JP2000195143A - Disk storage device and power controlling method in the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set an electric power mode, in which the speed of a data transfer with a host device or a bus utilization efficiency is reflected, without conducting a special information exchange with the host device and to reduce the power consumption. SOLUTION: A buffer measuring section 251 in a main controlling section 25 measures the utilization efficiency of a buffer 221, which temporarily stores the data transferred between a disk 11 and a host device, employing a certain interval measured by a timer 252 as a unit. Based on the measurement result, the section 25 determines an optimum power mode from two power modes having different amounts of power consumption, for example. If the determined power mode differs from a present power mode, the mode is switched and changes are made for the speed of revolution of an SPM 14, the driving speed of an actuator 13 and the frequency of the operating clock of the section 25.

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 in which data transfer between a disk recording medium and a host device is performed via a buffer, and relates to a data transfer speed between a special host device and a bus. The present invention relates to a disk storage device that dynamically switches and sets a power mode suitable for use efficiency and a power control method in the device.

[0002]

2. Description of the Related Art In recent years, small information processing apparatuses that can be driven by batteries, such as portable personal computers, have become widespread. In such devices, it is important to reduce power consumption. For example, when there is no key input for a certain period of time or when the remaining battery power is low, various measures are taken such as shifting to a low power consumption mode. Have been. The same applies to a disk storage device used in the above-mentioned device, for example, a magnetic disk device (hard disk device).

For example, in US Pat. No. 5,452,277, in a magnetic disk drive, power consumption is measured at regular time intervals, and the measured value is compared with a predefined power consumption pattern (average power consumption). A technique is described in which a comparison is made to make an optimal operation mode switching setting in consideration of power consumption. In this magnetic disk device, power supplied to a spindle motor, an actuator for moving a head, a read / write circuit, and a microcomputer is controlled according to a set operation mode.

[0004]

As described above, the technique for reducing the power consumption of a conventional magnetic disk drive (disk storage device) is to measure the power consumption of the drive at fixed time intervals and to measure the measured power consumption. By comparing the power consumption with the average power consumption, an operation mode taking power consumption into consideration is determined.

However, this prior art does not necessarily reflect the state of the host device. For example, despite the fact that the operation mode (power mode) has been set to the low power consumption mode on the host device side, On the side, there was a problem that the normal mode was set.

The present invention has been made in view of the above circumstances, and has as its object to monitor the state of a buffer for temporarily storing data transferred between a disk and a host device, and to monitor the monitoring result. By switching and setting the power mode based on the above, the data transfer speed with the host device or the supply power amount suitable for the bus use efficiency without exchanging special information with the host device. An object of the present invention is to provide a disk storage device and a power control method in the same device, which can set a different power mode and reduce power consumption reflecting the operation state of the host device.

[0007]

According to the present invention, there is provided a disk storage device having a buffer means for temporarily storing data transferred between a recording medium and a host device, wherein the disk storage device has a unit of a predetermined period. A buffer measuring means for measuring the use efficiency of the buffer means, and an optimum power mode is determined from at least two power modes having different power consumptions based on the measurement result of the buffer measuring means. When the power mode is different from the current power mode, a main control unit for switching the power mode is provided.

In the above configuration, assuming that the disk transfer speed in the disk storage device is constant, the use efficiency of the buffer means is such as that of a central processing unit of a host device or a magnetic disk device connected to the host device. It is determined by the operation speed of the interface circuit with the peripheral device. That is, the use efficiency of the buffer means reflects the data transfer speed with the host device or the use efficiency of the interface bus.

Therefore, the buffer measuring means measures the use efficiency of the buffer means during a certain period of time in units of a certain period, and from the measurement result, the operating speed of the host device in consideration of, for example, power consumption. It is possible to estimate the data transfer speed with respect to the host device or the efficiency of use of the interface bus to which the (operation mode to be reflected) is reflected.

