JPH01315071A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To increase the storage capacity of a magnetic disk by reading out specified information recorded on a specific track with a fixed head, generating an index signal and a reference clock signal and sending them to a host device. CONSTITUTION:The specified information recorded on the specific track 3a of the magnetic disk 3 and read out by the fixed head 4 is amplified by an amplifier AMP 5 to be inputted to a comparator CMP 6, whereas a read-out amplifying signal 11 of an analog waveform is converted into a comparator output signal 12 of a rectangular wave and inputted to a phase synchronizing circuit PLL 7 and a one-shot circuit 9. The index signal 13 generating once per revolution of the magnetic disk 3 is sent out by the one-shot circuit 9 in response to a particular long time part among the rectangular waves of the signal 12. The reference clock signal 14 is outputted by the PLL 7 in feedback of its output signal via a divider 8, while the signal 14 is sent as a pulse wave signal of a prescribed frequency to the host device, and this is sent as a write clock signal by the host device to the magnetic disk device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device having a magnetic head positioning device driven by a stepping motor or a torque motor.

[Conventional technology]

A magnetic disk device that has a magnetic head positioning device driven by a stepping motor or a torque motor relies on the motor, which is the driving source, to control the operation when positioning the magnetic head on a predetermined cylinder (track) of the magnetic disk. It is configured to perform control, and does not have a servo disk on which special information (servo information) for positioning is recorded and a dedicated servo head for reading this servo information.

Therefore, after positioning the magnetic head on a predetermined track, when writing or reading information to or from a magnetic disk, a signal that is used as a reference for the operation is used to control the operation of the magnetic disk drive. A clock signal (write clock signal) generated and sent out by a host device such as a control device is used. Also, the index for determining the starting point of each track is
It is generated by a signal generated from a Hall element that is a combination of a magnet attached to a spindle that rotates a magnetic disk, and this makes it difficult to obtain a stable intex.

On the other hand, magnetic disks have a fixed format for recording information, and the format is as illustrated in FIG. 4. That is, corresponding to the position of the index 110 that occurs once per rotation of the magnetic disk, the next index 110
A first gap portion (GAPI) 100 is provided to absorb variations in the timing of occurrence of the first gap portion (GAPI).
The part after GAPI) 100 is divided into multiple sectors (SE
The sector is divided into CO~5EC31) 101-0~101-31, and a fourth gap part (GAP 4) 102 is provided after the final sector (SEC31) 101-31. The format in each sector is after the ID-8YNC 102-1 for synchronization and the ID-Field 102-2 for specifying the cylinder number, head number, etc. A second gap part (GAP-2) 103 is provided,
A data field section (Data-Field) for recording desired information after this second gap section
l 02-3 is provided, and a data field section (Data-
A third gap portion (GAP-3) 104 is provided between the field) 102-3 and the starting point of the next sector.

[Problem to be solved by the invention]

In the conventional magnetic disk device as described above, the length of the second gap portion (GAP2) 103 during the format may be short, but the length of the first gap portion (GAP 1) 103 during the formatting may be short.
00, a third gap portion (GAP 3) 104,
The fourth gap portion (GAP4) 102 is caused by the fact that the timing of the generation of the index 110 is unstable and that the write clock signal is generated when the rotation of the magnetic disk changes due to the write clock signal being generated by the host device. In order to cope with the error that occurs between the two tracks, the track must be of considerable length, which has the disadvantage that the storage capacity per track is also small.

An object of the present invention is to provide a magnetic disk device that can have a large storage capacity by eliminating the drawbacks of the conventional magnetic disk device having a magnetic head positioning device driven by a stepping motor or a torque motor as described above. It's about doing.

[Means to solve the problem]

The magnetic disk device of the present invention includes a magnetic disk in which specific waveform information for clock signal and index signal generation is recorded on a specific track provided on the inner or outer circumferential side of a data information recording area, and a magnetic disk corresponding to the specific track. a fixed head provided with a fixed head; an amplifier for inputting and amplifying the signal of the specific waveform information read by the fixed head; and an amplifier for inputting and amplifying the signal of the specific waveform information read by the fixed head; A comparator to output, a one-shot circuit that outputs an index signal into which the output signal of the comparator is input, and a one-shot circuit that inputs the output signal of the comparator and a division signal obtained by frequency-dividing the signal output from the comparator for a certain period of time. It includes a phase synchronized circuit that outputs a reference clock signal having a pulse signal at intervals, and a frequency divider that inputs an output signal of the phase synchronized circuit, divides the frequency, and inputs the resultant signal to the phase synchronized circuit again.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a plan view showing the mounting state of the fixed head of the embodiment of FIG. 1,
FIG. 3 is a waveform diagram showing waveforms of main signals in the embodiment of FIG.

