JPH10340519A - Disk device and power save control method applied to the disk device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a standby mode, a buffer memory can be turned off without impairing the basic operation of various commands,
To further reduce power consumption. A CPU turns off a power supply of a buffer memory when shifting to a standby mode in which a spindle motor is stopped. When the HDC 14 receives a write buffer command from the host device in this state,
After turning on the power of the buffer memory 13, the buffer power control circuit 140 activates the automatic transfer circuit 141 so that the data from the host device is transferred to the buffer memory 13. Upon completion of the write buffer command, the CPU 16 causes the timer 17 to measure a predetermined time T. If the command is received within the time T, the process proceeds to the command. If the command is not received, the power of the buffer memory 13 is turned off. Turns off and returns to the command waiting state in the standby mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive having a buffer memory for temporarily storing read data from a disk and write data to a disk, and more particularly to turning on the power of the buffer memory in a standby mode with a motor stopped. The present invention relates to a disk device suitable for realizing power save by on / off control and a power save control method applied to the disk device.

[0002]

2. Description of the Related Art In a disk device in which data is recorded and reproduced on a disk as a recording medium by a head, for example, a magnetic disk device, data read from the disk and data written to the disk are written in block (sector) units. In general, a buffer memory for temporarily storing data is provided. One of the advantages of using the buffer memory is that the data transfer rate (disk transfer rate) between the disk and the buffer memory, which is mainly determined by the disk access speed, and the data transfer rate (host transfer rate) between the host device and the buffer memory ), The difference in transfer rate can be absorbed by the buffer memory. In addition, when there is a read request for data that has already been read into the buffer memory due to the execution of a read / write command from the host device issued earlier (at the time of a cache hit).
Has the advantage that the processing time can be reduced by transferring the data read into the buffer memory to the host device without reading from the disk.

In a magnetic disk device having a buffer memory, data transfer between a host device and a disk is controlled via the buffer memory. For example, when a write command is issued from the host device, the write data from the host device is automatically transferred to the buffer memory by hardware by the HDC (disk controller).

When a host device issues a write buffer command or a read buffer command, the magnetic disk device writes or reads data only in the buffer memory without accessing the disk. The write buffer command and the read buffer command are used as follows to check the buffer memory and the like. First, data is written to the buffer memory by a write buffer command. Next, the data written in the buffer memory is read by a read buffer command and transferred to the host device. The host device checks the buffer memory and the like by comparing the data written to the buffer with the data read from the buffer.

As described above, the write buffer command or the read buffer command does not involve a disk access. Therefore, it can be executed even when the rotation of the disk is stopped, that is, the motor (spindle motor) for rotating the disk is stopped. Therefore, even when the motor is in a stopped state, in a state in which a command from the host device is accepted, it is necessary that the buffer memory is always set to a usable state so as to be able to cope with the write buffer command or the read buffer command. Note that a state in which the motor is stopped and a command from the host device can be received is called a standby mode, and power consumption is saved when no command is received from the host device for a preset time (power saving). ) Set for.

[0006]

As described above, in a conventional magnetic disk device having a buffer memory, when a write command is given from a host device, write data from the host device is transferred to the buffer memory. Is automatically performed. Therefore, if the power of the buffer memory is turned off (OFF), the above-described write data is lost by the automatic transfer operation to the buffer memory (in the power-off state).

In addition, when a read buffer command is given from the host device, if the power of the buffer memory is turned off, undefined data is transferred to the host device.

For this reason, conventionally, in a state in which a magnetic disk device can receive a command from a host device, the power of the buffer memory is turned off even in a standby mode in which the motor is stopped for the purpose of saving power consumption. I had to keep it on. That is, conventionally, the buffer memory could not be turned off to save power consumption.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to impair the basic operation of various commands, particularly commands in which buffer access is performed without disk access, in a standby mode with motor stoppage. Another object of the present invention is to provide a disk device capable of turning off the power of a buffer memory and further saving power consumption, and a power save control method applied to the disk device.

