JPH02123560A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent a device from being influenced by noise which seeking operation generates by detecting the seeking operation based on servo data from a servo head and stopping the reproduction of data in course of the seeking operation. CONSTITUTION:When either of a power unsafe signal from a power unsafe detecting circuit 12 and a seeking/detect switching signal SD from a servo control circuit 10 is 'L', it is a seeking state or a power source abnormal state. Then, since a chip selection signal CS becomes 'H' through a NAND gate 16 and a data system preamplifier 1 is not selected, an analog signal is not amplified. Therefore, the stable and highly reliable device which is not influenced by the noise which the seeking operation generates by a data read pulse in course of the seeking operation is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device used as an external storage device for an electronic computer or its peripheral equipment.

[Conventional technology]

FIG. 3 is a block diagram showing a circuit configuration of a data reading system and a positioning system of a conventional magnetic disk device disclosed in, for example, Japanese Patent Laid-Open No. 61-260479.

In the figure, 2 is a data head coil that reads data recorded on a magnetic disk (not shown), and its both ends are
It is connected to a data system preamplifier 1 that amplifies the analog signal generated there during playback. Data preamplifier 1
(1 is an AGC amplifier 3 that keeps the difference in voltage of the analog signal at the inner and outer circumferences of the magnetic disk constant.
and a differentiator 5 via a low-pass filter 4 that removes noise superimposed on the analog signal. The signal differentiated by the differentiator 5 is given to a zero-crossing detector 6 that detects its zero-crossing point, and the zero-crossing point is reproduced as a read data pulse.

The data system preamplifier 1 also has a power unsafe detection circuit 12 that detects abnormality in the power supply voltage via an inverter 17.
A chip select signal C3 obtained by inverting the power unsafe signal PD from the detection circuit 12 by an inverter 17 is applied, and 1.11 of the chip select signal C3 is connected to the inverter 17.
The data system preamplifier 1 is selected and amplifies the analog signal.

On the other hand, 8 is a servo head coil that operates in conjunction with the data head coil 2 and reads servo data recorded on the servo surface of the magnetic disk, and both ends of the coil are connected to a servo system preamplifier 7 that amplifies the output signal generated there during playback. It is connected. The analog signal amplified by the servo system preamplifier 7 is given to a position signal reproducing circuit 9 that generates a position signal indicating position information necessary for positioning. The generated position signal is given to the servo control circuit 10, and the servo signal from there is given to the actuator drive circuit 11.
A head having a servo head coil 8 and a data head coil 2 is moved and positioned in the radial direction of the magnetic disk by an actuator (not shown) attached thereto. The servo control circuit 10 also receives a seek/detent switching signal C indicating whether or not the data head is in a seek state.
Generate S (see Figure 4).

Next, the operation of a conventional magnetic disk device will be explained.

Data recorded on the magnetic disk is continuously output as a voltage generated across the data head coil 2, and this analog signal is amplified by the data diameter preamplifier 1, which is the first stage amplifier. Then, the voltage difference between the analog signals is kept constant by the AGC amplifier 3, and the noise component is removed through the low-pass filter 4. The analog signal from which noise has been removed is differentiated by a differentiator 5 to detect its peak point, and the zero-crossing point at this time is reproduced by a zero-crossing detector 6 as a read data pulse.

On the other hand, the servo pattern recorded on the magnetic disk is read by the servo head coil 8 and amplified by the servo system preamplifier 7. From this amplified servo analog signal, a position signal reproducing circuit 9 generates a position signal indicating position information necessary for positioning. Using the generated position signal, the servo control circuit 10 performs head positioning control, and the actuator drive circuit 11
The actuator to which the head is attached is moved to any position in the radial direction of the magnetic disk to write data and output data.

Figure 4 shows the chip select signal C of data system preamplifier 1.
3 shows a tanning chart when 3 is generated. The data system preamplifier 1 is controlled by a chip select signal C3 from a power unsafe detection circuit 12. For example, when the power supply voltage is normal, the power-7 safe detection signal Pal
becomes II H11 level, and the chip select signal cs obtained by inverting it becomes "L" level, data system preamplifier 1 is selected and the amplification function is activated.
As shown in the figure, when the power unsafe detection signal 2 is at the "H" level, the chip select signal C8 becomes the "L11 level" regardless of the seek/detent switching signal SD generated by the servo control circuit 1O, and the data system preamplifier 1 is selected.

[Problem to be solved by the invention]

Conventional magnetic disk drives are configured to behave abnormally, so when the power supply voltage is determined to be normal by the power unsafe circuit, the data system preamplifier is always selected by the chip select signal, and the data head is activated when writing. Otherwise, the read data pulse is always regenerated from the zero-crossing detector regardless of whether a seek operation is in progress or not, so the noise generated by this read data pulse enters the positioning control system, making the seek operation unstable. There was a problem.

This invention was made to solve the above problems, and by not selecting the servo preamplifier by the chip select signal during the seek operation, it is possible to avoid noise generated by the read data pulse during the seek operation. The first object of the present invention is to obtain a magnetic disk device that performs stable seek operations.

[Means to solve the problem]

A magnetic disk device according to the present invention is provided with a reproduction stop means that detects a seek operation based on servo data from a servo head and stops reproduction of data when a seek operation is detected.

[Effect]

In this invention, data reproduction is stopped during a seek operation, and the seek operation is not affected by noise generated by data reproduction.

