JPH0198180A - Storage device - Google Patents

Abstract

PURPOSE:To decide an increase in a friction resistance between a head and a recording medium by changing the ambient temperature of a read write circuit, generating a regeneration error signal and detecting a change in a temperature fluctuation allowance. CONSTITUTION:The ambient temperature of the read/write circuit by the floating head is raised by a temperature control circuit 21 in accordance with a temperature raising command from an electronic computer 13 through a temperature fluctuation allowance detection circuit 22. Thus, a crossing position between a reproduction signal and a threshold voltage fluctuates by the heat noise of the read/write circuit, and the error of the reproduction signal is detected from an error detection circuit 20. An error detection signal is impressed on the temperature fluctuation allowance detection circuit 22 and the temperature fluctuation allowance of a difference between a steady temperature and a temperature when the error is detected. When the allowance is compared with a maximum temperature fluctuation allowance being the reference value of the difference between the steady temperature stored in the circuit 22 and the peripheral temperature when a signal C has outputted without the head 4 being brought into contact with the recording medium 3, the allowance change is detected, and an allowance range is narrowed, the increase in the friction resistance by the contact of the head and the recording medium is judged and head drop or the like are prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a storage device used in an electronic computer or computer peripheral equipment, etc., and in particular, to prevent information loss from being lost due to a head falling into a recording medium, etc. This is related to storage devices.

[Conventional technology]

FIG. 4 is a block diagram showing a conventional storage device, in which a recording medium 3 made of a magnetic disk or the like is mounted on a rotating shaft (not shown) and rotated, and a head 4 is placed opposite the recording surface of the recording medium 3. are arranged, and control from the read/write circuit 18 (No. 3) is performed based on a recording/reproducing command from the electronic computer 19 to perform recording on the recording medium 3 through the head 4 or reproduction from this point.

The positioning of the head 4 for recording and reproduction with respect to the recording medium 3 is performed by moving the actuator 7 connected to the head 4 based on a positioning command from the computer 19, position information from the sensor 13, and speed information from the speed demodulator 16. This is performed by driving and controlling the servo circuit 17, and when the positioning is completed, the above-mentioned information is recorded and reproduced.

The error detection circuit 20 outputs an error detection signal C to the electronic computer 19 when an error occurs in the reproduced signal A read through the read/write circuit 18, and repeats reproduction until the error is resolved. .

Reproduction is performed via the head 4 from trunks arranged radially at predetermined intervals on concentric circles of the recording medium 3, and this reproduction signal A is a sine wave as shown in FIG. The peak point represents information (1) recorded in each trunk, and error detection is performed as follows.

That is, the read/write circuit 18 compares the reproduced signal A with the threshold voltage B in an analog manner and inputs the comparison output to the error detection circuit 20. The error detection circuit 20 detects the position of the cross voltage when the position where the reproduced signal A intersects the threshold voltage B changes greatly, that is, the position of the cross voltage 9 is detected by digitally processing the reproduced signal A. At this time, it is determined that there is a reproduction error, and an error detection signal C is output to the electronic computer 19.

The electronic computer 19 causes the head 4 to perform the reproduction again until this error detection signal C is no longer generated.

[Problem that the invention seeks to solve]

-g, in a magnetic disk drive, the head 4 is subject to buoyancy due to the viscous air flow generated on the surface of the recording medium 3 as it rotates, so this buoyancy and the spring that holds the head 4 close to the recording surface are By balancing the urging force with the biasing force, recording and reproduction are performed in a state where the recording medium 3 is held facing the recording medium 3 with a small gap being maintained between the recording medium 3 and the surface thereof.

By the way, the main fluctuation factors in the cross voltage, which is used as a reference for the error detection circuit 20 to issue the error detection signal C, are frictional resistance due to contact between the recording medium 3 and the head 4, or the presence of foreign matter in the gap between the two. There is also the ambient temperature of the read/write circuit 18, etc.

