JP4707335B2 - Storage device, image forming apparatus, and file server - Google Patents

Description

  The present invention relates to a storage device that stores data to be read / written and data including identification information and storage address information of the data in a storage medium, an image forming apparatus including the storage device, and a file server.

  An image forming apparatus such as a copying machine or a multifunction peripheral that reads image data of a document and forms an image on a sheet is provided with a hard disk drive (hereinafter referred to as HDD), and the read image data is stored in the HDD. There is an image processing apparatus having an electronic filing function capable of reading out image data stored in the image forming apparatus and forming an image on a sheet.

  Management of data stored in the HDD is performed in units of files using a file system (data management system) such as FAT (File Allocation Table). The file includes one or more data or programs. The HDD stores a file to be read / written such as image data and data (hereinafter referred to as management data) including entry information and FAT information (storage address information) of the file. Here, the FAT information includes information such as a cluster in which the file is stored, and the entry information includes information such as a file name for identifying the file and a leading cluster in which the file is stored. 10A is a conceptual diagram illustrating an example of entry information, FIG. 10B is a conceptual diagram illustrating an example of FAT information, and FIG. 10C is an example of data stored in the HDD. FIG.

  In the example of FIG. 10C, the HDD cluster (0012) is not used in the defective cluster, and the first, second, third (last) of the file A obtained by dividing the file A based on the cluster size. Each data is stored in a cluster (0010), (0011), (0013) of the HDD. In the example of FIG. 10B, the cluster (0010) is linked to the cluster (0011), the cluster (0011) is linked to the cluster (0013), the cluster (0013) is the last, and the cluster (0012) ) Is managed to be a bad cluster. In the example of FIG. 10A, it is managed that the first cluster of file A is (0010).

  When reading file A, the first cluster (0010) of file A is obtained by referring to the entry information, and file A is stored in clusters (0010), (0011), and (0013) by referring to the FAT information. Data is read from the HDD clusters (0010), (0011), and (0013).

  When deleting a file stored in the HDD, the part corresponding to the file A of the entry information and FAT information is updated. FIG. 11 is a diagram showing an example of a conventional procedure for deleting file A. In FIG. 12A, 12B, and 12C show examples of entry information relating to file A, examples of FAT information, and examples of data stored in the HDD when a portion corresponding to file A is updated. FIG. The deletion of the HDD 20 is performed by the CPU 12 of the external system to which the HDD 20 is connected, for example.

  As shown in FIG. 12A, the entry information of the file A is invalidated by updating the file name to “file A (deleted)” ((1) in FIG. 11). For example, a deletion bit is provided in the bit string of “file name” of the entry information, normally the deletion bit is set to “0”, and the deletion bit is updated to “1” to invalidate it. Next, as shown in FIG. 12B, a FAT operation is performed ((2) in FIG. 11), and the link of the cluster corresponding to the file A is cleared (updated to “free”).

  In FIG. 12A, since the file A of the entry information is “deleted”, the file A cannot be read. In FIG. 12B, since the FAT information clusters (0010), (0011), and (0013) are “vacant”, they can be used for storing other data. However, as shown in FIG. 12C, the file A is still stored in the HDD (magnetic disk). As described above, when a file is deleted, the entry information and FAT information corresponding to the deletion target file are cleared, but since the deletion target file is still stored in the HDD, the HDD is removed from the image forming apparatus. Therefore, there is a possibility that the deletion target file stored in the HDD is read.

  Therefore, a file management method has been proposed in which when deleting a file, the entire contents of the file are deleted from the directory area and data area of the file (see, for example, Patent Document 1). In this method, the entry information and FAT information corresponding to the deletion target file are cleared, and the deletion target file stored in the HDD is overwritten and deleted (hereinafter referred to as overwriting deletion). Cannot be read.

