JPH05101514A - External storage device provided with wait state - Google Patents

Abstract

PURPOSE:To reduce the power consumption and to increase the response speed by executing instructions by delivery between a write data memory and a cache memory in the case of the wait state to reduce the frequency in start of a spindle motor. CONSTITUTION:When access is performed just after the spindle motor is stopped to enter into the wait state, write data is stored in a write data memory 8. The data volume of data written in this write data memory 8 is monitored by a data volume monitor circuit 13; and when this data volume exceeds a prescribed value, a driving part 24 and a write control part 10 are started to write data of the write data memory 8 in a storage medium 18. A cache memory 7 is provided where data selected by a prescribed logic is stored at the time of coming of a read instruction from a higher-order device in the case of the wait state, and thereby, required data of the read instruction is read out from the memory 7, and the frequency in start of the driving part 24 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external storage device having a standby state for low power consumption.

[0002]

2. Description of the Related Art At present, personal computers such as portable computers and notebook computers are rapidly becoming smaller. Further, it is becoming an important requirement for the market needs of these computers to have a large-capacity storage device. To meet this need, a relatively low price and small external storage device is considered to be optimal.

For this reason, small magnetic disk devices for these computers are rapidly becoming widespread, and it is conceivable that the condition for using them is to supply power from batteries outside the office, and the built-in magnetic disk device must also have low power consumption. Will be. For this reason, the magnetic disk drive, which is one of the peripheral devices, attempts to reduce power consumption, so if there is no access to the drive for a certain period of time under normal operating conditions, it will enter standby mode to reduce power consumption. There is a device.

FIG. 7 is a block diagram of a conventional magnetic disk device described as an example of an external storage device. In the figure, 1
Is a host computer (hereinafter abbreviated as "host") that issues a read / write command to the magnetic disk device 19, and 18 is a disk enclosure (hereinafter referred to as a magnetic disk storage medium, read / write head, spindle motor, actuator, etc. DE is abbreviated. 3 is an interface circuit for exchanging commands and information with a host. 4 is a microprocessor (hereinafter MP) for controlling the magnetic disk device 19.
(Abbreviated as U), 5 is a power mode setting MPU that sets the standby state of the magnetic disk device 19 and controls the power supplied to each circuit, 11 is a read circuit for reading the data written in DE 18, and 12 is DE 18. Write circuit for writing,
Reference numeral 9 is a read control unit for controlling the read circuit in the DE 18.
Is a write control unit for controlling the write circuit, 14 is a power supply switching circuit for dividing the magnetic disk device 19 into control unit / read / write control and circuit unit / driving unit and switching power supply according to a standby state, and 16 is a magnetic An actuator control circuit for controlling an actuator that moves the head of the disk,
Reference numeral 17 is a spindle motor drive circuit that drives a spindle motor that rotates a magnetic disk, and 19 is a magnetic disk device that stores the magnetic disk storage medium. The actuator control circuit 16 and the spindle motor drive circuit 17 constitute a drive unit, and the read circuit 11, the write circuit 12, the read control unit 9, and the write control unit 10 correspond to the read / write control and circuit unit.

In such a magnetic disk device,
If there is no access to the magnetic disk device 19 for a certain period of time, a standby state is entered, and power is not supplied to the drive unit, the read / write control and circuit unit by the power supply switching circuit 14, and there is no access for a certain period of time. An example of usage is considered in which, from the standby state, the interface between the host 1 and the magnetic disk device 19 is only physically connected and the sleep mode is shut off in terms of software.

In this case, if there is no access to the magnetic disk device 19 for a certain period of time and the access of the magnetic disk device 19 comes immediately after the spindle motor enters the standby mode of rotation stop, the magnetic disk device 19 will be It is necessary to start the spindle motor that consumes the most power, and the host 1 must wait for the spindle motor to rotate normally before issuing the command to the magnetic disk device 19 and executing it. It has drawbacks and causes a decrease in the processing capacity of host 1.

