JPS63155408A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent a data from being broken down by magnetic powder adhering to head, by detecting an amplitude drop of a read-out waveform. CONSTITUTION:The titled device is provided with a data processing circuit 7 for reading out output level information by a medium written in advance in a medium surface of a megnetic device and a head, and detecting an output level of a data, a level determining circuit 8 for generating the potential required for reading out exactly the data by address information, a level detector 5 for comparing an output of the level determining circuit 8 and an output waveform level of the data, and a displaying circuit 6 for displaying a level drop, in case an output level drop has occurred. In such a way, an amplitude drop of a read-out waveform can be detected, therefore, a breakdown of the data on the medium can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to protection of magnetic disk drives from data destruction, and particularly to detection of data output drop.

[Conventional technology]

Conventionally, this type of magnetic disk device did not have a function to detect a decrease in the amplitude of a read waveform due to magnetic powder adhering to the head and a decrease in amplitude due to off-track.

[Problem that the invention seeks to solve]

The above-described magnetic disk drive has the disadvantage that data on the medium is destroyed because it does not have a function to detect a decrease in the amplitude of the read waveform due to magnetic powder or the like adhering to the disk.

[Means for solving problems]

The magnetic disk device of the present invention includes a data processing circuit that detects the output level of data by reading out output level information from a medium written on the medium surface of the magnetic disk device in advance, and a level determining circuit that generates a potential necessary to accurately generate data; a level detector that compares the output of the level determining circuit with the data output waveform level; and a display circuit that displays a decrease in the level of.

〔Example〕

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 according to the present invention.

In FIG. 1, the output of a magnetic head 1 is input to an amplifier 2. In FIG. The output of the amplifier 2 is input to a peak detector 3 and a level detector 5. The output of the peak detector 3 is input to a demodulator 4. One of the outputs of the demodulator 4 is input to the data processing circuit 7, and the other is input to the next stage as a read signal.

The output of the data processing circuit 7 is input to a level determining circuit 8. Level determining circuit 8 outputs a signal corresponding to the address information to level detector 5. The output of the level detector 5 is input to a display circuit 6.

In FIG. 1, output level information written on the medium surface is read by a magnetic head 1 and amplified by an amplifier 2 when the magnetic disk device is started up. The output of the amplifier 2 is input to a peak detector 3, and a peak pulse is output. The output of the peak detector 3 is input to the demodulator 4,
The data demodulated into binary information is input to the data processing circuit 7. The data processing circuit 7 processes the input information into output level information corresponding to the address and outputs it.

The level determining circuit 8 inputs and stores the data from the data processing circuit 7, and when normal reading is performed, determines the required level based on the data address and inputs it to the level detector 5. At this time, the read data is input to the level detector 5 and compared with the level determined by the level determining circuit, and if it does not reach the required level, a signal is sent to the display circuit 6 to notify it.

FIG. 2 is a detailed block diagram of the level detector 5 and level determining circuit 8 shown in FIG.

The output level information read at the time of startup of the magnetic disk device is processed by the data processing circuit and input to the RAM 13. The information stored in R and AM13 is the level information corresponding to the address information of the data being read out.
Output to A converter 4. Data input to the DA converter 14 is converted into analog data and output. The output of the amplifier 2 is input to the peak hold circuit 9,
The peak hold circuit outputs a peak level.

Comparator 10 has an input from peak hold circuit 9 and D-
Compare the input level with the input from the A converter 14, and if the input level from the peak hold circuit is lower than the level from the D-A converter 14, it is a free signal.

It is output to the flop 11. The flip-flop 11 holds the signal input from the comparator 10, and turns on the light emitting diode 12 by its output.

A decrease in output can be detected by the lighting of the light emitting diode.

Further, the data processing circuit 7 has a function of once taking in the data output from the decoder 4, processing it into level information corresponding to an address, and outputting the level information.
In this apparatus, it is provided inside the magnetic disk device, but it can also be provided on the controller side outside the magnetic disk device.

C Effects of the Invention As explained above, the present invention has an excellent effect in that data destruction can be prevented in advance by knowing the amplitude drop of the read waveform. Further, there is an effect that amplitude reduction due to off-travel can be detected in the same way.

Furthermore, by writing the output level information on the medium surface, there is an effect that it is not necessary to set the output level information for each magnetic disk device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a magnetic disk drive according to an embodiment of the present invention, and FIG. 2 is a diagram showing a level detector, a display circuit, and a level determining circuit. 1...Magnetic head, 2...Amplifier, 3
... Peak detector, 4 ... Demodulator, 5
...Level detector, 6...Display circuit,
7... Data processing circuit, 8... Level determining circuit, 9... Peak hold circuit, 10...
...Comparator, 11...7 lip 70 tubes, 12...Light emitting diode, 13...
RAM, 14...D-A converter. Convergence [

Claims (1)

[Claims] A data processing circuit that reads output level information written in advance on the media surface of a magnetic disk device and detects the output level of data, a level determination circuit that generates a potential (generated level), and a The method further comprises: a level detector that compares the output of the determination circuit with the output waveform level of the data processing circuit; and a display circuit that displays a level decrease when a decrease in the output level is detected by the level detector. Features of magnetic disk device.