[0010]

According to a first aspect of the present invention, there is provided a disk drive provided with a buffer memory for temporarily storing read data from a disk and write data to a disk. First buffer power-off means for turning off the power of the buffer memory when shifting to the standby mode with the motor stopped; and a write buffer command for instructing data writing to the buffer memory in the host device in the standby mode. A buffer power-on means for turning on the power of the buffer memory when received from the buffer memory; and a data transfer means for transferring data specified by the write buffer command to the buffer memory powered on by the buffer power-on means. After the end of the write buffer command, If it does not receive a command from the host device in order was within a predetermined time, characterized in that a second buffer power-off means for turning off the power supply of the buffer memory.

According to such a configuration, in the standby mode in which the rotation of the motor is stopped, the power of the buffer memory is set to the off state, so that the power consumption can be further reduced. Moreover, when a write buffer command is issued from the host device in the standby mode in which the power of the buffer memory is off, the power of the buffer memory is turned on, and thereafter, the data specified by the command is changed to the power-on state. , The operation of the write buffer command can be guaranteed.

Now, next to the write buffer command,
In general, a command (for example, a read buffer command) for reading data written in the buffer memory and transferring it to the host device by executing the command is issued from the host device. Therefore, in the above configuration, it is expected that this type of command involving access to the buffer memory will be issued immediately after the write buffer command, and a certain period of time is measured after the end of the write buffer command. If a command is not received from the host device during this time, the prediction is deemed to be incorrect and the power to the buffer memory is immediately turned off to save power consumption. It is possible to prevent unnecessary power from being consumed to deal with the accompanying command.

As described above, according to the above configuration, the basic operation of various commands, in particular, a command in which buffer access is performed without disk access, is impaired by the on / off control of the power supply of the buffer memory in the standby mode. Instead, the power consumption in the standby mode can be further reduced.

When a command accompanied by read access to the buffer memory, for example, a read buffer command is received after the elapse of the predetermined time, the power of the buffer memory is already turned off and the data in the memory is lost. Therefore, it is preferable that the received command be an abort error. On the other hand, if the read buffer command is received within the above-mentioned fixed time, since the power of the buffer memory is turned on, the command can be executed, data can be read from the buffer memory and transferred to the host device. Thus, the operation of the read buffer command can be guaranteed. Also in this case, if the command is not received from the host device within a certain period of time after the end of the read buffer command, the power of the buffer memory may be immediately turned off to save power consumption.

According to a second aspect of the present invention, in the configuration according to the first aspect, there is provided a rewritable nonvolatile memory having an area for storing data in a buffer memory; Thereafter, when a command is not received from the host device within a predetermined period of time, a data storage unit for storing data in the buffer memory in the nonvolatile memory is added, and the second buffer power-off unit is added. Is characterized in that the power of the buffer memory is returned to the off state after the data is stored in the nonvolatile memory by the data storage means, and when the read buffer command is received after the lapse of the predetermined time, the buffer is turned off. New buffer power-on means (second buffer power-on means) for turning on the power of the memory; Data loading means for loading data stored in the non-volatile memory into a memory, and if the read buffer command is received within the fixed time, immediately if the read buffer command is received after the fixed time, After the data is loaded into the buffer memory by the data loading means, a new data transfer means (second data transfer means) for reading data from the buffer memory and transferring the data to the host device is added.

In such a configuration, if a command is not received from the host device within a certain period of time after the end of the write buffer command, the data in the buffer memory is stored in the non-volatile memory. Is turned off, so that the data written to the buffer memory by the write buffer command is prevented from being lost from the disk device, and the power consumption in the standby mode can be further reduced. . Also, even when the read buffer command is received after the elapse of the predetermined time, after the power of the buffer memory is turned on, the data stored in the non-volatile memory is loaded into the buffer memory so that the read buffer command can be correctly read. It is possible to execute.

As described above, in the above configuration, even if the power of the buffer memory is turned off in the standby mode to save power consumption, the operation of the write buffer command and the read buffer command can always be guaranteed.

The buffer memory is a DRAM (Dynami
c Random Access Memory)
Even if the memory refresh operation is turned off (stopped) instead of turning off the power, power consumption can be saved.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a block diagram showing a schematic configuration of a magnetic disk drive according to a first embodiment of the present invention.