[0007]

In the conventional external storage device having the standby state, when the drive is accessed immediately after the drive unit enters the standby mode, the spindle motor which consumes the most power is started. It is necessary to do so, and because the rotation is stopped, until the read / write command is executed,
There was a problem that we had to wait for the spindle motor to rotate normally. In view of such a point, the present invention has an object to provide means for reducing the frequency of activating the drive section in the standby state and improving the response speed in the standby state.

[0008]

The above-mentioned problems can be solved by an external storage device having a standby state configured as described below. FIG. 1 is a principle diagram of the present invention. (1) Control unit that controls the device in response to commands from the host device
25, a storage medium 18 for storing, a write control unit 10 for writing data to the storage medium 18, a read control unit 9 for reading data from the storage medium 18, and a drive unit for driving the medium.
In the external storage device 26 having a function of waiting for the next command in a standby state in which the drive unit 24 is stopped or rotated at a low speed, a host device after the drive unit 24 is placed in the standby state. A write data memory 8 for writing the write data received from the memory, and a memory data amount monitoring circuit 13 for monitoring the amount of data written in the write data memory 8 and sending a detection signal to the control unit 25 when the amount exceeds a predetermined amount. By providing the write data memory 8 with a predetermined amount of data,
When it is stored in the storage medium 18, the drive unit 24 and the write control unit 10 are activated to write the data in the write data memory 8 into the storage medium 18. (2) Control unit that controls the device in response to commands from the host device
25, a storage medium 18 for storing, a write control unit 10 for writing data to the storage medium 18, a read control unit 9 for reading data from the storage medium 18, and a drive unit for driving the medium.
A cache for storing data selected by a predetermined logic in an external storage device 26 having a function of waiting for the next command in a standby state for stopping or rotating the drive unit 24 at a low speed. By providing the memory 7, when the necessary data according to the read instruction from the higher-level device after putting the driving unit 24 in the standby state exists in the cache memory 7, the data is read from the cache memory 7 and the driving unit 24.
Configure to reduce the startup frequency of the.

[0009]

[Action]

(1) When the external storage device 26 enters a standby state in which the drive unit 24 is stopped or rotates at a low speed, and the write data from the host device is accumulated in the write data memory 8 by a predetermined data amount, the data amount is monitored. The memory data amount monitoring circuit 13 sends a detection signal to the control unit 25, and the control unit 25 causes the drive unit 24 to operate.
Then, the write controller 10 is activated to write the data in the write data memory 8 to the storage medium 18. (2) A cache memory 7 for storing data, which is selected by a predetermined logic when a read command from a higher-level device is received in the external storage device 26 that is in a standby state where the drive unit 24 is stopped or rotates at low speed, is provided. As a result, the necessary data according to the read instruction from the host device is stored in the cache memory 7
If it exists in the cache memory 7, it is read from the cache memory 7 and the activation frequency of the driving unit 24 is reduced.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The principle of the present invention is to equip a magnetic disk device with a memory for storing write data and a cache memory for storing pre-read data from the magnetic disk device. When the power of the magnetic disk device is turned on, the spindle motor rotates, waits for a read command to arrive for a certain period of time, performs read processing, writes data that is likely to come next in the cache memory, and And the mode for turning off all the power supplies except the cache memory and the write memory is entered. At this time, if a read command does not arrive within a certain period of time, the magnetic disk drive refers to the last data that was powered off last time, writes the data that is most likely to be accessed next, to the cache memory of its own, and writes the data to the spindle. While the motor is stopped, all the power supplies except the control circuit, the cache memory and the write memory are powered off, and a standby state is entered.

Control is facilitated by making the power-on / power-off timing of the write / read circuit the same as the on / off of the spindle motor, including the initial standby state. When a write command is sent to the magnetic disk device in the standby state, the address and write data to be written are stored in the memory provided in the magnetic disk device. At this time,
The amount of data written in the memory is constantly monitored, and when a certain amount of data in the memory is accumulated, the spindle motor is started, and at the same time, the write circuit is powered on and the data in the memory is transferred to the specified address of the magnetic disk device. Write. When a read command is received, the cache memory that stores a certain amount of data in the magnetic disk device is accessed in advance to read the target data. If there is no target data, the spindle motor is started and the read circuit is set. Power on and read from magnetic disk unit.

