JP2015204071A - Information processing device, information processing method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems, for example, in a non-volatile memory such as a NAND type flash memory, size of a writing unit and size of an erasure unit are different each other, and sometimes size of an area where actually erasure processing occurs in the non-volatile memory is larger than size of an object file which should be erased originally, thereby, resulting in difficulty of erasure processing on an SSD side on the object file, and there is time lag between issuance of a data erasure command and actual erasure processing.SOLUTION: An erasure command to data to be erased is issued and a writing command is issued to related data, simultaneously.

Description

  The present invention relates to an information processing apparatus, an information processing method, and a program using a nonvolatile memory such as a flash memory.

  2. Description of the Related Art In recent years, semiconductor disks (Solid State Drive, hereinafter referred to as SSD) using a flash memory as a storage medium have been increasingly used as an alternative storage for an HDD (hard disk drive) of an information processing apparatus. SSDs not only allow high-speed random access compared to HDDs, but also have the advantages of low power consumption, high impact resistance, light weight, and space saving.

  However, the flash memory mounted on the SSD has an upper limit on the number of writable times. Therefore, the flash memory controller mounted on the SSD distributes the write destination area on average so that writing concentrates on a specific area of the flash memory and a defective memory element is unlikely to occur at an early stage. Specifically, in order for the flash memory controller to equalize the number of times of writing to the flash memory, the correspondence between the logical address and the physical address of the flash memory is changed. For example, when a new write is performed, the physical address of the empty area with the smallest number of writes is made to correspond to the logical address specified in the write request. As a result, the lifetime of the flash memory, that is, the SSD is extended. This technique is called wear leveling.

  Here, from the viewpoint of security, it may be desired that data used for processing such as printout is not usable after processing. For example, Patent Document 1 proposes a method for making data difficult to be reused by encrypting data to be invalidated, writing it to an SSD, and erasing the encryption key.

  As another technique, a technique for overwriting an area holding data used for processing such as printout in the HDD with dummy data (fixed value, random value, etc.) is known. However, in the case of a conventional SSD, it is difficult to overwrite data to be invalidated because the write destination areas are distributed by wear leveling and the correspondence between physical addresses and logical addresses is also changed.

JP 2012-018501 A

  The technique of Patent Document 1 depends on the performance of the encryption protocol, and the data itself cannot be erased. In addition, with regard to the overwrite erasing technology, in an SSD that is executing wear leveling, the location and area (the physical address of the SSD) where data is actually written cannot be specified from the outside of the SSD (OS or application). In this method, overwriting and erasing were difficult.

  Accordingly, an object of the present invention is to provide a technique capable of efficiently erasing a file to be erased from a nonvolatile memory with a simple configuration.

  In order to solve the above-described problem, an information processing apparatus according to the present invention reads and writes data in units of first storage areas, and data in units of second storage areas having a plurality of first storage areas. An information processing apparatus including a nonvolatile memory that performs erasing of data, comprising: a control unit that controls access to the nonvolatile memory; and a management unit that manages a plurality of files held in the nonvolatile memory The management unit notifies the control unit of a first storage area corresponding to a file designated as an erasure target among the plurality of files, and data related to a file different from the file designated as the erasure target The data included in the second storage area including the first storage area that has been notified is different from the second storage area that includes the first storage area that has been notified. Characterized by an instruction to the control means to write to the storage area.

  According to the present invention, a file to be erased from a nonvolatile memory can be efficiently erased with a simple configuration.

It is a block diagram which shows the structure of a system. It is a block diagram which shows the structure of a SSD part. It is a block diagram which shows the data structure in a SSD part. It is a block diagram which shows the function structure regarding the input / output process to SSD. It is a flowchart regarding the input-output process to SSD. It is a flowchart regarding the input / output processing to the SSD. (A) It is a block diagram which shows the structure of a system. (B) It is a flowchart regarding the input / output process to SSD.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
<Overall configuration of information processing apparatus>
An example of the overall configuration of the information processing apparatus 100 in this embodiment is shown in FIG.

  In FIG. 1A, the information processing apparatus 100 includes a CPU 101, a ROM 102, a RAM 103, an I / F 104, an SSD 105, an operation unit 106, a display unit 107, and an engine 108, and each configuration is connected by a bus 109. .

