JPH06168171A - Data backup system - Google Patents

Abstract

PURPOSE:To decrease the data amounts of backup. CONSTITUTION:Small area information and large area information is stored in a main storage part 12, and a magnetic disk 14. Whether or not data are changed in the magnetic disk 14 is stored for each area, in those small and large area information. Then, normally the backup is operated by using only the small area information in the main storage part 12. On the other hand, the large area information is always updated when the data in the magnetic disk 14 are changed. And also, the small area information is transferred in a prescribed interval to the magnetic disk 14. Then, at the time of an abnormal end, the backup is operated based on the small area information and the large area information. Thus, the two kinds of large and small information related with change is provided, so that an operating time at the time of the normal processing can be sufficiently shortened by the integration, and the efficient backup can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data backup system for transferring data in an external storage device such as a magnetic disk in a computer to another storage means.

[0002]

2. Description of the Related Art A computer has an external storage device such as a magnetic disk and stores various data therein.
Then, the data stored in the external storage device is changed by the execution of the business. However, the external storage device such as a magnetic disk may be lost due to some failure, and it is necessary to take measures against such a situation. Therefore, when the work is completed,
Data in a magnetic disk is transferred to another recording medium such as a magnetic tape and backed up.

However, depending on the type of business, the amount of data is large, and if all data is backed up, the time will be extremely long. Therefore, JP-A-64-
In Japanese Patent No. 8848, not all data is backed up, but only changed data is backed up. With this method, the amount of data transferred in one backup can be reduced, and efficient backup can be performed.

[0004]

However, in the above-mentioned prior art, the magnetic disk device has a control memory,
Data about the changed portion is stored in the control memory. An ordinary magnetic disk device does not have such a control memory and cannot be applied as it is. Furthermore, if the unit (area) for determining whether or not there has been a change is made finer, the determination as to whether or not there has been a change can be set more finely, so the amount of backup data can be reduced. However, when the area is set small, there is a problem that the capacity of the control memory becomes large.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a data backup system capable of efficiently backing up a changed portion.

[0006]

According to the present invention, there is provided a main storage unit for temporarily storing data, programs, etc. necessary for various data processing, and a data storage unit for storing data obtained by the data processing. A data backup system including a first external storage means and a second external storage means for backing up data stored in the first external storage means, the data backup system being provided on a main storage part, A small area information storage unit that divides the first external storage unit into predetermined small areas and stores small area information regarding whether or not the data within the range has been changed, and is provided on the first external storage unit. The first external storage means is divided into predetermined large areas, and a large area information storage section for storing large area information indicating whether or not the data within the range is changed is provided, and the small area information in the main storage section is provided. Memory When the data is available, the data in the small area in which the data in the first external storage means is changed based on the data in the small area control memory is transferred to the second external storage means, and the data in the main storage section is stored. When the data in the small area information storage unit is unavailable, the data in the first external storage unit is transferred to the second external storage unit based on the data in the large area information storage unit to back up the data. And

Further, the small area information stored in the small area information storage section is transferred to the first external storage means and stored at predetermined intervals, and the data in the small area information storage section in the main storage section is used. If it is impossible, the backup is performed based on both the large area information and the small area information stored in the first external storage means.

Further, the large area information includes information on the writing time, and when the small area information in the main memory is transferred to the first external storage means, the information on the transfer time is written together with the small area information. When the data in the small area information storage unit in the main storage unit is unavailable, data backup is performed based on the small area information and the large area information after the transfer of the small area information.

Further, the small area information includes data indicating whether or not all the data in the small area is changed to 0.

[0010]

Since the changed portion for each small area in the main storage portion is stored, it is possible to have fine-tuned changed data, and the processing time can be suppressed to the minimum increase. Then, since the change information for each large area is stored in the magnetic disk, the increase in the access time to the magnetic disk each time can be minimized. Then, the data is backed up based on the small area information, but at the time of abnormal termination, the backup based on the large area information can be performed, and the backup can also be performed at the time of abnormality.

Further, the small area information is written in the first external storage means at predetermined time intervals. Therefore, backup at the time of abnormal termination can be performed based on the small area information for each predetermined time. Therefore, it is possible to improve the efficiency of backup as compared with the backup performed only from the large area information. Since the small area information is not stored every time, the adverse effect on the normal processing can be minimized.