The magnetic disk drive shown in FIG. 1 has a disk 11 as a recording medium, a spindle motor 12 for rotating the disk 1 at a high speed, and read data from the disk 11 and write data to the disk, for example, for one sector (here, (1 sector = 512 bytes). A buffer memory 13 having a buffer area for temporarily storing the data is provided. The buffer memory 13 is configured by a volatile memory, for example, a DRAM (Dynamic Random Access Memory). Note that the buffer memory 13 also has an area for storing information (defect information) of a defective sector on the disk 11 and its replacement destination sector. However, the area is not directly related to the present invention, and will not be described here. For the sake of convenience, description will be made assuming that only the buffer area is secured.

The magnetic disk drive shown in FIG. 1 also serves as an interface with a host device, and has a buffer memory 1.
An HDC (disk controller) 14 for controlling data transfer between the disk 11 and the host device via the host computer 3 is provided. The HDC 14 includes a buffer power supply control circuit 140 for controlling to automatically turn on the power of the buffer memory 13 when a write command is received from the host device in a standby mode, which will be described later. It has an automatic transfer circuit 141 that is activated by the power supply control circuit 140 and performs data transfer according to the command, and an ECC circuit 142.
When executing the write command, the ECC circuit 142 generates ECC (error detection / correction information) in units of, for example, one sector for write data from the host device,
An ECC generation function added to the end of the data, and an error detection / correction for performing error detection / correction on the data read from the disk 11 based on the ECC attached on a sector-by-sector basis when the read command is executed. It has a correction function.

The magnetic disk device of FIG. 1 further includes a ROM (Read Only Memory) storing a control program (firmware) for controlling the entire magnetic disk device.
ry) 15, a CPU (microprocessor) 16 for controlling the operation of each unit in the magnetic disk device such as the operation of the HDC 14 in accordance with the control program in the ROM 15, and a timer 17 for measuring time.

In FIG. 1, a head (magnetic head) used for writing data to the disk 11 (data recording) and reading data from the disk 11 (reproducing data), and an analog head read from the disk 11 by the head. A decode function (read channel) for inputting an output (head read signal) and performing signal processing necessary for data reproduction operation, and an encode function (write channel) for performing signal processing required for data recording on the disk 11
Are omitted because they are not directly related to the present invention.

Hereinafter, the operation of the configuration of FIG. 1 will be described with reference to FIGS.
This will be described with reference to the flowchart of FIG. First, the magnetic disk device of the present embodiment is provided with a standby mode in which the spindle motor 12 is stopped as one of the power save modes for saving power consumption. In this standby mode, the power of the read / write channel is also turned off. In addition, in standby mode,
Unlike the related art, the power supply of the buffer memory 13 is turned off (with an exception). An idle mode having a lower power save level than the standby mode is also provided. In this idle mode, the power of the read / write channel is turned off, but the spindle motor 12 is in a rotating state and the buffer memory 13 is turned on so as to be able to immediately respond to a command from the host device (including a cache or the like). Is in the ON state.

Now, it is assumed that a transition is made to the standby mode for power saving. In this case, the CPU 16
After controlling the motor driver (not shown) according to the control program (firmware) stored in M15 to stop the spindle motor 12 (step S1), and further turning off the power of the buffer memory 13 (step S2),
A command waiting state (from the host device) is set (step S3). Here, since the buffer memory 13 is configured by a DRAM, the memory refresh operation may be stopped (turned off) instead of turning off the power of the memory 13.

In the magnetic disk drive, the HDC 14 is in this standby mode (command waiting state S3).
Receives a command from the host device, determines the type of the command (step S21),
The processing described below is performed according to the command type.

First, when the command from the host device is a command that does not require access to the disk 11 and the buffer memory 13 (for example, a command for instructing a failure diagnosis), the CPU 16 turns off the buffer memory 13 and turns off the spindle. The command is executed while the motor 12 is stopped (off) (step S22).
When the command ends (step S23),
The process returns to the standby mode command waiting state (step S3).

Next, when the command from the host device is a read command or a read long command (that is, a read command), the CPU 16 first turns on the power of the buffer memory 13 according to the control program in the ROM 15 (step S24). Further, the spindle motor 12 is rotated (turned on) (step S25). And CPU16
The HDC 1 reads the data on the disk 11 specified by the read command or the read long command and transfers the data to the host device via the buffer memory 13.
4 (step S26), and when the command ends (step S27), the process proceeds to a command waiting state in the idle mode (step S13).

