JP2006155461A - Information processing apparatus, information processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up a recording process by deleting actual data which has been deleted on the FAT but remains on the memory or at the time of inserting a medium.
A directory entry of a file to be deleted is searched in step S11, a deletion mark is written to the directory entry in S12, and deletion is performed in blocks until starting at the first cluster number and reaching the end position EOF in S13. The cluster number to be searched is searched. List and hold information identifying the cluster number. In S14, the contents of the FAT entry are cleared from the start cluster number until the end position EOF is reached. In S15, the number of unused clusters is added by the number deleted. In S16, the start LBA for issuing the erase command and the number of sectors are calculated from the search result in S13. In S17, an erase command is executed, and the cluster group is erased in units of blocks.
[Selection] Figure 5

Description

  The present invention relates to an information processing apparatus, an information processing method, and a program applied to a batch erasing type semiconductor memory.

In digital video cameras, digital still cameras, personal computers, personal digital assistants, stationary video recorders, etc., MS-DOS (Microsoft Disc Operating
System (registered trademark) compatible FAT (File Allocation Table) file system is used to record various data such as still images, moving images, and audio (or music). For example, the following Patent Document 1, Patent Document 2, and Patent Document 3 describe data storage devices that apply a FAT file system to a memory card as a batch erase semiconductor memory (hereinafter referred to as a flash memory). .

JP 2003-263894 A

JP 2003-296177 A

JP 2003-308240 A

  In FAT16 / 32, even if file deletion processing is executed as a file system, only the contents of FAT are rewritten, and the contents of clusters in which actual data is recorded remain as they are. In other words, the erase block in which the cluster is located remains in the used state, and it cannot be reused unless the erase block contents are erased and returned to the unused state at some point before the next recording. There is a problem that the memory cannot be used effectively.

  In Patent Document 1, as an algorithm of a logical-physical conversion management table managed by a controller of a semiconductor memory, data is written to an unused block that has been erased in advance as much as possible, and an erasing operation is omitted to perform high-speed writing. It is described to do.

  The “unerased block” in Patent Document 1 is different from the above meaning that data is not deleted but remains in the FAT file system. The present invention eliminates the erasure overhead at the next recording by erasing the block holding the deleted data.

  That is, the object of the present invention is to quickly delete an erase block at the next recording time by deleting the actual data of the erase block when there is a cluster group to be deleted in erase block units when deleting a file. An information processing apparatus, an information processing method, and a program that can be recorded are provided.

  Another object of the present invention is to perform information processing in which when a removable data recording medium such as a memory card is inserted, an erasable block is checked by scanning the entire FAT of the medium, and erasing is performed after scanning. An apparatus, an information processing method, and a program are provided.

In order to solve the above-described problem, a first aspect of the present invention is an information processing apparatus for managing data on a recording medium on which data is recorded in units of erase blocks each having a predetermined data amount unit.
Search the actual data of the file that became erasable with the deletion of the corresponding management information on the file system, and the actual data that is an integer multiple of the unit that is determined as free space,
The information processing apparatus includes a control unit that controls the recording medium so as to erase the retrieved actual data.

According to a second aspect of the present invention, there is provided an information processing method for managing data on a recording medium on which data is recorded in units of erase blocks each having a predetermined amount of data.
Searching for real data of a file that has become erasable as a result of deleting the corresponding management information on the file system, which is an integral multiple of a unit determined as a free space;
An information processing method comprising a step of erasing retrieved real data.

According to a third aspect of the present invention, there is provided a program for causing a computer to execute an information processing method for a recording medium in which recorded data is collectively erased in units of a predetermined data amount.
Searching for real data of a file that has become erasable as a result of deleting the corresponding management information on the file system, which is an integral multiple of a unit determined as a free space;
An information processing method program comprising a step of erasing retrieved real data.

  According to the present invention, it is possible to prepare an unused block when deleting a file, and it is possible to quickly execute a recording process using the unused block at the next recording time. Compared to the conventional case, when deleting is deleted from the file system level, that is, when recording is performed on an erase block corresponding to a cluster that can be determined to be unused, the contents of the erase block are erased in advance and unused. Therefore, the time until recording is actually started can be shortened.