Further, since the transfer of the small area information to the magnetic disk and the large area information have a time stamp, the small area information and the large area information are preferably combined using this time stamp. You can

Further, when the rewritten data in the magnetic disk 14 is clear by 0 data, it can be identified and the amount of data to be backed up can be reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating the overall configuration of the embodiment, which includes a CPU 10 for controlling various processes and a C
A main storage unit 12 that is a volatile memory that stores data required when the PU 10 operates; a magnetic disk 14 that is an external storage device that stores data regarding processing results;
It has a magnetic tape 16 which is an external storage device for data backup. Then, in the storage unit 18, a business program 20, a backup program 22, a small area information recording program 24, an update information management program 2
6 and a small area information reproducing program 28 are stored.

Then, in the case of performing a normal business, the business program 20 is executed to process the data input from the input means (not shown) such as a keyboard, and the data about the processing result is stored in the magnetic disk 14. Write in. For example, in the case of a computer for medical office work, the registration process of a patient, the input of medical care data, the specification of a medical treatment fee statement, etc. are performed by executing a business program.

In the present embodiment, during the execution of such a business program, the data about the data change in the magnetic disk 14 is stored by a predetermined method, and the data in the magnetic disk 14 is recorded by the magnetic tape 16. Improve backup efficiency. Therefore, in the main memory 12,
Small area information and large area information are stored, and small area information and large area information are stored in the magnetic disk 14 in addition to normal information.

Here, the small area information and the large area information will be described.

Small Area Information Small area information is a relatively small area (for example, about 2 Kbytes) of data stored on the magnetic disk 14.
The information is stored for each of the small areas and stores information about whether or not the data has been changed. That is, when the entire area to be backed up on the magnetic disk 14 is divided into n small areas, the small area information is composed of n 2-bit small area data corresponding to each small area and one time stamp. To be done.

Here, in the 2-bit data corresponding to each small area, 1 bit is an identification as to whether or not the content of the change clears all to 0, and 00: no change 01: All are changed with 0. 10: Changed with others.

The time stamp represents a logical time managed in the system, and its initial state is 0. Then, when the small area information in the main storage unit 12 is transferred to the magnetic disk 14, 1 is added. Such small area information is stored in the main memory 12 and the magnetic disk 14.

Large Area Information The large area information is formed by dividing the area to be backed up on the magnetic disk 14 into large areas which are relatively large areas, and a time stamp corresponding to each large area. For example, when the area to be backed up on the magnetic disk 14 is divided into m large areas, m time stamps corresponding to these m large areas become large area data. This time stamp represents a logical time managed by the system as in the case described above, and the initial state is set to 0. In addition, in the large area,
Since the area is larger than the small area, there is a relation of n> m, and a plurality of small areas is represented by one large area.

Overall Operation of Backup FIG. 2 is a flow chart for explaining the overall operation of the backup processing in this apparatus. When the system is started up, first, a startup process (S1) is performed. This startup process is a process of reproducing the small area information in the main storage unit 12. That is, since the main storage unit 12 is a volatile memory, the stored contents are lost when the system ends. Therefore, this data is reproduced from the other storage medium (magnetic disk 14) by this startup processing. Next, during execution of the business program, small area information,
Manages large area information. By these processes, the small area information and the large area information in the main storage unit 12 are sequentially rewritten, and the large area information and the small area information are written to the magnetic disk 14 at an appropriate timing. Then, at the end of the processing in the system, the end processing is performed (S3). In this termination processing, the data in the magnetic disk 14 is backed up on the magnetic tape 16 based on the small area information and the large area information.

Reproduction of Small Area Information FIG. 3 is a flowchart showing the processing of reproducing the small area information in the start-up processing (S1). This processing is based on the small area information reproducing program 28 and is executed by the CPU 10
Is done by operating. First, when the system is started up, it is determined whether or not the immediately preceding system operation is normally completed (S11). This end information is written in the magnetic disk 14 in the end process described later.

When it is determined from the termination information that the termination is normal, the magnetic disk 14 is stored in the main storage unit 12.
The small area information stored in is read (S12). On the other hand, if it is an abnormal end, the small area information in the main storage unit 12 is reproduced (S14). The reproduction of the small area information is performed using the small area information and the large area information in the magnetic disk 14. That is, the magnetic disk 1
The small area information in 4 is read into the main storage unit 12, and the time stamp of this small area information is compared with the time stamp of each large area. Then, it is assumed that the data is updated for the large area having the same (not smaller) time stamp as the time stamp of the small area information. This is a magnetic disk 1 for small area information, as will be described later.
This is because only the large area data that has been changed after the copying to 4 has the same time stamp as the small area information. As a result, only when the small area information is written to the magnetic disk 14 after being transferred to the magnetic disk, it is determined that the data has been updated based on the large area information.

