JP2001202728A - Disk storage device, system mounted with the device and vehicle mounted with the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely unload a head to a prescribed position before a power source voltage becomes equal to below stipulated value. SOLUTION: An HDD 10 is mounted for downloading map information, etc., on a car navigation device 40 to be arranged on a vehicle 30 where a temporary interruption can occur in a device power source due to a specified operation required in usage, e.g. an operation for stating or stopping an engine. When the operation for starting or stopping the engine is detected, the engine start/stop operation detecting part 42 of the device 40 reports it to a power source interruption prediction report part 43. Then the report part 43 issues a power source interruption prediction report command to the HDD 10. A CPU in the HDD 10 forcibly halts an action being performed at that moment in accordance with the command and performs head unload control for unloading the head to the prescribed position (a lamp, e.g.) by prescribed speed control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk storage device mounted on a system in which the power supply of a device can be temporarily cut off in accordance with a specific operation required for use, and more particularly, to the temporary storage of the device power supply. The present invention relates to a disk storage device that performs head unloading when predicted, a system equipped with the storage device, and a vehicle equipped with the storage device.

[0002]

2. Description of the Related Art Recently, some disk storage devices, for example, magnetic disk devices, to which a head load / unload method is applied have begun to appear. The feature of the load / unload method of the head is that when the rotation of the disk as a recording medium is stopped, the head is retracted (unloaded) to a retracting portion called a ramp (ramp mechanism) provided outside the disk, and when the rotation is started, the head is stationary. After reaching the speed, the head is moved (loaded) to the data zone on the disk. This method is also called a ramp load method.

The details of the operation at the time of unloading the head in the ramp load type magnetic disk device will be described with reference to FIG. First, the head 12 is attached by driving a voice coil motor (VCM) according to a predetermined sequence and rotating the head actuator 13 (as a head driving mechanism) including the VCM by an angle. The suspension (arm) 141 is moved toward the outer periphery of the disk 11. Thereby, the tip portion (tab) 141a of the suspension 141 reaches the inclined portion 161 of the ramp 16 disposed outside the disk 11 and close to the disk 11. In this state, V
As the CM continues to be driven, the tab 141a slides on the inclined portion 161 of the ramp 16 and rides up. As a result, the head 12 is lifted from the disk 11 and stops at a position separated from the disk 11 and restricted by an outer peripheral stopper (not shown). Here, the head 12 is not located on the ramp 16, but it is described that the head 12 is retracted (unloaded) by the ramp 16 in order to avoid complicated expressions.

As described above, in the magnetic disk drive of the ramp load type, when the rotation of the disk is stopped, the head is separated from the disk surface by the speed control according to a predetermined sequence so that the head does not stick to the disk. It is common to appropriately control the state of riding (landing).

However, if unintended power-off of the apparatus occurs while the head is floating above the medium due to the rotation of the disk, the head may be attracted to the disk. Therefore, in the magnetic disk drive, the power supply voltage is monitored during operation, and when the power supply voltage falls below the specified value, the head is automatically (forcibly) unloaded by the lamp as "unintended power supply cutoff (abnormal)". There is a need to. However, at that time, the power supply to the magnetic disk device is cut off, and a mechanism for supplying power to the VCM from a device other than the device power supply is required.

Therefore, conventionally, as a power supply method when the power is turned off, a spindle motor (SP) for rotating a disk is used.
Emergency unloading method for forcibly unloading the head by rectifying the back electromotive force generated when M) is rotating due to inertia even after the power is cut off and supplying it to the VCM as power for head unloading Had been proposed.

[0007]

However, in emergency unloading when the power is cut off, it is natural that proper speed control cannot be performed unlike head unloading in a normal state. It was difficult to guarantee. In particular, if the magnetic disk device is downsized and the SPM is downsized, it is difficult to obtain a large back electromotive force from the SPM. It will be difficult.

Therefore, as described in Japanese Patent Application Laid-Open No. 5-174519, a voltage converter having a capacitor as a power supply (second power supply) used for unloading the head when the apparatus power supply (first power supply) is cut off. Means is provided, and in a normal state, the device power supply voltage of 12 V is boosted to 30 V by the voltage conversion means to store the charge in the capacitor, and when the device power is cut off, the charge stored in the capacitor is used for driving the VCM. Thus, a technique for performing emergency unloading when the power is cut off has been proposed.

However, in the technique described in this publication, the electric charge stored in the capacitor is only used for driving the VCM, and the speed control is not used for emergency unloading when the power is cut off. This is the same as the technique using the back electromotive force of the motor for driving the VCM. That is, even with the technology described in the publication, it is difficult to stably perform emergency unloading when the power is shut off.

