JP2011034125A - Information processing method, information processor, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the time required for writing data, while handling memory corruption. <P>SOLUTION: A physical block number of all updating blocks in a data area is referred to be recognized as updating blocks in the data area, in step S34. All the updating blocks recognized as the updating blocks in the data area are erased all together in step S35. Processing time is shortened as compared with the case where the data is erased every time the data are written in the physical block. The present invention is applicable when writing the data into a recording medium, such as an EEPROM, where the data recorded in a recording area cannot be overwritten, and the new data are recorded after erasing the data already recorded. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an information processing method, an information processing apparatus, and a program, and in particular, data that has already been recorded in a recording area, such as EEPROM (electrically erasable programmable ROM), cannot be overwritten and has already been recorded. The present invention relates to an information processing method, an information processing apparatus, and a program suitable for recording data on a recording medium on which new data must be recorded after erasing the recorded data.

  Currently, contactless communication systems represented by FeliCa (trademark) are widely put into practical use.

  In an existing contactless communication system, a reader / writer (hereinafter abbreviated as R / W) communicates data with an IC card in a contactless manner according to control from a controller.

  This IC card has a built-in recording medium. For example, when a non-contact communication system is used in an electronic money system, information such as a prepaid money balance and purchase history is recorded and used in a station ticket gate system. In such a case, commuter pass information and boarding / exiting history information are recorded.

  As a recording medium built in the IC card, an EEPROM of a nonvolatile memory is often applied. As a characteristic of the EEPROM, when data is written, the data already recorded in the recording area cannot be overwritten, and new data must be recorded after erasing the already recorded data.

  By the way, there is a battery-less IC card that does not have a battery by itself, and such a battery-less IC card is driven by electromagnetic induction using electromagnetic waves radiated from the R / W. It has been made to be able to get power.

  However, when data is communicated between the IC card and the R / W in a non-contact manner, sufficient drive power is acquired if the electromagnetic wave reception state becomes poor while accessing the memory built in the IC card. And the data consistency in the memory may be defective. Hereinafter, a state in which a defect occurs in data consistency in the memory is referred to as a memory corruption.

  In addition to non-contact communication, when the user can freely insert / remove the IC card into / from the R / W even when the IC card is in contact with the R / W to transmit / receive data. If the IC card is removed from the R / W while accessing the memory, memory corruption may occur.

  Thus, various countermeasures for memory corruption have been proposed.

  For example, the applicant records the previous communication result data and the previous communication result data in the IC card, and updates the older data (previous data) with the current communication result data. Thus, even when the update process cannot be performed satisfactorily (when old data is destroyed), a method is proposed in which the previous valid data remains (see Patent Document 1). ).

Japanese Patent Laid-Open No. 11-25003

  According to the method of Patent Document 1, even if the power is shut off while updating the older data, at least one of the previous data or the previous data can be stably read.

  However, the method of Patent Document 1 leaves room for further reduction in the time required for data write processing.

  The present invention has been made in view of such a situation, and when data is written, the data already recorded in the recording area cannot be overwritten, and the already recorded data is erased. It is intended to reduce the time required for data writing processing on a recording medium such as EEPROM in which new data must be recorded.

  An information processing method according to one aspect of the present invention is an information processing method for an information processing apparatus using a recording medium on which information is recorded in units of predetermined blocks. The recording medium includes a plurality of blocks. A data area for storing data in units, a pointer area for storing a plurality of block numbers assigned to each block of the data area, and a target block of the data area for storing data before update The first block number indicating the block number of the pointer area, the second block number indicating the block number of the pointer area indicating the update block of the data area in which the updated data is stored, and the newness of the stored contents And a first area for storing the latest information on the information stored in the first area by the information processing apparatus. A first erasing step for collectively erasing data stored in all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number; A write step of writing updated data into at least a part of all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number, A first storage step of storing the block number of the block of the data area in which the updated data is written in a block corresponding to the first block number of the pointer area; and storing the block number of the data area A second storage step of storing the first block number of the pointer area in the first area; No.

  The recording medium further includes a first block number indicating a block number of the pointer area indicating the target block of the data area in which data before update is stored, and the data area in which data after update is stored A second block number indicating the block number of the pointer area indicating the updated block, and a second area for storing the latest information on the freshness of the stored contents. In the erasing step, the block area corresponding to the block number stored in the pointer area corresponding to the second block number stored in one of the first or second area selected based on the latest information The data stored in all the update blocks in the data area is erased at once, and the second storage step is a block of the data area. A first block number of the pointer region in which to store the metric number, can be made to be stored in the other of said first or second regions. In the information processing method, after the second storing step, the first and second block numbers stored in the one of the first and second areas and the latest information are deleted. An erasing step can further be included.

  The processing of the first erasing step and the processing of the writing step can be executed in response to a write command.

  The processing of the writing step is executed according to a writing command, and the processing of the first erasing step is executed at a predetermined timing preceding the processing of the writing step regardless of the presence or absence of the writing command. can do.

  An information processing apparatus according to an aspect of the present invention is an information processing apparatus that records information on a recording medium on which information is recorded in a predetermined block unit. The recording medium includes a plurality of blocks, and the block A data area for storing data in units, a pointer area for storing a plurality of block numbers assigned to each block of the data area, and a target block of the data area for storing data before update The first block number indicating the block number of the pointer area, the second block number indicating the block number of the pointer area indicating the update block of the data area in which the updated data is stored, and the newness of the stored contents And the second block number stored in the first area. First erasure means for collectively erasing data stored in all the update blocks of the data area corresponding to a block number stored in the corresponding pointer area; Write means for writing the updated data in at least a part of all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the block number of 2, and the updated data First storage means for storing the block number of the block of the written data area in the block corresponding to the first block number of the pointer area, and the first of the pointer area storing the block number of the data area Second storage means for storing the block number in the first area.

  The program of the present invention is a program for controlling an information processing apparatus using a recording medium in which information is recorded in predetermined block units, and the recording medium is composed of a plurality of blocks, and data in the block units. A data area for storing data, a pointer area for storing a plurality of block numbers assigned to each block of the data area, and a pointer area for indicating a target block of the data area for storing data before update The first block number indicating the block number, the second block number indicating the block number of the pointer area indicating the update block of the data area in which the updated data is stored, and the latest information on the newness of the stored contents Corresponding to the second block number stored in the first area. A first erasure step for erasing data stored in all the update blocks in the data area corresponding to a block number stored in the pointer area, and the second erasure A write step for writing the updated data in at least a part of all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the block number; and the updated data is written A first storage step for storing the block number of the block in the data area in a block corresponding to the first block number in the pointer area, and a first block in the pointer area in which the block number of the data area is stored A process including a second storage step of storing a number in the first area. To be executed by the data.

  In one aspect of the present invention, the data is stored in all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number stored in the first area. At least a part of all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number, the data being erased all at once The updated data is written in, and the block number of the block of the data area in which the updated data is written is stored in the block corresponding to the first block number of the pointer area, and the block of the data area The first block number of the pointer area in which the number is stored is stored in the first area.

  According to one aspect of the present invention, memory corruption can be addressed.

  In addition, according to one aspect of the present invention, it is possible to reduce the time required for data write processing while coping with memory corruption.