  The CPU 101 controls the operation of each unit in the information processing apparatus 100 according to the contents of the ROM 102 and executes a program (OS or application) loaded in the RAM 103. The ROM 102 is a read-only memory, and stores a boot program and firmware, various processing programs for realizing processing to be described later, and various data. A RAM 103 is a work memory that temporarily stores programs and data for processing by the CPU 101, and various processing programs and data are loaded by the CPU 101.

  The I / F 104 is an interface for communicating with an external device such as a network device or a USB device, and performs data communication through the network and data transmission / reception with the external device. An SSD (Solid State Drive) 105 holds an OS (Operation System), various programs, or various data, and is a non-volatile storage device (non-volatile memory) using a NAND flash memory.

  The operation unit 106 is a user interface for receiving user operation instructions and various instructions including various parameter settings, and includes at least one of a keyboard, a mouse, a numeric keypad, a touch panel, and the like. The display unit 107 is a display device for notifying the user of operation confirmation, processing status, and the like, and includes at least one of a display, a touch panel, and the like. The engine 108 is an optional processing unit, and performs various processes such as printing and reading when instructed by the user. For example, a printer engine for printing image data on paper or a scanner engine for capturing image data from a recording medium. Here, the printer engine for printing image data on paper controls a plurality of printer heads according to bitmap data. A scanner engine that captures image data from a recording medium is one that, for example, transfers image data acquired by a line sensor to a RAM.

  The information processing apparatus 100 may be a generally used personal computer or an MFP (Multi Function Printer). Any device that can perform at least one of various operations such as printing, scanning, and copying by the engine 108 when an instruction is given using the operation unit 106 may be used.

  Next, FIG. 1B shows a program configuration of the information processing apparatus 100 in the present embodiment. The information processing apparatus 100 according to the present embodiment operates the OS 110 and the plurality of applications 111, and operates the plurality of applications 111 above the OS 110.

  The application 111 may be any application that performs information processing. For example, there are a document editing application, an image editing application, a Web connection application, a print processing application, a scan processing application, a copy processing application, and the like. When the application 111 writes data to the SSD 105, the application 111 performs a writing process via the OS 110. The reading process is the same. Here, on the OS 110 side, the logical address of the SSD 105 is designated, and the SSD 105 is read and written.

  The SSD 105 converts a logical address included in a write request or a read request from the OS 110 into a physical address using an address conversion table, and accesses its own nonvolatile memory.

<Configuration of SSD>
FIG. 2 shows the configuration of the SSD 105. The SSD 105 includes an SSD controller 200, an external I / F 201, a ROM 202, a cache memory 203, and a nonvolatile memory 204. The SSD controller 200 further includes a processor 205, an internal I / F 206, and a register 207.

  The SSD controller 200 controls the entire SSD 105. Data is written to the nonvolatile memory 204 based on a write command and data received from the CPU 101 or DMAC (not shown) of the information processing apparatus 100 via the bus 109 and the external I / F 201. Data is read from the nonvolatile memory 204 based on the read command. The SSD controller 200 may temporarily store write data or read data in the cache memory 203 in the course of these processes. A ROM 202 is a read-only memory and stores various programs and data used by the SSD 105. The cache memory 203 temporarily holds data in the course of processing by the SSD controller 200, and holds data in the nonvolatile memory 204. In the present embodiment, the nonvolatile memory 204 is a NAND flash memory.

<SSD processing>
FIG. 3 shows the configuration of the storage area of the SSD 105. The SSD 105 manages data in units called pages (first units) and units called blocks (second units). A page is the smallest unit of writing or reading processing, and usually has several kilobytes. A block is a unit of erasure processing and has a plurality of pages. FIG. 3A shows an example in which one block is composed of 64 pages. The SSD 105 cannot directly overwrite the page on which data has been written, and needs to perform an erasing process before writing. Since this erasing process must be performed not in units of pages but in units of blocks as deletion units, in the case of data writing processing in the state where there are no writable erased pages, block erasing processing is performed prior to writing processing. Do.

  The block erase uses a TRIM command and garbage collection. The TRIM command is an ATA standard command for notifying an area (page) that is no longer needed from the OS 110 side to the SSD 105. Garbage collection is a mechanism for rearranging valid pages to create erasable blocks having only invalid pages, and performing block erasure processing to increase free blocks. As a result, the block erase process is performed before the write process, and the block erase process during the write process is reduced. In this embodiment, an invalid page is notified by the TRIM command, and then garbage collection is performed to realize more efficient block erasure processing.

