JPS63225980A - Device for retracting head of disk storage device - Google Patents

Abstract

PURPOSE:To prevent the damage of a disk medium due to an unknown cause at a time except an access time from being generated, by starting up the escaping means of a head when an access signal is interrupted for a prescribed time interval. CONSTITUTION:When a time interval means 30 detects the existence of a drive select signal DS from a host computer, a storage device performs ordinary read and write operations. When no DS signal exists and the prescribed time interval is timed up, the escaping means 40 is started up, and the means 40 sends a driving signal CS for a prescribed number of times to a head operating means 10, and moves the head 2 almost in the center of a shipping zone 1b. Also, a recovery means 50 is started up immediately after the completion of an escaping operation, and a monitoring state for the signal DS is set until the appearance of the signal DS. Afterwards, a processor 201 on a controller 200 side starts the read and write operation under the condition that a seek completion signal SC outputted from the recovery means 50 exists.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a method for preventing damage to a storage medium in a disk storage device such as a fixed disk storage device by the head hitting the surface of the disk under the influence of shock or vibration. The present invention relates to a head retraction device for a disk storage device that retracts the head to an appropriate position outside the information recording area of the disk when the device is not accessed.

[Conventional technology]

As is well known, a plurality of trunks are set on a disk of a disk storage device for recording information, and when reading or writing information from a particular trunk, a head is placed at each corresponding radial position. However, the host computer, which is the user of the disk storage device, does not always access the disk storage device; rather, from the perspective of the disk storage device, the time when it is not being accessed by the host computer is longer than the time when it is being accessed. Of course, even during this non-access time, which is usually overwhelmingly long, the disk is rotating at high speed, and the head is normally moved away from the disk surface by an aerodynamic floating blade based on this rotation. Although they are separated by a microscopic space of less than m, if a shock force or vibration is applied to the disk storage device, the head will come into contact with the disk surface and easily damage the thin storage medium on top. When a power outage occurs, the rotation of the disk suddenly drops, and the flying blade for the head is also lost, and by the time the disk rotation has completely stopped, the head comes into contact with the disk surface over a wide area, causing major damage to the medium. I have something to give.

As a countermeasure against this problem, it is important to first turn the head away from the disk surface as much as possible when the disk storage device is not accessed. It is known to hold up. Electromagnetic force from a solenoid or the like is used as the operating source for this mechanism.

[Problem that the invention seeks to solve]

However, in such conventional means, the entire mechanism including the operating source is not necessarily simple, and this increases the number of causes of failures and troubles.

In addition, as mentioned above, the flying height of the head above the disk surface is extremely small, so extreme care must always be taken when lifting or lowering the head. If you are not careful when bringing the head close to the disk surface again, you may end up increasing the chances of damaging the medium. Although such necessary precautions should be taken, of course,
Since it inevitably takes some time to carefully carry out the lifting and unloading operations, such safety measures result in longer access times to the disk storage device than in the past.

SUMMARY OF THE INVENTION An object of the present invention is to provide a head evacuation device for a disk storage device in which the disk medium is less likely to be damaged due to unexpected causes when the disk is not accessed, using as simple a means as possible.

[Means for solving problems]

According to the present invention, this purpose is to serve as a head evacuation device for a disk storage v device, to constantly monitor the presence or absence of an access signal specifying reading/writing of information to a disk, and to detect the absence of an access signal within a predetermined time period. a timer; a head position evacuation means that is activated in response to the access signal non-existence detection result of the timer and moves the head to a predetermined evacuation position outside the information recording area in the disk via the head operation means; After the operation of the cough evacuation means is completed, the presence or absence of an access signal is monitored, and when an access signal is received, the head is operated via the head operation means to record the information on the disk. This is achieved by providing means for returning the head position to the flu region.