It is a block diagram which shows the structural example of the non-contact communication system to which this invention is applied. FIG. 2 is a block diagram illustrating a configuration example of a reader / writer in FIG. 1. It is a block diagram which shows the structural example of the IC card of FIG. It is a figure explaining the basic principle of the coping method with respect to memory corruption. It is a figure explaining a single pointer system. It is a figure explaining a single pointer system. It is a figure explaining a double pointer system. It is a figure explaining a double pointer system. It is a flowchart explaining the read-out process corresponding to a double pointer system. It is a flowchart explaining the write-in process corresponding to a double pointer system.

  Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.

<1. Embodiment>
[Configuration example of non-contact communication system]
FIG. 1 shows a configuration example of a contactless communication system including an IC card according to an embodiment of the present invention.

  The non-contact communication system 10 includes a controller 11, an R / W (reader / writer) 12, and an IC card 13. The R / W 12 performs non-contact communication using an electromagnetic wave with the IC card 13 according to control from the controller 11.

  That is, when the controller 11 transmits a command for instructing the R / W 12 to communicate with the IC card 13, the R / W 12 transmits a predetermined command to the IC card 13. The IC card 13 that has received the predetermined command performs processing corresponding to the command, and transmits response data indicating the processing result to the R / W 12.

[Configuration example of R / W12]
FIG. 2 shows a configuration example of the R / W 12 of FIG.

  The R / W 12 includes an IC 21, a flash memory 22, a modulation unit 23, an oscillation unit 24, a demodulation unit 25, and an antenna 26.

  The IC 21 is configured by connecting a DPU (Data Processing Unit) 31, an SPU (Signal Processing Unit) 32, an SCC 33, and a memory unit 34 to each other via a bus 35.

  In addition, a flash memory 22 for storing predetermined data is also connected to the bus 35.

  The DPU 31 outputs a command to be transmitted to the IC card 13 to the SPU 32 and acquires response data received from the IC card 13 from the SPU 32.

  The SPU 32 performs a predetermined modulation and coding process (for example, BPSK (Binary Phase Shift Keying) modulation and coding process) on the command transmitted to the IC card 13, and then outputs the command to the modulation unit 23 and the IC card. 13 is obtained from the demodulator 25, and a modulation decoding process (such as a BPSK modulation decoding process) is performed on the data.

  The modulation unit 23 performs ASK (Amplitude Shift Keying) modulation on a carrier wave having a predetermined frequency (for example, 13.56 MHz) supplied from the oscillation unit 24 with data supplied from the SPU 32, and the generated modulated wave is transmitted to the antenna. 27 is output as an electromagnetic wave to the IC card 13 via 27. At this time, the modulation unit 23 performs ASK modulation with a modulation degree of less than 1. That is, the maximum amplitude of the modulated wave is prevented from becoming zero even when the data is at a low level.

  The demodulator 25 demodulates the modulated wave (ASK modulated wave) received via the antenna 27 and outputs the demodulated data to the SPU 32.

[Configuration Example of IC Card 13]
FIG. 3 shows a configuration example of the IC card 13 of FIG.

  The IC card 13 includes an IC 51, a capacitor 52, and an antenna 53.

  The IC 51 receives the modulated wave transmitted by the R / W 12 via the antenna 53. The capacitor 52 forms an LC circuit together with the antenna 53, and is tuned (resonated) with an electromagnetic wave having a predetermined frequency (carrier frequency).

  The IC 51 includes an RF interface unit 61, a BPSK demodulation unit, a PLL (Phase Locked Loop) unit 63, a calculation unit 64, a ROM 65, an EEPROM (Electrically Erasable and Programmable ROM) 66, a RAM 67, and a BPSK modulation unit 68.

  The RF interface unit 61 is further subdivided into an ASK demodulation unit 81, a voltage regulator 82, an oscillation unit 83, and an ASK modulation unit 84.

  The RF interface unit 61 detects and demodulates the modulated wave (ASK modulated wave) received by the ASK demodulator 81 via the antenna 53, and outputs the demodulated data to the BPSK demodulator 62 and the PLL unit 63. Further, the RF interface unit 62 stabilizes the signal detected by the ASK demodulating unit 81 by the voltage regulator 82 and supplies the DC power obtained as a result to each unit of the IC 51 as driving power. Further, the RF interface unit 61 oscillates a signal having the same frequency as the data clock frequency in the oscillation unit 83 and outputs the signal to the PLL unit 63.

  Then, the ASK modulation unit 84 of the RF interface unit 61 varies the load of the antenna 53 as the power source of the IC card 13 corresponding to the data supplied from the calculation unit 64 (for example, a predetermined value corresponding to the data) The switching element is turned on / off, and a predetermined load is connected in parallel to the antenna 53 only when the switching element is in an on state), whereby the modulated wave received via the antenna 53 is ASK modulated, and the antenna 53 Is transmitted to the R / W 12 via.

  The PLL unit 63 generates a clock signal synchronized with the data from the data supplied from the ASK demodulation unit 81, and outputs the clock signal to the BPSK demodulation unit 62 and the BPSK modulation unit 68. When the data demodulated by the ASK demodulator 81 is BPSK modulated, the BPSK demodulator 62 demodulates the data (decodes Manchester code) in accordance with the clock signal supplied from the PLL unit 63 and demodulates the data. Is output to the calculation unit 64.

  The calculation unit 64 includes a sequence unit 91, an encryption / decryption unit 92, and a parity calculation unit 93. When the data supplied from the BPSK demodulation unit 62 is encrypted, the data is decrypted by the encryption / decryption unit 92. Then, the sequencer 91 processes the data of the decoding result. When the data supplied from the BPSK demodulator 62 is not encrypted, the data supplied from the BPSK demodulator 62 is directly supplied to the sequencer 91 without going through the encryption / decryption unit 92.

  The sequencer 91 performs processing corresponding to data as a command supplied thereto. That is, for example, the sequencer 91 performs processing such as data writing to and reading from the EEPROM 66. Furthermore, the sequencer 91 performs a process corresponding to the data as the command, generates response data (data to be transmitted to the R / W 12) corresponding to the process, and outputs the response data to the BPSK modulator 68.

  The parity calculation unit 93 calculates a Reed-Solomon code as parity from the data stored in the EEPROM 66 or the data stored in the EEPROM 66.

  The BPSK modulation unit 68 BPSK modulates the data supplied from the calculation unit 64 and outputs the modulated data to the ASK modulation unit 84 of the RF interface unit 61.

  The ROM 65 stores a processing program to be executed by the sequencer 91 and other necessary data. The RAM 67 temporarily stores data in the middle of processing when the sequencer 91 performs processing. The EEPROM 66 is a non-volatile memory, and retains stored data without loss even after the IC card 13 ends communication with the R / W 12 and power supply is stopped.

[Corrective action against memory corruption]
Next, a data read / write process with respect to the EEPROM 66 by the sequencer 91 of the IC card 13 will be described. Before that, as a preparation for the previous stage, a memory that means that information stored in the memory is destroyed. Explain how to deal with corruption (Memory Corruption).

  First, the basic principle of a method for dealing with memory corruption will be described.

  For example, assuming that reading and writing of information is performed on a memory (corresponding to EEPROM 66) in a predetermined block unit, data stored in a certain block B1 is updated (the data stored in the block B1 is changed to other data). To rewrite).

  In this case, if new data is written in the block B1 itself, the data already stored in the block B1 is overwritten, and power supply to the IC card is insufficient during the writing. If so, the new data will not be completely written. Furthermore, the data stored in the block B1 is destroyed, resulting in memory corruption.

