JP2015215656A - Information processor, replacement support method and replacement support program for flash memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the leakage of data by making only necessary parts easily replaceable in the case of replacing an NAND flash memory.SOLUTION: In an information processor using an NAND flash memory, a flash memory is configured of a plurality of flash memory main bodies for storing data and a controller for performing the writing/reading of data with respect to the plurality of flash memory main bodies. The plurality of flash memory main bodies include at least one first flash memory main body configured so as to be attachable/detachable to/from the controller, and the control part for controlling the flash memory includes: a flash memory state determination part for determining whether or not any flash memory main body among the plurality of flash memory main bodies is put in a predetermined prescribed state; and a notification part for, when it is determined that any flash memory main body is put in the prescribed state, issuing an alarm to encourage the replacement of the first flash memory main body.

Description

  The present invention relates to an information processing apparatus that uses a NAND flash memory as a storage medium, and a method and program for supporting replacement of the NAND flash memory.

  In recent years, NAND type flash (hereinafter referred to as NAND flash memory) such as SSD (Solid State Drive) and eMMC (embedded MultiMediaCard) as storage media that consumes less power than HDD (Hard Disk Drive) and can be read / written at high speed. Called it). In this NAND flash memory, a spare area (block) is generally prepared in advance. This is because the NAND flash memory has an error correction function as a countermeasure against the increase in bit errors (write errors, retention errors, read disturbs) over time, and blocks where errors exceeding a certain threshold have occurred. This is because the life of the product is guaranteed by replacing the spare area (block).

  It is also generally known that when this spare area is depleted, it becomes a read-only state and writing becomes impossible. This is because the manufacturing process rules are refined and technological advances such as MLC (Multi Level Cell) / TLC (Three Level Cell) can provide the benefits of cost reduction / capacity increase, but errors themselves are more likely to occur. It means that. Therefore, there is a tendency that a powerful error correction function is installed.

  As a technique related to such a NAND flash memory, for example, in Patent Document 1 below, a set of test memory cells distributed in a set of user data memory cells is used as a read threshold value used for the user data memory cells. A method is disclosed in which degradation information is acquired by reading sequentially using a selected reading threshold voltage with a resolution higher than the voltage.

  Patent Document 2 listed below describes the measured flash memory remaining lifetime for each disk in each flash memory medium group, the configuration of each flash memory medium group, and the write I / O type for each flash memory medium group. A method for evaluating the reliability of a flash memory medium by calculating the remaining lifetime of each flash memory medium group based on the sequential to random ratio is disclosed.

  In Patent Document 3 below, data is read from each logical block of the flash memory at the time of booting, and the read data is written back to the same logical block as the logical block from which the read data is read. There is disclosed a control method for a flash memory drive device comprising a block rewriting step and a physical block changing step for writing data back to a physical block different from that at the time of reading when writing by logical block writing.

  Patent Document 4 below rewrites card management information every time a defective block is replaced with a spare block, detects whether or not a spare block that can be replaced remains based on the result of the rewriting, and replaces the spare block that can be replaced. There is disclosed a flash memory replacement support method for performing a procedure for extending the life of the flash memory device before incurring the failure of the flash memory device due to the impossibility of replacement when it is detected that a block has been lost.

  In Patent Document 5 below, overerased cells in a flash memory array having a column having a first cell and a second cell are first checked to see if the first cell is overerased, If overerased, apply a programming pulse to the first cell, check if the second cell is overerased, if overerased, apply a programming pulse to the second cell; Disclosed is a method for repairing an overerased cell that is repaired by repeating the operation of incrementing the programming pulse voltage when one of the cells is overerased until no cells on the column are confirmed to be overerased. ing.

JP 2012-133875 A JP 2010-244521 A JP 2008-171246 A JP 09-198884 A Japanese Patent Laid-Open No. 06-290596

  An information processing device equipped with a NAND flash memory is not preferable from the viewpoint of holding data in the NAND flash memory in either case of writing / reading or doing nothing (the power is not turned on). Become.

  In other words, when the number of writes increases, a write error may occur due to a limit on the number of times of writing in the NAND flash memory itself (details will be described later). In addition, when the number of readings increases, the data holding performance deteriorates due to voltage application for reading, and a reading error (so-called reading disturb) may occur. If nothing is done, the charge retention of MOS (Metal Oxide Semiconductor) transistors constituting the NAND flash memory may be reduced, and a read error may occur. In these cases, the replacement of the block in which the error has occurred and the spare area is performed, so that the spare area is depleted and a read-only state is entered.