Here, the difference between the read command and the read long command is as follows. First, the disk 11
The data read out from the buffer memory 13 includes 1
An ECC of, for example, 20 bytes is added at the end of each sector, and when the read command is executed, only data (data in the data portion) excluding the ECC is stored in the buffer memory 13. At this time, the ECC circuit 142 in the HDC 14 operates to calculate the ECC from the data stored in the buffer memory 13, and to calculate the ECC following the data (disk 1
Error detection of the data is performed by comparing with ECC (from 1). If an error is detected and correctable, the ECC circuit 142 corrects the corresponding data in the buffer memory 13. As a result, data in the buffer memory 13 after error detection and correction, that is, correct data without ECC, is transferred to the host device by the HDC 14. The data with ECC may be stored in the buffer memory 13 as it is.

On the other hand, when the read long command is executed, the operation of the ECC circuit 142 is prohibited, and
Data read from the disk 11 is stored in the buffer memory 13 as it is with the ECC added.
Then, the data with the ECC is directly transferred to the host device by the HDC 14.

Next, when the command from the host device is a write command or a write long command (ie, a write command), the buffer power supply control circuit 140 in the HDC 14 receives the write command or the write long command, and 13 is automatically turned on (step S28). Then, the buffer power supply control circuit 140 monitors the state of the buffer memory 13 and, when detecting that the buffer
Activate the automatic transfer circuit 141 therein. As a result, the automatic transfer circuit 141 starts the automatic data transfer process of transferring data from the host device designated by the write command to the buffer memory 13 and further transferring the data from the buffer memory 13 to the disk 11. At the same time as the data transfer processing by the automatic transfer circuit 141, the CPU 16 starts the rotation of the spindle motor 12 according to the control program, and starts writing to the disk 11 via the buffer memory 13 (step S29). Is completed (step S30), the process proceeds to a command waiting state in the idle mode (step S13).

Here, the details of writing data to the disk 11 when the write command is a write long command will be described together with how to use the write long command. Generally, a write long command is used in combination with a read long command and a read command having the same disk address and transfer size for testing a magnetic disk device. First, the host device issues an ECC for one sector from the disk 11 by a read long command.
The attached data is read via the buffer memory 13. The host device processes the read data with ECC to generate write data for one sector for testing, for example. Here, the ECC added to the data is the length of the ECC originally written on the disk 11 (here, 20
Bytes). However, it is necessary for the host device to previously specify the length (number of bytes) of the ECC added to the magnetic disk device in units of one sector to the write data to be transferred to the magnetic disk device by a dedicated command. is there. When generating the write data for the write long command, the host device issues the command to the magnetic disk device (the HDC 14 therein), and when the command is accepted, transfers the generated write data to the magnetic disk device. .

When the write command from the host device is a write long command, similarly to the case of a read long command, the ECC circuit 142 in the HDC 14 is used.
Operation is prohibited. In this state, the automatic transfer circuit 141 in the HDC 14 is activated by the buffer power supply control circuit 140 to transfer write data (here, write data for one sector) from the host device to the buffer memory 13 as described above. Start the operation to transfer to.

At this time, the automatic transfer circuit 141 determines whether the ECC attached to the write data actually
It is determined from the ECC length specified in advance by the host device whether or not the length is shorter than the length of the ECC written in 1. If the ECC attached to the write data from the host device is shorter, the automatic transfer circuit 141
Extracts the contents of the ECC portion (20 bytes) of the same sector as the sector specified by the current write long command, which has been read into the buffer memory 13 by executing the previous read long command, and reads the ECC from the host device.
In addition, the remaining ECC part that is insufficient in the ECC is selected from the extracted ECC part and added to generate an ECC of a correct length, and the buffer memory 13
To be stored. The automatic transfer circuit 141 transfers the write data having the correct length ECC in the buffer memory 13 to the same disk 11 as in the case of the previous read long command.
Write to upper sector area. Thereafter, the host device issues a read command to the magnetic disk device, reads and transfers the data (test data) written on the disk 11 in accordance with the write long command, and the ECC circuit 142 and the like operate normally. Check if it was working.