Then, for the large area determined to have been updated in this way, the small area information is updated on the assumption that all the small areas included in the large area have been updated.

When the small area information in the main memory 12 is reproduced in this way, this small area information is copied into the magnetic disk 14 (S15). And then,
The large area information in the main memory 12 and the magnetic disk 14 is cleared (S16). This is because the updated small area information is written on the magnetic disk 14, and thus the large area information is not necessary.

At this stage, abnormal termination is set in the termination information (S17). By setting the abnormal termination in advance in this way, unless the normal termination is set in the termination processing, it is determined that the abnormality is abnormal in S11 at the next system startup.

Update Management FIG. 4 is a flowchart showing the procedure of the update information management program during execution of the business program. That is, when the output to the magnetic disk occurs during the execution of the business program, it is determined whether or not the output position information and the output data are all 0, and the small area information and the large area information are rewritten. .

That is, it is determined whether or not the output is to the magnetic disk 14 (S21), and if the output is to the magnetic disk 14, the small area of interest based on the output position information Determine the small area data to write.
That is, it is determined from the content of the data that outputs the 2-bit small area data as described above (S22). here,
When a plurality of small areas are targeted, the small area data to be written may be different for each small area. In other words, it is clear that data of all 0s is written to a certain small area, but if normal data writing is performed to another small area, the content of data differs for each small area. Become. Then, the position of the corresponding small area data is determined from the output position of the data, and the contents and S2
The small area data determined in 2 are compared, and if the change is necessary, the small area data is changed (S23).

Next, the target large area is determined from the information on the output position (S24). In this case, a plurality of areas may be targeted depending on the writing position.
Then, the target large area data in the main storage unit 12 is read, and this time stamp is compared with the time stamp of the small area information (S25). If the time stamps in both information are different, the main storage unit 1
The time stamp of the small area information is copied to the large area data in 2 and rewritten (S26), and the rewritten large area data is copied to the corresponding large area data of the magnetic disk (S27). In this way, the rewritten large area data is obtained by copying the time stamp of the small area information in the main storage unit 12. Therefore, the large area data corresponding to the output position becomes the same as the time stamp of the small area information. Also, S2
In 5, if the time stamps are the same,
Since it is not necessary to rewrite the data, the data is not copied to the magnetic disk 14 in S26. Therefore, when the data in the same area is rewritten a plurality of times, the magnetic disk is accessed once, and the number of accesses can be reduced. In this way
By executing the update management program 26, the magnetic disk 1
When the contents of 4 are rewritten, the small area information and the large area information in the main storage unit 12 are rewritten, and the large area information in the magnetic disk 14 is rewritten as necessary. . The data is rewritten only when the small area information and the large area information in the main storage unit 12 also need to be rewritten. In addition, the time required for rewriting the data in the main storage unit 12 is very short, and the data in the magnetic disk 14 is only a change in the large area information. I'm not told. Therefore, the information can be rewritten with almost no influence on the execution of the normal business program.

Recording of Small Area Information FIG. 5 is a flow chart for explaining the operation for rewriting the small area information in the magnetic disk 14 which is regularly performed. This operation is based on the execution of the small area information recording program 28 in the CPU 10. First, it is determined whether it is the write timing for transferring the small area information to the magnetic disk (S31). This writing timing is set when a predetermined time (several minutes to about 10 minutes) has passed or at a predetermined timing in the end work for ending the system. When it is the write timing, 1 is added to the time stamp of the small area information in the main memory 12 (S32), and the small area information with 1 added to the time stamp is copied into the magnetic disk 14. Yes (S33).

In this way, each time the small area information in the main memory 12 is copied to the magnetic disk 14, 1 is added to the time stamps of the small area information in the main memory 12 and the magnetic disk 14. It will be.

On the other hand, each time stamp of the large area information in the magnetic disk 14 is updated by copying the small area information when the corresponding data is updated. Therefore,
The large area information time stamp has the same value only when it is updated after the small area information is copied,
Otherwise, the value is smaller than the time stamp of the small area information. Therefore, when reproducing the small area information at the time of abnormal termination in S13 of FIG. 3, the time stamps can be compared.