  Further, as illustrated in FIG. 3B, the SSD 105 holds a correspondence table (address conversion table) of logical addresses and physical addresses in the internal I / F 206, and performs data write / read processing based on the correspondence table. . For example, the controller 200 may distribute physical data write areas by moving frequently changed data to physical pages with a small number of writes and moving data with few changes to physical pages with a large number of writes. it can. At this time, the correspondence table is updated so that the address of the physical page to which data is moved is associated with the original logical address. In addition, when there is a new write processing request, it is possible to preferentially write to an area where the number of times of writing is small. These mechanisms are called wear leveling. Furthermore, the controller 200 can also perform error correction coding processing in the course of data read processing / write processing with a configuration not shown.

  Further, by referring to the page and block management information (block management information) shown in FIGS. 3A and 3B, the correspondence between the logical page and the physical page and the correspondence between the physical page and the block are obtained. be able to. For example, when identifying a block corresponding to a certain logical page, it can be identified by referring to the management information and following the logical page, physical page, and block in that order. Conversely, when a logical page corresponding to a certain block is identified, it can be identified by referring to the management information and following the block, physical page, and logical page in this order.

<SSD I / O>
FIG. 4 shows a functional configuration of the OS 110 regarding input / output management of the SSD 105. Note that the OS 110 has a functional configuration such as a timer function, a process management function, a memory management function, a device management function, and other input / output management, as in a general operation system, but description thereof is omitted in this specification. To do. As input / output management for the SSD 105, the OS 110 includes a file I / O unit 401, a FAT (File Allocation Table) reference unit 402, and a logical data I / O unit 403. The file I / O unit 401 manages access in units of files, and the FAT reference unit 402 refers to the FAT held in the FAT area 405 of the SSD 105 to interpret the correspondence between the file and the logical page. Then, based on the interpretation of the FAT reference unit 402, the logical data I / O unit 403 accesses the SSD in units of logical pages. The FAT is a table in which file attribute information such as a file name, file generation date / time, and file size is associated with one or more logical page numbers for storing file data entities for each file. In the following description, a set of fail attribute information and logical page number corresponding to a single file in the FAT is referred to as a FAT entry. By referring to the FAT entry, the OS 110 can access the data area 404 and input or output a file.

  Next, a flowchart of the SSD input / output process is shown with reference to FIG.

  First, the file I / O unit 401 receives a request for file operation from the application 111 or the OS 110. Then, the file I / O unit 401 determines whether the file operation type is “read (READ)”, “write (WRITE)”, or “delete (REMOVE)”. There are other types of file operation requests such as file creation and renaming, but they are omitted for simplicity of explanation.

  First, the processing when the file I / O unit 401 receives a file read request (READ in S501) will be described. The file read request includes, for example, a system call “read ()”.

  The FAT reference unit 402 searches the FAT in the FAT area 405 of the SSD 105 and acquires a FAT entry corresponding to the request file (S502). If the FAT entry cannot be acquired, an error is output as the return value of the system call, and the process is terminated.

  Based on the logical page number of the FAT entry, the logical data I / O unit 403 sends a data read request to the SSD, reads the data (S503), and combines the read data as a file (S504). The file includes the read data and file attribute information of the FAT entry. The logical data I / O unit 403 combines a plurality of page data into a file when the file is composed of a plurality of logical pages. Further, the logical data I / O unit 403 may create a file by deleting unnecessary data based on the size information that is one of the file attribute information for the read data.

The FAT reference unit 402 updates the FAT entry as necessary. For example, if the file attribute information includes information related to reading processing such as access time information, the FAT reference unit 402 updates the information.
The file I / O unit 401 returns the file output by the logical data I / O unit 403 to the work area (on the RAM 103) of the requesting application 111 or OS 110 (S506).

  Next, processing when the file I / O unit 401 receives a file write request (WRITE in S501) will be described. The file write request includes, for example, a system call “write ()”.

  The FAT reference unit 402 searches for the FAT in the FAT area 405 of the SSD 105 and starts processing to acquire a FAT entry corresponding to a file for which there is a write request (S507).