[Effect]

The time limit means in the above configuration always monitors the drive select signal or read command or write command from the host computer side as an access signal to the disk storage device, and when this access signal is interrupted for a predetermined period of time, for example, several seconds, the present invention Evacuation means are activated. This evacuation means moves the head through the head operation means to record information.
The disk is evacuated to a evacuated position outside the iI area, for example, to a shipping zone set on the inner diameter side of the disk. Immediately after this evacuation is completed, the return means of the present invention is activated, and its operation is started simultaneously with the arrival of an access signal to the disk storage device to return the head to the information recording area within the disk. Therefore, there is no need for the host computer, which is the user of the disk storage device, to give any special instructions to implement the present invention, and it is sufficient to simply access the disk storage device when necessary as before, and interrupt the access signal. At times, the head is automatically operated to a retracted position by the disk storage device to minimize the risk of damage to the disk storage medium due to vibrations or shocks.

All of the above means for performing the above operations operate non-mechanically, except for the head operating means. Therefore, in order to carry out the present invention, a new head operating means is required in addition to the head operating means conventionally provided in disk storage devices. There is no need to add a mechanical operating mechanism, and therefore, according to the present invention, the storage medium can be protected without reducing the operational reliability of the disk storage device.

Since it takes some time to move the head to the evacuation position using the evacuation means described above, it is necessary to prevent unnecessary evacuation operations from prolonging the access time to the disk storage device.Access from the host computer The probability that an access signal to access the disk at the same head position will be issued again after the signal has been interrupted for a certain period of time is extremely low. When accessing data, subsequent access signals may be issued to the disk storage device after a brief interruption of the access signal. Therefore, the time limit that should be set in the timer for determining whether or not to cause the retracting means to perform the head retracting operation is as follows:
In the latter case, it is desirable to avoid unnecessary retraction operations, and from experience it is advantageous to select this time period to be slightly longer than the time required for retraction of the head. If this is done, even if the access signal is restarted after the above-mentioned brief interruption, in most cases the access signal will actually be issued again within the time period selected as above. .

When the disk storage device receives a new access signal after the non-access state continues for longer than the set time limit, time is required for the head to return to the information recording area in the disk from the position it was once evacuated to. However, in many cases the previously accessed track and the new trunk to be accessed are different, so the time it takes for the head to return is to move the head to the new track while the head remains in the previous trunk. There is no big difference in the time required for the access signal, and of course it may vary depending on the content of the access signal, but on average, the required time for both is substantially the same. That is, even if the head is retracted when not being accessed according to the present invention, the time required to access information is not substantially different from the conventional method unless an extra retraction operation is performed.

This does not apply to special cases where the same trunk is accessed repeatedly after a time interval longer than the set time limit, but even when reading and writing information on the same track, as is known, servo information is read and turned off. A minimum amount of time is required to detect and correct the track amount, and it also takes a considerable amount of time to move the head closer to the disk by operating the lifter as described above.

Preferred embodiments of the present invention are described in the next section.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings. 1st
The figure shows three means constituting the device of the present invention, ie, timer means 30. This figure shows a disk storage device 100 incorporating an evacuation means 40 and a restoring means 50 as software, and an attached controller 200, and the contents of these means are shown in the form of operational steps in the flowcharts of FIGS. 2 and 3, respectively. has been done.

In the upper left part of Figure 1, a disk l is shown in a front view, and on the disk surface there is an information recording area 1a consisting of several hundred tracks T and a hunting zone called a simping zone. The retracted position 1b is set. This evacuation position need only be outside the storage area and does not need to be within the disk surface, but it is usually set on the inner diameter side of the information recording area on the disk surface.

In addition, within the information record 116N area, a track for storing management data called a directory for file management of stored information is usually specified, and this specific track is located on the inner and outer diameter sides of the disk. However, in this embodiment, it is assumed that the management data is stored in the outermost track IC, that is, the track with track number O.

A spatula 2 for reading and writing information on the trunk T within the disk surface is supported by a carriage 3 that can move in the left-right direction in the figure via a thin leaf spring 2a, etc., and a head operating motor 4 moves the disk surface. The inner radial position 1 is controlled. This head operation motor 4 is, for example, a two-phase motor equipped with two phase coils 4a, and an attached drive circuit 5.
and the phase current control circuit 5a. The head operating motor 4 and its attached circuits constitute a head operating means 10 according to the present invention. Further, the head 2 is connected to a read/write circuit 6 for switching and amplifying read/write signals, and the disk is started at a constant speed at high speed by a spindle motor 7 controlled by a drive circuit 8.