  In order to prevent such a situation from occurring, new data to be written to the block B1 may be written to a block B2 different from the block B1. As a result, when a memory corruption occurs during writing to the block B2, new data is not completely written and the validity is not guaranteed, but at least the data stored in the block B1. Can be prevented. Then, after the writing to the block B2 is completed, the data stored in the block B1 is erased.

  When new data is supplied, the data is written in a block different from the block B2, for example, the block B1. As described above, when new data is supplied, the new data is written in a block other than the block in which the previously written data is stored. Accordingly, at least the previously written data is prevented from being destroyed by writing new data, so that the IC card is not disabled even in the worst case.

  Next, a memory read / write method to which the above basic principle is applied will be described with reference to FIG.

  In FIG. 4, for convenience of explanation, one block is composed of 1 byte (8 bits) up-to-date information, 8 bytes of data, and 2 bytes of validity information sequentially arranged from the head of 11 bytes. It shall be. However, the number of bits in one block, and further, the number of bits allocated to the freshness information, data, and validity information are not particularly limited to those described above.

  The up-to-date information indicates the newness of the stored contents of the block. For example, an absolute date and time, a sequential number, or the like can be used. That is, when using an absolute date and time, if the date and time at which the data is stored is stored as the latest information, the latest block in which the data is stored is determined based on the newness information. Can be detected.

  Also, when sequential numbers are used, each time data is written, for example, if the incremented number is stored as the freshness information, the block with the largest value is written with data. It will be the latest.

  Here, it is sufficient if it is possible to recognize which of at least two blocks is new. Therefore, it is sufficient that the up-to-date information can represent at least three states. That is, for example, if the three values 0, 1, and 2 are used as the up-to-date information that can represent the three states, 0 is written each time one of the two blocks is written. , 1, 2, 0,... May be written as the freshness information of the block in which the writing has been performed.

  In this case, if the up-to-date information of the two blocks is 0 and 1, the block of 1 is newer. If it is 1 and 2, the block of 2 is newer. If it is 2 and 0, the block of 0 is newer. It will be. As described above, when the three values 0, 1, and 2 are used as the up-to-date information, the number of bits is two. In addition, for example, as the up-to-date information, three 1-bit flags may be used, and each time the block is written, the bit-setting flag may be changed sequentially.

  Hereinafter, the three values 0, 1, and 2 described above are used as the freshness information.

  The validity information indicates whether or not the writing of the latestness information and data of the block has been completed normally, that is, the validity information and validity of the data (whether it is valid or invalid) For example, an RS (Reed Solomon) code can be used.

  The validity information is not limited to error correction codes such as RS codes. In other words, the validity information only needs to represent whether the latestness information and data are valid or invalid as described above. Therefore, the validity information is, for example, parity calculated while writing the freshness information and data, or, for example, a 1-bit flag added after the freshness information and data are normally written. It may be.

  In FIG. 4, the memory has two blocks as first and second areas, and FIG. 4A shows 01, 02, 03, 04, 05, 06, 07, 08 (each value is a hexadecimal number) has already been stored, and the second area shows that all data has been erased.

  In this state, when data 11 to 18 to be newly written are supplied, first, the validity of the two blocks as the first and second areas is determined based on the validity information. Here, it is determined that only the block as the first area is valid.

  When new data is written, as described above, new data is written to a block in which no data is currently recorded in order not to destroy previously written data. Therefore, as shown in FIG. B, new data 11 to 18 are written in the block as the second area. After the writing of the data 11 to 18 is finished, first, the latestness information of the block in which the writing has been performed is updated. That is, since the up-to-date information of the block as the first area, which was the most recent block, was 01, the up-to-date information of the block as the second area that has been written is A value 02 obtained by adding 1 to the freshness information 01 of the block as the area of the current area is written, and further, validity information indicating the validity of the freshness information 02 is written.

  Then, after all the writing to the block as the second area is completed, as shown in FIG. 5C, all the data recorded in the block as the first area is erased.

  By the way, the two blocks as the first and second areas in FIG. 4 are recognized as logical blocks which are the same logical block from the outside. That is, the blocks as the first and second areas are physical blocks that are physically present, and each physical block is assigned a unique physical block number for identification. ing. The physical block numbers of the physical blocks as the first and second areas are associated with the same number as the logical block number for identifying the logical block. The physical blocks as the first and second areas are recognized as one logical block from the outside.

  That is, in FIG. 4, the physical block numbers of the physical blocks as the first and second areas are different, but the same logical block number is assigned to both, and such a logical block number is externally assigned. A request for access is made to a logical block having On the memory side, when there is a request for access to a logical block, a data read process or a data write process is performed on a block having a physical block number corresponding to the request, that is, the first and second areas. Is called.

  In the following, it is assumed that both the physical block number and the logical block number are represented by 1 byte.

  Next, in the above-described case, after the completion of writing of data of one physical block, the latestness information and validity information of the physical block are updated. When writing to a block, mixed data may be generated.

  In other words, when memory corruption occurs when data for a plurality of blocks is being written to a plurality of logical blocks when viewed from the outside, new data is written to the logical block for which writing has been completed before the memory corruption occurs. However, old data exists after the logical block in which writing is performed during the occurrence of memory corruption.

  If the related blocks of data are meaningful in a lump and are useful in their entirety, as described above, if new and old are mixed, That consistency is lost. That is, when the data for a plurality of related blocks are, for example, as described above, the station and time of boarding, the station and time of getting off, the fare between the boarding and exiting stations, etc., new data for the boarding station Is written, and the time of boarding will be meaningless if the old data remains as it is.

  Therefore, when data for a plurality of related blocks is written in a plurality of logical blocks, if a memory corruption occurs before the writing of the data for the plurality of blocks is completed, the relationship from the outside is related to the logical block. It is necessary to make it recognize that there is old data for a plurality of blocks.

[Description of single pointer method]
Therefore, the memory is configured as shown in FIG. 5, for example. That is, the memory is configured with physical blocks as data areas for storing data and physical blocks as first and second areas for storing physical block numbers of physical blocks constituting the data area.

  In FIG. 5 as well, as in the case of FIG. 4, one physical block (one horizontal row in the figure) is composed of 11 bytes.

  Each physical block constituting the data area stores data in units of 11 bytes. In the case of the figure, the data area includes eight physical blocks to which physical block numbers # 00 to # 07 are assigned. It is composed of blocks (# represents a physical block number).

  In the case of the figure, #FE is assigned to the physical block number of the first area, and #FF is assigned to the physical block number of the second area.

  Note that the memory configured as shown in the figure recognizes four logical blocks from the outside, and each of the four logical blocks has a logical block number of% 00 to% 03. Is assigned. In the figure, physical block numbers # 00 to # 03 are associated with logical block numbers% 00 to% 03.

  As in the case of FIG. 4, the physical block as the first and second areas shown in the figure is allocated with the first 1 byte as the latestness information and the last 2 bytes as the validity information. ing. However, the physical block number of the physical block in the data area, that is, a pointer to the physical block constituting the data area is arranged in 8 bytes between the freshness information and the validity information.

  Of the 8 bytes in which pointers to physical blocks constituting the data area are arranged, the physical block number of the target block in the data area is arranged in the first 4 bytes, and the data area is updated in the latter 4 bytes. The physical block number of the block is arranged.

