JPH06332808A - Data protective device - Google Patents

Abstract

PURPOSE:To provide a data protective device capable of holding data in the middle of being written even when a power source is turned off in the middle of writing the data to a secondary storage device such as a magnetic disk or the like. CONSTITUTION:A memory 7 can hold the data even when the power source is turned off, a power failure detection circuit 7 detects the voltage drop of commercial power 1 and a power source device 2 converts the commercial power 1 which is AC to DC. At the time of writing the data to a magnetic disk storage device 10, the data are written in the memory 7 first and then, the data written in the memory 7 are written in the magnetic disk storage device 10. When the commercial power 1 is turned to a power source off state, a data write operation to the memory 7 is stopped and data write from the memory 7 to the magnetic disk storage device 10 is completed. Thus, the reliability of the contents of the data stored by the secondary storage device can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data protection device for protecting data relating to a secondary storage device such as a magnetic disk device used in an information processing system or the like.

[0002]

2. Description of the Related Art As a conventional data protection device, there is a data protection device having a memory capable of holding data even when power is cut off due to a power failure or the like, as data protection when writing data to a secondary storage device. When the power is cut off, the conventional data protection device temporarily writes data and data management information such as a storage start address, a sector, a data size, and a write completion flag to the memory, and monitors the write completion flag after the power is restored. If writing has not been completed, there is a method in which writing is performed again in the secondary storage device.

As such conventional data protection methods, for example, JP-A-58-9201 and JP-A-1-16 are available.
Some are disclosed in Japanese Patent No. 1458 and the like.

[0004]

However, in the above-mentioned conventional data protection technique, the power cutoff during the writing of data to the memory capable of holding the data even when the power supply is cut off is not taken into consideration. If the power is cut off during writing, the writing operation will be interrupted halfway, and it is determined that writing to the secondary storage device has not been completed after the next power restoration, and the data will be turned off. However, there is a problem in that the illegal data before the interruption is written to the secondary storage device and the data is not protected.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a data protection device capable of retaining the write data even if the power is cut off during the data write to the secondary storage device such as a magnetic disk.

[0006]

A data protection device of the present invention converts electric power input from a power source into a predetermined voltage and outputs the same, and also when the power from the power source is cut off, the output is cut off. Back up the power supply and a power supply that keeps the voltage at a predetermined voltage for a certain period of time, a power failure detection circuit that detects when the voltage of the power input by the power supply falls below a predetermined value, and generates a power failure detection signal. And a control device for controlling data writing using the output of the power supply device as a driving power source, the control device comprising:
When writing data to the secondary storage device, normally, the data is first written to the memory and then the data written to the memory is controlled to be written to the secondary storage device, and the power failure detection signal is generated. In this case, the control for stopping the data writing operation to the memory is performed.

Further, the data protection device of the present invention is characterized by having a secondary storage device which uses the output of the power supply device as a driving power source.

Further, the data protection apparatus of the present invention is characterized in that the power input by the power supply unit is commercial power.

Further, in the data protection device of the present invention, the control device controls to complete the operation of writing the data written in the memory to the secondary storage device within the predetermined time after the power failure detection signal is generated. It is characterized by doing.

Further, the data protection device of the present invention is characterized in that the control device controls to erase the data stored in the memory when the data writing to the secondary storage device is completed.

[0011]

According to the data protection apparatus of the present invention, in the data protection apparatus according to the present invention, when the input voltage, which is the voltage of the power input by the apparatus, is a predetermined value or more, that is, the detection power failure detection signal is not generated. In normal times, data is first written in the memory, and then the data written in the memory is written in the secondary storage device to write the data in the secondary storage device.

On the other hand, at the time of a power failure in which the input voltage falls below a predetermined value, the power failure detection circuit detects that the input voltage falls below a predetermined value and generates a power failure detection signal, and the control unit detects the power failure. The data write operation to the memory is stopped in response to the generation of the signal. Further, the control device controls to write the data written in the memory to the secondary storage device within a predetermined period. Since the power supply device outputs the driving power only for a predetermined period even after the power failure detection signal is generated, the data protection device according to the present invention can be used even if a power failure condition occurs during data writing to the secondary storage device. , All the data being written can be written to the secondary storage device.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a data protection device according to an embodiment of the present invention. The protection device includes a power supply device 2, a power failure detection circuit 3, a central processing unit 5, a system bus 6, a memory 7, a battery 8, a magnetic disk control unit 9, a magnetic disk storage device 10, and a direct disk. It is composed of a memory address controller (hereinafter, referred to as a DMA controller) 11.

The power supply device 2 is a device for converting the commercial power 1 which is AC power, which is power distributed from the power system provided by the power company, into DC power. Then, the power supply device 2 supplies DC power to the central processing unit 5, the memory 7, the magnetic disk control unit 9, the magnetic disk storage device 10 and the DMA controller 11. The power failure detection circuit 3 is a circuit that detects that the voltage of the commercial power 1 drops below a predetermined value and outputs a power failure detection signal 4 which is a detection signal thereof to the central processing unit 5. The central processing unit 5 controls various operations of the components of the data protection device. The system bus 6 is a bus for transmitting and receiving data and the like between the central processing unit 5, the memory 7, the magnetic disk control unit 9, the DMA controller 11, and the like. The memory 7 is a memory whose power source is backed up by a battery 8 and can retain the stored data even when the power source is cut off. The magnetic disk control unit 9 controls the magnetic disk storage device 10. The DMA controller 11 collectively transfers data at a high speed between the memory 7 and the magnetic disk control unit 9 regarding a data write or read operation.