  In the present invention, the contents of the erase block are erased in advance when recording is performed on an erase block corresponding to a cluster that has been deleted from the file system level, that is, can be determined as unused, as compared to the conventional system. Since it is returned to the unused state, the time until recording is actually started can be shortened. For example, in high-speed continuous shooting recording of still images and the like, unless the processing until the start of recording is performed promptly, there is a risk that the recording operation will fail. In such a case, the present invention is effective.

  Prior to the description of one embodiment of the present invention, the FAT16 and FAT32 file systems will be described. FIG. 1 shows a data structure when a removable semiconductor memory such as a flash memory is formatted with the FAT16. FIG. 2 shows a data structure when the semiconductor memory is formatted with FAT32. The FAT 16 manages FAT with 16 bits, and the FAT 32 manages FAT with 32 bits. A specific example of the flash memory is a memory stick (trade name), and its standard is defined in “Memory Stick PRO Format Specification Ver.1.01-01”.

  In the FAT file system, data is managed in units of clusters composed of a plurality of sectors. The cluster size is a multiple of the sector size. For example, one sector is 512 bytes, and the size of one cluster is m (m = 1, 2, 4,..., 64, 128). In the case of m = 64, one cluster is 32K bytes.

  Conventionally, this cluster size is larger than the size of the erase block of the flash memory. However, in recent years, with the increase in the capacity of the flash memory, the size of the erase block has come to exceed the maximum cluster size. In consideration of such circumstances, in Patent Document 2, the recording efficiency is improved by setting the size determined as an empty area at the time of moving image recording to an erase block unit (an integer multiple) instead of a cluster unit. In FIG. 1 and FIG. 2, it is represented as an erase block, but in the following description, it is simply referred to as a block.

  1 and 2, the cluster size is smaller than the block size, and n times the cluster size (n is an integer of 2 or more) is the size of one block. For example, the size of one block is 128 Kbytes, the size of one cluster is 32 Kbytes, and (n = 4) clusters are included in one block. Therefore, the cluster numbers 0-3 = block N, cluster numbers 4-7 = block N + 1,...

In MS-DOS or the like, MBR (Master Boot Record), PBR (Partition Boot Record), FAT, and root directory entry are defined as file management data. The PBR is sometimes called BPB (BIOS Parameter Block). As an example, one partition is formed for the flash memory.

  The MBR is arranged at the beginning (LBA = 0) of the recording medium. Information of each partition (for example, start LBA sector number and size) is recorded in the MBR.

  The PBR is arranged in the head sector of each partition. The sector in which the PBR is recorded is described in the start LBA sector number in the MBR. The LBA sector number is a number uniquely assigned to each sector in the valid block (or a substitute block of the valid block). LBA sector numbers are assigned in ascending order from the top of a block having an LBA (logical block number) of 0.

  The FAT is recorded over a plurality of sectors from the sector following the PBR. The FAT represents a connection state of files handled in the user area in cluster units. Note that two FAT1 and FAT2 (hereinafter simply referred to as FAT) are recorded for backup. In addition, the physical data size of one FAT is constant as long as the number of clusters in the flash memory does not change.

  Data recorded on the medium is managed in cluster units. When one file is composed of a plurality of clusters, it is necessary to read the next cluster after reading one cluster. However, the next cluster is not always recorded at physically continuous positions on the flash memory. The FAT is information indicating which cluster is a cluster following a certain cluster. The subsequent relationship of the clusters indicated by the FAT is referred to as a FAT chain.

  All clusters existing on the medium are assigned cluster numbers starting from cluster number 0002. A cluster number is uniquely assigned to each entry in the FAT. Each entry stores the next cluster number connected to the cluster of the assigned cluster number. Therefore, the cluster number of the next cluster can be known by referring to the cluster number stored in the entry to which the cluster is assigned.