  Here, the FAT reference unit 402 determines whether or not the corresponding FAT entry has been acquired (S508). If the FAT entry can be acquired, the logical data I / O unit 403 transmits a data write request to the SSD based on the logical page number of the corresponding FAT entry, and writes the write target data to the SSD 105 (S509). At this time, the FAT reference unit 402 updates the FAT entry as necessary (S511). For example, when the file attribute information includes information related to writing such as a logical page number and writing time information, it is an update target.

  On the other hand, if the FAT reference unit 402 determines that the FAT entry could not be acquired in step S508, the logical data I / O unit 403 sends a data write request to the SSD 105 using an unused logical page number. By sending a data write request, data is written to the SSD 105 (S510). Then, the FAT reference unit 402 newly generates a FAT entry corresponding to the written file (S512).

  Next, processing when the file I / O unit 401 receives a file deletion request (REMOVE in S501) will be described. The file deletion request includes, for example, a system call “remove ()”.

  The FAT reference unit 402 searches the FAT in the FAT area 405 of the SSD 105 and acquires a FAT entry corresponding to the target file of the deletion request (S513). If the FAT entry cannot be acquired, an error is output as a return value, and the process ends.

  The logical data I / O unit 403 issues a TRIM command to the logical page number of the corresponding FAT entry and notifies the SSD 105 of the logical page number corresponding to the file to be deleted (S514). When a plurality of logical page numbers are included in the FAT entry corresponding to the file to be deleted, a plurality of logical page numbers (or logical block numbers) are notified to the SSD by the TRIM command. Based on the notification of the invalid logical page by the TRIM command, the SSD controller 200 executes garbage collection within the SSD 105. Here, when an invalid logical page is notified by the TRIM command, if the entire block of the SSD 105 becomes invalid, it can be erased immediately. Otherwise, the block erase is performed until garbage collection is performed. There are times when it is not.

  Further, the logical data I / O unit 403 acquires other logical page numbers included in the block including the logical page number from the SSD (S515). When a plurality of logical page numbers are included in the FAT entry, for each logical page, a block including the logical page is identified, and another logical page number included in the identified block is acquired.

  The FAT reference unit 402 determines whether the logical page number acquired in step S515 is included in the FAT entry acquired in step S513 (S516). If it is included in the FAT entry acquired in step S513, the process proceeds to step S518.

  If it is not included in the FAT entry acquired in step S513, it corresponds to the fact that these logical pages can be detected as data related to a file different from the file to be deleted, so these logical pages ( Data). Therefore, the logical data I / O unit 403 issues a write command for copying the contents of the page with the logical page number acquired in step S515 to another empty page to the SSD 105 (S517). Based on this write command, the SSD 105 updates the logical page and physical page correspondence table shown in FIG. 3B and copies the data to different physical pages. As a result, all SSD blocks corresponding to the request file can be handled as invalid pages, so that the block can be efficiently erased by the garbage collection.

  Further, the FAT reference unit 402 initializes the logical page number of the FAT entry acquired in step S513 (S518), and deletes the FAT entry (S519).

  In general, the functions of garbage collection include a function of making a block an unnecessary area and a function of erasing this block when all pages included in the block become unnecessary areas. However, the function of setting a block including a page to be erased as an unnecessary area cannot be immediately implemented if there is a valid page in the block. As a result, there may be a large delay between when the OS 110 notifies the unnecessary area by the TRIM command and when the actual invalidation processing is started in the SSD 105.

  According to the present embodiment, even in an SSD in which a TRIM command and garbage collection are performed, it is possible to reduce a time lag from when an unnecessary area is notified by the TRIM command until invalidation processing is performed on the notified page. it can.

  Note that the present embodiment has been described on the assumption that the flash memory is an SSD. However, this embodiment is not limited to the SSD. The present invention can also be applied to a flash memory such as an SD (Secure Digital) card. In this case, an SD controller may be used instead of the SSD controller 200 shown in FIG.

  As described above, according to the present embodiment, the time lag from when the file invalidation notification (TRIM command) is issued until the actual erasure process (block erase) is performed can be reduced.

(Embodiment 2)
In the first embodiment, the OS 110 identifies other pages included in the same block as the page corresponding to the file to be erased. In the present embodiment, a method for identifying and similarly processing another file (corresponding to data other than data to be deleted) in a partition containing a file to be deleted will be described.