Next, if the command from the host device is a write buffer command (a kind of write command), the buffer power control circuit 140 in the HDC 14
As in the case of the write command or the write long command, the power of the buffer memory 13 is automatically turned on (step S31), and the automatic transfer circuit 141 is activated when the buffer memory 13 becomes available.
Accordingly, the automatic transfer circuit 141 starts data transfer for transferring data (here, 512-byte data corresponding to one sector) from the host device specified by the write buffer command to the buffer memory 13 (step S).
32).

When the data transfer by the automatic transfer circuit 141 is completed and the execution of the write buffer command is completed (step S33), the CPU 16 activates the timer 17 to measure a predetermined time T, for example, 5 seconds (step S3).
4).

The CPU 16 determines that the timer 17 has a time T (T =
(5 seconds), the host device issues some command before the timer 17 times out (steps S35 and S36), and resets the timer 17 (step S37). Proceed to command processing. Normally, when the host device issues a write buffer command, the host device issues a read buffer command following the command in order to read data written in the buffer memory 13 by the command. Therefore, after the end of the write buffer command, the timer 17
If the read buffer command is issued before the measurement of the time T is completed (while the power of the buffer memory 13 is in the ON state while in the standby mode),
The process proceeds to a read buffer command process described later.

On the other hand, if no command is issued from the host device before the timer 17 finishes measuring the time T, the CPU 16 turns off the power of the buffer memory 13 for power saving according to the control program in the ROM 15. After that (step S38), the process returns to the command waiting state in the standby mode (step S3).

When the command from the host device is a read buffer command, the CPU 16 checks whether or not the power of the buffer memory 13 is turned on (step S39). If the power of the buffer memory 13 is turned off, the CPU 16 determines that the read buffer command is not a read buffer command issued within the time T after the execution end of the write buffer command, and sets the read buffer command as an error (abort error). Discard (Step S
40), and notifies the host device of the fact.

On the other hand, if the power of the buffer memory 13 is turned on, the CPU 16 determines that the read buffer command has been issued before the timer 17 finishes measuring the time T, and the CPU 16 determines that the read buffer command has been issued. The HDC 14 performs an operation of reading the data in the buffer memory 13 and transferring the data to the host device (step S4).
1).

When the execution of the command (read buffer command) is completed (step S33), the CPU 1
6 starts the timer 17 and measures the time T in the same manner as when the execution of the write buffer command is completed (step S34), and if no command is issued from the host device until the measurement of the time T is completed (step S34). Step S35,
S36) The buffer memory 13 for saving power consumption
After turning off the power (step S38), the process returns to the standby mode command waiting state (step S3).

In the first embodiment described above, in the standby mode in which the rotation of the spindle motor 12 is stopped, the command is not issued from the host device until a predetermined time T has elapsed from the end of execution of the write buffer command. Is configured to turn off the power of the buffer memory 13 to save power consumption. In this case, since the data in the buffer memory 13 is lost, in the first embodiment, the read buffer command issued thereafter must be an abort error.

Therefore, even if a read buffer command is issued after a certain time T has elapsed from the end of execution of the write buffer command, the operation of the read command can be guaranteed while saving power consumption (thus, The second embodiment in which the operation of the previously executed write buffer command can be guaranteed will be described with reference to the drawings. [Second Embodiment] FIG. 6 is a block diagram showing a schematic configuration of a magnetic disk drive according to a first embodiment of the present invention. The same parts as those in FIG. .

The magnetic disk device of FIG. 6 differs from the magnetic disk device of FIG. 1 in that a rewritable nonvolatile memory in which a buffer data storage area 180 for storing data (512 bytes) in the buffer memory 13 is secured. EEPROM (Electrically Erasable and Pr
(grammable Read Only Memory) 18 is provided. The EEPROM itself is not shown, but is also provided in the magnetic disk device of FIG. 1 because it is used for storing parameters for controlling the magnetic disk device.

Another difference between the magnetic disk device of FIG. 6 and the magnetic disk device of FIG. 1 is that a command is not issued from the host device until a predetermined time T has elapsed from the end of execution of the write buffer command. Instead of immediately turning off the power of the buffer memory 13 as in the first embodiment, the data in the buffer memory 13 is stored in the buffer data storage area 18 in the EEPROM 18 before that.
0, and when the power of the buffer memory 13 is turned off at the time of receiving the read buffer command, instead of aborting the command as in the first embodiment, the buffer memory 13 is not aborted. 13 is turned on, data is loaded into the memory 13 from the buffer data storage area 180 in the EEPROM 18,
A control program including a procedure for transferring the data to the host device is stored in the ROM 15.