In order to control these circuits, a microprocessor 20 with a RAM 21 is incorporated in the disk storage device 100 as usual, and as described above, the three means 30 to 5o constituting the present invention are incorporated. It is embedded in the form of software. This processor 20 gives the above-mentioned read/write circuit 6 a read/write command R- for designating reading or writing, and a head selection command H5 for designating a specific head among a plurality of heads, and also sends the drive circuit 8 a command for selecting a disk. Gives a clock pulse that specifies the circuit speed.

The drive circuit 5 for the head operation motor 4 and the phase 1 flow control circuit 5a are also supplied with a drive signal CS having a plurality of bits from the processor 2o or the evacuation means 40 and return means 5o included therein. The drive signal C3a specified specifies the phase coil of the operating motor 4 to which the phase current is to be supplied and the positive/negative direction of the phase current, and the drive signal csb specifies the phase current value.

Although the controller 200 is originally a part of the disk storage device 100, it is shown separately from the main body in the figure for convenience, and for example, as shown in the figure, a separate processor 201. Bus interface circuit 2o2. Signal processing circuit 2o3 that handles signals from the head. This controller 200, which includes a signal conversion circuit 204, etc., is connected to a host computer (not shown) via a bus 205, and the interface circuit 202 is, for example, of a known 5C5I type, and connects this bus 205 to an internal bus 206. Connected. The illustrated disk storage value f from the host computer
Access to the i100 is usually done by sending a selection signal via the bus 205 to the processor 20.
1 receives this selection signal via the internal bus 206 and selects this disk storage value! A drive select signal DS indicating that has been selected is issued from the controller 200 side to the processor 20 in the disk storage device main body 100 as shown.

Now that we have finished explaining the general configuration of the device of the present invention and related circuits, we will now explain the overall operation of one embodiment of the present invention with reference to FIG. 2, which shows the operation of various means within the processor 20. .

The timer 30 always checks the presence or absence of the drive select signal DS, which is an access signal from the host computer, in the first step 531, and if the drive select signal is present, the operation of the disk storage device is as shown in the left side of the figure. This operation is a normal operation for a disk storage device, and after the head is placed at a specified position by the head operating means 10, The reading signal R5 from the head 2 is sent to the controller 200 via the read/write circuit 6.
Or, conversely, a write signal -3 is given to the head 2 via the read/write circuit 6. The aforementioned controller 20
The signal processing circuit 203 in 0 is for processing the read signal R5 and the write signal -8, and is used to process signals of the known MFM system.
Process the signal by converting it to an RZ signal or vice versa. The signal conversion circuit 204 converts a serial NRZ signal into parallel digital data and outputs it to the internal bus 206 or bus 205, or performs the inverse conversion. In any case, the read/write operation in this step SO is completely unchanged in the present invention from the conventional one.

When the determination result in step 531 is negative, that is, when the drive select signal DS is interrupted, the operation of the device of the present invention is started, and from step 531 to step S35
The timer operation for the time limit TL is performed by the above, and this operation can be performed by separately providing an electronic timer instead of using software as shown. As mentioned above, this set time limit TL is longer than the time required to evacuate the head from a certain track to the simping zone 1b, or substantially the time required to move the head between trunks, for example, about 1 second. In the case of the flow shown in the diagram, the time variable t is set to O in step S32, and the presence or absence of the drive select signal O3 is checked again in the next step S33. Proceeding to step SO, the disk storage device is put into read/write operation. If not, it is checked in step S34 whether or not the time is up, and as long as it is not, in step S35, the time t is advanced by the unit time Δt, and the flow is returned to the previous step S3.
3 to continue the timer operation. When the predetermined time limit TL times up without the drive select signal DS rising midway, the flow of operation immediately shifts to the operation of the saving means 40.