  Here, the target block means a physical block that should originally be a target of writing when information is written. That is, for example, in the basic principle described above, when data stored in the block B1 is rewritten to new data, the new data is not written to the block 1 but written to the block B2. The block B1 to be written corresponds to the target block.

  The update block means an update physical block used when information is written to a certain physical block and its stored contents are updated. That is, for example, in the basic principle described above, when the data stored in the block B1 is rewritten to new data, the new data is not written in the block B1, but is written in the block B2, but in this case, the block in which the new data is written B2 corresponds to an update block.

  The four physical block numbers arranged in the first 4 bytes of the 8 bytes between the freshness information and the validity information in the first and second areas are associated with the logical block numbers. ing. That is, for example, the physical block number arranged in the first to fourth bytes is associated with the logical block numbers% 00 to% 03, respectively.

  In the memory configured as shown in FIG. 5, related four blocks of data are stored in physical block # 00 (physical block whose physical block number is # 00) to # 03. The physical block numbers # 00 to # 03 are the first 4 bytes of the 8 bytes between the freshness information and the validity information in the first area (hereinafter referred to as appropriate for the target block in the data area). (Referred to as a pointer column) in that order.

  Therefore, for example, when attention is paid to the column of the pointer to the target block of the data area in the first area, the physical block numbers # 00 to 03 are associated with the logical block numbers% 00 to% 03.

  Here, when attention is paid to the first area, any one of the physical blocks # 00 to # 03 associated with the logical block% 00 (logical block whose logical block number is% 00) to% 03 is associated. The block to be accessed, that is, the target block.

  The update block can be a physical block of the data area that is not the target block at that time, that is, a physical block that is a free area. Therefore, in FIG. 5, when attention is paid to the first area, the physical blocks # 04 to # 07 can be update blocks, and therefore, 8 bytes between the freshness information and the validity information in the first area. In the latter 4 bytes (hereinafter, referred to as a column of pointers to update blocks in the data area as appropriate), physical block numbers # 04 to # 07 of these update blocks are arranged.

  Here, for example, assuming that only the first area of the first or second area is valid, two blocks corresponding to each of the logical blocks corresponding to the logical block numbers% 00 and% 02 are externally provided. Suppose that there is a request to write data.

  In this case, by referring to the column of the pointer to the target block in the data area in the valid first area, the physical block numbers corresponding to the logical block numbers% 00 and% 02 are # 00 and # 02. Is recognized. Then, physical blocks # 00 and # 02 are recognized as target blocks to which each of the related two blocks of data is to be written.

  Further, the physical block numbers of all the update blocks are recognized by referring to the column of pointers to the update blocks in the data area in the first area. In this case, physical block numbers # 04, # 05, # 06, and # 07 are recognized. Then, physical blocks respectively corresponding to all physical block numbers recognized as update blocks (in this case, physical blocks # 04, # 05, # 06, # 07) are erased collectively. Note that the time required for erasing a plurality of physical blocks at the same time is equivalent to the time required for erasing one physical block.

  Thereafter, the physical block numbers of the same number of update blocks as the number of target blocks (in this case, 2) are recognized in order from, for example, those arranged from the left of the column of pointers to the update blocks in the data area. Originally, two blocks of data to be written in the physical block # 00 or # 02 as the target block are written into the physical block # 04 or # 05 as the update block, respectively, as shown in FIG.

  In this way, by erasing all the physical blocks that have been designated as update blocks, the processing time can be reduced as compared with the case of erasing the physical block data each time data is written to the physical block. It can be shortened.

  6 shows that the two data to be written in the physical block numbers # 00 and # 02 corresponding to the logical block numbers% 00 and% 02 are 40, 41,..., 4A and 50, 51,. .., 5A, these indicate the states written in the physical blocks # 04 and # 05, which are update blocks.

  After the data is written to each of the physical blocks # 04 and # 05, the block numbers # 04 and # 05 of the physical block that was the update block are changed to the target block of the data area in the second area that has been invalid until now. Is written in the pointer field. That is, descriptions # 00, # 01, # 02, and # 03 in the column of the pointer to the target block of the data area in the first area are copied to the second area, and among these, the physical block number # 00 of the target block And # 02 are rewritten to physical block numbers # 04 and # 05 of the update block in which data is actually written, respectively, as shown in FIG.

  As a result, when focusing on the second area, it can be seen that the logical block number% 00 is associated with the physical block number # 04, and the logical block number% 02 is associated with the physical block number # 02.

  Also, the physical blocks # 00 and # 02 to which data should have been written are update blocks, and the physical block numbers # 00 and # 02 are written in the pointer field to the update block of the data area in the second area. It is. That is, descriptions # 04, # 05, # 06, and # 07 in the column of the pointer to the update block of the data area in the first area are copied to the second area, and among these, the physical block in which the data is written The physical block numbers # 04 and # 05 are rewritten to the physical block numbers # 00 and # 02 of the target block, respectively, as shown in FIG.

  As a result, when attention is paid to the second area, it is understood that the physical blocks # 00 and # 02 are newly updated blocks.

  As described above, after the pointer to the target block in the data area and the pointer to the update block in the data area in the second area are updated, the up-to-date information and validity information in the second area are updated. Are sequentially written (rewritten), and then all the data in the first area is erased.

  Accordingly, in this case, validity information indicating that the second area is valid is not written unless the writing of the pointer column to the target block in the data area is completed. In other words, in the above-described case, if the data writing to the two logical blocks% 00 and% 02 is not completed, the validity information indicating that the data is valid is not written in the second area.

  As a result, if memory corruption occurs while data is being written to the two logical blocks% 00 and% 02, only the first area remains valid, From the blocks% 00 and% 02, the old areas stored in the physical blocks # 00 and # 02 respectively associated with the logical blocks% 00 and% 02 are referred to by referring to the valid first area. Data will be read out.

  On the other hand, when the data writing to the two logical blocks% 00 and% 02 is completed, the latestness information and the validity information in the second area are updated, and all the data in the first area is erased The logical blocks% 00 and% 02 refer to the only valid second area, so that the physical blocks # 04 and # 05 respectively associated with the logical blocks% 00 and% 02 are referred to. New stored data will be read out.

  Accordingly, in this case, when two pieces of data as a plurality of data stored in the logical blocks% 00 and% 02 are related, even if a memory corruption occurs, the consistency of the individual data is It becomes possible to maintain the consistency between the two data.

  The read / write method for the memory described above with reference to FIGS. 5 and 6 uses a one-step pointer to the data area, and is hereinafter referred to as a single pointer method as appropriate.

  By the way, in the single pointer method shown in FIGS. 5 and 6, four physical block numbers can be described as a column of the pointer to the target block in the data area. Also, the pointer column to the update block in the data area can describe four physical block numbers in the same manner as the pointer column to the target block in the data area. As a result, data consistency for a maximum of 4 blocks can be maintained.

  In other words, however, it is difficult to maintain the consistency of more than four blocks with the single pointer method shown in FIGS.

  That is, in the single pointer method shown in FIGS. 5 and 6, the number of blocks that can maintain data consistency is limited to the number of blocks of pointers to the target block in the data area.

[Description of double pointer method]
Therefore, in order to remove the restriction on the number of blocks that can maintain data consistency, the memory configuration is expanded as shown in FIG. 7, for example.

