JP2002157052A - Memory backup system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent data saved in an unexpected power supply cut but lack in reliability from returning at the start of power supply. SOLUTION: This memory backup system 10 comprises a management information storage medium 5 which is backed up by a backup power supply circuit 2 together with a processing information storage medium 4 to write a data save record that is the record of saving data; and a processor 6 which receives a power supply from a main power supply circuit 1, performs delivery of data with the processing information storage medium 4 and the management information storage medium 5 to arithmetically process the data, confirms the presence of the data save record of the management information storage medium 5 at the start of the power supply from the main power supply circuit 1, and returns the data saved in the processing information storage medium 4 only when the data save record is present.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a memory backup system, and more particularly, to a memory backup system for improving the reliability of backup data.

[0002]

2. Description of the Related Art Memory (storage device) of various information processing devices
Semiconductor memories are widely used. This semiconductor memory is roughly classified into a volatile memory in which stored data is erased due to power-off (off), and a nonvolatile memory in which stored data is not erased even when power-off. Furthermore, volatile memory is a DRAM (Dynamic Random Acce
ss Memory) and SRAM (Static Random Access Memor)
These memories are preferably classified as MOS (Metal Oxide Semiconductor) transistors, which are excellent in terms of the degree of integration, so that a low-cost and large-capacity memory can be easily realized. Has been adopted.

By the way, as described above, the DRAM and the SR
Since volatile memories such as AM lose their stored data due to the nature of power loss, a backup power supply is prepared in advance in preparation for power loss. 2. Description of the Related Art A memory backup system has been constructed in which a memory is backed up to protect stored data. Therefore, in an information processing apparatus such as a computer using the memory as described above, by providing a memory backup system,
By saving important data during arithmetic processing to its memory as necessary, the data can be restored from the memory and used at any time.

[0004] The memory backup system as described above is disclosed in, for example, Japanese Utility Model Laid-Open No. Hei 4-201228. The memory backup system includes a main power supply circuit 51 and a backup power supply circuit 2 as shown in FIG.
When the main power supply circuit 51 is turned off, power is supplied (backed up) from the backup power supply circuit 52 and the backup power supply monitoring circuit 53 and the processing information storage medium 54
And a processor 55 that is supplied with power from the main power supply circuit 51 and exchanges data with the processing information storage medium 54 to perform arithmetic processing on the data.

In the memory backup system,
When the main power supply circuit 51 is detected to be off, the processor 55
Is written so as to save the data being processed in the processing information storage medium 54, and thereafter is switched to the backup power supply circuit 52. Then, when the supply of power from the main power supply circuit 51 is started again, the processor 55 checks the supply voltage of the backup power supply circuit 52 based on the report from the backup power supply monitoring circuit 53. If the supply voltage is within the specified value, the processor 55
Determines that the data saved in the processing information storage medium 54 has not changed (the data is normal), and restores this data.

However, in the memory backup system described in the above-mentioned publication, the main power supply circuit 51 is turned off due to a normal power supply stoppage (normal interruption) expected in advance, or a sudden power off of the main power supply circuit 51. There is a drawback in that it cannot be distinguished from an unexpected power supply stop due to a failure. If the main power supply circuit 51 is turned off in the latter case, the processor 55 is not normally interrupted and the processing information storage medium 54 is not interrupted.
Since the data that has been saved is restored, there is a possibility that data that has been saved but whose contents have changed and lacks reliability may be restored.

Another conventional memory backup system is disclosed, for example, in Japanese Patent Laid-Open No. 57-147198. As shown in FIG. 8, the memory backup system includes a main power supply circuit 61, a backup power supply circuit 62, a processing information storage medium 64 that is backed up by the backup power supply circuit 62 when the main power supply circuit 61 is turned off, and An inspection area 65 in the information storage medium 64, a main power supply monitoring circuit 63 that senses that the main power supply circuit 61 stops power supply within a specified time and reports to the processor 66, and a power supply from the main power supply circuit 61. And a processor 65 for exchanging data with the processing information storage medium 64 and the inspection area 65 to perform arithmetic processing on the data. The inspection area 65 is a processing information storage medium 64
Occupies a specific address. Further, the main power supply circuit 61 has a built-in means for temporarily holding a power supply such as a capacitor, and holds the power supply voltage for a specified time even after the power is turned off.