Now, as is well known, while reading and writing information, the head is always kept at the correct position on the track with the specified track number.
During this time, the processor 20 constantly sends a seek completion signal to the controller 200 indicating that the head is in the normal position.

Therefore, before retracting the head, the evacuation means 40 needs to notify the controller 200 that the head is no longer in its normal position (therefore, reading and writing is no longer possible).
In the first step S42 of the saving means 40 in this embodiment, this seek completion signal SC is first erased. The following step S43 is the actual evacuation operation step, which can be done by moving the head from the current position to the evacuation position.
HM! Track numbers O to 61 from the outer diameter side in la
Suppose that the track number 615 of section 4 has been set, and the simping zone 1b is specified as a trunk number between 640 and 650, and the trunk number at the current position of the head is 300. The means 40 is the head 2
For example, all you have to do is move it inside by 345 trunks.

For this purpose, the retracting means 40 issues the drive signal CS to the head operating means 10 345 times to move the head approximately to the center of the shipping zone. Since the repetition frequency of this drive signal is quite high, the head is moved to the retracted position within about a fraction of a second. of course,
The accuracy of the head position during this evacuation does not need to be high, and there is no need to perform closed-loop control of the position.

The recovery means 50 is activated immediately after the operation of the evacuation means 40 is completed, and in the first step S51 starts monitoring the presence or absence of the drive select signal DS.
This monitoring continues until S is present. In other words, it is in a state of waiting for an access signal, and as soon as the drive select signal DS arrives again, the operation of the return means 50 enters step S52. In step 552 in this embodiment, the head is moved from the simping zone to the track O1 where information management data is stored, that is, the outermost track IC in the disk whose trunk number is 0. That is, in this embodiment, whenever the disk storage device receives a new access signal from the host computer, it first reads the management data of the information in the disk, which is usually called a directory, in the aforementioned step SO, and then performs the actual read/write operation. Therefore, when the head returns to the information recording area, the head first performs a seek operation to the track containing the management data. After the return operation of the head to the information recording area is completed, the operation moves to step S53, and the above-mentioned seek completion signal SC
is set to complete the operation as the return means 50, and the flow returns to the first step 531. At this time, the step S
Since the determination in step 31 naturally indicates that a drive select signal is present, the operation of the disk storage device will enter the normal read/write operation described above in step SO. At this time, the processor 201 on the controller 200 side uses the seek completion signal SC issued from the return means 50 in the previous step S53.
A read/write operation is started under the condition that .

FIG. 3 shows a different embodiment of the invention. The operation mode in this embodiment is the evacuation means 40 and the return means 50.
Since this embodiment differs from the previous embodiment only in this embodiment, only this different part will be described to avoid duplication.

In this embodiment, when the operation is transferred from the timer means 30 to the evacuation means 40, first, in the first step S41, the position where the head was located immediately before the drive select signal O5 was interrupted is stored in the RAM 2 in the form of a track number TN.
Stored within 1. This is then used as the drive select signal D
This is because the return means 50 returns the head to its original position when S is issued.

The remaining operational steps S42 and 543 as the retraction means 40 are the same as in the previous embodiment. The return means 50 in this embodiment differs from the previous embodiment in the operation of step 352, and the drive select signal DS
In this step 552 after the return of , the easiest way is to change the head to the trunk number T stored in the previous step S41.
The operation of the 0th order step S53 for returning to the H position is the same as in the previous embodiment.

In the embodiment shown in FIG. 3, instead of once returning the head to the position before the evacuation operation as in step S52 in the return means 50, a so-called seek operation is performed during the read/write operation of the disk recording device. Combination is often preferable in terms of shortening access time; in other words, when an access signal is issued again, the track number to read and write the current information specified along with it may not match the previous trunk number. Rather, since this is common, it is preferable to directly move the head to the newly designated track number as a return means in order to shorten the access time.