Next, the operation of the configuration of FIG. 6 will be described with reference to the flowchart of FIG. 7, which is different from the first embodiment, for the operation at the time of receiving the write buffer command and the operation at the time of receiving the read buffer command in the standby mode. I will explain.

First, in the standby mode, when the HDC 14 in the magnetic disk device of FIG. 7 receives a write buffer command from the host device, the buffer power supply control circuit 140 in the HDC 14 performs the same operation as in the first embodiment. The power of the buffer memory 13 is automatically turned on (step S51), and the automatic transfer circuit 141 is activated when the buffer memory 13 becomes available. Accordingly, the automatic transfer circuit 141 starts data transfer for transferring data from the host device specified by the write buffer command to the buffer memory 13 (step S52).

When the data transfer by the automatic transfer circuit 141 is completed and the execution of the write buffer command is completed (step S53), the CPU 16 starts the timer 17 and measures a predetermined time T (= 5 seconds) (step S54). .
If any command is issued from the host device before the timer 17 finishes measuring the time T (steps S55 and S56), the CPU 16 resets the timer 17 (step S57) and proceeds to processing of the command. .

The processes in steps S51 to S57 are the same as those in steps S31 to S37 in the first embodiment.
The processing is the same as that described above. On the other hand, if the command is not issued from the host device by the time when the timer 17 finishes measuring the time T, the CPU 16 first reads the data in the buffer memory 13 (here, the execution of the write buffer command in accordance with the control program in the ROM 15). 512 bytes of data written to the buffer memory 13)
The data is saved (saved) in the buffer data saving area 180 in the ROM 18 (step S58), and thereafter, the power of the buffer memory 13 is turned off to save power consumption (step S59). Then, the CPU 16 returns to the standby mode command waiting state (step S3).

Next, when a read buffer command is received from the host device, the CPU 16 sets the buffer memory 1 (similar to step S39 in the first embodiment).
3 is turned on (step S).
60). If the power of the buffer memory 13 is off, the CPU 16 first turns on the power of the memory 13 (step S61), and thereafter, the EEPROM 1
8, the 512-byte data stored in the buffer data storage area 180 is loaded into the original buffer memory 13 (step S62). Next, the CPU 16 sets the buffer memory 13 (in the same manner as when the power of the buffer memory 13 is turned on at the time of receiving the read buffer command).
(Here, the data loaded from the EEPROM 18) is read out and transferred to the host device by the HDC 14 (step S63).

When the execution of the command (read buffer command) is completed (step S53), the CPU 1
6 starts the timer 17 and measures the time T in the same manner as at the end of the execution of the write buffer command (step S54). If no command is issued from the host device until the time T is measured (step S54). Step S55,
S56), the data in the buffer memory 13 is stored in the EEPROM
After the data is stored in the buffer data storage area 180 in the memory 18 (step S58), the power of the buffer memory 13 is turned off (step S59), and the process returns to the standby mode command waiting state (step S3).

If the processing in the case where the command is not issued from the host device until the time T is measured is divided into the execution of the write buffer command and the execution of the read buffer command, if the processing is not executed, the step is executed when the read buffer command is executed. Step S59 may be performed by skipping S58.

In the first and second embodiments described above, the buffer power supply control circuit 140 is provided in the HDC 14, and in the standby mode, the HDC 14 sends a write command (write command, write long command, or write long command) from the host device. When receiving the write buffer command), the buffer power control circuit 140 automatically turns on the power of the buffer memory 13 and activates the automatic transfer circuit 141 when the memory 13 becomes available. However, the present invention is not limited to this. For example,
In the standby mode, the function of the automatic transfer circuit 141 is turned off, and when a write command is received in this state, the CPU 16 turns on the power of the buffer memory 13 according to the control program, and the memory 13 becomes usable. It is also possible to adopt a configuration in which the automatic transfer circuit 141 is turned on (activated) at a stage.

In the first and second embodiments, the magnetic disk device has been described. However, the present invention includes a buffer memory for temporarily storing data read from a recording / reproducing disk and data written to the disk. Also, the present invention can be applied to disk devices other than magnetic disk devices such as magneto-optical disk devices.

