JPS5948820A - Track servo system of magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the S/N of the servo information in a record mode, by using either front or rear side of a magnetic double layer disk for record/reproduction of data information and the other side for detection of servo information. CONSTITUTION:For magnetic double layer disks 1-5 and head disk assemblies 6-11 of a magnetic head, a magnetic head 24 belonging to a head 8, for example, is used as a data head. While a magnetic head 25 belonging to a head 9 is used as a servo head. The record data is supplied to a record amplifier 21 and then transferred to the head 24 by a head selecting circuit 13. Then the data information is recorded on the upper side of a disk 3. For the servo information of a record mode, the servo information on the underside of the disk 3 is reproduced along with the data information by the head 25 selected by the circuit 13, and only the servo information is extracted by a reproduction amplifier 22 and an LPF23. The servo signal is detected in the same way in a reproduction mode, and the data information is reproduced from the upper side of the disk 3 by the head 24 and detected by a reproduction amplifier 16 and an HPF19.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a track-→no-vo method of a small air disk device H.

Currently, the servo surface servo force type is the mainstream for the zero book determination method for magnetic heads in magnetic disk drives.

+ In the J-BO11i1 servo system, the servo disk and data disk are placed far apart from each other, which causes errors in positioning accuracy due to differences in ambient temperature. , the positioning error of the magnetic head increases, making it difficult to achieve high track density; it becomes difficult to use W, making it difficult to realize high recording density.

Recently, various data surface servo systems have been studied to improve positioning accuracy. Currently, the data surface servo method is: ■ sector servo method that uses part of the data surface, ■ method that uses the data information itself, ■ uses a magnetic 2V/F disk, and uses the lower NI basic film as the servo information medium to use that information. Methods, etc. are being considered.

Method (2) divides the A track into two sectors lζ and partially inserts servo information, but it has the disadvantage that track-servo cannot be performed unless servo information is input.

Therefore, positioning accuracy is insufficient in high-tracking systems.

Furthermore, since the method (2) uses the data information itself, when the output envelope of the data information moves, a positioning error occurs accordingly.

The method (2) has a two-layer magnetic film, with the upper layer used for data information and the lower layer used for servo information. Therefore, one data head can detect data and servo information simultaneously,
'AAl1 is used, so the positioning error is small. However, in this magnetic double layer system, one data bed outputs data + TI information and →NO''-PO t'! at the same time. Separation is easily done by a filter, but when recording, a filter = - and a bias circuit are required in the recording circuit to detect the servo information. The object of the present invention is to improve the set point between these points, simplify the recording circuit, and eliminate the disadvantages of increasing the cost of the circuit system. An object of the present invention is to provide a track servo system for a magnetic disk device that improves the time → no-op information by 7% and also reduces the cost of the recording circuit. The track servo system for a magnetic disk device according to the present invention uses magnetic double layer When one side of the disk is used for recording and reproducing data information, the servo information (magnetic 2
When data information is recorded and reproduced on the back side of the multilayer (lower layer), servo information is detected on the opposite side.

The six characteristics of the track servo system by Moku and Omei will be explained below using comparative examples and examples.

Comparative Example Figure 1 shows a magnetic double-layer truck that simultaneously processes data information and servo information using the same disk surface and the same head.
It is a block diagram of a servo system. In FIG. 1, select one of the heads in the bed assembly disk assembly consisting of two magnetic layer disks numbered 1 to 5 and six magnetic heads numbered 6 to 11. This method uses a magnetic head to simultaneously detect curvature information and servo information.

Recording data is inputted to a recording amplifier Iζ 21, and its output is passed through a high-frequency F wave generator 18 and a servo notch filter 15, and a bias is applied by a bias driver 14.
It is necessary to detect the servo head even when a recording current is applied to the magnetic head and data is recorded on the disk, and the servo information is detected and processed by the blocking filter 17 and preamplifier 20. During this recording, there are several back voltages of the magnetic head in the system that generates data and "I-no-voice" information.
5 and Ryojo p-wave device 18 are finely tuned. However, even if these are added by me, the lj: recording command's -ri--bo information is degraded, and the circuit <j? It has the disadvantage that it depends on the Vt salary.

Embodiment FIG. 2 shows a configuration diagram of a track-revolve system according to the present invention 1 (1° in FIG. 2) to 5 magnetic double layer disks and 6 to 11 magnetic ＼ νF heads. - In the disk assembly, for example, the magnetic head U that is attached to the head 8 is used as a data head, and the magnetic head 25 to which the head 97 belongs is used as a servo head.

That is, one side of the magnetic disk is used for data fit information, and the back side is used for servo information. Also, when the back side is used for data information, the front side is used for servo information.With this method, the data information recording/reproducing circuit is very simple, and the servo information is not affected by back voltage during recording. % is improved and data information recording and reproducing circuits become simpler.

The flow of data and servo information in this embodiment will be explained as follows.

The recording data is input manually to the recording amplifier 21, and the recording amplifier 2
] is sent to the magnetic head 24 selected by the head selection circuit 13, and data information is recorded on the upper surface of the magnetic disk 3. The servo information at the time of recording is reproduced by the magnetic head 25 selected by the head selection circuit 13 from the servo information and data information on the lower surface of the disk 3, and only the servo 4'+1 information is extracted by the reproduction amplifier 22 and low-pass filter 23. and use that signal as a servo signal. Similarly, during playback, a →novo signal is detected, data information is played back from the top surface of the disk 3 by the head 24, and the playback amplifier 16 and bypass filter 59
Detect data information.

Adopting such a method has the advantage of eliminating 4F of the back voltage during recording, improving the servo signal efficiency and simplifying the recording circuit at the same time.

As shown in the comparative examples and examples above, when realizing data-side servo using magnetic double-layer disks, when one side of the same disk is used for data information, the other side is used for servo information. When one side is used for data information, the other side is used for servo information, thereby improving the SN ratio of the servo signal during recording and simplifying the data recording circuit.

[Brief explanation of the drawing]

FIG. 1 and Hatake 2 are configuration diagrams of the track servo system used in the comparative example and the example, respectively.

Claims (1)

[Claims] In the track servo system of the magnetic tisf device, a magnetic 2Mrf4 disk is used, and the surface of the disk and the 4f
Can either side of the data be recorded? This is a servo system for magnetic disk drives that is characterized by the fact that the double φ is used and the blank side is used to output 4A of servo information.