As shown in FIG. 2, this embodiment has a magnetic disk 3 in addition to the movable head 2 included in the conventional magnetic disk device.
One fixed head 4 is provided on the inner circumference side (or outer circumference side) of the information storage capacity. It records waveform information (specific information).

This specific information read by the fixed head 4 is
The signal is input to the index signal and clock signal generation circuit shown in the figure, where the index signal and reference clock signal are generated and sent to the host device. Therefore, the host device does not generate a write clock signal within itself, but sends this reference clock signal as a write clock signal together with the necessary write data information to the magnetic disk device, and the magnetic disk device uses this write clock signal as a reference. The above write data information is recorded.

FIG. 1 is a block diagram showing details of the above-described index signal and reference clock signal generation circuit.

As shown in FIG. 1, the specific information read by the fixed head 4 is amplified by an amplifier (AMP) 5 and sent to a comparator (CMP).
6 is input. This input signal is the read amplified signal 11
is an analog waveform signal as shown in Figure 3,
The comparator 6 converts this into a rectangular wave comparator output signal 12 and inputs it to a phase locked loop (PLL) 7 and a monostable multivibrator (one shot circuit) 9. The one-shot circuit 9 sends out an index signal 13 generated in response to a particularly long portion (reference numeral 12a) of the rectangular wave of the input comparator output signal 12. The long period portion 12a of the comparator output signal 120 corresponds to the long period portion 11a of the read amplified signal 11, and the long period portion 11a corresponds to the specific information recorded on the specific track 3a described above. It is provided at only one location in the waveform. Therefore, the index signal 13 is generated once per rotation of the magnetic disk.

The phase locked loop (PLL) 7 sends its output signal to a frequency divider 8.
A reference clock signal 14 is output from the feeder and the ivy via the feeder. Therefore, the reference clock signal 14 is sent to the upper level as a pulse wave signal of a predetermined frequency, and the upper level device sends this as a write clock signal together with the write data information to the magnetic disk device to write the data information. In this way, the index signal and the write clock signal are generated based on the signal read out by the fixed head from specific information recorded on a specific track, so that the signals are stable and synchronized with the rotation of the magnetic disk.

Therefore, based on these signals, it is possible to determine the starting point of the format of each track and the dividing point of each sector. It becomes possible to shorten the length of the fourth gap portion (GAP 4) 102, and it becomes possible to enlarge the data information recording area of each track accordingly.

〔Effect of the invention〕

As explained above, the present invention can synchronize with the rotation of the magnetic disk even in a magnetic disk device in which the positioning operation of the magnetic head is performed using a stepping motor or a torque motor, and the positioning control is not performed using a so-called servo surface servo system. Since stable index signals and write clock signals can be obtained, the length of the gap between each track can be shortened, and a magnetic disk device with a correspondingly larger storage capacity can be obtained. be.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a plan view showing the mounting state of the fixed head of the embodiment of FIG. 1,
FIG. 3 is a waveform diagram showing the waveforms of the main signals in the embodiment of FIG. 1, and FIG. 4 is a format diagram showing an example of the format of the magnetic disk. 2...Movable head, 3...Magnetic disk, 4...Fixed head, 5...Amplifier, 6...Comparator, 7 ...Phase synchronized circuit, 8... Frequency divider, 9... One shot circuit. Agent Patent Attorney Uchihara Oto No. 7 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] a magnetic disk in which specific waveform information for clock signal and index signal generation is recorded on a specific track provided on the inner or outer circumferential side of a data information recording area, and a fixed head provided corresponding to the specific track; an amplifier that inputs and amplifies the signal of the specific waveform information read by the fixed head; a comparator that inputs the read amplified signal from the amplifier, converts it into a rectangular wave signal, and outputs the signal; and the comparator. A one-shot circuit inputs the output signal of the comparator and outputs an index signal, and inputs a frequency-divided signal obtained by dividing the output signal of the output signal of the comparator itself to generate a pulse signal at constant time intervals. What is claimed is: 1. A magnetic disk drive comprising: a phase-locked circuit that outputs a reference clock signal having a reference clock; and a frequency divider that inputs an output signal of the phase-locked circuit, divides the frequency, and inputs the frequency-divided signal to the phase-locked circuit again.