As a storage device, an optical information processing apparatus and system in which a plurality of heads can independently access a plurality of locations have been proposed (see, for example, Patent Document 2). In this apparatus and system, for example, it is possible to perform an erasing process with one of a plurality of heads and perform a writing process or a reading process with another head, and file erasing can be performed efficiently.
Japanese Patent Laid-Open No. 01-053241 Japanese Patent Laid-Open No. 05-205285

  However, in the method of Patent Document 1, overwriting is erased by control of an external system such as a CPU external to the storage device, which increases the load on the external system and delays various processes executed by the external system. is there. In addition, during overwriting erasure, overwriting data is transferred from the external system to the storage device, which increases the data transfer traffic between the external system and the storage device and slows down other data transfer. is there. The apparatus and system of Patent Document 2 also have the same problem as described above because each head is controlled by the control of the external system and the erasing process and the reading process or the writing process are performed independently.

  The present invention has been made in view of such circumstances, and in response to an erasure request received from the outside, by overwriting and erasing data to be erased, the load on the external system at the time of overwriting erasure, And it aims at providing the memory | storage device which can reduce the data transfer traffic between an external system and a memory | storage device.

  In addition, the present invention provides a storage device capable of reliably performing erasure even when the power is turned off during or before erasing by detecting an erasure request when the power is turned on. For other purposes.

In addition, the present invention indirectly overwrites the number of times of overwriting and / or data used for overwriting by overwriting data to be erased based on rank information (hereinafter referred to as erasing method information). to provide a memory device capable of specifying the other purposes.

  Further, according to the present invention, when data is not written or read, overwriting is performed with a general configuration including one read / write means by overwriting the data to be erased. Another object is to provide a storage device that can perform the above-described operation.

  Further, the present invention performs overwriting erasure and writing and / or reading simultaneously by controlling at least one of a plurality of reading / writing means and overwriting data to be erased. Another object is to provide a storage device that can perform the above-described operation.

  The present invention also provides a storage device that can process overwriting erasures corresponding to a plurality of erasing requests in the order of generation by storing erasing requests in the order of detection and performing overwriting based on the erasing requests in the order of storage. The other purpose is to provide.

  Another object of the present invention is to provide an image forming apparatus capable of efficiently erasing image data stored in a storage device.

  Another object of the present invention is to provide a file server that can efficiently perform erasure processing of data stored in a storage device.

The storage device according to the present invention includes a read / write means for writing data to the storage medium identified by the identification information and reading from the storage medium, and data read by the read / write means. A communication means for receiving and transmitting the read data, wherein the communication device stores the identification information of the data to be read / written and the storage address information of the data in the storage medium in the storage medium. The means is configured to receive the data erasure request, the means for adding erasure request information to identification information of data to be erased based on the erasure request received by the communication means, and the storage medium detecting means for detecting the erasure request information from the stored identification information, storing means for storing the erasure request information is detection means detects the detection order, and controls the reading and writing means, to said memory means In憶順, and erasing means for erasing performing overwriting the predetermined data to the data identified by the identification information deletion request information is added, and means for initializing the storage address information of the data, the identification information Means for changing the erase request information added to the erased information.

The storage device according to the present invention is characterized in that the detection means is configured to detect erasure request information when the power is turned on.

Memory device according to the present invention, the erasure request information includes rank information corresponding to the difficulty of restoring the data to be erased, before Symbol erasing means, in response to the rank information that is included in the erase request information The present invention is characterized in that one or more types of predetermined data are overwritten.

  The storage device according to the present invention includes one read / write unit, and the erasing unit does not write data received by the communication unit or read data transmitted from the communication unit. The present invention is characterized in that the data to be erased is overwritten.

  The storage device according to the present invention includes a plurality of read / write means, and the erasure means is configured to control at least one read / write means to overwrite data to be erased. It is characterized by being.

  An image forming apparatus according to the present invention includes the above-described storage device that stores image data, and an image forming unit that forms an image on a sheet based on the image data stored in the storage device.

  A file server according to the present invention includes the storage device described above, and communication means for transmitting data stored in the storage device and receiving data stored in the storage device.

  In the present invention, a data erasure request is received from the outside. For example, an erase request command is received from an external system connected to the storage device. When an erase request is detected, the read / write means is controlled by the erase means of the storage device, and the data to be erased is overwritten and erased. The external system only needs to give an erase request to the storage device, and the storage device automatically performs erasure by overwriting (hereinafter referred to as overwriting erasure). Since the external system does not need to control the storage device for overwriting, the load on the external system during overwriting can be reduced, and data transfer traffic between the external system and the storage device during overwriting can be reduced. Can be reduced.

