JP2003122646A - Ic card and memory access control method for ic card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly solve the problem of mismatching of memory regions when a power source is interrupted during processing in the rewriting of data and garbage collection. SOLUTION: A memory managing part 3 manages a memory part 2 by using a leading unit for managing a logical address and a data unit for managing data rewriting. The leading unit is provided with the logical address of the data unit and the physical address of the leading unit of the data unit, and the data unit is provided with the physical address of the next data unit of its own unit and state information indicating whether its own units is in the middle of writing and real data. As for restoration processing, the progress situation of the processing is detected by making the logical address and physical address of the memory part correspond to each other by the leading unit and the data unit, and the overwriting processing of data is executed only to the data unit in the middle of writing the state information. Even when a power source is interrupted during the garbage collection processing, the garbage collection processing is executed only to the unit in the middle of rewriting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC card equipped with a flash memory and a memory access control method for the IC card.

[0002]

2. Description of the Related Art Since an IC card is generally highly secure and easy to carry, it is used as a medium for recording value information such as electronic money and electronic tickets. When the value information is processed in the card, a method of increasing the certainty of data writing by multiplexing the memory areas is taken as a countermeasure against the information failure due to power interruption during processing.

In addition, the demand for IC cards is increasing, and IC cards using flash memories of large capacity and high density are used.

The rewriting process of the flash memory is slow due to its characteristics. Therefore, as a memory management method for an IC card using a flash memory, the memory is accessed by a logical address, the rewriting process of the data on the logical memory is performed, the data is additionally written on the physical memory, and the correspondence relationship between the logical address and the physical address is then added. There is a method to speed up the process by changing the.

[0005]

However, the method of multiplexing the memory area is not suitable for the failure countermeasure in the IC card equipped with the flash memory because the flash memory is slow in the rewriting process.

Further, when a memory management system for separating a logical address and a physical address is adopted, it is not practical to multiplex the memory in a medium having a small memory capacity such as an IC card. Therefore, there is no memory management system that has both high speed and failure resistance in an IC card equipped with a flash memory.

The purpose of this method is to solve the above problems.
It is to provide a memory access control method for a C card and an IC card.

[0008]

SUMMARY OF THE INVENTION The present invention is an IC card using a flash memory, which manages a processing state and an update address at the time of rewriting data and garbage collection, so that when power is cut off during processing. , Is designed to eliminate inconsistencies in memory areas, and is characterized by the following configurations and methods.

(1) A flash memory is mounted, and when activated, it is detected whether or not the power supply was cut off during the previous processing, and if the power supply is cut off, the data in the memory section is restored. An IC card including means, comprising: a memory management unit that manages the memory unit on a unit-by-unit basis to perform data read / write and recovery processing against power interruption, and the unit is a head unit for logical address management. A data unit for managing data rewriting, the head unit has a format structure having a logical address of the data unit and a physical address of the head unit of the data unit, and the data unit is a data unit next to the own unit. Format, the physical address of the unit, status information of whether or not the own unit is writing, and a format with actual data In the recovery processing of the memory management unit, the head unit and the data unit detect the progress of the processing by associating the logical address and the physical address of the memory unit with each other, and the status information is written to the data unit. It is characterized by overwriting or discarding data.

(2) In the IC card described in (1) above, a garbage collection process for organizing a dust area on the memory generated at the time of rewriting the memory unit while managing the progress status of the process, and a garbage collection process A garbage collection management unit is provided for recovery processing against power interruption, and the memory unit displays garbage collection status information indicating whether or not garbage collection is in progress and unit status information indicating whether or not garbage collection processing has been completed for each logical address of each unit. Power recovery management information that is provided is provided, and the recovery processing by the garbage collection management unit performs garbage collection processing again for units whose unit status information has not been garbage collected when the garbage collection status information is being processed. It is characterized by

(3) A flash memory is mounted, and when activated, it is detected whether or not the power supply was cut off during the previous processing, and if the power supply is cut off, the data in the memory section is restored. A method for controlling memory access of an IC card having means, wherein data at a certain logical address is transferred to a physical memory space in order to detect whether or not power failure has occurred. The unit is composed of a combination of a next physical address part, which is a physical address indicating the unit, a state management part that holds the state of whether the unit is being rewritten, and an actual data part.

(4) In the memory access control method for an IC card described in (3) above, when writing data, the head unit corresponding to the logical address is searched and the physical address portion is set until the last unit. Trace the status of the new unit to the rewriting state, create a new unit that stores the data to be written to the actual data part, store the physical address of that unit in the physical address part of the last unit, and A feature is that the rewriting state of the state management unit is released.