  In the case of FAT16, only the root directory entry is recorded from the next sector following the last sector in which the FAT is recorded. In the root directory entry storage area starting immediately after the FAT, entries of files and directories arranged in the root directory are described. The data size of the root directory entry storage area is constant. The first cluster (cluster number “02”) in the user area starts from the next sector following the file management data described above. In FAT32, the root directory entry is also recorded in the user data area in the same manner as the subdirectory.

  FIG. 3 is an example of data for explaining the time when data is recorded in the flash memory according to the FAT file system, for example, FAT32. FIG. 3A shows the FAT, and FIG. 3B shows the information structure of the directory entry.

The directory entry consists of 32 bytes of data, including “name” (8 bytes), “extended name” (3 bytes), “attribute” (1 byte), “reserved (meaning undefined” (1 byte), “Creation time” (3 bytes), “creation date” (2 bytes), “last access date” (2 bytes), “first cluster number (high)” (2 bytes), “recording time” (2 bytes), “Record date” (2 bytes), “first cluster number (low)” (2 bytes), and “file size” (4 bytes) are arranged in order from the top in FIG. One is represented in hexadecimal, starting with 0, and the other in decimal, starting with 1.

  The directory entry corresponds to each file or each directory. In the example of FIG. 3, four entries are recorded corresponding to four files. In the directory entry of the first file, (00000007h) (h means hexadecimal notation, and so on) is recorded as the leading cluster number. (00000008h) is recorded in the entry corresponding to the FAT shown in FIG. 3A. In the entry corresponding to (00000008h), (00000009h) is recorded. In an entry corresponding to (00000009h), data EOF indicating a file end cluster, for example, (0FFFFFFFh) is recorded. The EOF in the case of FAT16 is (FFFFh). In FIG. 3E, “-” represents an entry corresponding to an unused cluster. For example, data of all 0 is written.

  The first file is continuously recorded from the cluster numbers (00000007h) to (00000009h). Cluster chain information regarding other files is also held in the FAT. For example, in the case of the third file, the leading cluster number is (0000001Bh), and (00000011h) → (00000012h) → (00000013h) → (00000014h) → (00000003h) is recorded.

  As described above, each file consists of a directory entry that holds the file name, creation date and time, top cluster number, file size, etc., FAT that holds the chain information of the cluster, and the substance of the file recorded in units of clusters. It is recorded on the recording medium based on three elements of certain actual data. The recording positions of the three elements are not grouped but scattered.

  Processing for deleting a recorded file in the FAT16 or FAT32 will be described with reference to FIG. First, in step S1, a directory entry having a file name to be deleted is searched. In step S2, the searched directory entry is deleted. In the deletion operation, a code E5h as a deletion mark is written to the first byte, that is, the head of the name. In step S3, the chain information regarding the FAT file is cleared until the end position EOF is reached while referring to the FAT starting from the top cluster number of the directory entry. Clearing is done by writing zero data.

  With the above processing, the file deletion processing is completed. That is, conventionally, the process of deleting a file in the FAT file system is to write a predetermined value to the directory entry and clear the FAT. At that time, the actual data written in the data area of the recording medium is not processed, and the actual data remains. The term “deletion” in this specification means a process of writing a predetermined value to a directory entry and clearing the FAT.

Thus, when reusing a block that holds the contents of actual data of a deleted file, it is necessary to erase the contents of the block. Here, erasing the contents of a block constituting a semiconductor memory such as a flash memory means that the contents of the block are all physically set to “1” in binary representation, for example, electrically. The flash memory holds the data by changing the corresponding bit to “0” according to the contents written from the information “1”. Because of the nature of the flash memory in one embodiment, “1” → “0” can be written, but “0” → “1” cannot be written. It is necessary to perform writing after erasing. The time required for this erasing occurs as overhead. In this specification, the term “erase” means that the contents of the block are physically returned to “1”.

Whether the value can be read as “1” or “0” when the host, for example, the recording / reproducing apparatus reads the contents of the unused block depends on the processing of the controller in the semiconductor memory. That is, as for the state held by the flash memory itself, even if it is "1", whether the controller in the semiconductor memory returns to the host as "1" as it is, or whether it is inverted and returned as "0" depends on the controller, It depends on the type of semiconductor memory. Of course, valid data in use is not inverted, but as long as it is not in use, it can be returned to the host with a value of “1” or inverted to “0”.