  Steps and configurations similar to those of the first embodiment are denoted by the same reference numerals, and descriptions of those that are not functionally changed are omitted. In the first embodiment, the arrangement of files to be invalidated, such as disk partitions and directories, has not been described. In the present embodiment, the files to be invalidated are arranged in specific disk partitions. This is to place files used in various jobs when the information processing apparatus 100 is an MFP in a specific disk partition. For example, in the general-purpose OS, this is the same as the idea of allocating a temporary file area (/ tmp) to a specific disk partition.

  The input / output processing to the SSD according to the second embodiment will be described with reference to FIG. Note that read processing and write processing are the same as those in the first embodiment, and thus description thereof is omitted.

  When the file I / O unit 401 receives a file deletion request (REMOVE in S501), the FAT reference unit 402 searches the FAT in the FAT area 405 of the SSD 105 and acquires a FAT entry corresponding to the target file of the deletion request. (S513). Then, the logical data I / O unit 403 issues a TRIM command for the logical page number of the corresponding FAT entry, and notifies the SSD 105 of the logical page number corresponding to the file to be deleted (S514).

  Next, the FAT reference unit 402 searches the FAT in the FAT area 405, acquires FAT entries of all files in the same partition as the file to be deleted (S615), and identifies the file indicated by the acquired FAT entry. (S616). Multiple files are often identified to identify other files in the same partition.

  Then, the logical data I / O unit 403 issues a write command for copying each of the files identified in step S616 to a partition different from the partition containing the file to be deleted (S617).

  Further, the FAT reference unit 402 initializes the logical page number of the FAT entry (S618), and deletes the FAT entry (S619).

  As described above, according to the present embodiment, by saving other files included in the partition containing the file to be erased, it is possible to save an effective file only by referring to the FAT in the FAT area 405. .

  In this embodiment, when management information such as FAT is created for each partition, the data area 404 and the FAT area 405 are deleted from the partition containing the file to be deleted instead of steps S618 and S619. You may make it do. For example, the OS 110 may be able to issue an ERASE command for performing complete erasure by designating a partition containing a file to be deleted. In the FAT file system, information defining the size and number of partitions is held as a partition information in a specific area (master boot record). Depending on the file system, partition information may be held for each partition.

(Embodiment 3)
In the present embodiment, a configuration including a plurality of SSDs is employed, and other files included in the SSD in which the OS 110 includes a file to be deleted are saved in a different SSD, and the SSECRE ERASE is stored in the SSD 105 in which the file to be deleted is stored. Execute. Steps and configurations similar to those in the first and second embodiments are denoted by the same reference numerals, and descriptions of those that are not functionally changed are omitted.

  SECURE ERASE is one of the commands defined in the ATA standard or SATA standard, and is used as a command for completely erasing the HDD or SSD device for each device.

  FIG. 7A is a block diagram illustrating a schematic configuration of the information processing apparatus according to the present embodiment. Each of the SSDs 701 to 703 has the configuration of FIG. 2 and is recognized by the OS 110 as a separate device.

  The SSD 701 holds a system program such as an OS, and the SSD 702 and the SSD 703 do not hold a system program. The SSD 702 and the SSD 703 hold data to be processed by the engine 108 of the information processing apparatus 100.

  FIG. 7B is a flowchart showing details of input / output processing to the SSD in this embodiment. A description of the read process and the write process is omitted.

When the file I / O unit 401 receives a file deletion request (REMOVE in S501),
The FAT reference unit 402 searches the FAT in the FAT area 405 of the REMOVE target device (here, SSD 702) and acquires the FAT entry corresponding to the deletion request target file (S513).

  Next, the FAT reference unit 402 searches the FAT in the FAT area 405 of the SSD 702, acquires FAT entries of all files other than the files to be deleted (S704), and identifies the file indicated by the acquired FAT entry (S705). ).

  Then, the logical data I / O unit 403 issues a write command for copying each of the files identified in step S616 to a different SSD (in this case, SSD 703) from the SSD containing the file to be deleted (here, SSD 703). S706).

  Further, the logical data I / O unit 403 issues a SECURE ERASE command to the SSD 702 containing the file to be deleted, and the SSD controller 200 of the SSD 702 performs complete erasure on the contents of the nonvolatile memory 204 of the SSD 702. (S707). By performing complete erasure, the storage state of the nonvolatile memory 204 of the SSD 702 becomes the same as that at the time of factory shipment.