[0055]

As described above in detail, according to the present invention, the power of the buffer memory is turned off in the standby mode, and when the write buffer command is received, the power of the buffer memory is turned on and the command is executed. If the command is not received within a certain time after the command ends, the power of the buffer memory is returned to the off state.
The power of the buffer memory can be turned off without impairing the basic operation of the write buffer command, and the power consumption can be further reduced.

According to the present invention, when a command is received within the above-mentioned fixed time, the power of the buffer memory is turned on. , The command can be correctly executed as it is.

As described above, according to the present invention, the power of the buffer memory is turned off without impairing the basic operation of various commands, in particular, commands such as a write buffer command and a read buffer command, which perform buffer access without disk access. Power consumption can be further reduced.

According to the present invention, the power of the buffer memory is turned off in the standby mode, and when a write buffer command is received, the power of the buffer memory is turned on and the command is executed. If no command is received, the data from the host device transferred to the buffer memory by executing the write buffer command is stored in a rewritable nonvolatile memory, and then the power of the buffer memory is turned off. Therefore, even if the read buffer command is received after the elapse of the predetermined time, if the power of the buffer memory is turned on and the data in the non-volatile memory is loaded into the buffer memory, the data (the buffer memory may be used in the previous write buffer command). After being transferred to the non-volatile memory, Data) loaded from nonvolatile memory into the buffer memory to be transferred from the buffer memory to the host device (i.e., executing the received command)
Can be.

As described above, according to the present invention, even if the power of the buffer memory is turned off in the standby mode to save power consumption, the operation of the write buffer command and the read buffer command can always be guaranteed.

[Brief description of the drawings]

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

FIG. 2 is an exemplary flowchart for explaining a processing procedure when shifting to a standby mode in the embodiment.

FIG. 3 is an exemplary flowchart for explaining a processing procedure when shifting to an idle mode in the embodiment.

FIG. 4 is a diagram showing a part of a flowchart for describing a processing procedure when a command is received in a standby mode.

FIG. 5 is a diagram illustrating the rest of the flowchart for describing the processing procedure at the time of receiving a command in the standby mode, and is a diagram illustrating the processing procedure at the time of receiving a write buffer command and receiving a read buffer command.

FIG. 6 is a block diagram showing a schematic configuration of a magnetic disk drive according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a processing procedure when a write buffer command and a read buffer command are received in a standby mode, which are applied in the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Disk 12 ... Spindle motor 13 ... Buffer memory 14 ... HDC (disk controller, data transfer means, 1st data transfer means, 2nd data transfer means) 15 ... ROM 16 ... CPU (1st buffer power-off means) A second buffer power-off means, a buffer power-on means, an abort means, a first buffer power-on means, a data storage means,
Second buffer power-on means, data loading means) 17 Timer 18 EEPROM (rewritable nonvolatile memory) 140 Buffer power control circuit (Buffer power-on means, first buffer power-on means) 141 Automatic transfer Circuit (data transfer means, first data transfer means) 142 ECC circuit 180 buffer data storage area

Claims (6)