(5) In the memory access control method for an IC card according to any one of (3) and (4) above, when reading data, the head unit corresponding to the logical address is searched and the status is With respect to the unit whose management unit is not in the rewriting state, the next physical address part is traced until the last unit, and the actual data part of the last unit is used as the data corresponding to the logical address.

(6) In the memory access control method for an IC card according to any one of the above (3) to (5), the units that become dust only for the number of times of update processing are sorted and the dust units In the garbage collection process that restores the non-existing state, the garbage collection state management unit that holds the state whether or not the garbage collection process is in progress, and the unit processing state management unit that holds the state whether processing is completed or not for each unit When the processing starts, the garbage collection processing status management unit of the power cut management means is set to the processing status, and only the head unit and the last tracked unit are connected to each head unit corresponding to the logical address. Generate a simple unit and process the garbage collection processing state management unit corresponding to that unit. When the processing to release the medium state is completed and all the units have been processed, erase all the garbage units, and perform the garbage collection by the procedure to release the in-process state of the garbage collection processing state management section of the power off management means. It is characterized by performing.

(7) In the memory access control method for an IC card according to any one of (3) to (6) above, whether there is a memory unit whose state management unit is rewriting when the IC card is activated. And the next physical address part of the unit being rewritten is not empty, the physical address of the last generated unit is written in the physical address part of the unit being rewritten.

(8) In the memory access control method for an IC card according to any one of (3) to (6) above, it is determined whether the garbage collection status section of the power-off management means is processing at card startup. However, if it is being processed, the unit status management unit creates a simple unit by connecting only the head unit and the last unit traced for units that have not completed processing, and the processing of the garbage collection processing status management unit corresponding to that unit. When the processing to release the medium state is completed and all the units have been processed, erase all the garbage units, and perform the garbage collection by the procedure to release the in-process state of the garbage collection processing state management section of the power off management means. It is characterized by performing.

[0017]

FIG. 1 is a block diagram of an IC card showing an embodiment of the present invention, mainly showing a memory access control block.

In FIG. 1, the control unit 1 controls the entire functions of the IC card and controls the exchange of control information and data with an external device.

The flash memory 2 has an area for storing value information such as electronic money and an area for storing power-off management information 2A for determining whether or not power-off during processing has occurred.

The memory management unit 3 has a data rewriting unit 3A and a data reading unit 3B for the memory 2, and a failure recovery processing unit 3C utilizing a memory management function for managing the correspondence between the logical memory space and the physical memory space. Have.

The garbage collection management unit 4 includes a garbage collection processing unit 4A that sorts out a dust area on the memory generated when information is rewritten to the memory 2 while managing the progress status of the processing, and a memory unit. And a means 4B for carrying out the failure recovery process. This failure recovery processing is executed with reference to the power-off management information 2A of the memory 2.

FIG. 2 shows a format of management data managed by the memory management unit 3 and the garbage collection management unit 3. A unit which is a management unit by the memory management unit 3 is divided into a head unit and a data unit.
The head unit is used for logical address management, and is composed of a logical address part for storing and managing the logical address of the data unit and a physical address part for storing and managing the physical address of the data unit.

The data unit includes a next physical address portion for storing a "next physical address" indicating a physical address of another unit when data added to the data of a certain unit exists as another unit, It is composed of a combination of a status management unit that holds the status of whether or not the local unit is rewriting and the actual data part of the local unit.

FIG. 3 shows a usage example of the memory 2. As the logical address management data, when the logical address part is # 1 and its head unit physical address part is set to% 1, the head data unit is allocated to the physical address% 1 and the physical address% 1 is rewritten. Management data (next physical address, status management data, and actual data) is written. When the physical address% 3 is written in the “next physical address part” of this data, the next data unit is allocated to the physical address% 3,
Data for data rewriting management is written in the physical address% 3. If NULL is written in the “next physical address part” of the physical address% 3 or if the value is a special value that is not a physical address, the latest unit in which the physical address% 3 is additionally written becomes the latest unit. In the logical address # 2 of the unit, NULL is written in the next physical address portion in the physical address% 2 of the head unit indicated by it, and therefore the unit does not have a write-once unit.

Next, as shown in FIG. 2, the format of the management data managed by the garbage collection management unit 4 with the power-off management information 2A indicates whether or not a failure such as power-off has occurred during garbage collection. And a state management unit for storing the state data indicating whether or not the power supply is cut off for each memory unit as a logical address.

The data read / rewrite processing and the recovery processing when a failure occurs in the IC card having the above configuration will be described in detail below.