As can be seen from the above description of the embodiments, according to the present invention, if the drive select signal DS as an access signal to the disk storage device is interrupted for a period longer than the predetermined time TL, the time limit means 30 ensures that the interruption is stopped. As a result, the evacuation means 40 is activated and the head is automatically moved to the evacuation position, thereby minimizing the risk of damage to the storage medium on the disk surface due to unexpected impact or power outage. Furthermore, when the access signal is issued again, the return means is automatically activated and returns the head from the retracted position to the information recording area, thereby enabling the disk storage device to begin normal reading and writing operations.

〔Effect of the invention〕

When the disk storage device is not accessed for a predetermined period of time or longer, the evacuation means in the device of the present invention automatically moves the head to the evacuation position, so even if a large impact is applied or there is an unexpected power outage, the head will remain intact. The present invention minimizes the risk of contacting and damaging the medium in the information recording area of the disc. Moreover, since no additional mechanism is required for such medium protection as in the prior art, the disk storage device can maintain high operational reliability. Furthermore, since the timer in the device of the present invention starts the evacuation means only when the above-mentioned non-access state continues for a predetermined period of time or more, unnecessary head evacuation operations are performed when the disk storage device is accessed again after a short period of time. The above effects can be obtained without sacrificing the access time to the disk storage device. The time required for the return means to return the head from the evacuation position to the information recording area is substantially the same as the time required for the head to move five tracks, and therefore the time required to access the disk storage device is particularly long. There is little risk.

Furthermore, as can be seen from the description of the embodiments, there is no need to add any hardware to implement the present invention, or even if a part of the timer is made into a hardware circuit, only a small amount of addition is required, and the disk storage As can be seen from the flowchart, the software for the built-in processor of the device can be short, so in practice, the effect of protecting the disk storage medium at the same cost as before can be achieved.

[Brief explanation of drawings]

All the figures are for explaining the present invention, and FIG. 1 is a block circuit diagram of the main parts of a disk storage device showing an embodiment of the head evacuation device for a disk i self-storage device according to the present invention, and FIG. 2 and FIG. Figure 3 is a flowchart showing the operation of various means constituting the apparatus of the present invention in different embodiments of the present invention. In Figure 0, 1: disk, 1a: information recording area in the disk, 1b
: Evacuation position or shipping zone, 1c: Outermost trunk of disk for storing information management data, 2: Head, 4: Head operating motor, 5: Drive circuit for head operating motor, 5a: Phase for head operating motor current control circuit,
6: read/write circuit, 7: spindle motor, 8 spindle motor drive circuit, 10: head operating means, 2
0: Processor with built-in disk storage device, 21; RAM,
30: Time limit means, 40: Evacuation means, 50: Return means, 1
00: Disk storage device main body, 200: Controller attached to the disk storage device, 201: Processor, 202
: interface circuit, 203: signal processing circuit, 20
4: Signal conversion circuit, 205: Bus for cooperation with host computer, 206; Internal bus of controller, C5, C
5a, C3b: Drive signal for head operating means, D
S: Drive select signal as access signal, FI
S: Head selection command, R3: Read signal, R-: Read/write command, SC: Seek completion signal, 531-S35: Operation step as time limit means, S41-343: Operation as evacuation means, step, 551-S53 : Operation step as return means, T Nidrak, t: Time, TN
F) Rack number, TL: time stamp, and S: write signal. Figure 1

Claims (1)

[Scope of Claims] 1) A timer that constantly monitors the presence or absence of an access signal specifying read/write of information to a disk and detects the absence of the access signal within a predetermined time period; Head position evacuation means that is activated in response to the presence detection result and moves the head to a predetermined evacuation position outside the information recording area in the disk via the head operation means, and detects the presence or absence of an access signal after the operation of the evacuation means is completed. A head retracting device for a disk storage device, comprising a head position return means for monitoring and returning the head to an information recording area in the disk via a head operation means when an access signal is received. 2) A head evacuation device for a disk storage device according to claim 1, wherein the evacuation position is a shipping zone set on the inner diameter side of an information recording area in the disk. 3) A head evacuation device for a disk storage device according to claim 1, wherein the return means returns the head to a storage position of information management data in an information recording area. 4) A head evacuation device for a disk storage device according to claim 1, wherein the return means returns the head to the head position before the operation of the evacuation means.