  That is, here, the memory includes physical blocks # 00 to # 17 as data areas for storing data, and physical blocks as pointer areas for storing the block numbers as pointers to physical blocks constituting the data area. It is composed of # 18 to # 1D and physical blocks # 1E and # 1F as first and second areas for storing the block numbers as pointers to physical blocks constituting the pointer area.

  In FIG. 7, one physical block is composed of 8 bytes for convenience of illustration.

  Each physical block constituting the data area is configured to store data in units of 8 bytes. In FIG. 7, the data area has 24 physical blocks assigned # 00 to # 17 as physical block numbers. Consists of physical blocks.

  Note that 16 logical blocks are recognized from the outside, and each of the 16 logical blocks is assigned% 00 to% 0F as a logical block number.

  However, for the convenience of explanation, it is assumed that there are as many logical blocks as the number of physical blocks (24) constituting the data area, and there are 8 physical blocks other than the physical blocks recognized as logical blocks from the outside. As a logical block number,% 10 to% 17 are temporarily allocated. In the example of FIG. 7, logical block numbers% 00 to% 17 and physical block numbers # 00 to # 17 are associated with each other.

  Each physical block constituting the pointer area (block number area) stores the physical block number as a pointer to the physical block constituting the data area in units of 8 bytes. In the case of FIG. 7, the pointer area is composed of six physical blocks to which # 18 to # 1D are assigned as physical block numbers. Here, each physical block constituting the pointer area stores a physical block number in units of 8 bytes, and the physical block number is represented by 1 byte. The physical block numbers are stored.

  Eight physical block numbers arranged in each physical block in the pointer area are associated with logical block numbers. That is, the physical block number arranged in the first to eighth bytes is a logical block number that is offset by 0 to 7 with respect to a certain logical block number (% 00,% 08, or% 10 as will be described later). It is associated.

  In the blocks as the first and second areas, the first byte is assigned to the freshness information, and the last byte is assigned to the validity information. In 6 bytes between the freshness information and the validity information, the physical block number as a pointer to the physical block in the pointer area is arranged.

  Of the 6 bytes between the freshness information and the validity information in the first and second areas, the first 3 bytes (hereinafter referred to as a pointer field to the target block in the pointer area as appropriate) have a pointer. The physical block number of the target block in the area is arranged, and the physical block number of the update block in the pointer area is arranged in the latter three bytes (hereinafter referred to as a pointer column to the update block in the pointer area as appropriate). The

  The physical block numbers stored in the physical blocks of the pointer area corresponding to the three physical block numbers arranged in the pointer column to the target block of the pointer area in the first and second areas correspond to the logical block numbers. It is attached. That is, for example, the physical block numbers stored in the physical block of the pointer area corresponding to the physical block number arranged in the first to third bytes are the logical block numbers% 00 to% 07 and% 08 to% 0F, respectively. Or% 10 to% 17.

  Specifically, in the case of FIG. 7, in the first area, 1 in the physical block # 18 in the pointer area pointed to by the physical block number # 18 in the first byte in the pointer field to the target block in the pointer area. The physical block numbers # 00 to # 07 arranged in the 8th byte to the 8th byte respectively correspond to the logical block numbers% 00 to% 07 corresponding to the 1st byte in the column of the pointer to the target block in the pointer area in the first area. It is associated.

  Also, the physical block numbers # 08 to ## arranged in the 1st to 8th bytes of the physical block # 19 of the pointer area pointed to by the physical block number # 19 of the second byte in the pointer field to the target block of the pointer area 0F is associated with each of logical block numbers% 08 to% 0F associated with the second byte in the column of the pointer to the target block in the pointer area in the first area.

  Similarly, the physical block numbers # 10 to # 17 arranged in the 1st to 8th bytes of the physical block # 1A of the pointer area pointed to by the physical block number # 1A of the 3rd byte in the pointer field to the target block of the pointer area Are associated with logical block numbers% 10 to% 17, respectively.

  In the memory configured as described above, for example, when attention is paid to the first area, the physical block corresponding to the physical block number described in the pointer column to the target block in the pointer area is the access target. It becomes the target block of the pointer area that should be.

  Therefore, in the case of FIG. 7, the physical blocks # 18 to # 1A in the pointer area are the target blocks in the pointer area, and the remaining physical blocks # 1B to # 1D are update blocks for updating the pointer area. ing. Thus, the physical block numbers # 1B to # 1D are described in the pointer column to the update block of the pointer area in the first area.

  Further, among the physical blocks in the data area corresponding to the physical block number described in the target block in the pointer area, for example, the blocks corresponding to the logical blocks% 00 to% 0F are the target blocks in the data area. In this case, physical blocks # 00 to # 0F corresponding to the logical blocks% 00 to% 0F are the target blocks of the data area, and the remaining physical blocks in the data area (physical blocks corresponding to the logical blocks% 10 to% 17) # 10 to # 17 are update blocks for updating the data area.

  Here, as described above, since the physical block number of the update block of the pointer area is described in the column of the pointer to the update block of the pointer area in the first or second area, It can be recognized by referring to it. On the other hand, since the update block in the data area is a physical block corresponding to the logical blocks% 10 to% 17, it corresponds to the physical block number described in the third byte of the pointer field to the target block in the pointer area. By referring to the physical block in the pointer area, it can be recognized from the physical block number described there.

  Now, assuming that only the first area is valid among the first or second areas, for example, two blocks related to the physical blocks corresponding to the logical block numbers% 00 and% 02 from the outside, for example. Suppose that there is a request to write data for the minute.

  In this case, it is related by referring to the column of the pointer to the target block in the pointer area of the first area that is valid, and further referring to the physical block corresponding to the physical block number described therein. A target block that is a physical block in a data area in which data for two blocks is to be written is recognized. Thereafter, an update block in the data area is recognized.

  Specifically, the physical block number of the physical block in the data area corresponding to the logical blocks% 00 and% 02 is obtained by referring to the first byte of the pointer area to the target block in the pointer area in the first area. The written physical block # 18 in the pointer area can be recognized. Then, by referring to the first byte and the third byte of the physical block # 18, the physical block numbers # 00 and # 02 of the physical block (target block) in the data area corresponding to the logical blocks% 00 and% 02 are obtained. Each can be recognized.

  Further, the physical block number of the physical block corresponding to the logical blocks% 10 to% 17 that become the update block of the data area by referring to the third byte of the pointer field to the target block of the pointer area in the first area Can be recognized in the pointer area physical block # 1A.

  Then, by referring to the physical block # 1A, it is possible to recognize the physical block numbers # 10 to # 17 of all the physical blocks that are the update blocks of the data area, and it is possible to recognize all the physical blocks that are the update blocks. Blocks # 10 to # 17 are erased collectively. Note that the time required for erasing a plurality of physical blocks at the same time is equivalent to the time required for erasing one physical block.

  After that, among all the update blocks in the data area erased in batch, the physical block numbers that are the same as the number of target blocks in the data area, to which data is to be written, are sequentially referred to from the left of the physical block # 1A, for example. And recognized as an update block for writing data. In this case, the physical blocks # 10 and # 11 in the data area corresponding to the physical block numbers # 10 and # 11 are update blocks to which data is written.

  Originally, the two data to be written in the physical blocks # 00 and # 02, which are the target blocks of the data area, corresponding to the logical blocks% 00 and% 02 are updated as shown in FIG. It is written in physical blocks # 10 and # 11 which are blocks.