In the memory backup system,
When the main power supply monitoring circuit 63 detects that the main power supply circuit 61 stops supplying power after a specified time, the main power supply monitoring circuit 63 reports this to the processor 66. Based on this, the processor 66 writes the data being processed in the processing information storage medium 64 so as to be saved, and writes the inspection data in the inspection area 65. Thereafter, the operation is switched to the backup power supply circuit 62. Then, when the power supply is started again by the main power supply circuit 61, the processor 66 compares the save data in the processing information storage medium 64 with the test data in the test area 65. When the two data match, the processor 66 determines that the data saved in the processing information storage medium 54 has not changed (the data is normal), and returns this data.

[0009] However, Japanese Patent Application Laid-Open No. 57-147198.
In the memory backup system described in Japanese Unexamined Patent Application Publication No. HEI 4-201228, although the disadvantage of Japanese Unexamined Utility Model Application Publication No. 4-20128 can be improved, the inspection area 65 for writing inspection data occupies a specific address in the processing information storage medium 64. There is a disadvantage that the usable capacity of the processing information storage medium 64 decreases accordingly.

As another conventional memory backup system, there is one disclosed in, for example, Japanese Patent Laid-Open No. 6-19808. As shown in FIG. 9, the memory backup system includes a power supply circuit 72 provided with a power switch 71, a control circuit 76 including a ROM 73, a RAM 74, a backup memory file 75, a processor (not shown), and a user interface. , A display 77 and a keyboard 78, and an external storage device 79 for storing application programs and the like.

In the memory backup system,
When processing such as data input and editing is performed by the control circuit 76,
The input / edit data file on the backup memory file 75 is processed, and the data file is saved to the external storage device 79 as necessary. At this time, the external storage device 79 is stored in the backup memory file 75.
A flag is added to indicate whether the data file has been saved to the server. As a result, at the time of system startup, if the result of checking the flag in the backup memory file 75 indicates that there is a file whose data has not been saved to the external storage device 79, a predetermined restoration process is performed. .

According to the memory backup system described in Japanese Patent Application Laid-Open No. 6-19808, even if an unexpected power failure occurs due to a power failure or an erroneous operation, data being processed by the running application program is stored in the external storage device 79. It is said that the data can be reliably prevented from being lost because the data is saved to the storage device.

[0013]

By the way, Japanese Patent Application Laid-Open No.
In the memory backup system described in Japanese Patent Application Laid-Open No. 19808, data being processed by an application program can be reliably protected, but data that is saved but lacks reliability when an unexpected power failure occurs is However, there is a problem that it is not possible to prevent the power supply from returning when the power supply is started. In other words,
In the memory backup system described in Japanese Patent Application Laid-Open No. 19808, a flag indicating whether data file saving has been performed is added to a backup memory file 75 different from the external storage device 79 for saving data being processed by the application program. Therefore, a specific address in the external storage device 79 is not occupied.
The disadvantage of the memory backup system described in Japanese Patent No. 47198 can be improved. However, since the purpose of JP-A-6-19808 is to ensure the protection of data being processed by the application program, the data saved in the external storage device 79 in the event of an unexpected power-off is lost. No consideration is given to the possibility of being restored as unreliable data at the start of supply.

The present invention has been made in view of the above-described circumstances, and data that is saved but loses reliability when an unexpected power failure occurs is restored when power supply is started. It is an object of the present invention to provide a memory backup system capable of preventing the problem.

[0015]

In order to solve the above-mentioned problems, the invention according to claim 1 switches from the main power supply circuit to the backup power supply circuit when the supply of power from the main power supply circuit is stopped. Power is supplied from the backup power supply circuit to the processing information storage unit, and the data being processed is written so as to be saved in the processing information storage unit;
A memory backup system configured to restore data saved in the processing information storage unit when the supply of power from the main power supply circuit is started, and the power supply from the backup power supply circuit together with the processing information storage unit Is supplied, and a management information storage unit that writes data save information, which is information obtained by saving the data, and data is transferred between the processing information storage unit and the management information storage unit that are supplied with power from the main power supply circuit. It exchanges data to perform arithmetic processing, and when the supply of power from the main power supply circuit is started, confirms the presence / absence of data saving information in the management information storage unit. Only when the data saving information exists, the processing information An operation control unit for restoring the data saved in the storage unit.