When the head 4 is maintained in the normal relationship as described above, the frictional resistance acting between the head 4 and the recording medium 3 is a small value due to the viscous air flow and the bearing friction force for sliding the head 4. This alone does not cause the position of the cross voltage to vary enough to generate an error detection signal. Furthermore, when the ambient temperature of the read/write circuit 18 is a steady temperature, the circuit thermal noise is theoretically small, and since the playback signal A has a large operating margin against disturbances, the position change of the playback signal A is also small. Error detection signal C is not output.

However, when dust or the like enters or exits the minute gap between the recording medium 3 and the head 4, or when the head 4 comes into strong contact with the recording medium 3 due to strong vibrations or shocks from the outside, the recording medium 3 and head 4 may be damaged. When the air gap between the read/write circuit 18 changes or the ambient temperature of the read/write circuit 18 rises abnormally, the reproduced signal A changes as shown from the broken line A1 to the solid line A2 in FIG. 5, and an error detection signal C is generated. For this reason, conversely, in the case of slight contact between the recording medium 3 and the head 4, the reproduction error detection signal C is not generated, and reproduction continues without the contact being detected.
There were problems such as the machine crashing, damaging the recording medium, and causing the recorded information to disappear.

The present invention has been made in view of the above circumstances, and its purpose is to focus on the relationship between the frictional resistance between the recording medium and the head and the ambient temperature of the read/write circuit, and to prevent the recording from occurring before the head crashes. It is an object of the present invention to provide a storage device that can prevent damage to a recording medium and loss of information by early detecting contact between a medium and a head.

[Means for solving problems]

The storage device according to the present invention includes a temperature control circuit that controls the ambient temperature of the read/write circuit, and a reproduction error detection signal that is output from the error detection circuit when the ambient temperature of the read/write circuit is made different from a steady temperature. and a temperature fluctuation margin detection circuit that determines the operating margin of the error detection circuit with respect to the ambient temperature and outputs an abnormality detection signal when the narrowing of the operating margin exceeds a predetermined value.

[Effect]

By changing the ambient temperature of the read/write circuit and generating a reproduction error signal, the present invention makes it possible to detect the temperature fluctuation margin change leading to a reproduction error, and the frictional resistance between the head and the recording medium. This means that it is possible to determine the increase in .

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a magnetic disk device will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of a magnetic disk device according to the present invention (hereinafter referred to as the device of the present invention), in which reference numeral 1 indicates a support base;
2 is a rotating shaft driven by a spindle motor or the like; 3 is a recording medium such as a magnetic disk; 4 is a head; and 7 is an actuator for the head 4.

The recording medium 3 is mounted on the rotating shaft 2 and rotated, and the head 4 is positioned at a predetermined position by performing a seek operation on the recording surface of the recording medium 3 using the actuator 4.
At that position, data is recorded on the recording medium 3 or data is reproduced.

The head 4 is supported by a carriage 8 constituting an actuator 7 via a pressure spring 5 and an arm 6, and is rotated by a balance between the elasticity of the pressure spring 5 and the buoyant force acting on the head 4 due to the viscous fluid on the surface of the recording medium. It is held opposite the recording surface of the recording medium 3 with a small gap therebetween, and the position of the recording medium 3 facing the recording surface can be adjusted by operating an actuator.

The carriage 8 is movably mounted on a support base 1 by bearings 9, and a cylindrical coil 10 extends from the side opposite to the side supporting the head 4. It is inserted inside a magnet 11 fixed to a yoke 12, and can be moved forward and backward relative to the recording medium 3 by adjusting the current to the coil 10.

The carriage 8 is equipped with an optical linear scale 15 and a sensor 13 that detects the relative movement amount with a transducer 14 fixed to the support base 1 to detect the position of the head 4.

FIG. 2 is a block diagram showing a magnetic disk drive system and its drive control system. The read/write circuit 18 outputs a control signal to the head 4 in accordance with a recording/reproduction command from the electronic computer 19, and performs recording on the recording medium 3 via the head 4.
It is also designed to allow future playback.