Therefore, an optimum power mode can be determined from at least two power modes having different power consumptions based on the measurement result of the buffer measuring means. For example, if the data transfer rate with the host device or the use efficiency of the interface bus is determined to be low based on the measurement result of the buffer measurement unit, the power mode may be set to reduce the power consumption from the current time. As a result, power consumption can be reduced without lowering the data transfer efficiency with the host device. In addition, the host device monitors the status of the disk storage device and instructs a mode switch based on the monitoring result, or the disk storage device exchanges information with the host device to operate the host device. Is not detected and the mode is not switched based on the detection result, so that no burden is imposed on the host device.

Here, in order to measure the use efficiency of the buffer means, for example, in the case of a read-only disk storage device, a state in which the buffer means becomes full when reading from the storage medium within the above-mentioned fixed period is considered. The number of times that the buffer means becomes full within a certain period of time may be determined as the measurement result. As is apparent, when the data transfer speed with the host device is lower than the disk transfer speed of the disk storage device, the above-mentioned number of times becomes a large value, and when the data transfer speed is opposite, the value becomes a small value.

Similarly, in the case of a writable disk storage device, the operation for detecting the first state in which the buffer means is full when reading from the storage medium is performed in the storage medium within the fixed period. The operation for detecting the second state in which the buffer means becomes empty at the time of writing is repeated, and the total value of the number of times of the first state and the number of times of the second state detected within a certain period is determined by the measurement result. It is good to As is apparent, when the data transfer speed with the host device is lower than the disk transfer speed of the disk storage device, the above total value becomes a large value, and when the data transfer speed with the host device is reversed, the total value becomes a small value.

As described above, only by monitoring the full state (at the time of reading) or the empty state (at the time of writing) of the buffer means, the data transfer speed with the host device reflecting the operation speed of the host device, or Bus usage efficiency can be easily measured (estimated).

In order to change the amount of power consumption (supply) by switching the power mode, the rotation speed of the recording medium rotated by the motor drive circuit, the drive speed of the actuator driven by the actuator drive circuit, and the It is sufficient to change at least one of the frequencies of the operation clock for determining the processing speed of the control means. For example, in the case of switching to a mode in which the power consumption is reduced from the current time, the rotation speed of the recording medium, the driving speed of the actuator, and What is necessary is just to reduce at least one of the frequencies of the operation clock of the main control means. Here, if these values are as small as possible within a range where normal operation is guaranteed and transfer efficiency in data transfer with the host device is not reduced, an optimal value corresponding to the data transfer speed of the host device is used. Power consumption can be reduced as much as possible while ensuring the efficiency of use of the interface bus.

Further, according to the present invention, when the mode switching is performed, for example, when the rotation speed of the spindle motor is reduced, the control from changing the rotation speed is started until a steady rotation is performed at the target rotation speed. Because there is a finite period of time, there is a time period during which access to the recording medium becomes impossible, and the connection between the disk controller (the host interface control unit) and the interface bus is disconnected (disabled) during that period. Connect) and reconnect after the mode switch is completed.
It is also characterized in that the main controller controls the disk controller (the host interface controller thereof).

In such a configuration, when the power mode is switched, the host interface control unit of the disk controller that has driven the interface bus is set to a quiescent state, and after the mode switching is completed, the power mode is switched to the expected power mode. Upon entry, the host interface controller of the disk controller is reconnected to the interface bus.

Thus, the power consumption of the host interface control unit of the disk controller at the time of mode switching can be reduced. Moreover, by opening the bus for other peripheral devices connected to the same interface bus as the disk storage device, the central processing unit of the host device needs to monitor the status of the disk storage device. And the resources of the central processing unit can be allocated to other devices, and the performance of the entire system can be improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, taking as an example a case where the present invention is applied to a magnetic disk drive (HDD).

FIG. 1 is a block diagram showing the configuration of a magnetic disk drive (HDD) according to an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a disk (magnetic disk) serving as a medium on which data is recorded; and 12, 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 assumed that the heads 12 are provided corresponding to each surface (recording surface) of the disk 11, respectively. Although the configuration of FIG. 1 assumes a magnetic disk drive on which a single disk 11 is disposed, a configuration in which a plurality of disks are stacked may be employed.