  In one embodiment of the present invention, as an additional process at the time of file deletion, it is determined whether or not there is a cluster group that can be deleted in block units, and if such a cluster group exists, that block is determined. The contents of are deleted. By performing such processing, it is handled as an unused block at the next recording, and it is not necessary to erase, so that the recording processing can be executed promptly.

  FIG. 5 shows a flow of processing at the time of file deletion executed under the control of the host, for example, the CPU of the recording / reproducing apparatus in the embodiment of the invention. First, in step S11, a directory entry of a file to be deleted is searched. In step S12, a code E5h serving as a deletion mark is written in the first byte of the searched directory entry, that is, in the head of the name. Steps S11 and S12 are the same as steps S1 and S2 in the conventional process shown in FIG.

  In step S13, the cluster number deleted in units of blocks is searched from the beginning cluster number of the directory entry until reaching the end position EOF while referring to the FAT. Information for identifying the searched cluster number, for example, information on the start cluster number and the number of blocks is listed and held. In step S14, the contents of the FAT entry are cleared until the end position EOF is reached from the head cluster number.

  In step S15, the number of unused (empty) clusters is added by the number deleted. Although not shown, the number of unused clusters held is subtracted by the recorded number. In step S16, the start LBA (logical block number) for issuing the erase command and the number of sectors are calculated from the search result in step S13. In step S17, an erase command is executed, and the cluster group is erased in units of blocks. In the memory stick PRO, the erase command is referred to as an “ERASE command”.

  FIG. 6 shows the flow of processing for calculating the relationship between the block size and the cluster size. In step S21, the block size of the memory card is acquired. As an example, the memory stick PRO is provided with an attribute information area in which information necessary for controlling the memory card is recorded for a system area different from the user data area shown in FIGS. ing. Since there is “block size” as one of the information held in “Device Information” in this area, the block size can be acquired by referring to this information.

Next, in step S22, the cluster size of the memory card is acquired. The cluster size can be calculated by multiplying “PBRSecClus” (number of sectors per cluster) in the PBR by “PBRBytsPerSec” (number of bytes per sector). In step S23, the quotient of block size / cluster size, that is, the number X of clusters constituting one block is calculated, and the value of X is held. The number X of clusters constituting one block is used in the process of step S13. In the example shown in FIGS. 1 and 2, X = 4.

  FIG. 7 shows the process of step S13 in more detail. In the first step S31, the cluster number is divided by X, and in step S32, it is determined whether or not it has been divided. The fact that it is divisible means that the cluster number is located at the head of the block. In step S32, if it is determined that it was not divisible, the next cluster is searched in step S33. In step S34, it is determined whether or not the next cluster is a file end EOF. If it is EOF, the process ends. Otherwise, the process returns to step S31, and steps S31 and S32 described above are performed.

  If it is determined in step S32 that it is divisible, the process moves to step S35, and the cluster number is held as the start cluster number. In step S36, the next cluster is searched, and in step S37, it is determined whether or not the next cluster is the end EOF of the file. If it is EOF, the process ends. Otherwise, the process returns to step S38, and it is determined whether or not it is continuous.

  If it is determined in step S38 that the data is continuous, the number of continuous data is incremented in step S39. If not, in step S40, the number of continuations is initialized to 0, and the process proceeds to the search for the next cluster in step S33. In step S41 after step S39 in which the continuous number is incremented, it is determined whether or not the continuous number is equal to X, for example, 4.

  If it is determined in step S41 that the continuous number has not reached X, the process returns to the search for the next cluster in step S36. If it is determined in step S41 that the continuous number has reached X, in step S42, the cluster number and block number held in step S35 are held. The retained cluster number is the start cluster number at the beginning of the block.