However, in a system in which a magnetic disk device is used as an auxiliary storage device in a personal computer or the like, it is assumed that the magnetic disk device always operates at a specified voltage. Is extremely rare. Therefore, in this type of system,
Emergency unloading when the power is turned off (power supply voltage drops) is not so problematic.

In some systems in which the magnetic disk device is used for purposes other than the computer system, some of the methods of use (operations) include a case where the power supply voltage falls below a specified value. One of this kind of system
One type of vehicle is equipped with an in-vehicle navigation device (a so-called car navigation device) incorporating a magnetic disk device for downloading map information and the like. In this vehicle (system), when the engine is started or stopped, the power is cut off (the power supply voltage is reduced) with a high probability. In other words, since the usage (operation content) includes the fact that the power supply voltage becomes equal to or lower than the specified value, power cutoff (power supply voltage drop) frequently occurs.

As described above, it is not preferable to perform emergency unloading that lacks stability each time in a magnetic disk device mounted in a system in which power interruption (power supply voltage drop) frequently occurs. However, the present inventor has found that in this type of system, power cutoff (power supply voltage drop) such as an engine start operation and an engine stop operation in the above-described vehicle example.
The operation from the time of operation to the time of power interruption (power supply voltage drop) is limited to a time (for example, several times) sufficient to perform unloading under the same speed control as head unloading in normal operation. (Ten ms to several hundred ms).

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to be applied to a system that includes, in a method of use, an operation in which a power supply voltage can be reduced to a specified value or less. When it is notified that an operation that can be equal to or less than the value has been performed, by performing head unloading with speed control instead of emergency unloading, before the power supply voltage actually becomes equal to or less than the specified value,
It is to ensure that the head can be unloaded to a predetermined position.

Another object of the present invention is to provide a system having a disk storage device capable of reliably unloading a head to a predetermined position before a power supply voltage actually falls below a specified value.
And a vehicle equipped with the storage device.

[0015]

SUMMARY OF THE INVENTION A disk storage device according to the present invention is a system in which the power supply of a device can be temporarily cut off in accordance with a specific operation required for use. The system is provided with a specific operation detection / notification unit that performs a power shutdown prediction notification that a cutoff is predicted, and the head is moved to a predetermined position according to the power shutdown prediction notification from the specific operation detection / notification unit. A head unload control unit for predicting power cutoff that preferentially performs head unload control for unloading by speed control is provided.

As described above, in a system in which the power supply of the apparatus may be temporarily cut off in accordance with a specific operation required for use, that is, in a method of use (operation contents), the power supply voltage may be lower than a specified value. In some systems, it can be predicted from the operation contents that a temporary cutoff of the device power supply will occur in due course. Therefore, by detecting that a specific operation has been performed and notifying the disk storage device, the disk storage device can perform the operation before the device power supply is actually cut off (the power supply voltage becomes equal to or lower than the specified value). That is, it is possible to perform stable head unloading by speed control without causing an emergency unloading state in which operation is unstable. However, in order for this to be possible, the time T1 from the specific operation until the device power is actually turned off must be longer than the maximum time T2 required for head unloading (head unloading control) by speed control. No. If not, a backup power supply may be provided to secure the time for the head unload control. Since this backup power supply requires only a small capacity unlike the conventional emergency unloading that is performed when the power supply is actually turned off, for example, the backup power supply may be configured using a small-capacity capacitor in which electric charges are accumulated by the apparatus power supply. It is possible.

Here, the power-off prediction notification can be made by either a command or a signal. In the case of a command, the command interpreting means of the disk storage device has a function of interpreting a power-off prediction notification command, and when interpreting the power-off prediction notification command, activates the power-off prediction head unload control means. The configuration may be such that

Further, when the power cut-off prediction notification is a signal, the power cut-off prediction head unload control means may be activated by the signal. In the case of the signal, the head unload control can be started promptly as much as the command interpretation is unnecessary. Here, the above signal may be used as the highest priority interrupt signal.

Further, according to the present invention, in a configuration in which a disk storage device mounted on the above-mentioned system has a write cache, cache on / off means for switching and setting use / non-use of the cache, and usually the cache A cache on / off control unit for controlling the cache on / off unit so as to set the cache on / off state.

As described above, by adopting a configuration in which the write cache is not basically used, even if the data specified by the write command is being written to the disk, the head unload can be performed in response to the power shutdown prediction notification. Even if the control is preferentially performed, the completion notification is not returned from the disk storage device side to the system side, so that the system side can issue the same write command again when the power is restored. If a disk write emphasizes performance, the write cache only needs to be turned on during that period.