  That is, FIG. 8 shows that two data to be written in the physical block numbers # 00 and # 02 corresponding to the logical block numbers% 00 and% 02 are 00, 00, 00, 00, 00, 00, 00, 00 and 02. , 02, 02, 02, 02, 02, 02, 02, they are written in physical blocks # 10 and # 11, which are update blocks in the data area, respectively.

  As described above, after data is written in the physical blocks # 10 and # 11 which are update blocks in the data area, the physical block numbers # 10 and # 11 are written in the update block in the pointer area and For example, the physical block numbers # 00 and # 02 of the physical block (target block) in the data area where data should have been written are written in other update blocks in the pointer area.

  That is, first, an update block in the pointer area is recognized by referring to the column of the pointer to the update block in the pointer area in the first area. Here, as the update blocks of the pointer area, the same number of physical blocks as the number of target blocks that need to be changed (updated) with the writing to the data area as described above among the target blocks of the pointer area. The pointer field to the update block in the pointer area is recognized by sequentially referring, for example, from the left.

  Therefore, in the present case, the physical block # 18 and the physical block # 18 of the pointer area in which the physical block numbers # 00 and # 02 of the physical block (the target block of the data area) to which data is to be originally written are stored. Since it is necessary to change the two physical blocks of the physical block # 1A in the pointer area in which the physical block numbers # 10 and # 11 of the written physical block are stored, the pointer area in the first area The update block pointer field is referenced by 2 bytes from the left, and physical blocks # 1B and # 1C are recognized as update blocks.

  Of the recognized update blocks # 1B or # 1C in the pointer area, one update block # 1B stores the physical block numbers # 00 and # 02 of the target block in the data area. The storage contents of the physical block # 18 are copied, of which the physical block numbers # 00 and # 02 of the target block of the data area are the physical block numbers # 10 and # of the update block of the data area where the data is actually written. 11 is rewritten.

  Of the recognized update block # 1B or # 1C in the pointer area, the other update block # 1C stores the physical block numbers # 10 and # 11 of the physical block to which data is actually written. The stored contents of the physical block # 1A in the pointer area are copied, and the physical block numbers # 10 and # 11 are the physical block numbers (target blocks in the data area) # 00 and # 11 of the physical block to which data should be originally written. Rewritten to 02.

  After this, the block numbers # 1B and # 1C of the physical block that was the updated block of the pointer area whose physical block number has been updated are stored in the column of the pointer to the target block of the pointer area in the second area that was not valid. Written. That is, the column of the pointer to the target block in the pointer area in the first area is copied to the second area, and the first byte corresponding to the logical addresses% 00 to% 07 is the physical block in the pointer area. And the third byte corresponding to the logical addresses% 10 to% 17 is rewritten to the physical block number # 1C of the physical block in the pointer area.

  As a result, when focusing on the second area, the physical blocks # 1B, # 19, and # 1C become the target blocks of the pointer area, and thereby the physical blocks # 10 and # 11 that are the update blocks of the data area are changed. The physical blocks # 00 and # 02, which are the target blocks of the data area, are newly associated with the logical block numbers% 00 and% 02 associated with each other. Furthermore, physical blocks # 00 and # 02 that are target blocks in the data area are associated with logical blocks% 10 and% 11 and are updated blocks.

  That is, referring to the first byte of the column of the pointer to the target block of the pointer area in the second area, the physical block number of the physical block of the data area corresponding to the logical blocks% 00 and% 02 is described. The physical block in the pointer area is physical block # 1B. Further, referring to the first byte and the third byte of the physical block # 1B, the physical blocks in the data area corresponding to the logical blocks% 00 and% 02 are the physical blocks # 10 and # 11, respectively.

  Further, referring to the third byte of the pointer field to the target block of the pointer area in the second area, the physical block numbers of the physical blocks of the data area corresponding to the logical blocks% 10 and% 11 are described. The physical block of the pointer area is the physical block # 1C. Further, referring to the first byte and the second byte of the physical block # 1C, the physical block of the data area corresponding to the logical blocks% 10 and% 11 That is, the update blocks in the data area are physical blocks # 00 and # 02.

  Further, in the pointer area, the physical block number # 18 of the physical block in which the physical block numbers # 00 and # 02 of the physical block to which the data is originally written is stored, and the physical block in which the data is actually written The physical block number # 1A of the physical block in which the physical block numbers # 10 and # 11 are stored is written in the pointer column to the update block of the pointer area in the second area that was not valid.

  That is, the pointer field to the update block in the pointer area in the first area is copied to the second area, and the physical block number # 1B or # of the physical block in the pointer area in which the stored contents are updated is stored. As shown in FIG. 8, 1C is the physical block number # 18 in which the physical block number corresponding to the logical addresses% 00 to% 07 is stored, or the physical block corresponding to the logical addresses% 10 to% 17. Each is rewritten to the physical block number # 1A in which the number is stored.

  As a result, when attention is paid to the second area, the physical blocks # 18, # 1A, and # 1D become update blocks in the pointer area.

  As described above, after the second area is updated, the freshness information and the validity information in the second area are sequentially written in the same manner as in the single pointer method.

  Then, after the latest information and validity information in the second area are written, the data in the first area is erased.

  Accordingly, in this case, the validity information indicating that the data area is valid is not written unless the writing of the data area and the pointer area is completed. In other words, in the above case, the validity information indicating that the data is valid is not written in the second area unless the data writing to the two logical blocks% 00 and% 02 is completed.

  As a result, if memory corruption occurs while data is being written to the two logical blocks% 00 and% 02, only the first area remains valid, From the blocks% 00 and% 02, the old areas stored in the physical blocks # 00 and # 02 respectively associated with the logical blocks% 00 and% 02 are referred to by referring to the valid first area. Data will be read out.

  On the other hand, when the writing of data to the two logical blocks% 00 and% 02 is completed and the latestness information and validity information in the second area are updated, the logical blocks% 00 and% 02 are updated. Is new and stored in the physical blocks # 10 and # 11 respectively associated with the logical blocks% 00 and% 02 by referring to the second area that is valid and latest. Data will be read out.

  Therefore, in this case, when two data as a plurality of data stored in the logical blocks% 00 and% 02 are related, even if a memory corruption occurs, the same as in the single pointer method Thus, it becomes possible to maintain the consistency between the two data.

  Furthermore, the physical block numbers of three blocks of the physical blocks in the pointer area can be stored in the column of pointers to the target blocks in the pointer area in the first and second areas. In addition, in one physical block in the pointer area, physical block numbers corresponding to 8 blocks in the data area can be stored.

  Therefore, 24 (= 3 × 8) physical blocks in the data area can be managed at the maximum, and 12 blocks at the maximum can be used as update blocks in the data area. That is, it is possible to maintain data consistency with a larger number of blocks than in the single pointer method.

  In FIG. 7 and FIG. 8, 8 blocks out of 24 blocks are used as update blocks, and data consistency for 8 blocks can be maintained.

  Since the read / write method for the memory described above with reference to FIGS. 7 and 8 uses a so-called two-stage pointer to the data area, it is hereinafter referred to as a double pointer method as appropriate.

  Next, data read / write processing by the double pointer method will be further described with reference to FIGS.

[Double pointer method read processing]
FIG. 9 is a flowchart for explaining the reading process.