  In step S42, the value of the number of blocks continuous with the cluster number in the form of a list is held. For example, when it is determined that three blocks can be erased from the erase block corresponding to the start cluster number OO, the contents of "cluster number OO 3" are written in one line of the list. In step S43 after step S42, the continuous number is set to 0, and the process returns to the search for the next cluster in step S36.

  FIG. 8 shows a formula for calculating the start LBA corresponding to the start cluster number. From the relationship between the block size and the cluster size calculated in the processing of FIG. 6, the “start LBA” and “sector number” required when issuing the erase command by converting the block number into the sector number I understand. Note that “Microsoft Extensible Firmware Initiative FAT32 File System” exists as a reference regarding details regarding FAT16 / 32, and each term in the calculation formula of FIG. 8 is a term in this reference. However, in this reference, “BPB” having the same meaning is used instead of “PBR”.

FIG. 8A shows a conversion formula in the case of FAT16. The start LBA of the data area corresponds to the start position A2 of the data area in FIG. “Partition start LBA” corresponds to the head position A1 of the PBR in FIG. “PBRRsvdSecCnt” represents the total data amount of the PBR and the data amount of the gap existing between the PBR and the FAT1, and is information included in the PBR. “PBRFATSz16” represents the size of the FAT. “PBRNumFATs” represents the number of FATs. These pieces of information are also included in the PBR. The number of FATs is two. “PBRRootEntCnt × 32 ÷ PBRBytsPerSec” represents the data amount of the root directory entry. When the total number of sectors exceeds the 16-bit space, the FAT size is changed to “PBRFATSz32” in the calculation of the FAT data amount.

The starting LBA of cluster number N is obtained by multiplying the value obtained by subtracting the number of clusters “PBRRootClus” (2 in this case) assigned to the directory entry from the total number of clusters N by the number of sectors per cluster “PBRSecPerClus”. Calculated.

In the case of FAT32 shown in FIG. 8B, the start LBA corresponding to the start cluster number and the start cluster number can be calculated as in the case of FAT16. The start LBA of the data area corresponds to the start position A12 of the data area in FIG. “Partition start LBA” corresponds to the head position A11 of the PBR in FIG. “PBRRsvdSecCnt” indicates a sum of the PBR, the data amount of the gap, and the data amount of FSinfo. In FAT32, there is no root directory entry as compared to FAT16, and therefore no item relating to the root directory entry exists in the formula.

  In the embodiment described above, when there is a cluster group that can be deleted in block units as an additional process when deleting a file, the contents of the block are deleted. In another embodiment of the present invention described below, an erasing process is performed when a recording medium such as a memory card is inserted.

  There may be two cases as the timing when the memory card is inserted. One is a case where the memory card is inserted in a power-on state, and the other is a case where the power is turned on after the memory card is inserted. In other cases, the erasing process may be performed every time the power is turned on, but it is not necessary to perform the erasing process every time the memory card is not replaced.

The flowchart of FIG. 9 shows the flow of processing of another embodiment for performing an erasing process when a memory card is inserted, which is executed under the control of a host, for example, a CPU of a recording / reproducing apparatus, in another embodiment of the present invention. In step S51, the block size and manufacturing serial number of the memory card are acquired. Next, in step S52, the cluster size of the memory card is acquired. In step S53, the quotient of block size ÷ cluster size, that is, the number X of clusters constituting one block is calculated and the value of X is held. The processes in steps S51, S52, and S53 are the same as the processes in steps S21, S22, and S23 in FIG. The serial number (4 bytes) of the memory card is "Device
Included in "Information".

  In step S54, the FAT is scanned. In this step, the erasure target is determined and the number of unused (empty) clusters is totaled. In the flowchart shown in FIG. 7 described above, a search is made for clusters that can be erased in block units from among the cluster groups that were deleted when the file was deleted. In the flowchart of FIG. 9, not only the deleted file but also the directory entry in which the code E5h as the deletion mark is written is searched in the entire FAT, and whether or not the cluster group corresponding to the directory entry can be erased in units of blocks. Is searched. In parallel, the number of unused (free) clusters in the entire memory card is counted. In addition to the processing according to another embodiment of the present invention, the FAT is usually scanned in order to check the remaining capacity of the semiconductor memory. Therefore, the erasing process can be performed during the scanning.