It should be noted that even when the latest diagnostic data obtained by monitoring various events that may be related to the failure of the disk storage device inside the disk storage device is written to the disk at least when the head is unloaded, In order to preferentially perform the head unload control according to the power shutdown prediction notification, the writing of the latest diagnostic data may be omitted. In this case, the latest diagnostic data may be lost. However, there is no significant effect because the old diagnostic data is not lost.

Further, according to the present invention, when the above power-off prediction notification is received, basically, the operation being executed is forcibly terminated irrespective of the current operation state to give priority to head unload control, and data to the disk It is also characterized in that the head unload control is started only when writing is in progress, and after the writing to the sector currently being written is completed.

As described above, by starting the head unload control after completing only the write operation to the sector currently being written, it is possible to prevent the data in the sector from being destroyed. In addition, the delay of the start time of the head unload control is about several ms, and can be ignored as compared with the time required for the head unload control (several tens to several hundreds of ms).
Here, with respect to the diagnostic data, if copies of the diagnostic data are provided at a plurality of locations on the same disk or for each disk surface, the diagnostic data can be restored after the power is restored.

The invention relating to the disk storage device described above is a system equipped with the device (for example, a navigation device or an audio device mounted on a vehicle) or a device equipped with the device (with an electronic device mounted thereon). ) The invention also holds as an invention relating to a vehicle. Further, the present invention is also realized as a head unloading method applied to the above system.

In the system equipped with a disk storage device, a specific operation detection / notification means for performing, to the disk storage device, a power shutdown prediction notification that the power shutdown is predicted by detecting the specific operation; A power cutoff predictive head unload control means for performing a head unload control for unloading the head to the predetermined position by speed control in response to a power cutoff prediction notification from the specific operation detection / notification means. It is good to have. here,
The specific operation detected by the specific operation detection / notification means is, for example, an engine start operation from a vehicle or an engine stop operation.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a ramp-load type magnetic disk device mounted on a car navigation device mounted on a vehicle will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a magnetic disk drive according to one embodiment of the present invention. In the magnetic disk drive (hereinafter referred to as HDD) 10 of FIG.
1 is a disk (magnetic disk) as a recording medium on which data is magnetically recorded, and 12 is a head (magnetic head) used for writing data to the disk 11 (data recording) and reading data from the disk 11 (data reproduction).
It is. It is assumed that the heads 12 are provided corresponding to the respective recording surfaces of the disk 11. In the configuration shown in FIG. 1, an HDD provided with a single disk 11 is assumed.
It may be D.

A large number of concentric tracks 110 are formed on the recording surface of the disk 11 (however, the number of tracks shown is significantly smaller than the actual number for convenience of drawing). Each track 110 has a seek /
Servo areas (not shown) in which servo information used for positioning or the like is recorded are arranged at equal intervals. A plurality (generally 2 to 5) of sectors (data sectors) as recording units are arranged between the servo areas. The servo areas are radially arranged on the disk 11 radially across the tracks from the center.

For example, an innermost area on the recording surface of the disk 11 is allocated to a system area 111 for storing system management information. This system area 11
The specific sector (data sector) in 1 is a result of monitoring various events (the number of occurrences, etc.) that may be related to a failure in the HDD 10 (the number of occurrences is deeply related to the failure) as parameters for failure prediction of the HDD 10. Used to store The result of this monitoring is data (diagnosis data) for judging whether or not the apparatus is in a dangerous state. A representative example is a start / stop of the SPM 13 (Start / Stop).
Stop) number of times, number of seeks, number of substitution processing (processing to substitute a spare sector on a spare track prepared in advance when a defective sector is detected), number of power cycles (number of power ON operations), read error And the number of occurrences of a seek error (seek error rate). These diagnostic data are stored in a RAM 27 described later when the HDD 10 is started up.
Or, it is loaded on a predetermined area of the buffer RAM 24,
Normally, it is sequentially updated at high speed on the predetermined area. Then, the data in the predetermined area is written back to the specific sector on the system area 111 at an appropriate timing including, for example, when performing head unloading (normal head unloading). The specific sector is secured, for example, for each system area 111 on each recording surface of the disk 11 or at a plurality of locations on the same system area 111.
Even if data on one specific sector is destroyed, it can be repaired with data from another specific sector.

The disk 11 is a spindle motor (hereinafter, referred to as a spindle motor).
(Referred to as SPM) 13. Head 1
Numeral 2 is attached to an actuator (rotary head actuator) 14 as a head moving mechanism.
The disk 11 moves in the radial direction according to the rotation (angular rotation) of the actuator 14. Thus, the head 12 is sought and positioned on the target track. The actuator 14 includes a voice coil motor (hereinafter referred to as V
CM 15) and is driven by the VCM 15.