As described above, the power consumed by the rotation of the spindle motor and the circuit is reduced, and the power consumption is reduced by reducing the number of times the spindle motor is started, and the response in the memory to the write / read command is reduced. Therefore, the problem of performance degradation is solved.

An example of a magnetic disk device when the present invention is implemented will be described. FIG. 2 is a configuration diagram of a magnetic disk device according to an embodiment of the present invention. In the figure, 7 is a cache memory for storing data selected by a predetermined logic, and 8
Is a write data memory for writing the write data received from the host device after putting the drive unit (24) in the standby state, 1
3 monitors the amount of data written in the write data memory (8), and when a predetermined amount is exceeded, a detection signal is sent to the controller (25).
A memory data amount monitoring circuit for sending to the
A memory reset circuit that resets the data memory (8),
21 is in the power mode setting MPU5 and 22 is in the power mode setting MPU5 when a predetermined time (5 minutes as an example below) has elapsed from the last command and sends a signal to the MPU4. A second timer 23 sends a signal to the MPU4 when a predetermined time (5 minutes as an example below) has elapsed from the last write command, and 23 is a predetermined time (hereinafter, referred to as a predetermined time from the last read command in the power mode setting MPU5). As an example, 5 minutes.) A third timer that sends a signal to the MPU 4 when the time has elapsed, 6 is a timer reset circuit that selects and resets the first timer 21, the second timer 22, and the third timer 23. Is. In addition, the same reference numerals as those in FIG. 7 are the same.

3 to 6 are flowcharts of the embodiment of the present invention, and the operation will be described below with reference to the drawings and the flowchart. First, when powered on, step 41
The MPU4 of the magnetic disk unit 19 is set to power mode M
The control is transferred to PU5, and the power mode setting MPU5 supplies all the necessary power supplies including the spindle motor drive circuit to the respective parts to bring the magnetic disk device 19 into the normal usable state. In step 42, control returns to MPU4 and M
According to the instruction of PU4, the first timer 21 of the three timers provided in the power 0 setting MPU5 is activated. From host 1 in step 43, interface circuit
If no write / read command has come to MPU4 via 3, the process proceeds to step 44, and if it does, the process proceeds to step 48.

Step 44 is a fixed time (5 in this example)
Minutes) to determine if it has passed, and if it has, step
Go to 45, return to step 43 if not, host
Wait for command from 1.

In step 45, the last read address before power-on stored in the MPU 4 is referred to, the data is stored in the cache memory 7, and it is determined in step 46 whether the data storage is completed, and it is not completed. Then, the process returns to step 45 again. When completed, proceed to step 47, MPU4
Resets the first timer 21 by the timer reset circuit 6 and proceeds to step 64, where the interface circuit 3
Power is supplied only to the memory and control unit such as the MPU 4, the cache memory 7, the write data memory 8 and the like, and the other power supply is stopped to enter the standby state.

When an instruction arrives within 5 minutes of a fixed time in step 43, it is determined in step 48 whether it is a write instruction or a read instruction. If it is a write instruction, the procedure proceeds to step 49, and if it is a read instruction, the procedure proceeds to step 57. Step when write command comes
At 49, the MPU 4 activates the second timer 22 in the power mode setting MPU 5 and at the same time resets the first timer 21.

Next, in step 50, writing to the DE 18 is performed via the write control unit 10 and the write circuit 12. In step 51, it is determined whether or not the process is completed, and if completed, the process returns to step 52, and if not completed, the process returns to step 50. If there is a next command in step 52, the process returns to step 43, and if there is no next command, the process proceeds to step 53.