  As described above, in this embodiment, the other files included in the SSD containing the file to be erased are saved to another SSD, and the SSD including the file to be erased is securely erased by the SECURE ERASE command. Can do.

  In addition, although it was set as the structure which has multiple SSD for convenience of explanation, if it makes it seem that it is a some device from OS110, a SECURE ERASE command can be issued for every device. Therefore, the same effect can be obtained even if a plurality of device IDs and storage areas corresponding to the device IDs are allocated to one SSD.

  In the above-described embodiment, the TRIM command has been described as an example, but the TRIM command is a name for an ATA standard deletion instruction. Although it corresponds to the UNMAP command in the SCSI standard and is sometimes called a “Discard command”, the present embodiment can be realized by using any command.

  In the above-described embodiment, an example in which a write command for saving data is issued after a TRIM command is issued has been described. However, when data to be saved can be specified at the time of issuing a TRIM command, write processing and notification are performed. Processing may be performed in parallel.

  In the above-described embodiment, the FAT table is used for simplicity of explanation. However, the present embodiment can be similarly applied to a file system other than the file system that handles the FAT table (for example, NTFS or ext4). it can.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media. This is a process of reading and executing a program that can be read by a computer (or CPU, MPU, etc.) of the system or apparatus.

Claims (12)

An information processing apparatus including a nonvolatile memory that reads and writes data in units of a first storage area and erases data in units of a second storage area having a plurality of first storage areas,
Control means for controlling access to the nonvolatile memory;
Management means for managing a plurality of files held in the non-volatile memory, wherein the management means controls the first storage area corresponding to a file designated as an erasure target among the plurality of files. The data that is related to a file different from the file designated as the erasure target and that is included in the second storage area including the first storage area that has made the notification An information processing apparatus that instructs the control means to write to a storage area different from the second storage area including the first storage area.   The management means obtains management information for managing a correspondence relationship between the first storage area and the second storage area from the nonvolatile memory, thereby relating to a file different from the file designated as the erasure target The information processing apparatus according to claim 1, wherein data to be detected is detected.   The information processing apparatus according to claim 1, wherein the first storage area is a page, and the second storage area is a block.   The information processing apparatus according to claim 1, wherein the first storage area is a page, and the second storage area is a device.   The information processing apparatus according to claim 2, wherein the management information is an address conversion table.   The information processing apparatus according to claim 1, wherein the first storage area is a page, and the second storage area is a partition.   The information processing apparatus according to claim 6, wherein the management information is partition information of a file system. The information processing apparatus according to claim 1, wherein the nonvolatile memory is an SSD (Solid State Drive). An information processing method in an information processing apparatus including a non-volatile memory that reads and writes data in units of pages and erases data in units of blocks composed of a plurality of pages,
A control step of controlling access to the nonvolatile memory;
A notification step for notifying that the data has been invalidated in the file system,
In the control step, the block including the page corresponding to the data notified in the notification step is copied to a block different from the block including the page corresponding to the data received for the other page of the block. An information processing method characterized by the above. An information processing method for an information processing apparatus including a non-volatile memory that reads and writes data in units of pages and erases data in units of blocks composed of a plurality of pages,
A control step of controlling access to the nonvolatile memory;
A notification step for notifying that the data has been invalidated in the file system,
In the control step, for a block including a page corresponding to the data notified in the notification step, a page corresponding to data other than the data notified to the block is detected, and the detected page is transferred to another block. An information processing method characterized by copying. An information processing apparatus including a non-volatile memory that reads and writes data in units of pages and erases data in units of blocks composed of a plurality of pages.
Control means for controlling access to the nonvolatile memory;
Function as a notification means for notifying the control means that the data has been invalidated in the file system;
The control means is a block different from the block including the page corresponding to the data notified by the notification means for the other pages of the block, including the page corresponding to the data notified by the notification means. A computer-readable program characterized by copying to a computer. An information processing apparatus including a non-volatile memory that reads and writes data in units of pages and erases data in units of blocks composed of a plurality of pages.
Control means for controlling access to the nonvolatile memory;
Function as a notification means for notifying the control means that the data has been invalidated in the file system;
The control means detects a page corresponding to other data other than the data notified to the block for a block including a page corresponding to the data notified by the notification means, and detects the detected page as another block. A computer-readable program characterized by copying to a computer.

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