  In the present invention, after overwriting the data to be erased, the erasure unit of the storage device corresponds to the data to be erased of the data including the identification information and the storage address information (hereinafter referred to as management data). Update the part. For example, the storage device side updates the portion of the management data corresponding to the data to be erased, such as updating the FAT included in the management data. After the data to be deleted is overwritten, the corresponding portion of the management data is updated on the storage device side in the same manner as normal data deletion. The external system only needs to give an erase request to the storage device, and the storage device automatically updates the corresponding portion of the management data after overwriting is erased. It is possible to efficiently perform erasure processing including overwriting data and updating corresponding portions of management data.

  In the present invention, the erasure request is included in the management data. For example, a flag indicating whether or not there is an erasure request is provided in the identification information included in the management data (the erasure request is “1”, usually “0”), and the above flag is updated to “1”. It is possible to erase a book. Since the erasure request is included in the management data, it is not necessary to change the communication procedure between the external system and the storage device for overwriting, such as adding a new command for overwriting.

  In the present invention, when the erasure request is included in the management data, and the power is turned off without erasing all of the data to be erased, the erasure request for the data for which the overwriting erasure is completed is derived from the management data. An erasure request for data that has been cleared but has not been overwritten yet remains included in the management data. Thereafter, when the power is turned on, overwriting erasure of data to be erased is performed in response to the erasure request included in the management data. Even when the power is turned off during or before erasing, the data to be erased can be surely erased by erasing after the power is turned on.

  In the present invention, the erasure request includes erasing method information for data to be erased. The erasing method information includes, for example, designation of the number of times of overwriting and / or type of overwriting data used for overwriting, and the designated number of times using the designated overwriting data. Overwrite. It is also possible to specify overwriting data for each overwriting. Generally, it is more difficult to restore erased data when the number of overwriting is larger, and it is more difficult to restore erased data using random data than using “00” or “FF” as overwriting data. The external system can indicate the overwriting data and / or the number of overwriting depending on the sensitivity or importance of the data to be erased.

  In the present invention, one read / write means is provided, and when data is not written or read, the data to be erased is overwritten. A general storage device cannot simultaneously write and read data, and cannot simultaneously write or read and erase. By performing erasing when writing or reading is not performed, writing or reading during execution is performed with priority.

  In the present invention, a plurality of read / write means are provided, and data to be erased is overwritten using at least one read / write means. Some storage devices can simultaneously write and read data using a plurality of independent read / write means, and can simultaneously write and / or read and overwrite erase. is there. By performing overwriting erasure and writing and / or reading simultaneously, overwriting erasing can be performed efficiently.

  In the present invention, the detected erasure requests are stored in the storage means in the order of detection. By performing overwriting based on the erasure request in the order of storage in the storage means, overwriting erasure corresponding to each of the plurality of erasure requests is processed in the order of occurrence.

  In the present invention, image data is stored in the storage device described above, and an image based on the stored image data is formed on a sheet. The image data stored in the storage device is erased efficiently as described above.

  In the present invention, data is stored in the above-described storage device, and the stored data is transmitted to an external communication network, or data received from an external communication network is stored in the storage device. The data stored in the storage device is erased efficiently as described above.

  According to the present invention, it is possible to reduce the load on the external system when overwriting is erased. Further, it is possible to reduce data transfer traffic between the external system and the storage device at the time of overwriting.

  According to the present invention, it is possible to efficiently perform an erasure process including overwriting data and updating corresponding portions of management data.

  According to the present invention, an erasure request can be accepted without changing the communication procedure between the external system and the storage device.

  According to the present invention, even if the power is turned off during erasing or before erasing, overwriting erasure of data to be erased can be performed reliably.

  According to the present invention, the number of times of overwriting and / or data used for overwriting can be designated from the outside. An erasing method corresponding to the confidentiality or importance of data to be erased can be designated from the outside.

  According to the present invention, overwrite erasure can be performed by a general storage device having one read / write unit.

  According to the present invention, overwrite erasure and writing and / or reading can be performed simultaneously. Overwriting is efficiently performed, and data to be erased can be quickly erased.

  According to the present invention, overwriting erasures corresponding to a plurality of erasure requests can be processed in the order of occurrence.