The positioning of the head 4 with respect to the recording surface of the recording medium 3 is performed using a positioning command from the electronic computer 19, head position information from the sensor 3, and a speed demodulator 16 that differentially shapes the position information to detect the positioning speed of the head 4. This is done by driving the actuator 7 by the servo circuit 17 based on the speed information.

In the apparatus of the present invention, in addition to the error detection circuit 20, the temperature control circuit 21. A temperature fluctuation margin detection circuit 22 is provided.

The error detection circuit 20 is configured to detect reproduction errors mainly based on changes in the cross voltage in the reproduction signal A read out by the read/write circuit 18, and detects reproduction errors when an error occurs in the reproduction signal A due to disturbance or the like. The error detection signal C is output to the electronic computer 19 and the temperature fluctuation margin detection circuit 22.

The temperature control circuit 21 is capable of raising the ambient temperature in accordance with an instruction signal issued from the temperature fluctuation margin detection circuit 22 based on an ambient temperature increase command from the electronic computer 19 to the read/write circuit.

The temperature fluctuation margin detection circuit 22 outputs an instruction signal to the temperature control circuit 21 to raise the ambient temperature based on a command from the electronic computer 19 to set the ambient temperature of the read/write circuit 18 higher than the steady temperature, and performs temperature control. The circuit 21 increases the temperature around the read/write circuit 18, and
When the error detection signal C from the error detection circuit 20 is input, an abnormality detection signal C is output to the computer 19 under predetermined conditions.

Now, if the ambient temperature of the read/write circuit 18 is increased by the temperature control circuit 21, the thermal noise of the read/write circuit in one day will theoretically increase, and the intersection position of the reproduction signal A and the threshold voltage B will fluctuate. When the position is normal, the fluctuation range is small, and the reproduced signal A has a sine waveform on which thermal noise is superimposed, as shown by a dashed line A3 in FIG.

However, if the ambient temperature rises further and the fluctuation range of the intersection position becomes larger as shown by the solid line A4 in FIG. An error detection signal C is output from the circuit 20.

For example, the maximum value of the temperature difference between the steady temperature and the ambient temperature when the error detection signal C is output (this is called a temperature fluctuation margin), that is, the steady temperature, comes into contact with the recording medium 3 and the head 4. The temperature fluctuation margin when the head 4 and the recording medium 3 face each other in a normal state is set as the standard width, and the recording range of the change in the sound fluctuation margin due to an increase in the frictional resistance between the head 4 and the recording medium 3 is determined in advance. It is stored in the margin detection circuit 22.

Thereafter, based on a predetermined inspection schedule, the electronic computer 19 issues a command to the temperature fluctuation margin detection circuit 22 to increase the ambient temperature of the read/write circuit 18, and the temperature control circuit 21 controls the ambient temperature of the read/write circuit 18. The temperature is raised from the steady state until the error detection signal C is generated from the error detection circuit 20.

Determine the ambient temperature when the error detection signal C is issued, determine the temperature fluctuation margin from this and the steady temperature, determine the deviation between this and the maximum sound fluctuation margin, that is, determined in advance, and determine if this deviation is larger than a certain level. In other words, if the temperature fluctuation margin is narrower than the predetermined range by a predetermined value or more, it is detected that the temperature fluctuation range is narrower than the reference width due to an abnormal increase in frictional resistance. As a result, the temperature fluctuation margin detection circuit 22 outputs an abnormality detection signal to the electronic computer 19.

Immediately upon receiving the abnormality detection signal, the electronic computer 19 issues a command to store the information from the recording medium 3 in another recording medium to prevent the information from being lost.

The cycle for determining the presence or absence of an abnormality is determined by the degree of use of the apparatus itself, the frequency of contact accidents between the head 4 and the recording medium 3, etc., and is normally performed once every several months.