A large number of concentric tracks (not shown) are formed on both recording surfaces of the disk 11, and each track has a servo area in which servo information used for seek and positioning of a head is recorded. They are arranged at equal intervals.
A user area is provided between the servo areas, and a plurality of (generally 2 to 5) sectors (data sectors) as recording units are arranged in the user area. The servo areas are radially arranged on the disk 11 radially across the tracks from the center.

The head 12 is mounted on a rotary actuator 13 as a head moving mechanism, and moves in the radial direction of the disk 11 according to the rotation (angular rotation) of the actuator 13. Thereby, the head 12
Are to be sought and positioned on the target track. The disk 11 is a spindle motor (hereinafter referred to as S
PM) (14). The actuator 13 has a voice coil motor (hereinafter, referred to as VCM) 15 which is a driving source of the actuator 13, and is driven by the voice coil motor 15.

The SPM 14 is driven by a control current (SPM current) supplied from an SPM driver (SPM drive circuit) 16. The VCM 15 (the actuator 13 having the) includes a control current (VCM) supplied from a VCM driver (VCM drive circuit, actuator drive circuit) 17.
Current). In the present embodiment, the SPM
The driver 16 and the VCM driver 17 are realized by a driver IC 18 integrated on one chip. A value (control amount) for determining the control current supplied from the SPM driver 16 to the SPM 14 and from the VCM driver 17 to the VCM 15 is determined by a main controller (main controller) 25 described later.

The head 12 seeks on the target track.
After the positioning, the disk 11 is rotated to scan the track. The head 12 sequentially reads the servo information of the servo areas arranged at equal intervals on the track by scanning. The head 12 reads and writes data from and to a target data sector by scanning.

The head 12 has a head amplifier circuit (head I) mounted on a flexible printed wiring board (FPC).
C) It is connected to 19. The head amplifier circuit 19
It controls switching of the head 12 (according to control from the main control unit 25), input / output of read / write signals to / from the head 12, and the like. The head amplifier circuit 19 amplifies the analog output (read signal of the head 12) read by the head 12, and reads / writes the read / write circuit (read / write I).
C) The write data sent from 18 is subjected to predetermined signal processing and sent to the head 12.

The read / write circuit 20 is read 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 in step 9 to a constant voltage, and a method for reproducing, for example, NRZ code data from the read signal amplified by the AGC function 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 21 described below. ing. The burst data is sent to the main control unit 25 and the head 12
Is used for positioning control for positioning a target track at a target position on a target track.

The gate array 21 has a function of generating various timing signals including a burst timing signal for acquiring servo information from a read pulse output from the read / write circuit 20, and extracts a cylinder code from the servo information. Function. The cylinder code is sent to the main control unit 25 and used for seek control for moving the head 12 to a target track. .

The RAM (Random Access Memory) 22
A buffer (buffer memory) 223 for temporarily storing data (read data) read from the disk 11 and transferred to the host device and data (write data) to be transferred from the host device and written to the disk 11 (write data).
Provide an area. The RAM 22 also provides a work area for the main control unit 25 and the like.

The HDC (disk controller) 23
It is responsible for command and data communication with the host device, buffer control, data transfer control with the disk 11 and the like. The HDC 23 has a host I / F control unit (host interface control unit) 231, a buffer control unit 232, and a disk control unit 233.

The host I / F controller 231 has a SCSI
(Small Computer System Interface) The buffer control unit 232, which is connected to the host device via an interface bus 24 represented by a bus and controls communication of commands and data with the host device according to the host interface standard, The access control to the buffer 221 and the management of the buffer 221 are performed.

The disk control unit 233 reads data requested by the host from the disk 11 via the read / write circuit 20 and transfers the data to the buffer 221 via the buffer control unit 232, and stores the data in the buffer 221. The read write data is fetched through the buffer control unit 232, and the disk write to the disk 11 is controlled via the read / write circuit 20.

The main control unit (main controller) 25 includes:
Control of the entire device (HDD), for example, the head 1 based on the cylinder code extracted by the gate array 21 and the burst data extracted by the read / write circuit 20
2 seek / positioning control, read from host device /
The read / write control or the like by the HDC 23 according to the write command is executed at an operation speed determined by the frequency of the operation clock.