  According to the present invention, it is possible to efficiently perform image data erasure processing stored in a storage device of an image forming apparatus that forms an image based on image data on a sheet.

  ADVANTAGE OF THE INVENTION According to this invention, the deletion process of the data memorize | stored in the memory | storage device of the file server which transmits / receives data with an external communication network can be performed efficiently.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. FIG. 1 is a block diagram showing a configuration example of an image forming apparatus provided with a storage device (HDD) according to the present invention. The image forming apparatus includes a CPU (Central Processing Unit) 12, a ROM (Read Only Memory) and a RAM (Random Access Memory) 16, a memory controller 14 to which the CPU 12, the ROM and the RAM 16 are connected, and the memory controller 14. The connected data control unit 18, the HDD (Hard Disk Drive) 20 connected to the data control unit 18, the compression / decompression unit 22, the image memory 24, the image processing unit 26, and the image processing unit 26 The image reading unit 28 and the image forming unit (image forming unit) 30 are provided.

  The image reading unit 28 includes an image scanner and the like, and reads image data of a document. The read image data is sent to the image processing unit 26. The image processing unit 26 performs various processes such as enlargement / reduction, density adjustment, and color correction on the image data. Further, the image processing unit 26 sends the image received from the image reading unit 28 to the data control unit 18 or sends the image data received from the data control unit 18 to the image forming unit 30. The image forming unit 30 includes a printer and the like, and forms an image based on the image data received from the image processing unit 26 on a sheet.

  The data control unit 18 controls data transfer among the memory controller 14, HDD 20, compression / decompression unit 22, image memory 24, and image processing unit 26. The compression / decompression unit 22 compresses the image data received from the data control unit 18 and decompresses the compressed image data received from the data control unit 18. The image memory 24 includes a DRAM (Dynamic RAM) and the like, and stores the image data received from the data control unit 18.

  The memory controller 14 controls data transfer among the CPU 12, the data control unit 18, the ROM, and the RAM 16. The CPU 12 executes a control program stored in the ROM, and controls each unit in the image forming apparatus. The RAM stores data temporarily generated during the control process.

  FIG. 2 is a block diagram illustrating a configuration example of the HDD 20. The HDD 20 includes an I / F (interface) 34 to which the data control unit 18 is connected, a storage medium 40 such as a magnetic disk, a head 42 for writing / reading data to / from the storage medium, the storage medium 40 and A drive unit 38 that drives the head 42; a control unit 32 that controls each unit in the HDD 20 such as control of the drive unit 38, data writing / reading using the head 42, and data transmission / reception of the I / F 34; And a cache 36 for temporarily storing data to be written to the storage medium 40 or data read from the storage medium 40.

  The storage medium 40 stores a file to be read / written such as image data, and management data including entry information (identification information) and FAT (File Allocation Table) information (storage address information) of the file. . The file includes one or more data or programs. FIG. 10A is a conceptual diagram illustrating an example of entry information, FIG. 10B is a conceptual diagram illustrating an example of FAT information, and FIG. 10C is a diagram illustrating data stored in the storage medium 40. It is a conceptual diagram which shows an example.

  In the example of FIG. 10C, the cluster (0012) of the storage medium 40 is not used as a defective cluster, and the first, second, third (last) of the file A obtained by dividing the file A based on the cluster size. ) Are stored in clusters (0010), (0011), and (0013) of the storage medium 40, respectively. In the example of FIG. 10B, the cluster (0010) is linked to the cluster (0011), the cluster (0011) is linked to the cluster (0013), the cluster (0013) is the last, and the cluster (0012) ) Is managed to be a bad cluster. In the example of FIG. 10A, it is managed that the first cluster of file A is (0010).

  In the HDD 20, an I / F (communication means) 34 receives a data deletion request in units of files. The control unit 32 detects a file erasure request and, when detecting the erasure request, controls the head (read / write unit) 42 and the drive unit 38 to overwrite the file to be erased. Operate as an erasing means for erasing. Note that the control unit 32 overwrites the file to be deleted when the file received by the I / F 34 is not written or the file transmitted from the I / F 34 is not read. The control unit 32 creates invalid data (overwriting data) used for overwriting. Further, after overwriting the file to be erased, the control unit (erasing unit) 32 controls the head 42 and the driving unit 38 to update the portion of the management data corresponding to the file to be erased.