  In step S55, the acquired manufacturing serial number or the like is compared with the currently held manufacturing serial number or the like. Not only the manufacturing serial number but also information that can uniquely identify the memory card can be used. For example, “Device Information” includes manufacturer code (1 byte), manufactured product code (3 bytes), ID (16 bytes), etc., and these information are used as information for uniquely identifying the memory card. You may do it.

  In step S56, it is determined whether or not both match. If it is determined that they match, in step S57, the number of unused clusters counted in step S54 is compared with the number of unused clusters currently held.

In the case of FAT32, the number of unused clusters currently held is known by looking at “FSIFreeCount” (4 bytes) in “FSInfo” (see FIG. 2). The position of “FSInfo” can be found by referring to “PBRFSInfo” in the PBR. In the case of FAT16, since “FSInfo” does not exist, information corresponding to “FSIFreeCount” is held using, for example, a sector (512 bytes) located immediately after PBR.

  The result of the comparison in step S57 is determined in step S58. If the total number of unused clusters matches the number of unused clusters currently held, the number of unused clusters in the memory card has not changed from the state in which it is held. Since it means that they have not been exchanged, it is determined that the erasure process can be omitted, and the process ends. If it is determined that the two do not match, the number of unused clusters is held in step S60.

  If it is determined in step S56 that the acquired manufacturing serial number does not match the currently held manufacturing serial number or the like, in step S59, the manufacturing serial number or the like acquired in step S51 is stored in the nonvolatile recording / reproducing apparatus. Is held in memory. In step S60, the number of unused clusters is held. In step S61, the cluster group searched for deletion in step S54 is deleted. The erasure process is executed when the host gives an erasure command to the memory card as in the above-described embodiment of the present invention.

  In the erasing process in step S61, the actual data on the memory card is erased.

  One embodiment and other embodiments of the present invention described above can be implemented by software, and are implemented in a hierarchical structure of application, file system, device driver, and recording medium as shown in FIG. The application makes an access request to the file system at the file level, and the file system makes an access response to the access at the file level. The file system makes an access request to the device driver at the cluster level, and the device driver makes an access response to the file system at the cluster level. The device driver makes an access request to the recording medium at the sector level, and the recording medium makes an access response to the device driver at the sector level.

  FIG. 11 shows a configuration example of a file system. The file system 11 includes a recording control unit 12 and a media control unit 13. The recording control unit 12 includes a directory entry control unit 14, a cluster control unit 15, and a FAT control unit 16. The media control unit 13 has a position calculation unit 17. The device driver 18 controls the semiconductor memory 19 as a medium. A position calculation unit 17 of the media control unit 13 is coupled to the device driver 18. As processing of the recording control unit 12, processing such as determination of a cluster group to be deleted in block units, issuance of an erase command, execution of erase processing, and the like are added to the conventional processing.

FIG. 12 schematically shows a configuration example when the present invention is applied to a digital video camera. The subject image is supplied to the photoelectric conversion unit 22 including an imaging element such as a CCD (Charge Coupled Device) via the optical lens unit 21, and an imaging signal corresponding to the subject image is obtained. An imaging signal is supplied to the image signal processing unit 23. The image signal processing unit 23 performs processing such as γ correction and resolution conversion on the imaging signal. The image signal processing unit 23 performs compression processing by JPEG (Joint Photographic Experts Group) in the case of a still image, and performs image compression processing such as MPEG2 (Moving Picture Experts Group Phase 2) in the case of a moving image.

An image input / output unit 24 and a liquid crystal display 25 are connected to the image signal processing unit 23. The image input / output unit 24 can input a video signal of a predetermined method from the outside. The input video signal can be displayed on the liquid crystal display 25 through the processing of the image signal processing unit 23. In addition, the image signal processing unit 23 converts the video signal input via the image input / output unit 24 into recording data in the same manner as the analog video signal input from the photoelectric conversion unit 22, and sends it to the drive 33. It can also be transferred. Correspondingly, the image input / output unit 24 includes a video (image) signal output terminal / video signal input terminal according to a predetermined method such as a DV (Digital Video) format. The liquid crystal display 25 is provided in the digital video camera body and displays an image being captured, a reproduced image, and the like.