In step 53, it is judged whether 5 minutes have passed since the last write command came, and if it has passed, step 54
If not, go back to step 52. Step 54
Then, the MPU4 refers to the written address and stores the data of the address that is likely to be read next in the cache memory.
Store in 7.

If the writing is completed in step 55, the process proceeds to step. If the writing is not completed, the process returns to step 54. In step 56, the MPU 4 sets the second timer 22 to the timer reset circuit 6
Is reset by, and the process proceeds to step 64 to enter the standby state.

When the read command is received in step 48, the process proceeds to step 57, where the MPU 4 operates the third timer 23 in the power mode setting MPU 5. MPU4 in step 58
Reads necessary data from the DE 18 through the read control unit 9 and the read circuit 11 and transfers the data to the host 1.

If the reading is completed in step 59, the process returns to step 60, and if it is not completed, the process returns to step 58. Step 60
Then, the read address is referred to and the data of the address which is likely to be read next is stored in the cache memory 7.

If the writing to the cache memory 7 is completed in step 61, the process proceeds to step 62.
Return to 60. In step 62, it is determined whether 5 minutes have passed since the last read command, and if it has passed, the third timer is reset in step 63, and the process proceeds to step 64 and is in a standby state. In the data storage in the cache memory 7, the data referred to the address by the read instruction is prioritized.

Next, the operation when a write / read command comes after entering the standby state will be described. Step 64 and subsequent steps show the operation in the standby state, and correspond to FIGS. 5 and 6 (flow charts (Nos. 3 and 4)).

In step 64, the power mode switching MPU5 activates the power supply switching circuit 14 to supply power only to the memory such as the interface circuit 3, MPU4, cache memory 7, write / data memory 8 and control section.
It goes into a standby state to stop the supply of other power. Step
If it is a write / read command in 65, the process proceeds to step 66, and if it is another command, the process proceeds to step 85. In step 66, whether write or read is determined, and if it is a write command, step 67
If it is a read command, the process proceeds to step 74.

In step 67, the MPU 4 records the write data in the write data memory 8 without driving the DE 18. At this time, the memory / data amount monitoring circuit 13 that constantly monitors the amount of data recorded in the write data memory 8
When a certain amount is recorded in step 68, the memory
The data amount monitoring circuit 13 reports to the MPU 4 and proceeds to step 69. When the amount does not reach the fixed amount, the process returns to step 65 and waits for the next instruction.

In step 69, the MPU 4 accesses the power mode setting MPU 5 to enter the power-on mode and supplies power to the spindle motor drive circuit 17,
Power the write circuit with the write data memory 8
Data of the DE through the write control unit 10 and the write circuit 12
Record at 18.

At step 72, it is judged that the writing to the DE 18 is completed, and at step 73, the write / data memory 8 is reset by the memory reset circuit 15 and the process proceeds to step 64 to return to the standby state. Next, when a read command is received in step 66, the process proceeds to step 74 and the MPU 4 accesses the cache memory 7.

If the desired data is stored in the cache memory 7 in step 75, the process proceeds to step 76 and the data is stored in the host 1
Transfer to. If the cache memory data does not hit the desired data, proceed to step 77 and MP
U4 accesses the power mode setting MPU5 to enter the power-on mode, supplies power to the spindle motor drive circuit 17, supplies power to the read circuit in step 78, and supplies read power to the read circuit 9 and read circuit 11 in step 79. Then, the desired data is read from the DE 18 and transferred to the host.

Next, at step 80, the power mode setting MPU
Activate the third timer 23 in 5. In step 81, it is determined that 5 minutes have passed since the last read command came, the process proceeds to step 82, and the third timer 23 is reset in step 82. In step 83, the most recently accessed address is referred to and the data of the address with the highest probability of being read next is recorded in the cache memory 7. Step 84
Then, it is judged that the writing to the cache memory 7 is completed, and the process returns to step 64 to enter the standby state.