According to a second aspect of the present invention, there is provided the memory backup system according to the first aspect, wherein the arithmetic control unit senses that power supplied from the main power supply circuit is stopped within a specified time. And a main power supply monitoring circuit.

According to a third aspect of the present invention, there is provided the memory backup system according to the first or second aspect, wherein the arithmetic control unit determines that there is no data to be saved in the processing information storage unit. A switch means for stopping power supplied from the backup power supply circuit under the control of the arithmetic control unit is provided.

Further, the invention described in claim 4 is based on claim 1,
4. The memory backup system according to item 2 or 3, wherein the arithmetic control unit initializes the contents of the management information storage unit when confirming that there is no data save information in the management information storage unit.

According to a fifth aspect of the present invention, there is provided the memory backup system according to any one of the first to fourth aspects, wherein the management information storage unit has a one-bit memory capacity for writing the data saving information. It is characterized by having.

According to a sixth aspect of the present invention, there is provided the memory backup system according to any one of the first to fifth aspects, wherein the backup power supply circuit comprises a chargeable power supply. And

[0021]

Embodiments of the present invention will be described below with reference to the drawings. The description will be made specifically using an embodiment. First Embodiment FIG. 1 is a block diagram showing a configuration of a memory backup system according to a first embodiment of the present invention, and FIG. 2 is a flowchart showing an operation of the memory backup system. The memory backup system 10 of this example has the configuration shown in FIG.
As shown in FIG. 1, a main power supply circuit 1, a backup power supply circuit 2, and a processing information storage medium (processing information storage unit) to which power is supplied (backed up) from the backup power supply circuit 2 when the main power supply circuit 1 is turned off. 4) and a management information storage medium (management information storage unit) 5; a main power supply monitoring circuit 3 which senses that the main power supply circuit 1 stops supplying power within a specified time and reports to the processor 6; A processor (arithmetic control unit) 6 is supplied with power from the circuit 1 and exchanges data with the processing information storage medium 4 and the management information storage medium 5 to perform arithmetic processing on the data. The main power supply circuit 1 has a built-in means for temporarily holding a power supply such as a capacitor, and holds the power supply voltage for a specified time after the power is turned off. The backup power supply circuit 2 uses a rechargeable battery, and is charged by the main power supply circuit 1 when backup is unnecessary. As a result, the main power supply circuit 1 can be used repeatedly, thereby simplifying maintenance. The processing information storage medium 4 is, for example, a DIM
A memory module such as an M (Dual In Memory Module) is used, and is configured by a volatile memory such as a DRAM and an SRAM. The management information storage medium 5 is constituted by, for example, an SRAM having a flip-flop circuit.

Next, the operation of the memory backup system will be described with reference to the flowcharts of FIGS. First, a description will be given of a case where power supply is stopped in FIG. First, the main power supply monitoring circuit 3 senses that the main power supply circuit 1 stops supplying power after a specified time (step S1). This is because the power supply of the main power supply circuit 1 is not instantaneously turned off, but has a built-in means for temporarily holding the power supply such as a capacitor. , So that the specified time is sensed.

Next, the main power supply monitoring circuit 3
, A notice of power supply stop by the main power supply circuit 1 is reported (step S2). Next, based on the report from the main power supply monitoring circuit 3, the processor 6 writes the data being processed in the processing information storage medium 4 so as to be saved (step S3).

Next, the processor 6 writes a data save record (data save information) indicating that the data has been saved in the management information storage medium 5 (step S4). this is,
As shown in FIG. 4, it is only necessary to add the flag 1 using the 1-bit memory 7 in the management information storage medium 5. Therefore, data save recording can be written with a minimum memory capacity. After a prescribed time, the main power supply circuit 1 stops supplying power (step S5).

Next, a description will be given of the start of power supply in FIG. First, the main power supply circuit 1 starts power supply (step S11). Next, the processor 6 includes the main power supply circuit 1
Then, based on the power supply from the server, it is checked whether or not there is a data save record in which the management information storage medium 5 has been previously written (step S12). This can be done by checking the flag in the memory 7 shown in FIG. If there is data save recording, that is, if the flag remains 1, the processor 6 saves the data saved in the processing information storage medium 4 during the period when the backup power supply circuit 2 backs up the power when the power supply is stopped. Is not changed (data is normal), and this data is restored (step S13).

