JPH06161882A - Ic card - Google Patents

Abstract

PURPOSE:To accelerate the DRAW (direct read after write) processing of new data to a file. CONSTITUTION:Plural file recording areas are defined inside the EEPROM of the IC card. Six records (1)-(6) are recorded in a file F1. A leading address A of the file F1, entire capacity T and remaining capacity R are recorded in a directory concerning this file F1. An address B in the case of performing the DRAW of a new record (7) is calculated by (leading address A + entire capacity T - remaining capacity R). When the DRAW of the record (7) is performed, the remaining capacity R is updated. Written capacity W can be recorded in place of recording the entire capacity T and the remaining capacity R. In this case, the address B is calculated by (leading address A + written capacity W).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC card, especially an IC card.
The present invention relates to a method of writing data to an EEPROM in a card.

[0002]

2. Description of the Related Art IC cards are in the spotlight as new information recording media replacing magnetic cards. This IC card can record a large amount of information as compared with a magnetic card, and has high security. Currently popular IC cards include RAM, ROM, and E.
It contains three types of EPROM memories and a CPU for accessing the memories. Usually this I
Since the C card itself does not have a built-in power supply,
It operates by receiving power supply from a reader / writer having a function of writing and reading data to and from the C card. Therefore, if the reader / writer is disconnected, the power supply is interrupted and the data in the RAM is lost. On the other hand, the data in the EEPROM is saved as it is even if the power supply is interrupted. Therefore, the data that needs to be stored is recorded in the EEPROM.

In order to systematically record data in the IC card, it is common to define a plurality of file recording areas in the EEPROM and classify the data for each file for recording. Also, to access each file,
A directory having information such as the head address and attributes of the file is created, and this directory is also recorded in the EEPROM. When adding new data to a specific file, rewriting data, reading data, etc., first read the directory for this file, and based on the information recorded in this directory. The file recording area is accessed.

[0004]

As described above, the data to be stored in the IC card is classified into a plurality of files and recorded. Moreover, one file is composed of a plurality of records. Here, when a new record is additionally written for a certain file, this new record is normally written in the address area following the last record written in the corresponding file recording area. Therefore, before adding a new record,
It is necessary to perform a process of searching an address area for additional writing. Such a search process has a problem that it takes a considerable amount of time because it is necessary to confirm the recorded contents of the corresponding file recording area byte by byte.

Therefore, an object of the present invention is to provide an IC card which can speed up the process of additionally writing new data to a file.

[0006]

[Means for Solving the Problems]

(1) The first invention of the present application is a memory for recording data,
A CPU having a function of accessing this memory is built-in, a plurality of file recording areas are defined in the memory, data is classified and recorded for each file, and at least the start address of each file recording area is set. In an IC card in which a directory having the information shown is prepared for each file, information indicating the total capacity of the corresponding file recording area and the remaining capacity of this file recording area is recorded in the directory, and the total capacity is recorded. And a function to calculate an address to write new data based on the remaining amount.

(2) The second invention of the present application is a memory for recording data, and a C having a function of accessing this memory.
It has a built-in PU and defines a plurality of file recording areas in the memory so that data can be classified and recorded for each file, and each file can be a directory having at least information indicating the start address of each file recording area. Information indicating the written capacity of the corresponding file recording area is recorded in the directory in the IC card prepared for each, and the address to write new data is calculated based on the written capacity. It has a function.

[0008]

[Operation] In the IC card according to the first invention of the present application, the total capacity and the remaining amount of the file recording area indicated by the directory are recorded in the directory. Therefore, when adding new data to the file, start address +
By performing the calculation of (total capacity-remaining amount), the write address of the data to be additionally written can be obtained. Similarly, in the IC card according to the second aspect of the present invention, the written capacity of the file recording area indicated by the directory is recorded in the directory. Therefore, when new data is additionally written to the file, the write address of the data to be additionally written can be obtained by calculating the start address + the written capacity. In either case,
If the remaining amount or the written capacity is updated after the additional writing of data, the address can be calculated by the same method at the next additional writing.

[0009]

The present invention will be described below based on illustrated embodiments. FIG. 1 is a block diagram showing an overall configuration of an IC card 10 currently generally used and a reader / writer 20 used for the IC card 10. The main components of the IC card 10 are a CPU 11, a ROM 12, a RAM 13, and an EEPR.
OM14. The CPU 11 communicates with the reader / writer 20 via an interface (not shown) and also performs a process of accessing each of the memories 12, 13, and 14. When the IC card 10 is inserted into the housing of the reader / writer 20, the connection terminal on the IC card 10 side and the reader / writer 2
The 0-side connection terminal comes into contact, and the two are electrically connected. That is, G that establishes a common ground potential between them
ND line, VCC line for supplying power from the reader / writer to the IC card, CLK line for supplying clock, and RST for supplying reset signal
A line and an I / O line for bidirectionally transmitting data are secured. Data transmission between the two is alternately performed in one direction through the I / O line.

The CPU 11 executes various processes based on the programs prepared in the ROM 12. RAM1
3 is used as a work area for the CPU 11 to perform various processes. Further, the EEPROM 14 is an electrically rewritable memory, and can store data even when the IC card 10 is separated from the reader / writer 20 and the power supply is cut off. Therefore, the user data to be stored in the IC card 10 is stored in the reader / writer 20 in the connected state.
It is necessary to write it in the EEPROM 14.