The (SPM 13)
A ramp (retracting portion) 16 for retracting (retracting) the head 12 when the rotation of the disk 11 is stopped (according to the rotation stop of the disk 11) is arranged. Lamp 16
As shown in FIG. 2, is provided at a predetermined position on the movement path of the tip (tab) 141a of the suspension (arm) 141 attached to the actuator 14 in the vicinity of the disk 11.

The SPM 13 is driven by an operation current (SPM current) supplied from the SPM drive circuit 17. V
The CM 15 (having the head actuator 14) has a V
It is driven by an operation current (VCM current) supplied from a CM drive circuit (head actuator drive circuit) 18. In the present embodiment, the SPM drive circuit 17 and the VC
The M drive circuit 18 is realized by a driver IC 19 integrated on one chip. SPM drive circuit 1
7 to the SPM 13 and the VCM drive circuit 18 to the VCM 1
5, the value (operation amount) for determining the operation current to be supplied is determined by the CPU 25.

After the head 12 seeks and positions on the target track 110, the head 12 scans the track 110 by rotating the disk 11. Also the head 12
Reads the servo information of the servo areas arranged at equal intervals on the track 100 by scanning. The head 12 reads and writes data from and to a target sector by scanning.

The head 12 is connected to a head amplifier circuit (head IC) 20 mounted on, for example, a flexible printed wiring board (FPC). Head amplifier circuit 20
Controls switching of the head 12 (under the control of the CPU 25), input / output of read / write signals to / from the head 12, and the like. The head amplifier circuit 20 amplifies an analog output (read signal of the head 12) read by the head 12, and reads and writes a read / write circuit (read / write I).
C) The write data sent from 21 is subjected to predetermined signal processing and sent to the head 12.

The read / write circuit 21 reads data from the disk 11 by the head 12 and
An AGC (automatic gain control) function for amplifying the analog output (read signal of the head 12) amplified by 0 to a constant voltage, and a method for decoding the read signal amplified by the AGC function into, for example, NRZ code data. A decoding function (read channel) for performing necessary signal processing, an encoding function (write channel) for performing signal processing required for recording data on the disk 11, and a servo function for enabling servo information extraction from the read signal. It has a pulsing function of pulsing a read signal and outputting it as pulsed read data, and a function of extracting burst data in servo information according to a timing signal (burst timing signal) from the gate array 22 described below. ing. The burst data is sent to the CPU 25 and used for positioning control for positioning the head 12 at a target position on a target track.

The gate array 22 has a function of generating various timing signals including a burst timing signal for obtaining servo information from a read pulse output from the read / write circuit 21, and a function of extracting a cylinder code from the servo information. Function. This cylinder code is sent to the CPU 25 and used for seek control for moving the head 12 to a target track.

The HDC (disk controller) 23
A host system using the HDD 10, for example, a car navigation device 40 mounted on a vehicle 30 as shown in FIG.
Is connected via a host interface 23a to a host system 41 which is a control center of the system. HDC23,
An interface control function for controlling communication of commands (write command, read command, etc.) and data with the host system 41, a disk control function for controlling data transfer to and from the disk 11 and a buffer RAM 24 described below. And a buffer control function for controlling the

Here, a schematic configuration of the car navigation device 40 mounted on the vehicle 30 shown in FIG. 3 will be described.
First, the car navigation device 40 is an HD having the configuration shown in FIG.
D10 and a host system 41 which forms the center of the car navigation device 40 and uses the HDD 10. The host system 41 includes various sensors for position measurement and the like, a control unit for performing position measurement, map display, and the like, and a well-known configuration such as a display (none is shown). Start / stop operation detecting section 42 for detecting that the operation of the engine and the operation for stopping the engine have been performed, and a power cutoff notifying section 43
It has.

When the engine start / stop operation detecting unit 42 detects that the engine start operation or the engine stop operation has been performed, the power cut-off prediction notifying unit 43 outputs at least the time T1 (several tens to several hundreds of ms). Later, a new command (hereinafter, referred to as a power-off prediction notification command) for predicting that the power will be cut off (the power supply voltage falls below a specified value) and notifying the power-off will be described below.
Issue for Here, T1 is the time when the head 12 is
It is longer (T1> T2) than the maximum time T2 (several tens to hundreds of ms) required to properly unload the lamp 16 under the control of the PU 25.

It should be noted that the power cut-off prediction notifying section 43 may be provided in the control section of the car navigation device 40 as a function of the control section. Further, the engine start / stop operation detecting unit 42 may be provided on the vehicle 30 side.