On the other hand, if there is no data evacuation record in the management information storage medium 5, that is, if the flag is set to 0, the processor 6 operates during the period in which the backup was performed by the backup power supply circuit 2 when the power supply was stopped. It is determined that the data saved in the processing information storage medium 4 has changed (data is abnormal) or that no saved data exists, and the processing information storage medium 4 is initialized (step S14).

As described above, according to the configuration of the memory backup system of this example, when the power supply from the main power supply circuit 1 is stopped, the backup power supply circuit 2 backs up the processing information storage medium 4 and Writing to the storage medium 4 so as to save the data being processed,
In a memory backup system configured to restore saved data in the processing information storage medium 4 when power supply from the main power supply circuit 1 is started, the backup data is backed up by the backup power supply circuit 2 together with the processing information storage medium 4. Data is exchanged between the management information storage medium 5 for writing the data save record, which is the data saved data, and the processing information storage medium 4 and the management information storage medium 5 which are supplied with power from the main power supply circuit 1. When the power supply of the main power supply circuit 1 is started, the presence or absence of the data save recording in the management information storage medium 5 is checked, and the data is saved in the processing information storage medium 4 only when the data save record exists. With the processor 6 for restoring the data, the reliability of the backup data can be improved.
Therefore, it is possible to prevent data that is saved but loses reliability when an unexpected power failure occurs from being restored at the start of power supply.

Second Embodiment FIG. 5 is a block diagram showing the configuration of a memory backup system according to a second embodiment of the present invention, and FIG. 6 is a flowchart for explaining the operation of the memory backup system. The configuration of the memory backup system according to the second embodiment of the present invention is significantly different from the configuration of the first embodiment in that unnecessary power consumption of the backup power supply circuit is suppressed. In the memory backup system 12 of this example, as shown in FIG. 5, a switch (switch means) 7 is connected in the power supply path of the backup power supply circuit 2 to the processing information storage medium 4 and the management information storage medium 5. I have.

When notified of the power supply stop notice from the main power supply monitoring circuit 3, the processor 6 determines whether or not there is data to be saved in the processing information storage medium 4 in the data being processed. When it is determined that there is no data to be saved in the processing information storage medium 4, the switch 7 is controlled so that the backup power supply circuit 2 with respect to the processing information storage medium 4 and the management information storage medium 5 thereafter. Stop the power supply circuit. Therefore, useless power consumption of the backup power supply circuit 2 can be suppressed. Other than this, it is substantially the same as the first embodiment described above.
Therefore, in FIG. 5, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

Next, referring to the flowchart of FIG.
The operation of the memory backup system when power supply is stopped will be described. First, the main power supply monitoring circuit 3 detects that the main power supply circuit 1 stops supplying power after a specified time (step S21). This is because the power supply of the main power supply circuit 1 is not instantaneously turned off, but has a built-in means for temporarily holding the power supply such as a capacitor. , So that the specified time is sensed.

Next, the main power supply monitoring circuit 3
, A notice of power supply stop by the main power supply circuit 1 is reported (step S22). Next, based on the report from the main power supply monitoring circuit 3, the processor 6 determines whether or not the data being processed has data to be saved in the processing information storage medium 4 (step S23). If there is data to be saved, the processor 6 writes the data being processed in the processing information storage medium 4 so as to save the data (step S24). If there is no data to be saved, the processor 6 controls the switch 7 to be turned off to stop the power supply of the backup power supply circuit 2 (step S25).

Next, the processor 6 writes a data save record indicating that the data has been saved in the management information storage medium 5 (step S26). As shown in FIG. 4, it is only necessary to add the flag 1 using the 1-bit memory 7 in the management information storage medium 5. Therefore, data save recording can be written with a minimum memory capacity. After the specified time, the main power supply circuit 1 stops supplying power (step S27). Note that the operation at the start of power supply is substantially the same as in the first embodiment, and a description thereof will be omitted.

