Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
1999-11-23
2003-10-21
Sparks, Donald (Department: 2187)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
C711S165000, C711S170000
Reexamination Certificate
active
06636951
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data storage system, a data relocation method and a recording medium recording programs for executing the method, and more particularly to a technique for determining timing at which data stored in a storage unit is relocated, on the basis of the estimated load condition and/or current load condition.
2. Description of the Related Art
Continuous data, which meaningfully forms a file, may be scattered and stored in a data storage unit such as a magnetic disk unit, etc., on account of various factors in a data storage process. If continuous data is thus scattered and stored in the data storage unit, the problem arises that access efficiency when accessing the continuous data becomes poor.
In order to overcome the above problem, Unexamined Japanese Patent Application KOKAI Publication No. H7-200369 discloses a file system, which secures a blank storage area in order to relocate already-stored data not to be stored after being scattered and store continuous data in continuous areas. This Patent Application also discloses a method for securing continuous blank areas necessary in an operation for transferring a minimum-required file.
However, the above Patent Application does not disclose a method regarding timing at which data is relocated. Thus, in a case where to perform a process of data relocation when a processing load on the system is large, such as a case where to record and reproduce data by means of the method described in the Patent Application, a delay in a process for storing and reproducing data in a data storage device may possibly occur.
Particularly, in a case where to relocate a large volume of data, such as image data, etc. or to simultaneously process plural pieces of data, a delay in the data storage and reproduction process is likely to occur. In a case where to relocate a large volume of data into completely continuous areas, the number of read/write data pieces becomes extremely large. Therefore, the method described in the Patent Application entails a problem that the processing time necessary for data relocation is quite long.
In order to avoid such problems, it is suggested to relocate data when a load on the system is small. However, conventionally, an operator has to make sure whether the load on the system is small and instruct a process of data relocation when determined that the load on the system is small, resulting in so many tasks for the operator.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a data storage system, a data relocation method and a computer readable recording medium, which records programs for realizing the data storage system, all of which perform a process of data relocation with efficiency, by determining timing at which data is relocated based on a condition of the estimated load and/or the current load of the system.
In order to achieve the above object, according to the first aspect of the present invention, there is provided a data storage system comprising:
a data storage unit which has a data storage area divided into a plurality of blocks and which stores data in the data storage area in unit of blocks;
a main memory unit which has a program area and a data area; and
a processing unit which executes programs stored in the main memory unit, wherein the main memory unit
stores, in the data area, location information which represents in which block the data is located and stored in the data storage area of the data storage unit, and
stores, in the program area, a relocation program for relocating the data stored in each block of the data storage area in the data storage unit by referring to the location information which is stored in the data area, a load condition output program for outputting a load condition signal indicating a load on a system resource including the data storage unit and a control program for controlling whether to execute the relocation program in accordance with the output load condition signal, and
the processing unit
monitors the load condition signal which is output when executing the load condition signal output program, by executing the control program stored in the program area, and
executes the relocation program which is stored in the program area, based on a monitored result of the load condition signal.
In the above-described data storage system, a process for relocating the data stored in the data storage unit is executed in accordance with the load condition signal which indicates a load on a predetermined system resource. Therefore, in a time slot in which the load condition signal being monitored by the execution of the control program indicates that the load on the system resource is relatively small, the relocation program is executed so that the data stored in each block of the data storage unit can be relocated. As a result of the above, the data can be relocated with efficiency.
Different processing units may be prepared for respectively executing the control program, the load condition signal output program and the relocation program. In this case, an instruction for executing the load condition signal or the relocation program is transmitted as a message between the processing units. The main memory unit may be arranged in each processing unit. The system may include a plurality of processing units or main memory units, without departing from the scope of the present invention.
In the data storage system according to the first aspect of the invention,
the data storage unit may include an area for storing location information indicating in which block the data in the data storage area is located and stored. In this case,
the control program is one for transferring the location information stored in the data storage unit into the data area of the main memory unit, when executing the relocation program.
In the data storage system according to the first aspect of the invention, the main memory unit further stores operational setting requirements of the system in the data area. In this case,
the control program includes an operational setting requirement determination program for determining whether a operating condition of the system meets a stored operational setting requirement, and controls execution of the relocation program in accordance with a determined result processed by the operational setting requirement determination program.
In this case, if a time slot in which a noise may possibly annoy people is set as an operational setting requirement in order to restrict the data relocation program to perform the data relocation, for example, the data can be relocated at timing at which a load on the system resource is low, while taking effects on the environment into consideration.
The data storage system according to the first aspect of the invention may further comprise a relocation program storage unit which stores a plurality of relocation programs. In this case,.
the control program includes a relocation program selection program for selecting either one of relocation programs stored in the relocation program storage unit, when performing data relocation, and for starting the relocation program which has been selected by the relocation program selection program.
The relocation program storage unit may be realized by one or more than one data storage area included in the data storage unit.
The relocation program selection program may be used for selecting either one of relocation programs from the relocation program storage unit, in accordance with the location information store in the data area.
The relocation program selection program may be used for selecting either one of relocation programs from the relocation program storage unit, in accordance with the output load condition signal.
For example, in a case where the load on the system resource is relatively small so that the data relocation process can be performed for a long time, the data stored in the data storage unit can be relocated in such a way that identical data are located in continuous block of the
Chace C. P.
Sparks Donald
TDK Corporation
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