The main control unit 25 also performs control for dynamically switching and setting an operation mode (power mode) reflecting the data transfer speed with the host device or the use efficiency of the interface bus 24, and the operation. The power supply to each unit in the apparatus is controlled based on the mode. Therefore, the main control unit 25 includes a buffer measurement unit 251 for measuring the use state (use efficiency) of the buffer 221 and a timer 252 used to determine the measurement timing of the buffer measurement unit 251. The relationship between the data transfer speed with the host device or the use efficiency of the interface bus 24 and the use status of the buffer 221 will be described later. The main control unit 25 includes, for example, a ROM as a nonvolatile memory in which a control program and the like are stored in advance.
(Read Only Memory) and a microprocessor that performs the above control according to the control program.

Next, the operation of the magnetic disk drive having the configuration shown in FIG. 1 will be described. First, the host device connected to the magnetic disk device of FIG.
For example, it is assumed that a personal computer as a portable small information processing device is configured, and a commercial power supply and a battery can be used as the type of driving power source.

In such a host device, in a situation where a battery is used as a power source, in order to reduce power consumption, a central processing unit (CPU), which is a control center of the host device, or a host computer, In general, an operation mode (power mode) is set so that the operation speed of an interface circuit with a peripheral device such as a magnetic disk device connected to the device is lower than usual, thereby ensuring a long operation.

On the contrary, in a situation where a commercial power supply capable of supplying power stably for a long time is used as a power source, the host device operates in such a manner that the CPU and the interface circuit can operate at the highest speed. Set the mode (power mode). In some cases, even when the battery is used, the operation speed of the CPU or the interface circuit varies depending on the remaining amount of the battery.

The operation mode switching setting in the host device described above is also applied to the magnetic disk device having the configuration shown in FIG. For example, when it is difficult to supply a sufficient amount of power, the operation mode is set to an operation mode (low power consumption mode) for reducing power consumption in the magnetic disk drive. On the other hand, if a sufficient amount of power can be supplied, the operation mode (normal mode) is set so that the maximum performance of the magnetic disk device can be exhibited. In the present embodiment, what is changed by the switching of the operation mode is the rotation speed of the SPM 14, the driving force (driving speed) of the actuator 13, and the frequency of the operation clock of the main control unit 25.

In the present embodiment, the switching setting of the operation mode (power mode) in the magnetic disk device of FIG. 1 is performed in accordance with the operation mode of the host device, and a special operation is performed between the host device and the magnetic disk device. The information is exchanged autonomously on the magnetic disk device side without exchanging information. Therefore, in the magnetic disk drive of FIG.
The buffer 22 in the buffer measurement unit 251 of the main control unit 25
The use efficiency of No. 1 is measured. The relationship between the operation mode of the host device and the use efficiency of the buffer 221 will be described below.

First, when the host device is set to the operation mode in which the CPU and the interface circuit operate at the highest speed because a sufficient amount of power can be supplied, the host device and the magnetic disk device of FIG. , The data transfer rate via the interface bus 24 becomes high,
The use efficiency of the interface bus 24 also increases. In this case, if the state of the buffer 221 is read, the buffer becomes full (full state), and if it is write, the buffer 221 is unlikely to become empty (empty).

On the other hand, when it is difficult to supply a sufficient amount of power and the host device is set to an operation mode in which the CPU and the interface circuit operate at a low speed,
Generally, the data transfer speed between the host device and the magnetic disk device is lower than the disk access speed (disk transfer speed) of the magnetic disk device, and the use efficiency of the interface bus 24 is generally lowered. In this case, when the state of the buffer 221 is monitored, it is highly possible that the buffer becomes full at the time of reading and becomes empty at the time of writing.

Therefore, by monitoring the state of the buffer 221, the data transfer speed between the host device and the magnetic disk device or the use efficiency of the interface bus 24 is estimated, and the operation mode set on the host device side is set. Can be determined only on the magnetic disk device side, and a power mode suitable for the situation can be set autonomously.

