UPDATE LOG MANAGEMENT DEVICE AND AN UPDATE LOG MANAGEMENT METHOD DECREASING THE DATA AMOUNT OF TRANSMITTING AND THE UPDATE LOG AMOUNT OF HOLDING BASED ON THE RESULT OF COMPARING THE AMOUNT OF THE UPDATE LOG WITH THE AMOUNT OF THE UPDATED DATA PLUS THE LOG APPLIED INFORMATION
First Claim
1. An update log management device used in a data sharing system for maintaining and storing a data replicated among a plurality of devices connected in a network, comprising:
- a storage for recording a plurality of update logs wherein each one of the plurality of update logs shows an update of the data;
an extracting unit for extracting at least one of update logs from the plurality of update logs stored in the storage to transmit to another device to maintain the identical data among the plurality of devices;
a comparing unit for calculating data amount X which is an addition of data amount of the at least one of update logs for transmitting to the another device extracted by the extracting unit, and for calculating data amount Y which is an addition of data amount of the data itself plus data amount of log applied information indicating that the at least one of update logs is already applied to the data itself, and for comparing the data amount X and the data amount Y;
a transmitting unit for transmitting the data itself and the information indicating that the at least one of update logs is already applied to the data to the another device if the data amount X of the at least one of update logs exceeds the data amount Y (X>
Y), and for transmitting the at least one of update logs to the another device if the data amount X of the at least one of update logs does not exceed the data amount Y (X≦
Y); and
a deleting unit for deleting the at least one of update logs from the storage if X>
Y is true for all of the devices.
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Abstract
In the data sharing system which maintains the identical data among the all terminals, the update log of the updated data is deleted as early as possible. This way, the amount of data of the update logs to be recorded in a terminal can be made small. Instead of transmitting the update logs (for example, total 100 bytes) which are extracted by the extracting unit to the other terminals, an amount of data involved in transmitting is less by transmitting the data copy of the inspection data and the log applied information (for example, total 90 bytes). Because of this, the comparing unit decides that the update logs are the update logs that need not be transmitted to the other terminals. The transmitting unit transmits the data copy of the inspection data and the log applied information to the other terminals. The deleting unit decides that the update logs need not be transmitted to all the terminals, therefore, the update logs are deleted from the terminal.
156 Citations
10 Claims
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1. An update log management device used in a data sharing system for maintaining and storing a data replicated among a plurality of devices connected in a network, comprising:
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a storage for recording a plurality of update logs wherein each one of the plurality of update logs shows an update of the data;
an extracting unit for extracting at least one of update logs from the plurality of update logs stored in the storage to transmit to another device to maintain the identical data among the plurality of devices;
a comparing unit for calculating data amount X which is an addition of data amount of the at least one of update logs for transmitting to the another device extracted by the extracting unit, and for calculating data amount Y which is an addition of data amount of the data itself plus data amount of log applied information indicating that the at least one of update logs is already applied to the data itself, and for comparing the data amount X and the data amount Y;
a transmitting unit for transmitting the data itself and the information indicating that the at least one of update logs is already applied to the data to the another device if the data amount X of the at least one of update logs exceeds the data amount Y (X>
Y), and for transmitting the at least one of update logs to the another device if the data amount X of the at least one of update logs does not exceed the data amount Y (X≦
Y); and
a deleting unit for deleting the at least one of update logs from the storage if X>
Y is true for all of the devices.- View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An update log management device used in a data sharing system for maintaining and storing an identical data between a plurality of devices connected in a network, comprising steps of:
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recording a plurality of update logs, wherein each one of the plurality of update logs shows an update of the data;
extracting at least one of update logs from the plurality of update logs stored in the storage to transmit to another device to maintain the identical data among the plurality of devices;
calculating data amount X which is an addition of data amount of the at least one of update logs for transmitting to the another device extracted by the extracting unit, and for calculating data amount Y which is an addition of data amount of the data itself plus data amount of log applied information indicating that the at least one of update logs is already applied to the data itself, and for comparing the data amount X and the data amount Y;
transmitting the data itself and the information indicating that the at least one of update logs is already applied to the data to the another device if the data amount X of the at least one of update logs exceeds the data amount Y (X>
Y), and for transmitting the at least one of update logs to the another device if the data amount X of the at least one of update logs does not exceed the data amount Y (X≦
Y); and
deleting the at least one of update logs from the storage if X>
Y is true for all of the devices.
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9. An update log management device used in a data sharing system for maintaining and storing a data replicated among a plurality of devices connected in a network, comprising:
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a storage for recording a plurality of update logs wherein each one of the plurality of update logs shows an update of the data;
an extracting unit for extracting at least one of update logs from the plurality of update logs stored in the storage to transmit to another device to maintain the identical data among the plurality of devices;
a comparing unit for calculating data amount X which is an addition of data amount of the at least one of update logs for transmitting to the another device extracted by the extracting unit, and for calculating data amount Y which is an addition of data amount of the data itself plus data amount of an information indicating that the at least one of update logs is already applied to the data itself, and for comparing the data amount X and the data amount Y;
a transmitting unit for transmitting the data itself and the information indicating that the at least one of update logs is already applied to the data to the another device if the data amount X of the at least one of update logs exceeds the data amount Y (X>
Y), and for transmitting the at least one of update logs to the another device if the data amount X of the at least one of update logs does not exceed the data amount Y (X≦
Y) ; and
a deleting unit for deleting the at least one of update logs from the storage if the deleting unit decides that the at least one of update logs are not required to be transmitted to any of the other devices, or if X>
Y is true for all of the other devices that have not yet received the extracted at least one of update logs.
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10. An update log management device used in a data sharing system for maintaining and storing an identical data between a plurality of devices connected in a network, comprising steps of:
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recording a plurality of update logs, wherein each one of the plurality of update logs shows an update of the data;
extracting at least one of update logs from the plurality of update logs stored in the storage to transmit to another device to maintain the identical data among the plurality of devices;
calculating data amount X which is an addition of data amount of the at least one of update logs for transmitting to the another device extracted by the extracting unit, and for calculating data amount Y which is an addition of data amount of the data itself plus data amount of an information indicating that the at least one of update logs is already applied to the data itself, and for comparing the data amount X and the data amount Y;
transmitting the data itself and the information indicating that the at least one of update logs is already applied to the data to the another device if the data amount X of the at least one of update logs exceeds the data amount Y (X>
Y), and for transmitting the at least one of update logs to the another device if the data amount X of the at least one of update logs does not exceed the data amount Y (X≦
Y) ; and
deleting the at least one of update logs from the storage if the deleting unit decides that the at least one of update logs are not required to be transmitted to any of the other devices, or if X>
Y is true for all of the other devices that have not yet received the extracted at least one of update logs.
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Specification