Of course, the operator may perform this periodically using a program in the electronic computer 19.

In the above-described embodiment, a configuration was described in which the ambient temperature of the read/write circuit 18 is made higher than the steady temperature to detect a temperature fluctuation margin in which no reproduction errors are detected. The determination may be made using a method.

Furthermore, it goes without saying that the above-mentioned determination may be made using a microcomputer or the like.

Furthermore, although the above-mentioned embodiment has been described with respect to a magnetic disk device, the present invention is not limited to this, but can also be applied to recording devices, recording devices, etc. using optical methods, magneto-optical methods, laser methods, electric field methods, electric charge methods, and other methods. It goes without saying that it can be done.

(Effects of the Invention) As described above, the present invention detects changes in the temperature fluctuation margin of the ambient temperature based on the relationship between the ambient temperature of the read/write circuit and load fluctuations that lead to the generation of a reproduction error signal. Since load fluctuations, that is, increases in the frictional resistance between the head and the recording medium, are detected, it is possible to store information in another device before an accident such as head deterioration occurs.
The present invention has excellent effects such as being able to prevent information from disappearing.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a magnetic disk device to which the present invention is applied;
FIG. 2 is a block diagram including the control system thereof, FIG. 3 is a waveform diagram of the reproduced signal, FIG. 4 is a block diagram including the conventional device and its control, and FIG. 5 is a waveform diagram of the reproduced signal. 3...Recording medium 4...To7 26...Error detection circuit 21...Temperature control circuit 22...Temperature fluctuation margin detection circuit A...Reproduction signal C...Error detection signal D
. . . Abnormality Detection Signal In the drawings, the same reference numerals indicate the same or corresponding parts. Procedural amendment (spontaneous) Showa year/month/day/indication of case Patent application No. 1982-255373 2,
Invention title storage device 3, representative of the person making the amendment Moriya Shiki 4, agent 5, "Detailed description of the invention" and "Brief description of the drawings" column 6 of the specification to be amended, contents of the amendment 6-1 "Detailed Description of the Invention" column (1) On page 7, line 20 of the specification, "Actuator 4j
Correct it to "r actuator 7". (2) "Sensor 3" on page 9, lines 11 and 12 of the specification is corrected to "sensor 13." (3) On page 11, line 18 of the specification, the phrase "recording range of changes in sound fluctuation margin" is corrected to "range of change in temperature fluctuation margin." (4) On page 12, line 9 of the specification, the phrase "with the maximum sound fluctuation margin, that is," is corrected to "with the maximum temperature fluctuation margin." (5) On page 14, line 5 of the specification, the phrase "Head deterioration, etc." is corrected to "Head deterioration, etc. J. 6-2 Brief explanation of drawings" column, page 14, page 15 of the specification. The line "26...error detection circuit" is corrected to "20...error detection circuit".

Claims (1)

[Scope of Claims] 1. A read/write circuit that uses a head to record information on a rotationally driven recording medium and reproduces the information, and detects reproduction errors based on reproduction signals and outputs error detection signals. a temperature control circuit that controls an ambient temperature of the read/write circuit; and an error detection circuit that outputs an output from the error detection circuit when the ambient temperature of the read/write circuit is made different from a steady temperature. and a temperature fluctuation margin detection circuit that detects a reproduction error detection signal, determines an operating margin range for the ambient temperature in which no reproduction error is detected, and outputs an abnormality detection signal when this operating margin range becomes narrower than a predetermined range. A storage device characterized by: 2. The storage device according to claim 1, wherein the temperature fluctuation margin detection circuit outputs an abnormality detection signal based on an error detection signal when the ambient temperature of the read/write circuit is higher than the steady temperature. 3. The storage device according to claim 1, wherein the temperature fluctuation margin detection circuit outputs an abnormality detection signal based on an error detection signal when the ambient temperature of the read/write circuit is lower than the steady temperature.