Referring again to FIG. 1, the buffer RAM
The (Random Access Memory) 24 mainly includes a write cache for temporarily storing data (write data) transferred from the host system 41 and written to the disk 11, and data read from the disk 11 and transferred to the host. It is used as a read cache for temporarily storing (read data).

The CPU 25 has an HD according to the control program.
Control of the entire D10, for example, seek / positioning control of the head 12 based on a cylinder code extracted by the gate array 22 and burst data extracted by the read / write circuit 21, and disk access control by the HDC 23 according to a read / write command from the host (Read / write access control) and the like.

When stopping the rotation of the SPM 13, the CPU 25 performs well-known head unload control for unloading the head 12 to the ramp 16 by speed control according to a predetermined sequence. The CPU 25 further includes an HD
When a power shutdown prediction notification command is received from the host system 41 through C23, the operation being performed at that time is stopped immediately or after a minimum operation, and the SPM1
As in the case of stopping the rotation of No. 3, head unload control for unloading the head 12 to the ramp 16 is performed.

The CPU 25 includes a ROM (Read Only Memory) 26 in which the control program is stored in advance,
RAM (Random A) that provides a work area for the CPU 25, etc.
ccess Memory) 27 is connected. These ROMs
26 and the RAM 27 can be built in the CPU 25.

The HDD 10 shown in FIG. 1 has an emergency unload circuit 28 for forcibly retreating the head 12 to the lamp 16 when the power is turned off, as described in the section of the prior art, that is, for performing an emergency unload. Is provided. The emergency unload circuit 28 monitors a power supply voltage, detects a power supply cutoff when the power supply voltage becomes equal to or lower than a specified voltage, and sets a power supply cutoff detection signal 281a to a low level, for example, a power cutoff detection circuit 281; A back electromotive force rectifier circuit 282 for rectifying the back electromotive force generated in the SPM 13 when the SPM 13 is rotating due to inertia even after the power is cut off. The emergency unload circuit 28 responds to the power cutoff detection by the power cutoff detection circuit 281,
82 as the drive voltage of the VCM 15
An emergency unload of the head 12 is performed by supplying a VCM current to M15.

Therefore, the HDD 10 shown in FIG.
Controls the VCM drive circuit 18 to control the head 12
Switch SW for switching between unloading, loading, seek / positioning, and emergency unloading by the emergency unloading circuit 28. In a normal state in which the power cutoff detection signal 281a from the power cutoff detection circuit 281 is at a high level, the changeover switch SW outputs the output of the VCM drive circuit 18 out of the outputs of the VCM drive circuit 18 and the emergency unload circuit 28 to the VCM15. In the power cutoff state where the power cutoff detection signal 281a is at a low level, the output of the emergency unload circuit 28 is switched to the input of the VCM 15 and connected. Here, the changeover switch SW is constituted by an FET or the like, and can operate even in a power-off state.

Next, the operation of this embodiment will be described. First,
The HDD 10 having the configuration shown in FIG. 1 is mounted on a car navigation device 40 as shown in FIG. The power supply voltage supplied to the HDD 10 is 5 V, and the vehicle 30 equipped with the car navigation device 40 built in the HDD 10 is
The fact that the power supply voltage becomes equal to or lower than a specified value (for example, 4.1 V) is also included in the method of use (that is, a system that can inevitably occur with the operation necessary for use).
It is assumed that H applied to such a system
In the DD 10, as described later, the write cache is always turned off (not used).

The engine start / stop operation detecting section 42 in the system (vehicle 30) detects whether an operation for starting the engine or an operation for stopping the engine has been performed. A detection signal (engine start / stop operation detection signal) 42a to the effect is output to the power cutoff notifying unit 43.

When a valid engine start / stop operation detection signal 42a is output from the engine start / stop operation detection unit 42, the power cutoff prediction notification unit 43 turns off the power supply at least after the time T1 when the engine starts or stops. It predicts that the power supply will be temporarily cut off (the power supply voltage will drop below a specified value), and issues a power supply cutoff prediction notification command for notifying that. This command is transmitted to the car navigation device 40 having the engine start / stop operation detecting unit 42.
Is transmitted from the host system 41 to the HDD 10 mounted on the car navigation device 40 via the host interface 23a.

The power shutdown prediction notification command sent from the host system 41 to the HDD 10 is received by the HDC 23 and passed to the CPU 25. The CPU 25 controls the HDC2
If the command passed from 3 is a power-off prediction notification command, a process at the time of power-off prediction notification command reception including head unload control is performed. Hereinafter, the processing at the time of receiving the power shutdown prediction notification command will be described with reference to the flowchart of FIG. 4 and the timing chart of FIG.

