Electrical computers and digital processing systems: memory – Storage accessing and control – Specific memory composition
Reexamination Certificate
1998-03-09
2002-07-02
Kim, Matthew (Department: 2186)
Electrical computers and digital processing systems: memory
Storage accessing and control
Specific memory composition
Reexamination Certificate
active
06415350
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a card-type storage medium comprising a memory built in a card-type casing, such as an IC card, and particularly, to a card-type storage medium in which destruction of files can be prevented even if an accident, such as a power interruption, occurs while data is written in the file.
2. Description of the Related Art
In recent years, IC cards have been used as media of electronic money, credit cards, ID cards, self-governing body cards and so on. In order to facilitate practical use of such IC cards, it is indispensable to establish technologies for protecting files in case power failures, errors, etc, occur while data is written in the files, as well as security technologies for preventing rewriting of files by unauthorized persons. For this purpose, various technologies have been conventionally proposed for the protection of files. These technologies are roughly divided into two types, as described below.
A first conventional technology is that a higher-class unit accessing an IC card (writing data in the file) recovery files inside the IC card. In this case, the higher-class unit keeps retaining a file to be overwritten on the IC card until the overwriting on the ID card of the file is completed, and, in case power failures or errors occur while the file is overwritten, recovers a file inside the IC card based on the file retained.
A second conventional technology is the one disclosed in Japanese Patent Application Laid-open No. Hei. 7-239928, in which a processor inside an IC card recovers a file based on recovery information prepared in advance. In this case, once a file is written inside the IC card (or overwritten), the processor inside the IC card generates recovery information consisting of data with identical composition as the file and stores the information inside the IC card. Then, when power failures or errors occur during renewal of the file, the processor copies the recovery information and overwrites it in the storage position of the original file.
However, the above mentioned conventional technologies, while accepting that an objective file is destroyed in case power failures or errors occur while data is written in the file, are used for the purpose of restoring the file after the destruction of the file. Therefore, various problems, as mentioned hereinafter, arise. This means that, according to the above-mentioned first conventional technology, since a normal file cannot exist inside an IC card until a file is recovered by a higher-class unit, the IC card becomes absolutely unavailable until the recovery. In addition, according to the above-mentioned second conventional technology, although data is recovered autonomically at the time when an IC card is supplied power again, since the recovery information must include data of the entire original file, the data volume to be retained by the IC card becomes enormous. For this reason, such problems as the delay of a response has become significant because of the increase of time required for a file search or the increase of time for preparing recovery information.
Further, in case a memory of an IC card is a flash memory, writing of data in a file retained by a certain storage area may be impossible due to the expired life of an element in the storage area. In such a case, backups have been conventionally executed in ways such that an application program of a higher-class unit rearranges the entire file by removing the storage area impossible to be written in or transfers the entire file to another IC card while the original IC card is treated as an invalid medium. For this reason, autonomical restoring by an IC card itself has been impossible, which has resulted in the increase of load for the higher-class unit.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above described circumstances, and therefore, a first object of the present invention is to provide a card-type storage medium which can prevent the destruction itself of a file in case power failures, errors, etc, occur while data is written in the file inside the storage medium; prevent the increase of data volume retained by the storage medium and improve a response to a higher-class unit.
A second object of the present invention is to provide a card-type storage medium in which autonomic rearrangement of a file becomes possible inside the storage medium even in case writing of data in a certain storage area becomes impossible due to the expired life of an element, etc.
According to a first aspect of the present invention, a card-type storage medium is provided for attaining the above mentioned first object. The card-type storage medium is detachably connected to a higher-class unit writing data into the media. The card-type storage medium is comprised of a first non-volatile storage area storing data, a second non-volatile storage area temporarily storing data input by the higher-class unit, and a writing element which writes the data stored in the second non-volatile storage area into the first non-volatile storage area when the storing of data into the second non-volatile storage area by the higher-class unit is completed.
According to the first aspect of the present invention, in a card-type storage medium composed as mentioned above, a second non-volatile storage area in which data input by the higher-class unit is stored temporarily is prepared as well as a first non-volatile storage area for storing data to be read by the higher-class unit. The writing element writes data stored in the second non-volatile storage area into the first non-volatile storage area after the data input by the higher-class unit is completely stored in the second non-volatile storage area. Therefore, even if a power interruption occurs while data is input to a card-type non-volatile storage medium by the higher-class unit, since data inside the second non-volatile storage area is merely destroyed and data actually stored in the first non-volatile storage area is never destroyed, the higher-class unit can refer to data stored in the first non-volatile storage area and the card can be continuously used as it is. Further, once data is completely stored normally in the second non-volatile storage area, even if a power interruption occurs the writing element can write the data stored inside the second non-volatile storage area into the first non-volatile storage area without requiring recovery processing by the higher-class unit. In addition, since the second non-volatile storage area need not retain all the data stored inside the first non-volatile memory area and may only store the data input by the higher-class unit, the data volume to be retained within the entire card-type non-volatile storage medium never becomes excessive. Moreover, once the higher-class unit inputs data into the second non-volatile storage area, the higher-class unit can take a next action immediately because it is exempted from the duty of recovering, etc, thereafter. This means that a response to the higher-class unit is improved.
A card-type storage medium may take, for example, the form of a PC card according to PCMCIA. A higher-class unit to which the card-type storage medium is connected detachably may be a computer which can write data into and read data from the card-type storage medium. As an example of such a computer, a computer used for a electronic money system is given. In addition, a higher-class unit may be a computer which can write data only in a card-type storage medium and a computer which can read data only from a card-type storage medium. Examples of such computers are computers for a credit card system and a self-governing body card system.
A first non-volatile storage area and a second non-volatile storage area may be established either on the same semiconductor device or on independent semiconductor devices. An element may be, for example, a flash memory or an E
2
ROM.
According to a second aspect of the present invention, in the above-described card-type storage
Chace C. P.
Fujitsu Limited
Kim Matthew
LandOfFree
Card-type storage medium does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Card-type storage medium, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Card-type storage medium will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2913495