  The erasure request is written in the management data, and the control unit (detection means) 32 detects the erasure request written in the management data. For example, an erase request bit is provided in the bit string of “file name” of entry information, and the CPU 12 of the image forming apparatus normally sets the erase request bit to “0” and updates the erase request bit to “1”. It is possible to make an erasure request. In this case, the control unit 32 detects that the erase request bit has been updated to “1”.

  The control unit 32 includes an erasure queue (storage means) that stores the detected erasure requests in the order of detection, and performs overwriting based on the erasure requests in the order of storage in the erasure queue. The control unit 32 detects an erasure request when the image forming apparatus is powered on. The control unit 32 operates as an identification unit for identifying a file system (data management system) used in the storage medium 40, detects an erasure request based on the identified file system, and adds it to the file to be erased. Write a letter.

  Next, erasure of data stored in the storage device (HDD 20) according to the present invention will be described by taking the case of erasing the file A shown in FIGS. 10 (a) to 10 (c) as an example. FIG. 3 is a diagram showing an example of a procedure for deleting the file A. The CPU 12 requests the HDD 20 to delete the file A via the memory controller 14 and the data control unit 18 ((1) in FIG. 3). 4A, 4B, and 4C show an example of entry information related to the file A, an example of FAT information, and an example of data stored in the storage medium 40 when an erasure request is made. It is a conceptual diagram. As shown in FIG. 4A, the file name is updated from “file A” to “file A (necessary for deletion)” by updating the deletion request bit of the entry information in response to the deletion request. . As shown in FIGS. 4B and 4C, the FAT information and the data stored in the storage medium 40 at this time are the same as those shown in FIGS. 10B and 10C.

  It is detected by the control unit 32 (detection means) that the CPU 12 has issued an erasure request and the entry information of the file A has been updated ((2) in FIG. 3). Normally, the update of the file name of the entry information is monitored, and the erase request is detected by checking whether the update is an erase request (erase request bit = “1”). The control unit 32 that has detected that the entry information has been updated from “file A” to “file A (deletion required)” (the deletion request bit has been updated from “0” to “1”) The file A stored in the storage medium 40 is overwritten and erased based on the “first cluster” and the FAT information ((3) in FIG. 3). More specifically, the invalid data generated by the control unit 32 is overwritten in the file A.

  5A, 5B, and 5C are examples of entry information related to file A when file A is overwritten, examples of FAT information, and examples of data stored in storage medium 40. FIG. FIG. As shown in FIG. 5C, the first, second and third (last) data of the file A are overwritten and deleted by invalid data. As shown in FIGS. 5A and 5B, the entry information and FAT information at this time are the same as those shown in FIGS. 4A and 4B.

  After overwriting and erasing the file A stored in the storage medium 40, the control unit 32 performs FAT operation to update the FAT information in response to the file A being overwritten and erased. Further, the entry information is updated to invalidate the entry of the file A ((5) in FIG. 3). 6A, 6B, and 6C show examples of entry information relating to file A when FAT information and entry information are updated after overwriting and erasing file A, examples of FAT information, and storage. 4 is a conceptual diagram illustrating examples of data stored in a medium 40. FIG. As shown in FIG. 6B, the links of the clusters (0010), (0011), and (0013) corresponding to the file A are cleared (updated to “free”). Further, as shown in FIG. 6A, the file name of the entry information is changed from “file A (necessary for deletion)” to “file A (erased)” according to overwriting erasure in accordance with the update of the FAT information. ”Has been updated. Here, in the erased update, for example, the erased bit included in the file name can be updated in the same manner as the erase request. As shown in FIG. 6C, the data stored in the storage medium 40 at this time is the same as in FIG. 5C.

  As shown in FIG. 3, the CPU 12 only needs to issue an erasure request, and overwrite erasure, FAT operation, and entry invalidation are automatically executed on the HDD 20 side. Further, the HDD data can be erased without affecting the data transfer of the data control unit 18 such as the transfer of image data between the image memory 24 and the image processing unit 26. Note that normal reading or writing of data is performed under the control of the CPU 12 or the data control unit 18 as in the prior art. When the image processing apparatus is turned on, the control unit 32 identifies the file system applied to the storage medium 40 and detects the erasure request.

