same shaft as a head disk assembly, and a two-layer magnetic disk disposed on the disk. For the T-rance clock, ・For the selection circuit and index at the throat. ・For the index and reference clock mechanism consisting of the throat, and from the mechanism for the reference clock signal on the double-layer disk surface. Recording servo information simultaneously Therefore, in order to record servo signals on each disk surface simultaneously, the time to record servo information on a magnetic double layer disk is the same as the time to record servo information on a conventional single layer disk for servo surface servo. The features of the servo track writer for a magnetic disk device according to the present invention will be explained with reference to comparative examples and examples.

Comparative example Figure 1 shows the conventional servo face-to-bottom system,
FIG. 2 is a configuration diagram of a writer. In FIG. 1, the lower surface of the disk t in the conventional single-layer magnetic disks numbered 1 to 5 is the servo surface. ``Zubo surface servo system''? And,
1: Head positioning on all other disk surfaces is performed based on the hit information on the lower surface of the lid disk 3. Therefore, writing the bottom surface of the magnetic disk 30 requires a servo track writer for recording servo information, and a block diagram of the servo track writer is shown in FIG.

In FIG. 1, index information is first recorded by the head 9 on the lower surface of the disk 4 through the index recording circuit 16. The recorded index signal is reproduced by the head 9, amplified by the reproduction amplifier 17, and pulsed to be used as a reference signal. Using this index signal as a reference signal, a reference clock signal is passed through the head 8 by a reference clock recording circuit 18.
Record on the top surface of the disc 4. Then, the reference clock signal regenerated by the head 8 is amplified by the reference clock regenerative amplifier 19, and the pulse generator 20
This signal is converted into a pulse and used as a reference clock signal. Based on this reference clock signal, servo signals for odd and even tracks are recorded on the servo surface (lower surface) of the disk 3 by the servo recording circuit 14 and the magnetic head 10. Positioning of the actuator 11 and the servo recording head 10 at this time is performed by a head positioning mechanism having a highly accurate distance measuring mechanism and a control section 15.

In the conventional servo track writer as mentioned above, it is only necessary to record servo information on a single disk surface.
The reference clock and index clock signals can be detected using other disk surfaces in the hard disk assembly. However, magnetic 2
In the case of a head-disk assembly using a multi-layered disk, it is necessary to record servo information on all sides of the disk, but when using a conventional servo trunker, the magnetic disk used for index and reference clocks is required. Since servo information will be recorded on each magnetic double layer disk surface other than 7-7f, the time required to record the servo information will be equal to N times the number of surfaces of the magnetic double layer disk to be recorded. It has the disadvantage of significantly increasing the cost.

Embodiment FIG. 2 shows a configuration diagram of a servo track writer for a magnetic disk device according to the present invention. t (In Figure 12, the main layer magnetic disk 27 and the reference clock head 2
9, 30 and an index head 40, 22 to 26 magnetic double layer disks and 41 to 50
A head/disk assembly consisting of a magnetic head is set, and the heavy index/reference clock mechanism is coupled to the same rotating shaft 28. A servo signal recording circuit and a servo signal recording magnetic head are generated on each magnetic double layer disk surface of the head/disk assembly by reproducing the frequency reference clock signal and using the frequency reference clock signal. As a result, servo information is simultaneously recorded on each magnetic double layer disk surface.

In this way, the servo information recording time by a servo track writer for a magnetic disk device using a magnetic 27# layer disk can be significantly shortened, and the manufacturing cost of the magnetic double layer disk can be reduced. When applying a conventional servo trunk writer for a single-layer magnetic disk drive to a buried servo servo trunk writer for a magnetic disk drive, recording of servo signals on the magnetic double-layer disk other than the magnetic disk surface for index and reference clock is performed on the magnetic disk. Although the recording time is very long since the recording is repeated for the number of surfaces N, and the manufacturing cost of the magnetic double layer disk is high, as in the present invention, the servo signal recording circuit and the servo magnetic head are connected to each magnetic layer. By connecting the number of devices corresponding to the surface of the double-layer disk and simultaneously recording servo information, the time required to record the servo information can be shortened, which is the same time as recording servo information on one surface of the disk.

This embodiment will be specifically explained as follows.

? in the index/reference clock mechanism 57 connected to the rotary motor 7 in FIG. The index signal and reference clock number 41 (two low frequency signals) recorded in advance on the lt layer magnetic disk 27 are reproduced by the magnetic head 4n, 29°30. The reference clock T1 clock signal is reproduced by the head 29 (or 30) selected by the upper head selection circuit 55, and the reference clock reproduction multiplier 1
The reference clock pulse is amplified by 9, detected by the pulse generator 20, and passed through the gate circuit 56 controlled by the servo track writer controller 58 to the servo signal recording circuits 59, 60, 61.6'2, 63, 6.
4°65, 66, 67, 68, 69 at the same time, and the output current of each recording circuit is input to the corresponding magnetic heads 41, 42, 43, 44. /15°46.47,4
8, 49, 50 at the same time, magnetic 2 from 22 to 26
Record servo information on each disk surface of the multilayer disk. At that time, the positioning of the servo recording head is performed by the high-precision head positioning mechanism and the control unit 54.As in this embodiment, the servo signal recording circuit and the servo recording magnetic head are positioned on each magnetic double layer disk surface ((compatible By placing as many as possible and recording servo information at the same time,
It is possible to realize a servo track writer for buried servo magnetic disk system V11 that enables low manufacturing costs of double-layer magnetic disks.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are device configuration diagrams of a comparative example and an example, respectively. 1. 2, 3, 4, 5...Single layer magnetic disk, 6°° shaft, 7° rotation motor, 8... Magnetic head for riff, r-lance clock, 9... Magnetic head for indesokube, 10... Servo information recording head, 11... Actuator, 13... Servo signal reproducing circuit, 14...
Servo signal recording circuit, 15... Head positioning mechanism and control circuit, 1G... L'112 recording circuit for index, 17... Reproducing circuit for index, 18... Reference clock, recording circuit for 19...Reference clock regeneration circuit, 20...Pulsing circuit, 21
... Servo trunk writer control section, 22, 23, 24
゜25.26...magnetic double layer disk, 41. /12
゜43.44,45,46,47,48,49゜50・
...-Leebo Gogo recording head, 27-゛Index Ring-J Lance clock single-layer magnetic disk, 28.
... Rotating shaft, 29... νF (odd R) for reference clock, 3o... Head for reference clock (even number), 40... Head for index,
51゛... Actuator, 54... Head positioning control unit, 55... Head selection circuit for reference clock, 58... Servo track writer control unit, 57
・・・Mechanism for index/reference clock,
56...Gate circuit, 59, 60, 61°62.63
, 64, 65, 66, GV, 68° 69... Servo signal recording circuit.

Claims (1)

[Claims] A magnetic head for reference clock and a recording and reproducing circuit for the reference clock connected to it, a magnetic head for indexing and a recording and reproducing circuit for indexing connected to this, a servo controller/fter control unit to which these are connected, and servo signal recording. A servo track writer for a magnetic disk drive with a circuit and a head positioning control unit? A single-layer magnetic disk coupled to the same shaft as the head disk assembly, and two reference clocks arranged on the disk - for index and reference clocks consisting of a head selection circuit and an index head at the node and rl. (・Glue from the engineering section and the mechanical section) -R The surface of the magnetic double layer disk where the signals are recorded simultaneously on the entire magnetic double layer disk surface in the head disk assembly by the lance clock signal. A servo track recorder for a magnetic disk device, characterized in that the number of servo signal recording circuits corresponds to the number of servo signal recording circuits.