When the work is completed and the power is turned off, the end command is instructed from the host 1. Therefore, at step 65, if the command from the host 1 is not the write / read command, the process proceeds to step 85. In step 85, it is judged whether or not it is an end instruction, and if not so, the flow returns to step 65 to wait for the next instruction. If it is an end command, the process proceeds to step 86, where the MPU 4 determines whether or not there is data in the write data memory 8, and if there is no data, the process proceeds to step 92, where all the power supplies are cut off and the process ends. If there is data, the process proceeds to step 87, power is supplied to the spindle motor drive circuit 17 to drive the DE 18, power is supplied to the write circuit 12 at step 88, and the data in the write data memory 8 is supplied to the DE 18 at step 89. Write. In step 90, it is judged whether or not the writing is completed. If the writing is not completed, the processing returns to step 89 to perform the writing again, and if the writing is completed, the processing proceeds to step 91. In step 91, the data in the write data memory 8 is reset by the memory reset circuit 15. In step 92, all power supplies are turned off and the process ends.

Although the present embodiment is for a magnetic disk device, the same control can be performed for other media such as an optical disk, which is useful for improving performance.

[0033]

As is apparent from the above description, according to the present invention, when there is no access to the external storage device for a certain period of time, the spindle motor is stopped and the next command is issued at the time of waiting for the next command. In the conventional external storage device, the spindle motor must be activated to execute the command. However, according to the present invention, after entering the standby state in which the spindle motor stops, the instruction is executed by passing the write / data memory and the cache memory. In addition to reducing power consumption and executing instructions using memory, it is possible to process instructions without waiting for the driving part to be in a ready state, and performance is improved compared to conventional devices. Have a positive effect.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram of a magnetic disk device according to an embodiment of the present invention.

FIG. 3 is a flowchart (part 1) of an embodiment of the present invention.

FIG. 4 is a flowchart (part 2) of the embodiment of the present invention.

FIG. 5 is a flowchart (part 3) of the embodiment of the present invention.

FIG. 6 is a flowchart (part 4) of the embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional magnetic disk device.

[Explanation of symbols]

1 host device 3 interface circuit 4 MPU 5 power mode setting MPU 6 timer reset circuit 7 cache memory 8 write data memory 9 read control unit 10 write control unit 11 read circuit 12 write circuit 13 memory data amount monitoring circuit 14 power supply switching circuit 15 memory reset circuit 16 actuator control circuit 17 spindle motor drive circuit 18 storage medium
Or DE 19 magnetic disk device 21 first timer 22 second timer 23 third timer 24 drive unit 25 control unit 26 external storage device 41 to 92 operation step

Claims (2)

[Claims] 1. A control unit (25) for controlling the device in response to a command from a host device, a storage medium (18) for storing, and a write control unit (10) for writing data to the storage medium (18). And a read control unit (9) for reading data from the storage medium (18),
A drive unit (24) for driving the medium, and the drive unit (24)
In the external storage device (26) having a function of waiting for the next command in a standby state of stopping or rotating at low speed, write data received from the host device after putting the drive unit (24) in the standby state Write data memory (8)
And the amount of data written in the write data memory (8) is monitored, and if a predetermined amount is exceeded, a detection signal is sent to the control unit (25).
When a predetermined data amount is accumulated in the write data memory (8) by providing a memory data amount monitoring circuit (13) for sending to the drive unit (24) and the write control unit (10). ) And writing the data of the write data memory (8) into the storage medium (18). 2. A control unit (25) for controlling the device in response to a command from a host device, a storage medium (18) for storing, and a write control unit (10) for writing data to the storage medium (18). And a read control unit (9) for reading data from the storage medium (18),
A drive unit (24) for driving the medium, and the drive unit (24)
In the external storage device (26) having a function of waiting for the next command in a standby state for stopping or rotating at low speed, by providing a cache memory (7) for storing data selected by a predetermined logic, When the necessary data according to the read command from the host device after putting the drive unit (24) in the standby state exists in the cache memory (7), the data is read from the cache memory (7) and the drive unit (24) is read. An external storage device characterized by reducing the activation frequency.