Data is recorded in the EEPROM 14 for each file. For example, in the example shown in FIG. 2, three files F1 to F1 are stored in the EEPROM 14.
The file recording area for F3 is defined, and the data is classified and recorded in any of these three files. A directory is prepared for each file in the same EEPROM 14. Figure 2
In the example shown in (1), directories D1 to D3 are prepared for the files F1 to F3, respectively. Various information about the corresponding file is recorded in this directory. Specifically, the start address of the corresponding file, the attribute of the file, and the like are recorded. When accessing a specific file, first, the contents of the corresponding directory are read out, and the target file is accessed based on the contents of this directory.

Next, the data structure in each file will be described. FIG. 3 is a memory map showing the data structure in the file F1. The memory area shown in FIG. 3 corresponds to a recording area defined in advance for the file F1, and the data in the file F1 is always written somewhere in this recording area. The data written in the file constitutes a unit called a record. In the example shown in FIG. 3, six records to have already been written. In order to efficiently write the records, each record is sequentially written from the head address A.
Then, in the directory D1, the start address A
Is written. In FIG. 3, “FFFFFF ...
... "and the hexadecimal data" FF "are listed, indicating an area where data is not yet written.

Now, as shown in FIG. 3, it is considered that a seventh record is newly added in a state where six records are written. In this case, it can be recognized from the information in the directory D1 that the file in which the record is to be written starts from the head address A. However, the writing process cannot be actually performed unless the specific address B to which the record is to be written is obtained. Therefore, in the conventional IC card, the address B is obtained by performing a process of searching the recording area of the file F1. Specifically, the data is searched byte by byte in descending order from the last address C of this recording area to the head address A, and the enumeration of the data “FF” is followed, and the address B The search process for searching for is being performed. As described above, such a search process has a problem that it takes a long processing time.

In the IC card according to the first embodiment of the present application,
As shown in FIG. 4, the file F is stored in the directory D1.
This problem is solved by writing the information indicating the head address A, the total capacity T, and the remaining amount R regarding 1. If such information is written in the directory, the search process for obtaining the address B becomes unnecessary. That is, the address B can be obtained only by performing the calculation of (start address A + total capacity T−remaining amount R). Thus, when the process of writing the new record from the address B is completed, the process of rewriting the remaining amount R of the directory D1 is performed. That is, the remaining amount R is updated to a value reduced by the length of the record. In this way, when performing a process of additionally writing a new record in the future, the address value to be written can be calculated based on the updated remaining amount R.

Further, in the IC card according to the second embodiment of the present application, as shown in FIG. 5, information indicating the head address A, the total capacity T, and the written capacity W of the file F1 is written in the directory D1. This solves this problem. If such information is written in the directory, the search process for obtaining the address B becomes unnecessary. That is, the address B is (start address A
It can be obtained by simply performing the operation of (+ written capacity W). Thus, when the process of writing the new record from the address B is completed, the process of rewriting the written capacity W of the directory D1 is performed. That is, the written capacity W is updated to a value increased by the length of the record. By doing so, when performing a process of additionally writing a new record in the future, the address value to be written can be calculated based on the updated written capacity W. In the second embodiment, since the total capacity T is not necessary for calculating the address value, it is not always necessary to write the total capacity T in the directory, but the size of the file recording area is known. For convenience, it is preferable to write the total capacity T in the directory.

Although the present invention has been described above based on the illustrated embodiment, the present invention is not limited to this embodiment and can be implemented in various modes other than this. For example, in the above-described embodiment, in each file recording area, the records are sequentially written from the head address A in the direction of increasing addresses, but conversely, the records may be sequentially written in the direction of decreasing addresses.

[0017]

As described above, according to the IC card of the present invention, the total capacity and the remaining capacity of the file recording area indicated by the directory, or the written capacity is recorded in the directory. Based on these pieces of information, the write address of the data to be additionally written can be obtained, and the additional write processing speed can be increased.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a general IC card and a reader / writer.

FIG. 2 is a diagram showing an example of a recording structure of files and directories in a general IC card.

FIG. 3 is a memory map showing an example of a data structure in a file in a general IC card.

FIG. 4 is a diagram showing a directory structure in the IC card according to the first invention of the present application.

FIG. 5 is a diagram showing a directory structure in an IC card according to a second invention of the present application.

[Explanation of symbols]

 10 ... IC card 11 ... CPU 12 ... ROM 13 ... RAM 14 ... EEPROM 20 ... Reader / writer A, B, C ... EEPROM address value D1 to D3 ... Directory F1 to F3 ... File T ... Total capacity of file recording area W ... Written capacity of file recording area R ... Remaining amount of file recording area ~ ... Record

Claims (2)

[Claims] 1. A memory for recording data and a CPU having a function of accessing the memory are built-in, a plurality of file recording areas are defined in the memory, and the data is classified and recorded for each file. In the IC card in which a directory having information indicating at least the head address of each file recording area is prepared for each file, the total capacity of the corresponding file recording area and the remaining capacity of this file recording area are stored in the directory. An IC card having a function of recording information indicating an amount and calculating an address to write new data based on the total capacity and the remaining amount. 2. A memory for recording data and a CPU having a function of accessing this memory are built-in, a plurality of file recording areas are defined in the memory, and the data is classified and recorded for each file. In such an IC card in which a directory having information indicating at least the head address of each file recording area is prepared for each file, information indicating the written capacity of the corresponding file recording area is recorded in the directory. The IC card is provided with a function of calculating an address at which new data should be written based on the written capacity.