Hereinafter, the operation of the magnetic disk device for switching and setting the power mode suitable for the data transfer speed with the host device or the bus use efficiency by monitoring the status of the buffer 221 will be described with reference to the flowchart of FIG. It will be described with reference to FIG. First, at the start of operation, the main control unit 25
A check counter (not shown) is set to an initial value 0, and the timer 252 is started (step S1).

Next, the main control unit 25 includes a buffer measurement unit 251.
Start Thus, the buffer measuring unit 251 monitors the state (usage state) of the buffer 221 via the buffer control unit 232, that is, the state of data transfer with the host device, during the period when the timer 252 is measuring the fixed time. I do. Then, when reading (READ), the main controller 25 compares the transfer speed from the buffer 221 to the host device via the interface bus 24 with respect to the transfer speed (disk transfer speed) from the disk 11 to the buffer 221. Since the (host transfer speed) is slower (due to a factor on the host device side), a buffer full state that causes interruption of disk transfer is detected (steps S2 and S3), and if it is a write (WRITE) time, The transfer speed (host transfer speed) from the host device to the buffer 221 via the interface bus 24 is higher than the transfer speed (disk transfer speed) from the buffer 221 to the disk 11 (due to a factor on the host device side). A buffer empty state that causes interruption of disk transfer due to the delay is detected (steps S2 and S4).

When the buffer measuring section 251 detects the buffer full state at the time of reading, it increments the check counter by 1 (step S5), and
If 2 is in operation, that is, if the timeout has not occurred (step S6), the process returns to step S2 to continue the buffer monitoring. Similarly, the buffer measurement unit 251
When the buffer empty state is detected at the time of writing, the check counter is incremented by 1 (step S5), and if the timer 252 has not timed out (step S6), the process returns to step S2 to continue monitoring the buffer. .

If the buffer full state cannot be detected at the time of reading, or if the buffer empty state cannot be detected at the time of writing, the buffer measuring section 251 determines that the timer 252 has not timed out (step S6). ), The process returns to step S2 and the buffer monitoring is continued. The buffer measuring unit 251 repeats the above operation until the timer 252 times out.

When the timer 252 eventually times out, that is, when the buffer measurement unit 251 monitors the buffer 221 for a certain period (step S6), the main control unit 25
Compares the value of the check counter, which is the measurement result of the buffer measuring unit 251, with a predetermined specified value (threshold) (step S7).

If the value of the check counter is equal to or more than the specified value, that is, during the operation of the timer 252, the total number of times that the buffer becomes full at the time of reading and the number of times that the buffer becomes empty at the time of writing is equal to or more than the specified value. In this case, since the host device is set to the mode for reducing power consumption, the main control unit 25 determines that the CPU in the host device and the magnetic disk device connected to the host device are connected. It is determined that the operation speed of the interface circuit with the peripheral device is set to be lower than normal.

In this case, the main control unit 25 operates in the operation mode in which the magnetic disk device (own device) does not reduce the power consumption and therefore can exhibit the maximum performance (here, the normal mode).
It is checked whether or not it is set to (step S8). If the normal mode is set, the main control unit 25
Determines that even if the power consumption of the magnetic disk device is reduced, there is no danger of lowering the data transfer efficiency with the host device, and performs processing for switching to the low power consumption mode.

However, when the mode is switched in the magnetic disk device, a time zone occurs in which the disk read processing and the disk write processing are not possible. During this time, connecting the host I / F control unit 231 and the interface bus 24 is useless in terms of bus utilization efficiency.

Therefore, in this embodiment, when switching from the normal mode to the low power consumption mode, the host I / F control unit 231 is controlled by the main control unit 25 so that the host I / F control unit 231 and the interface bus are controlled. Then, the host I / F control unit 231 is disconnected from the connection by disconnecting the bus 24 and the bus 24 is released (step S9), and then the mode is switched to the low power consumption mode (step S10). Then, when the mode switching is completed, the main control unit 25 controls the host I / F control unit 231 again so that the host I / F control unit 2
Reconnection (reconnect) between the interface bus 31 and the interface bus 24 is performed (step S11), and the process returns to step S1.
As a result, it is possible to reduce the power consumption in the host I / F control unit 231 and to effectively use the interface bus 24.