FIG. 4 shows a data reading procedure by the data reading means 3A of the memory management unit 3. First, the head unit is searched based on the value of the logical address part of the logical address management data (S1), and the physical address is searched based on the value of the head unit physical address part (S2). next,
It is checked whether or not the value of the "next physical address part" of the retrieved head unit is NULL (S3), and if it is not NULL, the physical address indicated by the "next physical address part" is searched (S4). . This "next physical address part"
Check whether or not is NULL and search physical address N
By repeating the process until the occurrence of the ULL, the physical address of the latest additional write unit is searched. Finally, when the latest write-once unit is searched, the actual data is read from the actual data section and the process is terminated.

FIG. 5 shows a data writing procedure by the data rewriting unit 3B of the memory management unit 3. First, a new unit for writing data is created (S11).
Next, information indicating that data is being rewritten is held in the state management unit of the new unit (S12). Next, write the data in the data section of the new unit (S1
3). Next, the "next physical address part" of the current unit
Write the physical address of the new unit to (S1
4). Finally, the state in which data is being written in the state management unit of the new unit is released (S15).

FIG. 6 shows the recovery processing means 3 of the memory management unit 3.
A data recovery procedure by C for a failure occurring during data writing is shown. First, the process is started when the IC card is activated (power-on), and it is searched whether or not there is a unit in which data is being written (S21). If there is a unit in which data is being written, it is confirmed whether or not the content of the "next physical address part" of the unit is NULL (S22). In the case of NULL, the restoration process is not performed because the data has not been updated but the data has not been updated. If it is not NULL, the physical address part of the unit created last is overwritten on the physical address part of the current unit (S23). These processes are repeated for all units (S24).

Therefore, the recovery processing can be performed by overwriting only the unit in which the state management unit of the data unit is writing.

FIG. 7 shows a processing procedure of the processing means 4A of the garbage collection management section 4. First, the garbage collection status management unit of the power-off management information 2A is set to the processing status (S31).

Next, the following is repeated for the unit size of the memory area (S32 to S43).

(S32 to S37) The "next physical address" information of the unit is traced to retrieve the latest information.

(S38, S39) A new memory unit is created, and a set of a logical address corresponding to the head unit and a physical address of the new unit is registered.

(S40-S42) The data of the current unit is stored in the data section of the new unit, and the current unit is erased and the original set corresponding to the logical address is erased.

(S43) The state management unit corresponding to the current unit stores the state in which the unit has been updated.

(S44) The memory unit that is no longer referenced is deleted.

(S45) The state during the garbage collection process is canceled.

FIG. 8 shows a recovery processing procedure by the recovery processing means 4B when the power is cut off during the garbage collection processing shown in FIG. When turning on the IC card power,
The garbage collection status management unit of the power-off management information 2A determines whether or not the garbage collection processing is interrupted by checking whether the processing is in progress (S51). If the processing is interrupted, the unit status management unit of each unit It is checked whether or not the processing has been completed (S52), and only the units for which the processing has not been completed are processed S38 to S43 for each unit in FIG.
Is executed to bring the state management unit of the unit into the processing completed state (S53). When processing is completed for all units that have not been processed (S5)
4) The processing of the garbage collection status management unit is canceled and the recovery processing ends (S55).

Therefore, since the data rewriting process is mapped to the additional recording process, the data can be retained in the state before the rewriting, and by managing the processing state, the recovery process is simplified.

[0041]

As described above, the present invention has the following effects.

(1) It is possible to recover even if the information on the memory is inconsistent due to power failure during processing. The reason is that the memory rewriting can be mapped to the additional write process and the write process state can be appropriately managed.

(2) It is possible to recover even if the power is cut off during the garbage collection processing for deleting the dust on the memory generated by the additional recording processing. The reason is that state transitions can be defined in the garbage collection process and managed appropriately.

(3) The memory rewriting process can be made faster than the normal flash memory rewriting process. The reason is that the rewriting process is mapped to the additional recording process.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an IC card showing an embodiment of the present invention.

FIG. 2 is a format of management data in the embodiment.

FIG. 3 is a usage example of a memory in the embodiment.

FIG. 4 is a data read processing procedure of a memory management unit according to the embodiment.

FIG. 5 is a data write processing procedure of the memory management unit according to the embodiment.

FIG. 6 is a recovery processing procedure of the memory management unit according to the embodiment.

FIG. 7 shows a garbage collection processing procedure according to the embodiment.

FIG. 8 is a garbage collection recovery processing procedure according to the embodiment.