  In the embodiment described above, it is also possible to specify a method for erasing data to be erased. For example, it is possible to include erasing method information including the number of overwriting and / or designation of overwriting data used for overwriting in the erasing request. The control unit (erasing unit) 32 controls the head (reading / writing unit) 42 to perform overwriting based on the erasing method information.

  FIG. 7 is a conceptual diagram showing an example of entry information when importance or confidentiality rank is used as erasing method information. As for the rank, “1” has the highest importance or confidentiality, and the higher the rank, the more difficult it is to restore data by increasing the number of overwriting. For adding a rank to a file name, for example, a rank bit can be added similarly to an erasure request. The correspondence between each rank and the erasing method (overwriting count, overwriting data) is stored in advance in the storage medium 40 or the like.

  For example, if rank 5 is overwritten with the specified invalid data, rank 4 is overwritten with random invalid data, then overwritten with random invalid data, and finally "00" invalid data. Overwrite with. For example, in the case of rank 3, overwrite with invalid data of “00”, then overwrite with invalid data of “FF”, and finally overwrite with invalid data of “00”. Is overwritten with invalid data “00”, overwritten with invalid data “FF”, and finally overwritten with predetermined invalid data. For example, in the case of rank 1, it is overwritten with invalid data “00”, then overwritten with invalid data “FF”, then overwritten with invalid data “00”, and then “FF”. Overwritten with invalid data of “00”, overwritten with invalid data of “00”, overwritten with invalid data of “FF”, and finally overwritten with predetermined invalid data.

  In each of the embodiments described above, the storage device cannot perform writing and reading simultaneously, but some storage devices can perform writing and reading simultaneously using a plurality of independent heads. is there. FIG. 8 is a block diagram illustrating a configuration example of the HDD 21 including a plurality of independent heads (read / write means). The HDD 21 includes an I / F 34 to which the data control unit 18 is connected, a storage medium 40 such as a magnetic disk, two heads 42 a and 42 b for writing and reading data to and from the storage medium 40, and the storage medium 40. The drive unit 39 for driving the heads 42a and 42b, and the control for controlling each unit in the HDD 21, such as control of the drive unit 39, writing / reading using the heads 42a and 42b, and data transmission / reception of the I / F 34, etc. And a cache 36 for temporarily storing data to be written to the storage medium 40 or data read from the storage medium 40.

  The drive unit 39 drives the two heads 42a and 42b independently. Also, under the control of the control unit 33, writing or reading is performed independently using both of the two heads 42a and 42b, writing is performed on one of the two heads 42a and 42b, and reading is performed on the other. It is possible. Therefore, under the control of the control unit (erase unit) 33, overwriting is performed using both the two heads 42a and 42b, overwriting is performed on the one hand, and normal data writing or reading is performed on the other hand. Is possible.

  In each of the embodiments described above, the storage device of the present invention is used for an image forming apparatus. However, the present invention is not limited to the image forming apparatus, and the storage device of the present invention can also be used for a file server, for example. FIG. 9 is a block diagram showing a configuration example of a file server including a storage device (HDD) according to the present invention. The file server 60 is connected to a communication network 62 such as a LAN or the Internet. The file server 60 includes a CPU 12, a main memory 52 such as a DRAM, a host bridge 50 connected to the CPU 12 and the main memory 52, a bus master 54 connected to the host bridge 50, the HDD 20, and a communication I / F (communication means). 58. The communication I / F 58 is connected to the communication network 62.

  Although not shown, a client device such as a computer is connected to the communication network 62, and the data stored in the HDD 20 is communicated from the communication I / F 58 under the control of the CPU 12 as in a general file server. Data transmitted to the network 62 or received by the communication I / F 58 from the communication network 62 can be stored in the HDD 20.

  The HDD 20 shown in FIG. 9 is the same as the HDD 20 shown in FIGS. 1 and 2, and when erasing data stored in the HDD 20, the CPU 12, the host bridge 50, and the bus master 54 shown in FIG. The same operation as the CPU 12, the memory controller 14, and the data control unit 18 shown in FIG. That is, as shown in FIG. 3, the CPU 12 issues an erasure request (1) to the HDD 20, and the HDD 20 side detects the erasure request (2), overwrite erasure (3), FAT operation (4), entry invalidation (5 )I do.