First, the CPU 25 checks whether or not a write command from the host system 41 is being executed (step S1). If a write command is being executed, the CPU 25 checks whether or not writing to the disk 11 is in progress (step S2).

The CPU 25 immediately waits for the end of the data write operation to the currently-written sector (current sector) if it is not being written, or waits for the end of the data write operation to the currently written sector (current sector) if it is being written (step S3). Head unload control for unloading the ramp 16 is performed by speed control according to the sequence (step S4).

On the other hand, if the write command is not being executed, the CPU 25 checks whether or not the diagnostic data is being written to a specific sector on the system area 111 of the disk 11 (step S5).

If the diagnostic data is not being written, the CPU 25 immediately waits for the completion of the diagnostic data write operation to the current sector (step S3). Under the control, head unload control for unloading the lamp 16 is performed (step S4).

As described above, when the CPU 25 receives the power-off prediction notification command, when the disk write is not in accordance with the write command, and when the diagnostic data is not in the disk write mode, the CPU 25 determines whether the HDD 10 is being read or seeking. Even if the operation is in an unsatisfactory operation state, the operations are forcibly terminated and the head unload control is immediately performed. Therefore, in the present embodiment, when starting the head unloading, the RAM 27 or the buffer RA
The diagnostic data updated on the predetermined area of the M24 is written back to the specific sector on the system area 111 of the disk 11. However, when the head is unloaded according to the power-off prediction notification command, the diagnostic data is written. Return is omitted.

On the other hand, if the disk is being written according to the write command or if the diagnostic data is being written, the CPU 25 waits only for the end of the write operation to the current sector, that is, performs only the minimum operation. The operation being executed is forcibly terminated, and head unload control is performed.
By performing this minimum operation, it is possible to prevent the contents of the sector being written from being destroyed due to the forced termination of the operation being executed. Moreover, the waiting time is at most about several ms,
Maximum time T2 required for head unload control (several tens ms)
(Several hundreds of ms), which is negligible, so that there is no effect on head unload control.

In this embodiment, the buffer RAM 24
Of the read cache and the write cache realized by using, the write cache is always set to off (not used). This setting is controlled by the CPU in the HDD 10 in accordance with the designation from the car navigation device 40.
25. Unless otherwise specified (for example, when used after being removed from the car navigation device 40)
, The write cache is always set to the ON (used) state.

In addition, a means for detecting whether or not the car navigation device 40 is mounted on the vehicle 30 is provided, and the CPU 25 turns on / off the write cache in accordance with the detection result of the detection means. Is also possible.

The car navigation device 40 has an HD
An operation means such as a switch or a button for designating ON / OFF of the write cache in D10 is prepared. Basically, the write cache is initially set to always off (not used) and a large amount of data such as map information is prepared. Fast disk 1
When the performance is prioritized, for example, when the user wants to store the data in the write cache, the user can operate the operation unit to turn on the write cache, and the CPU 25 in the HDD 10 turns on the write cache in accordance with the specification. It may be set to ON.

When the write cache is off, the host system 41 transfers a write command and write data in units of a predetermined data size while synchronizing with the HDD 10 (inside the HDC 23). When a write command is given from the host system 41, the HDD 10 writes all data specified by the command to the disk 11, and returns a completion notification to the host system 41.

Therefore, during a disk write according to the write command from the host system 41, a power-off prediction notification command is sent from the host system 41,
When the head unload control is performed by forcibly terminating the ongoing disk write operation, the HDD 10 does not return a write command completion notification to the host system 41. For this reason, the host system 41
10, the same write command is again issued to the HDD 10
Can be issued to

Note that, unlike the method applied in this embodiment, when the write cache is set to the ON state,
At the stage when the write data sent from the host system 41 is stored in the write cache, a completion notification is returned from the HDD 10 to the host system 41. In this case, the host system 41 determines that the execution of the write command has been completed and proceeds to the next process. Further, since the contents of the write cache are lost by the power supply means, even if the HDD 10 returns,
It is difficult for the host system 41 to perform the intended disk write.

If the head unload control is performed in response to the power shutdown prediction notification command while the diagnostic data is being written back to a specific sector in the system area 111, the diagnostic data is written back (updated). There may be a specific sector that has been written and a specific sector that has not been written back (updated). In this case, counter information for counting the number of updates is added to the diagnostic data, and when the HDD 10 recovers, the counter information is compared between the specific sectors so that the updated specific sector and the pre-update specific sector are compared. By identifying the sector, the contents of the updated specific sector can be reflected on the specific sector before the update.