(Example) Hereinafter, the present invention will be described based on drawings showing one example thereof. FIG. 1 is a block diagram showing the circuit configuration of a data reading system and a positioning system of a magnetic disk device according to the present invention. In the figure, reference numeral 2 denotes a data head coil for reading data stored on a magnetic disk (not shown), and both ends thereof are connected to a data system preamplifier 1 for amplifying an analog signal generated there during reproduction. The analog signal amplified by the data system preamplifier 1 makes the difference in voltage of the analog signal between the inner and outer circumferences of the magnetic data constant.
The signal is supplied to a differentiator 5 via a C amplifier 3 and a low-pass filter 4 that removes noise superimposed on the analog signal.

The signal differentiated by the differentiator 5 is applied to a zero-crossing detector 6 that detects its zero-crossing point, and the zero-crossing point is reproduced as a read data pulse.

Further, the data system preamplifier 1 is given a chip select signal C8 from the NAND gate 16, thereby controlling its amplification function. The NAND gate 17 includes a power unsafe detection circuit 12 that detects an abnormality in the power supply voltage.
A power unsafe signal PD from the servo control circuit 10 and a seek/detent switching signal S from the servo control circuit 10, which will be described later.
D, and outputs their inverted AND as a chip select signal C8.

On the other hand, 8 is a servo head coil that works in conjunction with the data head coil 2 to read servo data recorded on the servo surface of the magnetic disk, and both ends of the coil are connected to a servo system preamplifier 7 that amplifies the output signal generated there during playback. has been done. The analog signal amplified by the servo system preamplifier 7 is given to a position signal reproducing circuit 9 that generates a position signal indicating position information necessary for positioning. The generated position signal is given to a servo control circuit 10, and the servo signal from there is given to an actuator drive circuit 11 to drive a head having a servo head coil 8 and a data head coil 2 to which it is attached (not shown). The actuator moves and positions the magnetic disk in the radial direction. The servo control circuit 10 also generates a seek/detent switching signal SO indicating whether the data head is in a seek state.

Next, the operation will be explained.

Data recorded on the magnetic disk is read out as a voltage generated across the data head coil 2, and this analog signal is amplified by the data system preamplifier 1, which is the first stage amplifier. Then, the voltage difference between the analog signals is kept constant by the AGC amplifier, and the noise components are removed through the low-pass filter 4. The analog signal from which noise has been removed is differentiated by a differentiator 5 to detect its peak point, and the zero cross point at this time is detected by a zero cross detector 6.
is reproduced as a read data pulse.

On the other hand, the servo pattern written on the magnetic disk is read by the servo head coil 8 and amplified by the servo system preamplifier 7. From this amplified servo analog signal, a position signal reproducing circuit 9 generates a position signal indicating position information necessary for positioning. Using the generated position signal, the servo control circuit 10 performs head positioning control, and the actuator drive circuit 11 moves the actuator to which the head is attached to any position in the radial direction of the magnetic disk, thereby reading and writing data. I do.

Figure 2 shows the chip select signal C of the data diameter preamplifier 1.
8 shows a tanning chart when a number 8 is generated.

The data system preamplifier 1 is controlled by a chip select signal C8 which is reproduction stop means. For example, when the power unsafe signal PD is at the "H11 level", the power supply voltage is normal, and when the chip select signal C3 is at the "°L" level, the data system preamplifier 1 is activated and the seek/detent switching signal SD is "L". If it is assumed that the seek state is set when the power unsafe detection signal PD is at the "H" level, the power supply voltage is normal, and the seek/detent switching signal SD is at the "H" level, as shown in FIG. When it is at the "H" level and is not in the seek state, the chip select signal C3"L I+ is output from the NAND gate 16, and the data system preamplifier 1 is selected.

Further, when at least one of the seek/detent switching signal SD and the power unsafe signal PD is at the "L" level, that is, when the seek state or the power supply abnormality state occurs, the chip select signal C8'H' is outputted, The data system preamplifier 1 is not selected and does not amplify the analog signal. Therefore, when the power supply voltage is normal and the seek state is not active, the analog signal read out by the data head control 2 is amplified by the data system preamplifier 1 and read. Although it is reproduced as a data pulse, in the seek state during a seek operation, the analog signal is not amplified by the data system preamplifier 1 and is not reproduced.Also, since the data system preamplifier is not selected during the seek operation, the power consumption during that time is Reduce consumption.

In this embodiment, the data system preamplifier is selected and its amplification function is controlled by the chip select signal, but the present invention is not limited to this.
It goes without saying that the function of any one of the AGC amplifier, differentiator, or zero-cross detector may be controlled by the chip select signal.

〔Effect of the invention〕

As described above, according to the present invention, since the data read pulse is not reproduced during the seek operation, the seek operation is not affected by the noise generated by the data read pulse during the seek operation, so that A stable and highly reliable magnetic disk device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the circuit configuration of a data reading system and a positioning system of a magnetic disk device according to the present invention, and FIG.
The figure is a timing chart when the chip select signal of the data system preamplifier of the present invention is generated, FIG. 3 is a block diagram showing the circuit configuration of the data reading system and positioning system of a conventional magnetic disk device, and FIG. 4 is a conventional one. 3 is a timing chart when a chip select signal of a data system preamplifier is generated. 1... Data system preamplifier 2... Data head coil 8... Servo head coil 10... Servo control circuit 12... Power unsafe circuit C3
. . . Chip select signal 16 . . NAND gate In the drawings, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa Diagram Rara Diagram Procedure Correction Amount (Voluntary)

Claims (1)

[Claims] 1. A magnetic disk having a recording surface on which data is recorded and a servo surface on which servo data for seek operation is recorded, a data head for reproducing data on the recording surface, and servo data on the servo surface. A magnetic disk drive comprising: a servo head for reproducing data; seek detection means for detecting the seek operation based on the servo data from the servo head; and when the seek detection means detects the seek operation, the data is 1. A magnetic disk device comprising: reproduction stop means for stopping reproduction of a head.