As described above, according to the configuration of this embodiment, substantially the same effects as those described in the first embodiment can be obtained. In addition, according to this example, useless power consumption of the backup power supply circuit can be suppressed.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and there are design changes and the like that do not depart from the gist of the present invention. Is also included in the present invention. For example, the backup power supply circuit has been described using an example in which a rechargeable battery is used. In particular, when there is a space constraint in a place where a memory backup system is installed, a small and lightweight primary battery that does not require charging is used. May be used. Also, the management information storage medium has been described as an example in which the management information storage medium is configured by an SRAM having a flip-flop circuit. However, when the backup power supply circuit stops power supply when the main power supply circuit stops power supply, or when the main power supply circuit If there is no saved data in the processing information storage medium at the start,
If it is guaranteed that the data save record will be cleared from the management information storage medium, S (Synchronous) DR
A memory such as an AM may be used.

[0035]

As described above, according to the memory backup system of the present invention, the processing information storage medium is backed up by the backup power supply circuit when the power supply from the main power supply circuit is stopped, and the processing information storage medium is stored. In a memory backup system configured to write data to be processed to a medium to save the data being processed and to restore the saved data in the processing information storage medium when the power supply of the main power supply circuit is started, a backup power supply is provided together with the processing information storage medium. Data is exchanged between a management information storage medium that is backed up by a circuit and writes a data save record, which is a record of data saved, and a processing information storage medium and a management information storage medium that are supplied with power from a main power supply circuit. To process the data and store the management information at the start of power supply to the main power supply circuit. A processor is provided for checking the presence / absence of data evacuation recording and restoring the data saved in the processing information storage medium only when data evacuation recording is present, so that the reliability of backup data can be improved. . Therefore, it is possible to prevent data that is saved but loses reliability when an unexpected power failure occurs from being restored at the start of power supply.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a memory backup system according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the memory backup system.

FIG. 3 is a flowchart showing an operation of the memory backup system.

FIG. 4 is a diagram schematically showing a memory used in the memory backup system.

FIG. 5 is a block diagram showing a configuration of a memory backup system according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the memory backup system.

FIG. 7 is a block diagram showing a configuration of a memory backup system.

FIG. 8 is a block diagram showing a configuration of a memory backup system.

FIG. 9 is a block diagram illustrating a configuration of a memory backup system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 main power supply circuit 2 backup power supply circuit 3 main power supply monitoring circuit 4 processing information storage medium (processing information storage unit) 5 management information storage medium (management information storage unit) 6 processor (operation control unit) 7 in management information storage medium Memory 8 Switch (switch means) 10, 12 Memory backup system

Claims (6)

[Claims] When the supply of power supplied from a main power supply circuit is stopped, the main power supply circuit is switched to a backup power supply circuit, and power is supplied from the backup power supply circuit to the processing information storage unit to perform arithmetic processing. A memory backup system configured to write data in the processing information storage unit so as to save the data therein, and to restore the data saved in the processing information storage unit when power supply from the main power supply circuit is started. Power is supplied from the backup power supply circuit together with the processing information storage unit, and a management information storage unit that writes data saving information that is information obtained by saving the data, and power is supplied from the main power supply circuit. The data is exchanged between the processing information storage unit and the management information storage unit to perform data arithmetic processing, and from the main power supply circuit An operation control unit that checks the presence / absence of data saving information in the management information storage unit when the supply of the source is started, and restores the data saved in the processing information storage unit only when the data saving information exists. A memory backup system comprising: 2. The main power supply monitoring circuit according to claim 1, further comprising a main power supply monitoring circuit that senses that power supplied from the main power supply circuit is stopped within a predetermined time and reports the result to the arithmetic control unit. Memory backup system. 3. When the arithmetic control unit determines that there is no data to be saved in the processing information storage unit,
3. The memory backup system according to claim 1, further comprising switch means for stopping power supplied from the backup power supply circuit under the control of the arithmetic control unit. 4. The method according to claim 1, wherein the arithmetic control unit initializes the contents of the management information storage unit when confirming that there is no data save information in the management information storage unit. The memory backup system as described. 5. The memory backup system according to claim 1, wherein the management information storage unit has a 1-bit memory capacity for writing the data saving information. 6. The memory backup system according to claim 1, wherein said backup power supply circuit comprises a chargeable power supply.