In the HDD 10 of the present embodiment, when the power supply is cut off (here, the power supply voltage is changed from 5 V to the specified value 4.1).
When the voltage drops below V), the power cutoff detection circuit 281 detects this and sets the power cutoff detection signal 281a to a low level. Then, the switch SW switches the drive current source of the VCM 15 from the output side of the VCM drive circuit 18 to the output side of the emergency unload circuit 28. Thus, an emergency unload operation using the output of the back electromotive force rectifier circuit 282 by the emergency unload circuit 28 (without speed control) is performed. However, at this time, as shown in the timing chart of FIG. 5, the head unloading operation under the control of the CPU 25 has been completed, that is, the head 12 has been retracted to the ramp 16, and substantial emergency unloading is suppressed. Will be done.

In this embodiment, the case where the present invention is applied to the ramp load type HDD has been described. However, before stopping the rotation of the disk of the contact start / stop type (CSS type), the head is moved over the disk. After retracting (unloading) the disk to a predetermined location different from the data zone (for example, a dedicated ring-shaped evacuation zone secured on the inner peripheral side of the data zone) and rotating the disk from a stopped state to a steady speed, the head Can be similarly applied to an HDD of the type in which the head is moved to the data zone, only the head unload destination is different.

In this embodiment, when the operation for starting or stopping the engine is detected by the engine start / stop operation detecting unit 42, the output from the engine start / stop operation detecting unit 42 is output. The host system 4 responds to the detected engine start / stop operation detection signal 42a.
1 (internal power-off prediction notification unit 43) issues a power-off prediction notification command to notify the HDD 10 that power will be temporarily interrupted (the power supply voltage will drop below a specified value). Although explained, it is not limited to this. For example, an engine start / stop operation detection signal 4
2a as an interrupt signal for requesting head unloading by speed control as it is
a, via the HDC 23 in the HDD 10, the same HDD 1
It may be configured to send to the CPU 25 within 0.

In this embodiment, T1> T2
However, when T1 and T2 are substantially the same, there is a possibility that power cutoff is detected before head unloading by the speed control ends, and an emergency unloading operation is performed.

Therefore, when the system is applied to a system in which T1 and T2 are almost the same or T1 is somewhat shorter than T2, as shown by a broken line in FIG. It is preferable that the power supply cutoff detection timing is delayed by a minute time Δ so that the head unloading by the speed control can be surely ended before the power supply cutoff is detected. Here, the backup power supply 2
No. 9, it is possible to use a small-capacity capacitor in which electric charges are stored by the power supply of the apparatus.
Since a booster circuit as described in Japanese Patent Application Laid-Open No. H10-260, is unnecessary, a small backup power supply 29 is sufficient.

Although the present invention has been described with reference to the case where the present invention is applied to a magnetic disk drive mounted on a car navigation device mounted on a vehicle, the present invention is not limited to a magnetic disk drive, but may be applied to a disk drive such as a magneto-optical disk drive. When the rotation is stopped, a disk storage device that unloads the head from the data zone on the disk to a predetermined position outside the data zone by speed control can be similarly applied. The device on which the disk storage device is mounted is not limited to the car navigation device, but may be, for example, an audio device. Further, the system in which the device mounted with the disk storage device is mounted is not limited to the vehicle, and the system in which the power supply voltage is equal to or lower than the specified value is applicable as long as the system is included in the method of use. .

[0070]

As described above in detail, according to the present invention, in a configuration in which a disk storage device is mounted in a system in which the power supply of the device can be temporarily cut off in accordance with a specific operation necessary for use, When the specific operation is performed, the head unloading by the speed control is started on the disk storage device side. Therefore, before the device power supply is actually cut off (the power supply voltage becomes equal to or less than the specified value), The head can be reliably retracted to a predetermined position by performing stable head unloading by speed control without causing an unstable emergency unloading state.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of loading and unloading a head 12.

FIG. 3 is a block diagram showing a configuration of a car navigation device 40 mounted on the vehicle 30 and incorporating the HDD 10 in FIG. 1, which is directly related to the present invention.

FIG. 4 is a flowchart illustrating a procedure of a process at the time of receiving a power shutdown prediction notification command.

