Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
1998-07-28
2001-03-27
Ho, Ruay Lian (Department: 2172)
Data processing: database and file management or data structures
Database design
Data structure types
Reexamination Certificate
active
06209001
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data back-up operation of an information processing apparatus, and more particularly to a data backup operation into a storage unit in an information processing apparatus.
2. Description of the Related Art
A conventional example of a data back-up system of an information processor is described in Japanese Laid Open Patent Application (JP-A-Heisei 4-311219). In the conventional example, 2 input/output (I/O) interfaces are provided for each of large capacity storage units to back up data stored in the large capacity storage unit into a back-up unit. As is known in the art, a large capacity storage unit typically refers to mass storage devices such as an array of disks or other large capacity storage devices that generally have slower access times than main memory devices and are used for storing information that is not constantly being addressed. By using one of the I/O interfaces, a normal data transfer is performed between a main memory and the large capacity storage unit, and by using the other, the data back-up is performed from the large capacity storage unit into the back-up unit.
FIG. 1
is a block diagram illustrating the structure of the data back-up system which is proposed in the above Japanese Laid Open Patent Application (JP-A-Heisei 4-311219). Referring to
FIG. 1
, the data back-up system is composed of a data bus
51
, a control bus
52
, a central processing unit (CPU)
53
, a main memory
54
, a main disk control mechanism
55
, a back-up disk control mechanism
56
, N magnetic disk units
70
X (
701
to
70
N) each having two I/O interfaces, a back-up RAM
60
as a back-up file memory, and a back-up unit
61
. In
FIG. 1
,
80
X (X=1, 2, . . . , N) is a main I/O interface and
90
X (X=1, 2, . . . , N) is a back-up I/O interface.
However, the conventional back-up system has the following problems.
That is, the first problem is in that if the content of the storage unit
70
X is updated while the back-up operation is performed, there is possibility that it becomes not possible to take the coincidence between the updated content of the storage unit
70
X and the backed-up content. In such a case, the back-up operation needs to be immediately stopped such that the back-up operation needs to be re-started. This is because the single storage unit
70
X can be accessed through the two I/O interfaces in the above conventional back-up apparatus. Accordingly, when one storage unit is accessed so that a plurality of portions of the content of the storage unit is updated, there is possibility that a part of the content of the storage unit is updated well sum of the content is not updated.
The second problem is in that a complicated mechanism is needed for the back-up operation. This is because each of the plurality of storage units needs to have the two I/O interfaces.
SUMMARY OF THE INVENTION
The present invention is accomplished in view of the above problems. Therefore, an object of the present invention is to provide a back-up system which can perform a back-up operation of the storage content of a storage unit at an optional time.
Another object of the present invention is to provide a back-up system in which the operation of the whole system is not limited because of a back-up operation.
Still another object of the present invention is to provide a back-up system in which the storage content of a storage unit always coincides with a backed-up content.
Yet still another object of the present invention is to provide a back-up system which has a simple structure with high reliability and operability.
In order to achieve an aspect of the present invention, a back-up system includes a main storage unit, a buffer storage unit, an auxiliary storage unit, and a back-up storage unit. A control unit controls the main storage unit and the auxiliary storage unit in a normal operation such that a first data is written in the main storage unit and the auxiliary storage unit. Also, the control unit controls the auxiliary storage unit and the back-up storage unit in a back-up operation such that the first data stored in the auxiliary storage unit is transferred to the back-up storage unit, and controls the main storage unit, the buffer storage unit and the auxiliary storage unit during the back-up operation such that a second data is stored in the main storage unit and the buffer storage unit but is not stored in the auxiliary storage unit. Also, the control unit controls the buffer storage unit and the auxiliary storage unit after the back-up operation such that the second data is transferred from the buffer storage to the auxiliary storage unit.
In order to achieve another aspect of the present invention, a back-up system includes a main storage unit, an auxiliary storage unit for storing a same data as that stored in the main storage unit, and a back-up storage unit. A control unit sets a back-up mode in response to a back-up start instruction, and controls the auxiliary storage unit in the back-up mode such that the auxiliary storage unit does not store any data. Also, the control unit controls the auxiliary storage unit and the back-up storage unit in the back-up mode during the back-up mode such that a first data stored in the auxiliary storage unit is transferred to the back-up storage unit, and resets the back-up mode. In addition, the back-up system may further include a buffer storage unit. In this case, the control unit controls the buffer storage unit to store a second data during the back-up mode when the second data is stored in the main storage unit, and controls the buffer storage unit and the auxiliary storage unit such that the second data is transferred from the buffer storage to the auxiliary storage unit when the back-up mode is reset.
In order to achieve still another aspect of the present invention, a back-up system includes a main storage unit, an auxiliary storage unit, and a back-up storage unit. A control unit controls the main storage unit and the auxiliary storage unit to store a first data in a normal operation, and controls the auxiliary storage unit and the back-up storage unit in a back-up operation such that the first data is transferred from the auxiliary storage unit to the back-up storage unit.
When the back-up system further includes a selector, the control unit controls the selector such that the first data is supplied to the auxiliary storage unit in the normal operation. When the back-up system further includes a buffer storage unit, the control unit controls the selector during the back-up operation such that a second data is supplied to the buffer storage unit when the second data is stored in the main storage unit. Also, the control unit controls the buffer storage unit and the auxiliary storage unit after the back-up operation such that the second data is transferred from the buffer storage unit to the auxiliary storage unit.
In order to achieve yet still another aspect of the present invention, a method of backing up a first data stored in a main memory into a back-up storage unit in an information processing system, includes the steps of:
storing a first data in an auxiliary storage unit during a normal operation when the first data is stored in a main storage unit,
inhibiting update of a storage content of the auxiliary storage unit in a back-up operation,
transferring the first data from the auxiliary storage unit to the back-up storage unit during the back-up operation, and
storing a second data in a buffer storage unit during the back-up operation when the second data is stored in the main storage unit, and
transferring the second data from the buffer storage unit to the auxiliary storage unit after the back-up operation.
In addition, in order to achieve an aspect of the present invention, a method of backing up a first data stored in a main memory into a back-up storage unit in an information processing system, includes the steps of:
storing a first data in a main storage unit and an auxiliary storage unit in a normal operation,
Ho Ruay Lian
NEC Corporation
Ostrolenk Faber Gerb & Soffen, LLP
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