Next, the operation of this embodiment will be described.
First, the operation of writing data to the magnetic disk storage device 10 will be described. At the time of writing data, the data to be written in the magnetic disk storage device 10 is written in the memory 7 by the control operation of the central processing unit 5. afterwards,
The central processing unit 5 sends a data transfer request signal to the DMA controller 11 and the magnetic disk control unit 9. Upon receiving the data transfer request signal, the magnetic disk control unit 9 transfers the data written in the memory 7 and writes the data in the magnetic disk storage device 10.

Here, it is generally known that writing a large amount of data in the memory 7 shortens the write processing time with respect to the amount of data and improves the write efficiency. In the present embodiment, for example, A method of writing a small amount of data of 1 sector to the memory 7 is adopted. This is to shorten the processing time for the magnetic disk control unit 9 receiving the data transfer request signal to write the data written in the memory 7 to the magnetic disk storage device 10. When the writing to the magnetic disk storage device 10 is completed, the magnetic disk control unit 9 sends a write completion signal 12 to the central processing unit 5, and the central processing unit 5 clears the data written in the memory 7. To do.

Next, the operation of this embodiment when the power is turned off will be described. When the voltage of the commercial power 1 drops below a predetermined value, the power failure detection circuit 3 detects the voltage drop and outputs the power failure detection signal 4 to the central processing unit 5 as an interrupt signal. When the central processing unit 5 receives the power failure detection signal 4, the central processing unit 5 stops writing data to the memory 7, and at the same time, the central processing unit 5 sends a data transfer request signal D
The signal is sent to the MA controller 11 and the magnetic disk controller 9. Upon receiving the data transfer request signal, the magnetic disk control unit 9 writes all the data written in the memory 7 into the magnetic disk storage device 10 by the time the data writing to the memory 7 is stopped. In this embodiment, since the amount of data to be written to the memory 7 is small, the amount of data to be written to the above-mentioned magnetic disk storage device 10 is kept from when the power failure detection circuit 3 detects the AC voltage drop to when the DC power is cut off. Data writing is completed.

Here, the central processing unit 5, the memory 7, the magnetic disk control unit 9, the magnetic disk storage device 10, and D
In the MA controller 11, the power failure detection circuit 3 uses the commercial power 1
Since it operates with the DC power output from the power supply device 2 for a certain period of time after the detection of the voltage drop of the above, the normal operation is performed from the generation of the power failure detection signal 4 to the completion of writing to the magnetic disk storage device 10 described above. The write data to the magnetic disk storage device 10 is not destroyed or lost. Furthermore, if the write completion signal 12 is not transmitted to the central processing unit 5 after the occurrence of the power failure detection signal 4 until the DC power output of the power supply device 2 is cut off, the data written in the memory 7 is not cleared, so that the data It is possible to realize a highly reliable data protection device without destruction or loss.

As a result, the data protection apparatus of this embodiment is provided with the memory 7 capable of retaining data even when the power is cut off, and the power failure detection circuit 3 detects the voltage drop of the commercial power 1 and detects the voltage drop. Since all the data being written to the magnetic disk storage device 10 can be completed between the detection and the interruption of the DC power output by the power supply device 2, the secondary storage device such as the magnetic disk storage device 10 can be completed. Even if the commercial power 1 is cut off during the writing of the data, the excellent effect that the data during the writing can be protected can be exhibited.

In the present embodiment, the commercial power 1 is used as the power source of this device, but the present invention is not limited to this, and for example, a diesel engine or the like may be used as a power source. However, the present invention can be used.

[0022]

As described above, according to the present invention, a power failure detection circuit for detecting that the voltage of the electric power input to the device has become a predetermined value or less, and a memory capable of retaining data even when the power is cut off. Since the data is written to the secondary storage device by the operation of writing data to the memory first and then writing the data written to the memory to the secondary storage device, the magnetic disk storage device, etc. Even if the commercial power is cut off during the writing of data to the secondary storage device, the data can be written to the secondary storage device, and the data can be protected.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a data protection device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Commercial Power 2 Power Supply Device 3 Power Failure Detection Circuit 4 Power Failure Detection Signal 5 Central Processing Unit 6 System Bus 7 Memory 8 Battery 9 Magnetic Disk Controller 10 Magnetic Disk Storage Device 11 DMA Controller 12 Write Completion Signal

Claims (5)

[Claims] 1. A power supply device which converts electric power input from a power supply into a predetermined voltage and outputs the same, and holds the output at a predetermined voltage for a certain period of time even after the electric power from the power supply is cut off. A power failure detection circuit that generates a power failure detection signal by detecting that the voltage of the power input by the power supply has dropped below a predetermined value, a memory whose power is backed up, and an output of the power supply. A control device for controlling data writing as a driving power source, and when writing data to the secondary storage device, the control device normally writes data to the memory first and then to the memory. The data stored in the secondary storage device is controlled to stop the data writing operation to the memory when the power failure detection signal is generated. And a data protection device. 2. The data protection device according to claim 1, further comprising a secondary storage device having an output of a power supply device as a driving power source. 3. The data protection device according to claim 1, wherein the power input by the power supply device is commercial power. 4. The data protection device according to claim 1, wherein the control device stores the data written in the memory in the secondary storage device within the fixed time period after the power failure detection signal is generated. A data protection device characterized by controlling to complete the write operation to. 5. The data protection device according to claim 1, 2, 3 or 4, wherein the control device erases the data stored in the memory when the data writing to the secondary storage device is completed. A data protection device characterized by controlling.