[Explanation of symbols]

1 ... Control unit 2 ... Memory section 2A ... Power-off management information 3 ... Memory management unit 3A ... Data rewriting means 3B ... Data reading means 3C ... Restoration processing means 4 ... Garbage collection management department 4A ... Garbage collection processing means 4B ... Recovery processing means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinichi Hirata             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Goromaru Hideki             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F-term (reference) 5B018 GA04 HA22 MA24 QA05                 5B035 AA02 BB09 CA29                 5B058 CA23 CA26 KA08 KA27                 5B060 AA10 MM09

Claims (8)

[Claims] 1. A means for mounting a flash memory, detecting whether or not power was cut off during the previous processing when activated, and recovering data in the memory unit when the power is cut off. An IC card comprising: a memory management unit that manages the memory unit in units to perform data reading / writing and recovery processing against power interruption, wherein the unit includes a head unit for logical address management and data. A data unit for rewriting management, the head unit has a format structure having a logical address of the data unit and a physical address of the head unit of the data unit, and the data unit is a data unit of the next data unit of the own unit. Format with physical address, status information of own unit writing or not, and actual data The recovery process of the memory management unit detects the progress of the process by associating the logical address and the physical address of the memory unit with the head unit and the data unit, and the status information is being written to the data unit being written. An IC card characterized by overwriting or discarding data. 2. The IC card according to claim 1, wherein a garbage collection process for organizing a dust area on the memory generated when the memory unit is rewritten while managing the progress status of the process, and a power-off during the garbage collection. A recovery unit is provided with a garbage collection management unit, and the memory unit has a garbage collection status information indicating whether or not garbage collection is in progress and a unit status information indicating whether or not garbage collection processing has been completed for each logical address of each unit. The disconnection management information is provided, and the recovery processing by the garbage collection management unit, when the garbage collection status information is being processed, performs the garbage collection processing again on the unit whose unit status information is not already garbage collected. Characteristic IC car De. 3. A means for mounting a flash memory, detecting whether or not there is a power failure during the previous processing when activated, and recovering the data in the memory section when the power failure has occurred. A method for controlling memory access of an IC card comprising: a method for detecting whether or not a power failure has occurred, in which data at a certain logical address is transferred to a physical memory space Memory access of an IC card characterized by using a unit composed of a next physical address part which is a physical address indicating a unit, a state management part for holding a state of whether the unit is being rewritten, and an actual data part Control method. 4. The memory access control method for an IC card according to claim 3, wherein when writing data, the head unit corresponding to the logical address is searched, and the physical address part is traced until the end unit. , The state management section of the new unit is being rewritten, a new unit that stores the data to be written to the actual data section is generated, the physical address of that unit is stored in the physical address section of the last unit, and the state management of the new unit is performed. A method for controlling memory access of an IC card, which is characterized by canceling a rewriting state of a section. 5. The IC card memory access control method according to claim 3, wherein when reading data, the head unit corresponding to the logical address is searched and rewritten by the state management unit. A memory access control method for an IC card, characterized in that, for a unit that is not in a medium state, the next physical address part is traced until it reaches the last unit, and the actual data part of the last unit is used as data corresponding to that logical address. . 6. The I according to any one of claims 3 to 5.
In the memory access control method of C card, the garbage collection process that sorts out the number of times of the updating process is sorted and the state without the garbage unit is restored. It has a garbage collection status management unit and a power-off management means that holds the unit processing status management unit that holds the status of processing completion or not for each unit, and the garbage collection processing status management of the power-off management means at the start of processing. A part is set to the processing status, and for each head unit corresponding to a logical address, a simple unit is created by connecting only the head unit and the last tracked unit, and the garbage collection processing status management unit corresponding to that unit is processing. Performs processing to release the status and all units are completed A memory access control method for an IC card, characterized in that all garbage units are erased, and then the garbage collection is performed by the procedure of releasing the processing status of the garbage collection processing status management unit of the power-off management means. 7. I according to any one of claims 3 to 6.
In the C card memory access control method, when the IC card is started, the state management unit searches for a memory unit that is being rewritten. If the next physical address of the unit that is being rewritten is not empty,
The physical address of the last generated unit is written in the physical address part of the unit being rewritten I
C card memory access control method. 8. I according to any one of claims 3 to 6.
In the C card memory access control method, it is determined at the time of card activation whether the garbage collection status section of the power-off management means is processing. If processing is in progress, the unit status management section traces the unit that has not completed processing to the head unit. Generate a simple unit by connecting only the last unit that was done, perform processing to release the processing status of the garbage collection processing status management unit corresponding to that unit, and when all the units have completed processing,
A memory access control method for an IC card, characterized in that garbage collection is performed in a procedure of erasing all the dust units and releasing the processing status of the garbage collection processing status management unit of the power-off management means.