On the other hand, when the value of the check counter is smaller than the specified value, that is, during the operation of the timer 252, the total number of times the buffer becomes full at the time of reading and the number of times the buffer becomes empty at the time of writing becomes the specified value. If it has not reached, the main control unit 25 determines that the host device is set to the mode in which it operates at the highest speed.

In this case, the main control unit 25 checks whether or not the magnetic disk device (own device) is set to an operation mode for reducing power consumption (here, a low power consumption mode) (step S12). If the low power consumption mode is set, the main control unit 25 is in a state where a sufficient amount of power can be supplied. Therefore, although the supplied power increases, the maximum performance of the magnetic disk device is exhibited. It is determined that it is possible to switch to the possible normal mode, and processing for switching to the normal mode is performed.

At this time, the main controller 25 controls the host I / F controller 231 first, as in the case of switching from the normal mode to the low power consumption mode described above.
The host I / F control unit 231 is disconnected from the interface bus 24 to disconnect the bus 24 (step S13), and then switches to the normal mode (step S14). Then, when the mode switching is completed, the main control unit 25 controls the host I / F control unit 231 again so that the host I / F control unit 2
Reconnection (reconnect) between the interface bus 31 and the interface bus 24 is performed (step S15), and the process returns to step S1.
This makes it possible to effectively use the interface bus 24.

Here, regarding the details of switching to the low power consumption mode, the magnetic disk drive shown in FIG.
An example will be described in which data (magnetic recording information) can be read / written at any one of a plurality of different rotation speeds, for example, two rotation speeds, that is, a case where dual mode is supported.

The main control unit 25 determines that there is no risk of lowering the transfer efficiency in data transfer to and from the host device even if the disk transfer speed is lowered, and switches from the normal mode to the low power consumption mode. In this case, the power consumption is reduced by reducing the control amount supplied to the SPM driver 16 to reduce the rotation speed of the SPM 14 from the first rotation speed, which is the rotation speed in the normal mode, to the second rotation speed. The main control unit 25 also reduces power consumption by reducing the amount of control supplied to the VCM driver 17 to reduce the driving force (drive speed) of the actuator 13 and reducing the speed of moving and positioning the head 12. I do. Further, the main control unit 2
5 reduces power consumption by lowering the processing clock frequency by lowering the frequency of its own operation clock. Here, the completion of the mode switching, which is the timing of the reconnection (reconnect) with the interface bus 24, is performed, for example, when the rotation speed of the SPM 14 is changed (for changing the supplied power amount).
The determination can be made by confirming that the rotation speed is changed to the target rotation speed and the normal rotation is performed at the target rotation speed. To do so, as a means to monitor the change status of mode switching,
It is preferable to prepare a motor monitoring circuit that monitors the rotation speed of the SPM 14.

The mode switching described above is performed based on the data transfer rate with the host device or the use state of the buffer 221 reflecting the bus use efficiency. This is done regardless of the source.

In order to reduce power consumption in the power consumption reduction mode, at least one of the rotation speed of the SPM 14, the driving force (driving speed) of the actuator 13, and the frequency of the operation clock of the main control unit 25 is used. It may be smaller.

In the above embodiment, the operation modes (power modes) are two modes: the normal mode and the low power consumption mode.
Although the case of the type has been described, the present invention is not limited to this. For example, two or more types of reference values to be compared with the value of the check counter are prepared, and the power consumption (supplied power amount) is respectively set
, One of three or more different modes may be selected. In this case, finer power control becomes possible.

In the above, the case where the present invention is applied to a magnetic disk device has been described. However, the present invention relates to a disk storage device in which data transfer between a disk as a recording medium and a host device is performed via a buffer. Then, the present invention is similarly applicable to disk storage devices other than magnetic disk devices, such as a floppy disk device, a magneto-optical disk device, a (read-only) CD-ROM device, and a DVD device.

