Electrical computers and digital processing systems: memory – Storage accessing and control – Specific memory composition
Reexamination Certificate
1998-07-08
2001-12-11
Yoo, Do Hyun (Department: 2187)
Electrical computers and digital processing systems: memory
Storage accessing and control
Specific memory composition
C365S218000, C365S230030, C365S185290, C711S160000
Reexamination Certificate
active
06330633
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data processing method and a data processing apparatus. In particular, it relates to a data processing method and a data processing apparatus preferably used in, for example, an IC (Integrated Circuit) card or the like which performs transmitting and receiving of data.
2. Description of the Related Art
An IC card (smart card) has been developed which is expected to find application in electronic money systems or security systems.
The IC card incorporates a CPU (Central Processing Unit) for carrying out various kinds of processing and a memory for storing data or the like necessary for processing in which transmitting and receiving of data is carried out in a state where the IC card is brought into contact with a predetermined reader/writer (R/W).
On the other hand, there is an IC card of a batteryless type having no battery of its own, and power is supplied to the IC card from a R/W unit.
Further, there is an IC card which performs transmitting and receiving of data between the IC card and the R/W without physical contact by using electromagnetic waves, and obtains the necessary power from the electromagnetic waves.
However, when data is transmitted and received between an IC card and a R/W without physical contact, a problem known as memory corruption occurrs if sufficient power cannot be obtained when reception of electromagnetic waves fails while accessing a memory in the IC card, and a compatibility defect occurs in the data in the memory.
Further, when data is transmitted and received by bringing the IC card into contact with the R/W, in the case where a user can freely insert or withdraw the IC card to or from the R/W, memory corruption may again occur if the IC card is withdrawn from the R/W while accessing the memory.
When data is held in units (sector in the case of MS-DOS) for storing data as in, for example, the File Allocation Table (FAT) of the MS-DOS (Microsoft-Disc Operating System) (registered trademark), if memory corruption occurs in the FAT, all the positional information of the data (file) is lost and data cannot be accessed.
Accordingly when memory corruption occurs, in the worst case, the IC card cannot be used and therefore, some countermeasure is needed against this memory corruption.
One method of dealing with this problem would be to leave data from the immediately preceding occasion and two occasions before, and update the data from two occasions before to new data so that, even if the data could not be satisfactorily updated (when the data from two occasions before is damaged), the data from the immediately preceding occasion would still remain.
When this was done however, if for example the power supply failed while the data from two occasions before was being updated, an unstable situation arose where it was impossible to read the updated data as correct or incorrect or the immediately preceding data was read.
OBJECT AND SUMMARY OF THE INVENTION
The present invention, which was conceived in view of such a situation, provides a way of ensuring that stable reading of one data is always possible.
The information processing method and apparatus according to this invention is characterized in that a memory comprises a data region for storing data in block units and a first and a second region for storing plural block numbers which are numbers assigned to blocks in a data region, data is written to a block of the data region corresponding to a block number stored in one of the first and second regions, the block number of the block to which data was written is stored in the other of the first and second regions, and the data in the one of the first and second regions is erased.
The invention is further characterized in that the memory may comprise a data region for storing data in said block units, a pointer region for storing plural block numbers assigned to blocks in the data region, and a first and second region for storing plural block numbers assigned to blocks in the pointer region, data is written to a block number of a block in the pointer region corresponding to a block number stored in the one of the first and second regions, and to a corresponding block in the data region, the block number of the block to which data was written is stored in a block of the pointer region, the stored block number of the block in the pointer region is stored in the other of the first and second regions, and the data stored in the one of the first and second regions is erased.
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Kusakabe Susumu
Takada Masayuki
Moazzami Nasser
Sonnenschein Nath & Rosenthal
Sony Corporation
Yoo Do Hyun
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