Backup Process FIG. 6 is a flow chart showing the operation of the backup process at the time of ending work. First, in this end process,
It is determined whether or not there is a backup command (S41).
In this case, the user is inquired whether or not to make a backup, and the answer is from the user. In a normal case, a question as to whether or not to back up is displayed on a display or the like, and YES or NO is input from the keyboard in response to this. If the backup is not performed, the end information is set to normal end (S45),
The process ends. On the other hand, when backing up,
Backup is performed according to the small area information in the main storage unit 12. That is, in the case of "all written with 0" from the small area information, the information showing the range of the area and the information showing "all written with 0" are backed up. On the other hand, in the case of “written in other area”, the information indicating the range of the area, the information indicating “written in other area” and the data on the disk device in the area are copied to the magnetic tape 16 together. To do. And
The normal end is set in the end information (S45), the small area information on the magnetic disk is cleared, and the process ends. Thus, according to this embodiment, the small area data is updated for the small area changed by the processing. The small area information is stored in the main storage unit 12. Therefore, even if the small area is made relatively small and detailed change information is provided, the access is very fast and there is no problem in other processing. On the other hand, in the case of abnormal termination, the small area information is reproduced from the small area information and the large area information stored in the magnetic disk 14. That is, the small area information in the magnetic disk 14 is compared with the time stamps in the large area information, and the small area information is reproduced by the large area information having the time stamp after recording the small area information. Therefore, the backup information can be reproduced while minimizing the use of recording a relatively rough change by the large area information. Then, at the time of backup, it is possible to add data of subsequent changes to the small area information reproduced in this way and perform backup based on this.

Therefore, even if the system ends abnormally, efficient backup can be performed. In particular, the large area information is sequentially written on the magnetic disk 14, but the small area information is performed at a predetermined frequency. Therefore, efficient backup can be performed while shortening the access time to the magnetic disk 14.

[0036]

As described above, according to the backup system of the present invention, since the changed portion for each small area in the main storage portion is stored, it is possible to have fine-tuned changed data and to reduce the processing time. Can be kept to a minimum increase. Then, since the change information for each large area is stored in the magnetic disk, the increase in the access time to the magnetic disk each time can be minimized. Then, the data is backed up based on the small area information, but at the time of abnormal termination, the backup based on the large area information can be performed, and the backup can also be performed at the time of abnormality.

Further, the small area information is written in the first external storage means at predetermined time intervals. Therefore, backup at the time of abnormal termination can be performed based on the small area information for each predetermined time. Therefore, it is possible to improve the efficiency of backup as compared with the backup performed only from the large area information. Since the small area information is not stored every time, the adverse effect on the normal processing can be minimized.

Since the small area information is transferred to the magnetic disk and the large area information has a time stamp, the small area information and the large area information are preferably combined using this time stamp. You can

Further, when the rewritten data in the magnetic disk 14 is clear by 0 data, this can be identified and the amount of data to be backed up can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment.

FIG. 2 is a flowchart illustrating the overall operation of processing.

FIG. 3 is a flowchart showing an operation of reproducing small area information.

FIG. 4 is a flowchart showing a procedure of update management.

FIG. 5 is a flowchart showing an operation of periodically storing small area information.

FIG. 6 is a flowchart showing a procedure of backup processing.

[Explanation of symbols]

 10 CPU 12 Main memory 14 Magnetic disk 16 Magnetic tape

Claims (4)

[Claims] 1. A main storage unit for temporarily storing data, programs, etc. necessary for various data processing, and a first external storage means for storing data obtained by the data processing, A second external storage means for backing up data stored in the first external storage means, and a data backup system including: a first external storage means provided on the main storage unit. A small area information storage unit, which is divided into predetermined small areas and stores small area information regarding whether or not data within the range is changed, and a first external storage provided on the first external storage means. A large area information storage unit that stores the large area information indicating whether or not the data within the range has been changed, and the data of the small area information storage unit in the main storage unit. Profit If possible, based on the data in the small area control memory, the data in the small area in which the data in the first external storage means is changed is transferred to the second external storage means, and the small area information in the main storage section is transferred. When the data in the storage unit is unavailable, the data in the first external storage unit is transferred to the second external storage unit based on the data in the large area information storage unit to back up the data. Backup system. 2. The system according to claim 1, wherein the small area information stored in the small area information storage section is transferred to a first external storage means and stored at predetermined intervals,
When the data in the small area information storage unit in the main storage unit is unavailable, backup is performed based on both the large area information and the small area information stored in the first external storage unit. Data backup system. 3. The system according to claim 2, wherein the large area information includes information about the writing time, and when the small area information in the main storage unit is transferred to the first external storage means, the transfer time is about the transfer time. Information is written together with the small area information, and when the data in the small area information storage section in the main storage section is unavailable, based on the small area information in the first external storage section and the large area information after the small area information transfer. A data backup system characterized by backing up data. 4. The data backup system according to claim 1, wherein the small area information includes data indicating whether or not all the data in the small area has been changed to 0.