JPH0795306B2 - Data storage device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a data storage device for storing data in a data memory of an IC card, for example.

(Prior Art) Recently, as a new portable data storage medium, an IC having a nonvolatile data memory and a control element such as a CPU
IC cards with built-in chips have been developed. Of this kind
The IC card accesses the built-in data memory by the built-in control element and inputs / outputs necessary data in response to a request from an external device. Further, the data memory is divided into a plurality of areas, and the target area is selectively accessed.

Conventionally, in such an IC card, as a data storage method for a data memory, data is arranged and stored in the order of access. With this method, when there are multiple data in the area and some arbitrary data is rewritten,
The length of the data before rewriting and that of the rewriting data had to match. This is because, for example, when the former data length is larger than the latter data length, a space of several bytes (or several words) is generated between the data to be rewritten and the next data, which is also small. In this case, it is necessary to shift the next data and subsequent data to secure a space for storing the rewrite data.

As a countermeasure against such a defect, a unit of data to be stored is divided into a plurality of pieces by the concept of word, and each divided data is stored by adding chain information to them, thereby making a word storage method. A method of giving a degree of freedom can be considered. However, in this case, when storing each divided data, if the method of sequentially adding chain information at the same time is stored, for example, power supply to the IC card due to disturbance etc. while all the data is stored If the data is read after the system is restored when the system is shut down and the system goes down, the chain information of the incomplete data stored earlier is cut off on the way, so there is a risk of reading the incorrect data.

(Problems to be Solved by the Invention) According to the present invention, when storing each divided data as described above, if chain information is also added at the same time, power is cut off during storage operation. This was done to solve the problem that if the system is down and the data is read after the system is restored, it may read out improper data. In this case, it is an object of the present invention to provide a data storage device in which the data in the middle of the storage becomes invalid, and there is no fear of reading the incorrect data even if the data is accessed after system recovery.

[Structure of the Invention] (Means for Solving Problems) A data storage device of the present invention is a data storage device for storing data in a storage medium, and a dividing means for dividing the data into a plurality of pieces. Means for storing each data divided by the dividing means in the storage medium, holding means for holding the storage position information of each divided data when storing the divided data, and each divided data Discriminating means for discriminating whether or not all are stored normally, and storage position information retained by the retaining means when the discriminating means discriminates that all of the divided data are normally stored. First addition means for adding storage position information of the next data following each data as chain information of each data, and all the divided data by the discrimination means are normally processed. When it is determined that the data has been stored, a second adding means is provided for adding identification information for identifying the first data among the respective data stored in the storage medium. There is.

(Function) When all the divided data are stored normally, the chain information is added to each of the divided data, so that the system is shut down due to power shutdown during the storage operation of each divided data. The data in the middle of storage is invalid because the chain information has not been added yet, and there is no possibility of reading the incorrect data even if the data is accessed after the system is restored.

(Example) Hereinafter, one example of the present invention will be described with reference to the drawings.

FIG. 9 shows a configuration example of a card handling device to which the IC card according to the present invention is applied and which is used as a terminal device such as a financial system or a shopping system. That is, this device enables the IC card 1 to be connected to the control unit 3 including a CPU via the card reader / writer 2, and the control unit 3 includes a keyboard 4 and a CR.
The T display device 5, the printer 6, and the floppy disk device 7 are connected to each other.

FIG. 8 shows an example of the configuration of the IC card 1, which includes a control element (eg, CPU) 11 as a control unit, a nonvolatile data memory 12 whose stored contents can be erased, a program memory 13, and a card reader / writer 2. It is composed of a contact part 14 for obtaining electrical contact with the IC card body, and the part within these broken lines (control element 11, data memory 12, program memory 13) is composed of one IC chip. It is buried inside. The program memory 13 is composed of a mask ROM, for example, and stores a control program for the control element 11 and the like. The data memory 12 is used to store various data and is composed of, for example, an EEPROM.

The data memory 12 is divided into a plurality of areas, for example, as shown in FIG. 5, and area numbers [00, 01, ...] Are given to the respective areas. Of these, in the area [00], the respective start addresses of the areas [01, 02, ...], the number of words dividing the area, and the number of bytes of the word are stored in correspondence with the area number. For example, the start address of area [01] is aaa address, the number of words dividing the area is Wa, and the number of bytes of word is Sa.
Corresponds to being a byte. Each area [01, 02, ...] Is divided into words having a fixed length (S bytes), and word numbers are given to these words. The word number is represented by hexadecimal (Hex) data in which the word located at the beginning of the area is set to "1" and sequentially increases by one.

FIG. 6 shows a state in which data is stored in a certain area. Chain information and identification information are added to each divided data. As the chain information, the word number of the word in which the data that follows is stored (that is, the storage position information of the divided data that continues thereafter) is used. The identification information defines whether it is the tip data of the chain,
For example, as shown in FIG. 7, it is composed of 1 byte (8 bits), of which the most significant bit (MSB) is used and the others are dummy. That is, if the MSB is “0”, it indicates that the data is the head data, and if the MSB is “1”, it indicates that it is other than that.