[0059]

As described above in detail, according to the present invention, the state of the buffer for temporarily storing data transferred between the disk recording medium and the host device is monitored, and the monitoring result is also displayed. In addition, since the power mode that provides the optimum power supply amount is switched and set, there is no need to exchange special information with the host device and to instruct from the host device without instructing from the host device. The power mode reflecting the data transfer speed or the bus use efficiency, that is, the power mode reflecting the operation mode of the host device can be automatically set, and the power consumption can be effectively reduced.

[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 flowchart for explaining an operation for switching and setting an operation mode suitable for a data transfer speed with a host device or a bus use efficiency by monitoring a state of a buffer 221 in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Disk (disk recording medium) 12 ... Head 13 ... Actuator 14 ... Spindle motor (SPM) 15 ... Voice coil motor (VCM) 16 ... SPM driver (spindle motor drive circuit) 17 ... VCM driver (actuator drive circuit) 20 ... Read / write circuit 23 ... Disk controller (HDC) 24 ... Interface bus 25 ... Main controller 221 ... Buffer 231 ... Host I / F controller 232 ... Buffer controller 233 ... Disk controller 251 ... Buffer measuring unit 252 ... Timer

Claims (6)

[Claims] 1. A motor drive circuit for driving a spindle motor for rotating a disk recording medium, and a head used for at least reading out and writing data from and to the recording medium. An actuator for moving the medium in a radial direction,
An actuator drive circuit for driving the actuator, a read channel function for decoding a signal read from the recording medium by the head, and a write channel for performing signal processing required for writing data on the recording medium by the head A signal processing circuit having at least a read channel function among the functions, a buffer means for temporarily storing data transferred between the recording medium and the host device, and an interface bus between the host device and the host device. Command, communication of data, control of the buffer means, and a disk controller that controls access to the recording medium performed through the signal processing circuit. Measures the use efficiency of the buffer means during the period A buffer measuring unit that determines an optimal power mode from at least two power modes having different power consumptions based on the measurement result of the buffer measuring unit, and the determined power mode is different from the current power mode. And a main control means for switching the power mode in such a case. 2. The buffer measuring means repeats an operation for detecting a state in which the buffer means is full at the time of reading from the storage medium within the fixed time period. 2. The disk storage device according to claim 1, wherein said power mode is determined based on the number of times that said buffer means detects that said buffer means is full within said predetermined period. 3. The method according to claim 2, wherein the buffer measuring unit performs an operation for detecting a first state in which the buffer unit is full when reading from the storage medium within the certain period of time. The main control unit repeats an operation for detecting a second state in which the buffer unit is empty, and the main control unit determines the number of times of the first state detected within the fixed period by the buffer measurement unit and the second state.
2. The disk storage device according to claim 1, wherein the power mode is determined based on a total value of the number of states. 4. The main control means determines a rotation speed of the recording medium rotated by the motor drive circuit, a drive speed of the actuator driven by the actuator drive circuit, and a processing speed of the main control means. 2. The disk storage device according to claim 1, wherein the power mode is switched by changing at least one of the operating clock frequencies. 5. The main control means causes the disk controller to disconnect from the interface bus when switching the power mode, and after the power mode switching is completed, causes the disk controller to connect to the interface bus. 2. The disk storage device according to claim 1, wherein reconnection is performed. 6. A motor drive circuit for driving a spindle motor for rotating a disk recording medium, and a head used for performing at least reading out or reading out of data for the recording medium. An actuator for moving the medium in a radial direction,
An actuator drive circuit for driving the actuator, a read channel function for decoding a signal read from the recording medium by the head, and a write channel for performing signal processing required for writing data on the recording medium by the head A signal processing circuit having at least a read channel function among the functions, a buffer means for temporarily storing data transferred between the recording medium and the host device, and an interface bus between the host device and the host device. A power control method for a disk storage device, comprising: a disk controller that controls communication of all commands and data, control of the buffer means, and control of access to the recording medium performed through the signal processing circuit. The buffer during the period in units of the period Measuring the use efficiency of the means; and determining an optimal power mode from at least two power modes having different power consumptions based on the measurement result in the predetermined period, and determining the determined power mode as the current power. Switching the power mode if the mode is different from the power mode.