FIG. 5 is a timing chart for explaining an operation when a power shutdown prediction notification command is received.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... HDD (magnetic disk device, disk storage device) 11 ... Disk 12 ... Head 13 ... SPM (spindle motor) 14 ... Actuator 15 ... VCM (voice coil motor) 16 ... Lamp (predetermined position) 18 ... VCM drive circuit 23 ... HDC (disk controller, cache on / off means) 24 ... buffer RAM (write cache) 25 ... CPU (head unload control means at power cutoff prediction, cache on / off control means, running operation forced termination means, diagnostic data recording Means, power interruption prediction notification command interpreting means) 28 emergency unload circuit 29 backup power supply 30 vehicle 40 car navigation device (electronic device) 41 host system 42 engine start / stop operation detection unit (specific operation detection /
Notifying means) 43: power cut-off prediction notifying section (specific operation detecting / notifying means) SW: changeover switch

Claims (13)

[Claims] 1. A system in which the power supply of a device can be temporarily cut off in accordance with a specific operation necessary for use, and a power cut prediction notification that power cut is predicted by detecting the specific operation. A disk storage device that is mounted on a system equipped with a specific operation detection / notification unit and that unloads the head from a data zone on the disk to a predetermined position outside the data zone by speed control when the rotation of the disk is stopped. In response to the power shutdown prediction notification from the specific operation detection / notification unit, a power unload prediction head unload control for giving priority to head unload control for unloading the head to the predetermined position by speed control. A disk storage device comprising load control means. 2. A transfer speed of write data from the system, which is used for temporarily storing write data specified by a write command given from the system, and a write to the disk in the disk storage device. A write cache for absorbing a difference from a data transfer speed; a cache on / off means for switching and setting use / non-use of the write cache; and usually, the write cache is set to a non-use state. 2. The disk storage device according to claim 1, further comprising: cache on / off control means for controlling said cache on / off means. 3. The power unloading predicting head unload control means includes a running operation forcible ending means for forcibly terminating an operation being performed in order to give priority to the head unload control in response to the power off prediction notification. 2. The disk storage device according to claim 1, further comprising: 4. The operation unloading predicting head unload control means for executing the operation unloading forcibly terminating the operation being executed in order to give priority to the head unload control in response to the power shutdown prediction notification. 2. The disk storage device according to claim 1, further comprising an in-operation forcibly terminating unit that waits for the end of writing to the sector currently being written only when data is being written to the disk. 5. A diagnostic data recording means for writing diagnostic data to the disk, the diagnostic data recording means comprising:
When notifying the power cut-off prediction from the notifying means, in order to give priority to the head unload control by the head unload control means at the time of power cut prediction, diagnostic data recording means for omitting the diagnostic data writing may be further provided. 2. The disk storage device according to claim 1, wherein: 6. The disk storage device according to claim 1, further comprising a backup power supply for backing up the device power supply. 7. The disk storage device according to claim 6, wherein said backup power supply includes a capacitor in which electric charges are stored by said apparatus power supply. 8. The power shutdown prediction notification is a command, and interprets a command given from the system to the disk storage device. If the command is the power shutdown prediction notification command, the power shutdown prediction head command 2. The disk storage device according to claim 1, further comprising command interpretation means for activating the load control means. 9. The disk storage device according to claim 1, wherein the power-off prediction notification is a signal, and the power-off prediction head unload control unit is activated by the signal. 10. When stopping the rotation of the disk,
A disk that has a disk storage device that unloads the head from a data zone on the disk to a predetermined position outside the data zone by speed control, and that can temporarily turn off the power of the device with a specific operation required for use In the storage device-equipped system, a specific operation detection / notification unit for performing a power cutoff prediction notification to the effect that power cutoff is predicted by detecting the specific operation to the disk storage device, and provided in the disk storage device, The specific operation detection /
Power unloading prediction head unload control means for performing head unload control for unloading the head to the predetermined position by speed control in response to the power shutdown prediction notification from the notifying means. Disk storage system. 11. The specific operation detected by the specific operation detection / notification means is an engine start operation or an engine stop operation from a vehicle.
The disk storage device mounting system as described in the above. 12. When stopping the rotation of the disk,
Equipped with an electronic device with a built-in disk storage device that unloads the head from the data zone on the disk to a predetermined position outside the data zone by speed control, and temporarily shuts off the device power supply in accordance with a specific operation required for use A specific operation detection / notification unit for performing a power cutoff prediction notification to the disk storage device that the power cutoff is predicted by detecting the specific operation, provided in the disk storage device. , The specific operation detection
Power unloading prediction head unload control means for performing head unload control for unloading the head to the predetermined position by speed control in response to the power shutdown predicted notification from the notifying means. Vehicle. 13. When stopping the rotation of the disk,
A system in which a disk storage device that unloads a head from a data zone on a disk to a predetermined position outside the data zone by speed control is mounted, and the power supply of the device may be temporarily shut off with a specific operation necessary for use A head unloading method applied to the disk storage device, wherein a power shutdown prediction notification that the power shutdown is predicted by detecting the specific operation is performed to the disk storage device, and the power shutdown prediction notification is received. In a disk storage device, a head unload method for unloading the head to the predetermined position by speed control is preferentially performed.