  An audio signal is input from the outside such as a microphone or a recording medium via the audio input / output unit 26, and the input audio signal is supplied to the audio processing unit 27. The audio processing unit 27 performs compression processing such as ATRAC (Adaptive Transfer Acoustic Coding) and MP3 (MPEG1 Audio Layer 3). The audio signal output via the audio input / output unit 26 is reproduced by a reproduction device such as headphones, and the output compressed audio signal is recorded on a recording medium.

Reference numeral 28 denotes a CPU (Central Processing Unit).
The AM 29, the ROM 30, the operation input unit 31, the communication unit 32, and the drive 33 are connected.

  A RAM 29 that is a built-in memory is a work memory that the CPU 21 uses for processing. The ROM 30 which is a built-in memory stores data such as programs. The operation input unit 31 is a plurality of keys such as operation buttons. You may use the operation input part of the structure of GUI. A wired network (USB, Ethernet (trademark), IEEE (Institute of Electrical and Electronics Engineers) 1394, etc.) or a wireless network (IEEE802.11a / b / g, Bluetooth, etc.) is connected to the communication unit 32. The drive 33 is a drive that controls a removable semiconductor memory such as a memory card.

  The CPU 28 writes data to the semiconductor memory via the drive 33 and reproduces data from the semiconductor memory. The captured image data is compressed and recorded in the semiconductor memory. Data recorded in the semiconductor memory is managed by the FAT16 / 32 file system. As described above, when the CPU 28 manages the semiconductor memory, an erasable cluster group is searched for as a block as an additional process at the time of file deletion or as a process performed at the time of insertion of the semiconductor memory. Erased.

  FIG. 13 schematically shows a configuration example when the present invention is applied to a personal computer. In FIG. 13, reference numeral 41 indicates a CPU, and 42 indicates a CPU bus. A ROM 43 and a RAM 44 which are built-in memories are connected to the CPU bus 42. The ROM 43 stores data such as programs. The RAM 44 is a work memory that the CPU 41 uses for processing.

  An input / output interface 45 as a device controller is connected to the CPU bus 42. As devices, an input unit 46, an output unit 47, a communication unit 48, and a storage unit 49 are provided. The input unit 46 includes a keyboard, a mouse, a scanner, and a microphone. The output unit 47 includes a display, a speaker, a printer, and a plotter. The communication unit 48 includes a part that performs communication by the USB, IEEE 1394, Bluetooth, and IEEE 802.11a / b / g methods. The storage unit 49 includes an optical disk, a magnetic disk, a magneto-optical disk, and a semiconductor memory.

  The CPU 41 writes data to the semiconductor memory included in the storage unit 49 via the input / output interface 45 and reproduces data from the memory card. As described above, data recorded in the semiconductor memory is managed by the FAT16 / 32 file system, a cluster group that can be erased in block units is searched, and the cluster group is erased.

  FIG. 14 schematically shows the management of a semiconductor memory according to the present invention. The semiconductor memory 51 includes a flash memory 52, a controller 53, and an interface 54 with a host. The controller 53 is not limited to a configuration controlled only from the recording / reproducing device 61 on the host side, but may be configured as a CPU, and may be controlled separately from the CPU 62 of the recording / reproducing device 61. The recording / reproducing apparatus 61 has an interface 63 between the CPU 62 and the semiconductor memory 51.

  The recording / reproducing device 61 accesses the semiconductor memory 51 by LBA (logical address). The logical-physical conversion is performed by the logical-physical conversion table 54 managed by the controller 53 of the semiconductor memory 51, and the page in the corresponding block is accessed.

  In Patent Document 1 listed at the beginning, as an algorithm of the logical-physical conversion management table 54, data is written (including update and change) to an unused block erased in advance as much as possible, and an erase operation is performed. It is described that writing is performed at high speed by omitting. The “unerased block” in Patent Document 1 refers to “a block that does not need to hold data by assigning a new unused block for write access”.