  In step S61, the validity is determined by referring to the validity information of the first and second regions. If it is determined that only the block as the first area is valid, the process proceeds to step S62. On the other hand, when it is determined that only the block as the second area is valid, the process proceeds to step S65. If it is determined that both the first and second area blocks are invalid, the life of the IC card 2 as hardware (fatal error) is reached, so the process ends without reading. (Error processing is performed).

  When only the block as the first area is valid and the process proceeds to step S62, the logical block number of the data to be read out is referred to by referring to the column of the pointer to the target block in the pointer area in the first area The physical block number (pointer) of the physical block in the pointer area in which the physical block number corresponding to is stored is recognized.

  For example, when the memory is configured as described with reference to FIG. 7, when the logical block number of the data to be read is% 00 to% 07, it is stored in the first byte of the pointer field to the target block in the pointer area. Physical block number # 18 is recognized. For example, when the logical block number of the data to be read is% 08 to% 0F, the physical block number # 19 stored in the second byte of the pointer column to the target block in the pointer area is recognized.

  In step S63, the physical block number corresponding to the logical block number of the data to be read is recognized by referring to the physical block in the pointer area corresponding to the physical block number recognized in step S62.

  That is, when the logical block number of the data to be read is a value that is offset by 0 to 7 from a certain reference value (% 00 or% 08 in the case of FIG. 7), the physical block recognized in step S62. The physical block number stored at a position shifted from the left of the physical block corresponding to the number by the offset is recognized as the physical block number corresponding to the logical block number of the data to be read.

  In step S64, data is read from the physical block corresponding to the physical block number recognized in step S63, and this reading process is terminated.

  On the other hand, when only the block as the second area is valid and the process proceeds to step S65, the data to be read out 2 is read by referring to the pointer field to the target block in the pointer area in the second area. The physical block number (pointer) of the physical block in the pointer area in which the physical block number corresponding to the logical block number is stored is recognized.

  For example, when the memory is configured as described with reference to FIG. 8, when the logical block number of the data to be read is% 00 to% 07, it is stored in the first byte of the pointer column to the target block in the pointer area. Physical block number # 1B is recognized. For example, when the logical block number of the data to be read is% 08 to% 0F, the physical block number # 19 stored in the second byte of the pointer column to the target block in the pointer area is recognized.

  In step S66, the physical block number corresponding to the logical block number of the data to be read is recognized by referring to the physical block in the pointer area corresponding to the physical block number recognized in step S65.

  That is, when the logical block number of the data to be read is a value that is offset by 0 to 7 from a certain reference value (% 00 or% 08 in the case of FIG. 8), the physical block recognized in step S65. The physical block number stored at a position shifted from the left of the physical block corresponding to the number by the offset is recognized as the physical block number corresponding to the logical block number of the data to be read.

  In step S67, data is read from the physical block corresponding to the physical block number recognized in step S66, and this reading process is terminated.

[Double pointer writing]
Next, FIG. 10 is a flowchart for explaining the writing process.

  In step S31, the validity is determined by referring to the validity information of the first and second regions. If it is determined that only the block as the first area is valid, the process proceeds to step S32. Conversely, if it is determined that only the block as the second area is valid, the process proceeds to step S40. If it is determined that both of the blocks as the first and second areas are invalid, the life of the IC card 2 as hardware (fatal error) is reached, so the processing ends without writing. (Error processing is performed).

  When only the first area is valid and the process proceeds to step S32, it is determined whether or not the data of the second area that is not valid has been erased. If it is determined that it has not been erased, the process proceeds to step S50, and after the data in the second area that is not valid is erased, the process proceeds to step S33. On the other hand, if it is determined that it has been erased, step S50 is skipped, and the process proceeds to step S33.

  In step S33, the pointer field to the target block of the pointer area in the first area is referred to and the physical block number of the pointer area in which the physical block number of the physical block of the data area that can be used as the update block is stored. The physical block number is recognized. That is, for example, when the memory is configured as shown in FIG. 7, the physical block number # 1A stored in the third byte of the pointer field to the target block in the pointer area in the first area is recognized. Is done.

  In step S34, the physical block numbers of all the update blocks in the data area stored in the physical block (in the case of FIG. 7, physical block # 1A) corresponding to the physical block number recognized in step S33 are referred to. Recognized as an update block in the data area.

  In the case of FIG. 7, physical block numbers # 1A, # 11, # 12, # 13, # 14, # 15, # 16, and # 17 recorded in the physical block # 1A are recognized as update blocks in the data area. The

  In step S35, data recorded in all physical blocks recognized as update blocks in the data area are erased collectively. Here, by erasing the data all at once, the processing time can be shortened as compared with the case where the data of the physical block is erased each time data is written to the physical block.

  Thereafter, in step S36, the data to be written supplied from the outside or the like is written into the update block in the data area after the data is erased at once.

  When data to be written to a plurality of logical blocks is supplied from the outside, the data is sequentially written from left to right, for example, in the physical block recognized in step S34.

  Thereafter, the process proceeds to step S37, and a part of the physical block that stores the physical block number associated with the logical block number of the logical block that is the target of data writing has been updated. Is copied to the update block in the pointer area.

  That is, for example, in the case described with reference to FIGS. 7 and 8, the physical block numbers # 00 and # 02 associated with the logical block numbers% 00 and% 02 of the logical block to which data is written are stored. The stored physical block # 18 is copied to the update block # 1B in the pointer area in a state where the stored physical block numbers # 00 and # 02 are updated to # 10 and # 11, respectively.

  Further, in step S37, the physical block storing the pointer to the update block in the data area (physical block number of the update block in the data area) is copied to the update block in the pointer area with a part thereof updated. Is done.

  That is, for example, in the case described with reference to FIGS. 7 and 8, the physical block # 1A storing the physical block numbers # 10 to # 17 of the update block of the data area is stored in the physical block number # 10. , # 11 are updated to # 00 and # 02, respectively, and copied to the update block # 1C in the pointer area.

  In step S38, the pointer field to the target block in the pointer area and the pointer field to the update block in the pointer area in the first area are updated, and the latestness information and validity information are updated. Is copied to the second area.

  That is, for example, in the case of FIG. 7 and FIG. 8, the column of the pointer to the target block in the pointer area in the first area is associated with the logical block to which data supplied from the outside is written. The physical block number # 18 stored in the first byte, which is the pointer of the pointer to the physical blocks # 00 and # 02 in the data area, is the physical block # 10 and # in the data area where the data is actually written. 11 is updated to physical block number # 1B which is a pointer of the pointer to 11.

  In addition, the physical block number # 1A that is the pointer of the pointer to the physical blocks # 10 and # 11 in the data area in which the data is actually written is associated with the logical block in which the data is written. It is updated to the physical block number # 1C that becomes the pointer of the pointer to # 00 and # 02.

  Further, for the column of the pointer to the update block of the pointer area in the first area, the physical block numbers # 1B and # 1C of the physical block (physical block that was the update block) of the pointer area with the updated physical block number Are updated to the physical block numbers # 18 and # 1A of the physical block that has become the update block of the pointer area, respectively.

  Furthermore, the latestness information and validity information in the first area are updated, and the above update result is written in the second area.

  Thereafter, the process proceeds to step S78, all data in the first area is erased, and the writing process is ended.

  On the other hand, if it is determined in step S31 that the second area is valid, in steps S40 to S47 and S52, the processing for the first or second area is reversed for the second or first area, respectively. Except that it is performed, the same processing as in steps S32 to S39 and S50 is performed, and the writing processing is terminated.