Next, the data storage system of the present invention having such a configuration will be described in detail. When writing data in the data memory 12, write command data having a format as shown in FIG. 3 is input from the card reader / writer 2 to the IC card 1. In the IC card 1, the control element 11 recognizes the write function code included in the write command data,
A writing process based on the flowchart shown in FIG. 1 is executed. That is, first, the total number of bytes of the write data is recognized based on the data length included in the input write command data, and then it is determined whether or not all of the write data can be stored in the access target area. If the data cannot be stored, the response data indicating a byte number error is output and the process ends. If the data can be stored, the write data contained in the input write command data is divided for each byte number of words, and sequentially written in the access target area of the data memory 12 in word units. At this time, the word number of the written word is set to the control element 11
Hold it in the internal RAM temporarily. Then, when it is recognized that all the divided data have been normally written, the word numbers held in the RAM are sequentially added as chain information from the last written word. In this case, the chain information of the last written word is set to "0" to indicate that it is the data at the end of the chain, and subsequent chain information is sequentially allocated from the word number last stored in the RAM. The MSB of the identification information of the word to which the chain information is assigned last
Is set to "0" to indicate that the data is the data at the end of the chain, the response data indicating the normal end is output, and the process ends.

More specifically, referring to FIG. 6, for example, write data is divided into W11, W12, W13, and sequentially written in each word of word numbers “1, 2, 3” in this order. At this time, R
Word numbers “1, 2, 3” are stored in AM in this order. Next, "0" is added to the chain information part of the data W13, "3" is added to the chain information part of the data W12, and "2" is added to the chain information part of the data W11. Then, the MSB of the identification information of the word W11 to which the chain information is added last is set to "0".

Next, when reading data from the data memory 12,
Read command data having a format as shown in the figure is input to the IC card 1 from the card reader / writer 2. I c
In the card 1, the control element 11 recognizes the read function code included in the read command data and executes the read process based on the flowchart shown in FIG. That is,
First, refer to the identification information section in the access target area, and
Find one with "0". If not found, the response data indicating that the data has not been written is output, and the process ends. If found, then counting from the beginning, it is checked whether or not there is a word having "0" or more from the read target data number included in the input read command data.
If not, the response data indicating that there is no data number to be read is output and the process ends. If so, it refers to the word whose MSB of the identification information that matches the data number to be read is "0", reads the data in that word, and writes it to RAM.
Hold temporarily. Next, the word having the following data is recognized by the corresponding chain information, the data in the word is read and added after the data previously held in the RAM. Then, this operation ends when the data of the word whose chain information is "0" is held in the RAM, the data held in the RAM is output, and the processing ends.

In this way, when storing each divided data, the chain information to be added to each data is temporarily stored, and only when all the divided data are normally stored, By adding the chain information that was temporarily stored, if the system goes down due to power shutdown during the storage operation of each divided data, the data being stored is invalid because the chain information has not been added yet. Therefore, there is no possibility of reading invalid data even if accessed after the system is restored.

In the above embodiment, the case where the data is stored in the data memory built in the IC card has been described, but the present invention is not limited to this, and the data is stored in another storage medium. The same can be applied to the case.

[Effects of the Invention] As described in detail above, according to the present invention, when the system goes down due to power interruption during the data storage operation, the data in the middle of the storage becomes invalid, and it is not appropriate to access after the system is restored. It is possible to provide a data storage device that has no risk of reading data.

[Brief description of drawings]

FIG. 1 is for explaining an embodiment of the present invention, and FIG. 1 is a flow chart for explaining a data writing process, and FIG.
FIG. 4 is a flow chart for explaining a data read process, FIG. 3 is a diagram showing a format example of write command data, FIG. 4 is a diagram showing a format example of read command data, and FIG. 5 is a diagram showing a configuration of a data memory. , FIG. 6 is a diagram showing a state in which data is stored in an area, FIG. 7 is a diagram showing a configuration of identification information, FIG. 8 is a block diagram showing a configuration of an IC card, and FIG. 9 is a configuration of a card handling device. It is a block diagram showing. 1 …… IC card, 2 …… Card reader / writer, 11 ……
Control element (control section), 12 ... Data memory (storage medium), 13 ... Program memory.

Claims (1)

[Claims] 1. A data storage device for storing data in a storage medium, comprising: dividing means for dividing the data into a plurality of pieces; and means for storing each data divided by the dividing means in the storage medium. When storing each of the divided data, a holding unit that holds the storage position information of each of the divided data, a determination unit that determines whether or not all of the divided data are normally stored, and this determination When it is determined by the means that all of the divided data have been normally stored, the storage position information of the next data following the respective data among the storage position information held by the holding means is set as a chain of the respective data. First addition means for adding information, and when the determination means determines that all of the divided data are normally stored, each data stored in the storage medium is stored. Data storage device, characterized by comprising a second adding means for adding identification information for identifying that the head of the data of the data is the head of the data.