  The “unerased block” in Patent Document 1 is different from the meaning of “a block in which data is not deleted in the FAT file system” in the present invention. As described above, the present invention eliminates the overhead of erasure at the next recording by erasing the block holding the deleted data. It is different.

Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and various modifications based on the technical idea of the present invention are possible. For example, in the above description, one block is determined to be a free area. However, depending on the size of the block, a size smaller than one block, for example, ½ block, or a plurality of blocks can be determined as a free area. is there. Further, the present invention is not limited to a memory stick, but can be applied to a compact flash specified in “CF + and CompactFlash Specification Revision 2.1”. Furthermore, the present invention can also be applied to an SD memory card. Furthermore, the present invention can be applied to a file system other than FAT16 / 32, for example, UDF (Universal Disc Format) as a file system.

It is a basic diagram used for description of the semiconductor memory formatted by FAT16 which can apply this invention. It is a basic diagram used for description of the semiconductor memory formatted by FAT32 which can apply this invention. It is a basic diagram for demonstrating an example of FAT and a directory entry. It is a flowchart for demonstrating the conventional file deletion process. It is a flowchart for demonstrating the file deletion process by this invention. It is a flowchart for demonstrating the process which calculates the relationship between a block size and a cluster size. It is a flowchart for demonstrating the process which determines the cluster group which can be deleted per block. It is a basic diagram which shows the calculation formula of the logical address corresponding to a cluster number. It is a flowchart for demonstrating the erasure | elimination process performed at the time of media insertion (at the time of power ON). It is a basic diagram for demonstrating the positioning of the file system which can apply this invention. It is a block diagram which shows the structural example of the FAT16 / 32 file system which can apply this invention. It is a block diagram which shows the structural example of the digital video camera which can apply this invention. It is a block diagram which shows the structural example of the personal computer which can apply this invention. It is a block diagram for demonstrating the relationship between a recording / reproducing apparatus and semiconductor memory.

Explanation of symbols

21 Optical lens unit 22 Photoelectric conversion unit 28, 41 CPU
33 drives

Claims (9)

In an information processing apparatus for managing data of a recording medium on which data is recorded in units of erase blocks configured in units of a predetermined data amount,
Search the actual data of the file that became erasable with the deletion of the corresponding management information on the file system, and the actual data that is an integer multiple of the unit that is determined as free space,
An information processing apparatus having a control unit for controlling the recording medium so as to erase the searched actual data. The information processing apparatus according to claim 1,
An information processing apparatus, wherein the recording medium is a semiconductor memory. The information processing apparatus according to claim 1,
The information processing apparatus, wherein the control unit additionally deletes the searched actual data when deleting data held in the recording medium. The information processing apparatus according to claim 1,
The recording medium is a removable recording medium,
The information processing apparatus, wherein the control unit scans the file system management information to retrieve the actual data when the recording medium is inserted, and erases the retrieved actual data. In an information processing method for managing data of a recording medium on which data is recorded in units of erase blocks configured in units of a predetermined data amount,
Searching for real data of a file that has become erasable as a result of deleting the corresponding management information on the file system, which is an integral multiple of a unit determined as a free space;
An information processing method comprising: erasing the retrieved actual data. The information processing method according to claim 5,
An information processing method, wherein the recording medium is a semiconductor memory. The information processing method according to claim 5,
An information processing method for additionally deleting the retrieved actual data when deleting data held in the recording medium. The information processing method according to claim 5,
The recording medium is a removable recording medium,
An information processing method for scanning the file system management information when the recording medium is inserted, searching for the actual data, and erasing the searched actual data. In a program for causing a computer to execute an information processing method for a recording medium in which recorded data is collectively erased in units of a predetermined amount of data,
Searching for real data of a file that has become erasable as a result of deleting the corresponding management information on the file system, which is an integral multiple of a unit determined as a free space;
A program of an information processing method comprising the step of erasing the searched actual data.

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