  Of the processes described above, the processes in steps S31 to S35 and S50 and the processes in steps S31, S40 to S43 and S52 (hereinafter referred to as command-independent processes) are performed regardless of the presence or absence of a write command. It is possible to execute in advance.

  Thus, for example, if a command-independent process is executed immediately after receiving a poll from the R / W 12, when a write command is actually instructed, the processing time required for the write process can be shortened.

  By the way, when memory corruption has occurred, it is determined in step S31 that both the first area and the second area are valid, and in this case, the process proceeds to step S48.

  In step S48, the freshness of the first area and the second area is determined. If it is determined that the first area is newer than the second area, the process proceeds to step S49, and the second area is changed to a block as the first area that is newer than the second area. The pointer to the pointer area in is overwritten. Furthermore, the freshness information and validity information of the first area are updated. Thereafter, the process proceeds to step S50, and thereafter, the same process as described above is performed.

  On the other hand, when it is determined that the second area is newer than the first area, the process proceeds to step S89, and the first area is changed to a block as a second area that is newer than the first area. The pointer to the pointer area in is overwritten. Further, the latestness information and validity information of the second area are updated. Thereafter, the process proceeds to step S52, and thereafter, the same process as described above is performed.

According to the writing process described above, all the update blocks in the data area where data may be written will be erased all at once. Compared with the case where data is erased each time data is written to the update block. Thus, the processing time required for erasing can be shortened. Therefore, a series of processing time required for the writing process can be shortened.

  In addition, if command-independent processing is executed in advance in the write processing, the processing time required from when the write command is actually instructed until the write processing is completed can be shortened.

  As described above, the case where the present invention is applied to a non-contact communication system has been described. However, the present invention, as represented by an EEPROM, records data that needs to be erased prior to the writing when data is written. It can be applied to any device that writes data to a medium.

  In addition, the present invention is particularly capable of transmitting and receiving data such as the above-described contactless communication system and a system that allows a user to freely insert and remove an IC card even in a contact type. Useful for systems that run in an unstable state.

  In the present embodiment, the physical block number of the update block in the pointer area or the physical block number of the update block in the data area as the empty area of the pointer area or the data area, or the physical block number of the update block in the data area is indicated in the validity determination block or pointer area Each was memorized. However, the physical block numbers of these update blocks are not necessarily stored. However, if the physical block number of the update block is not stored, it is necessary to detect the physical block to be the update block by searching the storage content of the EEPROM 66 when data is written. From the standpoint of speeding up, it is desirable to store the physical block number of the update block.

  In the present embodiment, an area for storing the validity determination block, a pointer area, and a data area are allocated to predetermined positions in the EEPROM 66. However, the positions to which these areas are allocated are not particularly limited. Absent. Further, it is not necessary to secure these areas as areas in a continuous range with the EEPROM 66. That is, the area for storing the validity determination block, the pointer area, or the data area can be secured at discontinuous positions on the EEPROM.

  Furthermore, in the present embodiment, only the previous storage contents are stored in the EEPROM 66, but other storage contents, for example, the previous storage time and the previous storage time can also be stored. . In this case, however, more storage capacity is required.

  By the way, the above-described series of processing can be executed by hardware or can be executed by software.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  The program may be processed by a single computer, or may be distributedly processed by a plurality of computers. Furthermore, the program may be transferred to a remote computer and executed.

  Further, in this specification, the system represents the entire apparatus constituted by a plurality of apparatuses.

  The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

  10 contactless communication system, 11 controller, 12 reader / writer, 13 IC card, 64 operation unit, 91 sequencer, 92 encryption / decryption unit, 93 parity operation unit, 66 EEPROM

Claims (6)

In an information processing method of an information processing apparatus using a recording medium on which information is recorded in a predetermined block unit,
The recording medium is
Consists of multiple blocks,
A data area for storing data in block units;
A pointer area for storing a plurality of block numbers assigned to each block of the data area;
A first block number indicating a block number of the pointer area indicating the target block of the data area in which data before update is stored, and an update block in the data area in which data after update is stored A first area for storing the second block number indicating the block number of the pointer area, and the latest information on the freshness of the stored contents;
According to the information processing apparatus,
Erase data stored in all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number stored in the first area in a batch A first erasing step that causes
Write to which updated data is written in at least a part of all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number, which is erased in a batch Steps,
A first storage step of storing a block number of a block of the data area in which the updated data is written in a block corresponding to the first block number of the pointer area;
A second storage step of storing a first block number of the pointer area in which the block number of the data area is stored in the first area. The recording medium further includes:
A first block number indicating a block number of the pointer area indicating the target block of the data area in which data before update is stored, and an update block in the data area in which data after update is stored A second area for storing the second block number indicating the block number of the pointer area, and the latest information on the freshness of the stored contents;
According to the information processing apparatus,
The first erasing step uses a block number stored in the pointer area corresponding to the second block number stored in one of the first or second areas selected based on the latest information. The data stored in all the update blocks in the corresponding data area are erased collectively,
The second storing step stores the first block number of the pointer area in which the block number of the data area is stored in the other of the first or second area,
After the second storing step, the method further includes a second erasing step for erasing the first and second block numbers and the latest information stored in the one of the first or second areas. The information processing method according to claim 1. The information processing method according to claim 2, wherein the processing of the first erasing step and the processing of the writing step are executed according to a write command. The processing of the writing step is executed according to a write command,
3. The information processing method according to claim 2, wherein the process of the first erasing step is executed at a predetermined timing preceding the process of the write step regardless of the presence or absence of the write command. In an information processing apparatus for recording information on a recording medium on which information is recorded in predetermined block units,
The recording medium is
Consists of multiple blocks,
A data area for storing data in block units;
A pointer area for storing a plurality of block numbers assigned to each block of the data area;
A first block number indicating a block number of the pointer area indicating the target block of the data area in which data before update is stored, and an update block in the data area in which data after update is stored A first area for storing the second block number indicating the block number of the pointer area, and the latest information on the freshness of the stored contents;
Erase data stored in all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number stored in the first area in a batch First erasing means for causing,
Write to which updated data is written in at least a part of all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number, which is erased in a batch Means,
First storage means for storing a block number of a block of the data area in which the updated data is written in a block corresponding to the first block number of the pointer area;
An information processing apparatus comprising: a second storage unit configured to store a first block number of a pointer area in which a block number of a data area is stored in the first area. A program for controlling an information processing apparatus using a recording medium on which information is recorded in predetermined block units,
The recording medium is
Consists of multiple blocks,
A data area for storing data in block units;
A pointer area for storing a plurality of block numbers assigned to each block of the data area;
A first block number indicating a block number of the pointer area indicating the target block of the data area in which data before update is stored, and an update block in the data area in which data after update is stored A first area for storing the second block number indicating the block number of the pointer area, and the latest information on the freshness of the stored contents;
Erase data stored in all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number stored in the first area in a batch A first erasing step that causes
Write to which updated data is written in at least a part of all the update blocks in the data area corresponding to the block number stored in the pointer area corresponding to the second block number, which is erased in a batch Steps,
A first storage step of storing a block number of a block of the data area in which the updated data is written in a block corresponding to the first block number of the pointer area;
A program for causing a computer of an information processing device to execute a process including a second storage step of storing a first block number of a pointer area in which a block number of a data area is stored in the first area.

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