[Claims] 1. A disk drive comprising a buffer memory for temporarily storing read data from a disk and write data to a disk, wherein the buffer is used when shifting to a standby mode in which a motor for rotating the disk is stopped. First buffer power-off means for turning off the power of the memory; and a buffer for turning on the power of the buffer memory when a write buffer command instructing data writing to the buffer memory is received from the host device in the standby mode. Power on means; data transfer means for transferring data specified by the write buffer command to the buffer memory powered on by the buffer power on means; and a predetermined constant after completion of the write buffer command. Said host device in time If it does not receive the Luo command, the disk apparatus characterized by comprising a second buffer power-off means for turning off the power supply of the buffer memory. 2. A disk device comprising a buffer memory for temporarily storing read data from a disk and write data to a disk, wherein the buffer is used to shift to a standby mode in which a motor for rotating the disk is stopped. First buffer power-off means for turning off the power of the memory; and a buffer for turning on the power of the buffer memory when a write buffer command instructing data writing to the buffer memory is received from the host device in the standby mode. Power-on means; first data transfer means for transferring data specified by the write buffer command to the buffer memory powered on by the buffer power-on means; predetermined after completion of the write buffer command Within a certain period of time A second buffer power-off means for turning off the power of the buffer memory when no command is received from the host device, and a read buffer command for instructing data read from the buffer memory being issued within the predetermined time by the host device. A second data transfer unit that reads data from the buffer memory and transfers the read buffer command to the host device when receiving the read buffer command after a lapse of the predetermined time. And a disk device. 3. A disk device comprising a buffer memory for temporarily storing read data from a disk and write data to a disk, a rewritable nonvolatile memory having an area for storing data in the buffer memory, A first buffer power-off means for turning off the power of the buffer memory when shifting to a standby mode with a stop of a motor for rotating the disk; and a write buffer command for instructing data writing to the buffer memory. First buffer power-on means for turning on the buffer memory when receiving data from the host device in the standby mode; and the write buffer in the buffer memory powered on by the first buffer power-on means. Transfer data specified by command A first data transfer unit that, when the command is not received from the host device within a predetermined time after the end of the write buffer command, the data in the buffer memory is transferred to the nonvolatile memory. A data storage unit for storing, and a second power supply for turning off the power of the buffer memory after the data storage unit stores the data in the nonvolatile memory.
Buffer power-off means, and a second buffer power-on means for turning on the power of the buffer memory when receiving a read buffer command instructing data reading from the buffer memory after the lapse of the predetermined time, Data loading means for loading data stored in the non-volatile memory into the buffer memory powered on by the second buffer power-on means; if the read buffer command is received within the predetermined time, Immediately, if the data is received after the elapse of the predetermined time, a second data transfer unit that reads data from the buffer memory and transfers the data to the host device after the data load unit loads the data into the buffer memory. A disk device, comprising: 4. A power saving control method applied to a disk device having a buffer memory for temporarily storing read data from a disk and write data to a disk, wherein the standby mode includes stopping a motor for rotating the disk. When transitioning to, the power of the buffer memory is turned off, and when a write buffer command instructing data writing to the buffer memory is received from the host device in the standby mode, the power of the buffer memory is turned on. Starting data transfer for transferring data specified by the write buffer command to the buffer memory, and not receiving a command from the host device within a predetermined time after the end of the write buffer command. The power of the buffer memory A power saving control method characterized by turning off a power source and proceeding to a command waiting state in the standby mode. 5. A power save control method applied to a disk device having a buffer memory for temporarily storing read data from a disk and write data to a disk, wherein the standby mode involves stopping a motor for rotating the disk. When transitioning to, the power of the buffer memory is turned off, and when a write buffer command instructing data writing to the buffer memory is received from the host device in the standby mode, the power of the buffer memory is turned on. Starting data transfer for transferring data specified by the write buffer command to the buffer memory, and not receiving a command from the host device within a predetermined time after the end of the write buffer command. The power of the buffer memory Turn off the power supply, and proceed to a command waiting state in the standby mode. When a read buffer command instructing data reading from the buffer memory is received from the host device within the fixed time, data is read from the buffer memory. Power transfer control for starting data transfer for reading and transferring the read buffer command to the host device, and when the read buffer command is received after the predetermined time has elapsed, the read buffer command is aborted. Method. 6. A power save control method applied to a disk device having a buffer memory for temporarily storing read data from a disk and write data to a disk, wherein the standby mode involves stopping a motor for rotating the disk. When transitioning to, the power of the buffer memory is turned off, and when a write buffer command instructing data writing to the buffer memory is received from the host device in the standby mode, the power of the buffer memory is turned on. Starting data transfer for transferring data specified by the write buffer command to the buffer memory, and not receiving a command from the host device within a predetermined time after the end of the write buffer command. The data in the buffer memory The data is stored in the non-volatile memory, and thereafter, the power of the buffer memory is turned off to proceed to a command waiting state in the standby mode, and a read buffer command for instructing data reading from the buffer memory is transmitted for a predetermined time. If received later, after turning on the power of the buffer memory,
Loading the data stored in the non-volatile memory into the buffer memory, and immediately when the read buffer command is received within the fixed time, and when the read buffer command is received after the fixed time, the buffer memory A data transfer for reading data from the buffer memory and transferring the data to the host device after loading the data into the host device.