  In each of the above-described embodiments, the HDD (hard disk drive) has been described as an example of the storage device. However, the storage device is not limited to the HDD, and writing and reading to and from an arbitrary storage medium that stores data and management data are performed. The present invention can be applied to a storage device. Further, the storage medium may be removable from the storage device such as a flexible disk.

1 is a block diagram illustrating a configuration example of an image forming apparatus including a storage device (HDD) according to the present invention. It is a block diagram which shows the structural example of HDD. FIG. 10 is a diagram illustrating an example of a procedure for deleting a file A. (A), (b), and (c) are conceptual diagrams showing an example of entry information related to file A, an example of FAT information, and an example of data stored in a storage medium when an erasure request is made. is there. (A), (b), and (c) respectively show an example of entry information related to file A when file A is overwritten, an example of FAT information, and an example of data stored in a storage medium. It is a conceptual diagram. (A), (b), and (c) are examples of entry information relating to file A when FAT information and entry information are updated after overwriting and erasing file A, examples of FAT information, and storage media It is a conceptual diagram which shows the example of the respectively stored data. It is a conceptual diagram which shows the example of the entry information at the time of using the rank of importance or confidentiality as deletion method information. It is a block diagram which shows the structural example of HDD provided with several independent heads. It is a block diagram which shows the structural example of the file server provided with the memory | storage device (HDD) which concerns on this invention. (A) is a conceptual diagram showing an example of entry information, (b) is a conceptual diagram showing an example of FAT information, and (c) is a conceptual diagram showing an example of data stored in the HDD. It is a figure which shows the example of the conventional deletion processing procedure of the file A. (A), (b), and (c) are examples of entry information relating to file A, examples of FAT information, and examples of data stored in the HDD when a portion corresponding to file A is updated by conventional deletion. FIG.

Explanation of symbols

12 CPU
14 Memory controller 16 ROM and RAM
18 Data control unit 20 HDD
22 compression / decompression unit 24 image memory 26 image processing unit 28 image reading unit 30 image forming unit 32, 33 control unit 38, 39 drive unit 40 storage medium 42, 42a, 42b head 50 host bridge 52 main memory 54 bus master 58 communication I / F

Claims (7)

Reading and writing means for writing data to the storage medium identified by the identification information and reading from the storage medium, reception of data to be written by the reading and writing means, and reading of the read data A storage device for storing the identification information of the data to be read / written and the storage address information of the data in the storage medium in the storage medium.
The communication means is configured to receive a request to erase the data;
Means for adding erasure request information to identification information of data to be erased based on the erasure request received by the communication means;
Detecting means for detecting erasure request information from the identification information stored in the storage medium;
Storage means for storing the erasure request information detected by the detection means in the order of detection ;
An erasure unit that controls the read / write unit and overwrites the data identified by the identification information to which the erasure request information is added in the storage order in the storage unit to erase the predetermined data;
Means for initializing storage address information of the data;
Means for changing erasure request information added to the identification information to erased information.   The storage device according to claim 1, wherein the detection unit is configured to detect erasure request information when the power is turned on. The erasure request information includes rank information corresponding to the degree of recovery of data to be erased ,
Before SL erasing means, in response to the rank information included in the erase request information, according to claim 1 or 2, characterized in that are configured to perform one or more of overwriting the predetermined data Storage device. One reading / writing means,
The erasing unit is configured to overwrite data to be erased when writing of data received by the communication unit or reading of data transmitted from the communication unit is not performed. The storage device according to any one of claims 1 to 3. A plurality of reading and writing means,
5. The storage according to claim 1, wherein the erasing unit is configured to overwrite at least one read / write unit to overwrite data to be erased. 6. apparatus. A storage device according to any one of claims 1 to 5 for storing image data;
An image forming apparatus comprising: an image forming unit that forms an image on a sheet based on image data stored in the storage device. A storage device according to any one of claims 1 to 5 ;
A file server comprising: communication means for transmitting data stored in the storage device and receiving data stored in the storage device.

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