  When an event occurs in which the spare area is depleted and the read-only state occurs, wear leveling for extending data retention (details will be described later) cannot be performed, so that the write / read performance is lowered or the data is lost. The probability of being unable to recover due to breakage increases. This problem is an essential problem of the NAND flash memory, and even if the life extension process disclosed in Patent Documents 1 to 5 is performed, it is impossible to prevent the occurrence of an event that causes a read-only state.

  In particular, in the case of a device with a complex structure such as MFP (Multi Function Peripheral), if this happens while the power is on, an SC (Service Man Call) error will occur and the main power will be turned off / on. It is assumed that it is not possible to start. Also, in the case of equipment that is stored for a long time in the warehouse after manufacturing the equipment, such as MFP, even if there is no problem at the time of shipment inspection, troubles such as start-up errors occur at the time of arrival, or during shipment adjustment If the value of becomes an incorrect value, troubles such as printing defects and reading errors may occur.

  Therefore, when it becomes a read-only state or when it is predicted that a read-only state is expected, it is necessary to replace the device immediately. However, since the conventional NAND flash memory has an integral structure, the NAND flash memory Even if some of the blocks are in a read-only state, the entire NAND flash memory must be exchanged including the part where no error has occurred and the part of the controller, which wastes resources. Moreover, if the entire NAND flash memory is replaced, the amount of data to be transferred increases, so that the replacement work takes time.

  In addition, it is necessary to securely erase the data stored in the NAND flash memory to prevent leakage of confidential information during replacement, but the NAND flash memory will be erased if it is overwritten several times like an HDD. It is not a thing. Therefore, it is necessary to physically destroy the data in order to erase it securely. However, with the NAND flash memory with an integral structure, physical destruction is not easy, and there is no error or part of the controller. If it remains without being destroyed, there is a risk that confidential information will be leaked.

  The present invention has been made in view of the above-mentioned problems, and its main purpose is when an information processing apparatus using a NAND flash memory as a storage medium needs to be replaced with a NAND flash memory. An object of the present invention is to provide an information processing apparatus, a flash memory replacement support method, and a replacement support program that can easily replace only a portion that needs replacement.

  Another object of the present invention is to provide an information processing apparatus, a flash memory replacement support method, and a replacement support that can reliably prevent leakage of data stored in the replaced NAND flash memory when the NAND flash memory is replaced. To provide a program.

  One aspect of the present invention is an information processing apparatus that uses a NAND flash memory as a storage medium, wherein the flash memory includes a plurality of flash memory main bodies for storing data, and data writing / writing to the plurality of flash memory main bodies. A controller that performs reading, wherein the plurality of flash memory bodies includes at least one first flash memory body that is detachable from the controller, and the control unit that controls the flash memory includes the plurality of flash memory bodies. A flash memory state determination unit that determines whether any one of the flash memory main bodies is in a predetermined state, and any one of the flash memory main bodies is in the predetermined state If it is determined, the first flash memory body is replaced. A notification unit that issues a warning prompting the user.

  One aspect of the present invention is a flash memory replacement support method in an information processing apparatus that uses a NAND flash memory as a storage medium, and the flash memory includes a plurality of flash memory bodies that store data, and the plurality of flash memories. A controller for writing / reading data to / from the flash memory main body, and the plurality of flash memory main bodies include at least one first flash memory main body detachable from the controller, and the information processing The apparatus determines whether any one of the plurality of flash memory bodies is in a predetermined state, and determines that any one of the flash memory bodies is in the predetermined state. If a warning is issued, the first flash memory body should be replaced. It is characterized by that.

  One aspect of the present invention is a flash memory replacement support program that operates in an information processing apparatus that uses a NAND flash memory as a storage medium, the flash memory including a plurality of flash memory main bodies that store data, A controller for writing / reading data to / from a plurality of flash memory bodies, wherein the plurality of flash memory bodies include at least one first flash memory body that can be attached to and detached from the controller, and the information A processing device determines whether any one of the plurality of flash memory bodies is in a predetermined state, and determines whether the flash memory body is in the predetermined state. When it is determined that the first state is reached, the first frame A notification process for issuing a warning prompting replacement of the rush memory main body is executed.

  According to the information processing apparatus and flash memory replacement support method and replacement support program of the present invention, in an information processing apparatus that uses a NAND flash memory as a storage medium, when the NAND flash memory needs to be replaced, Only the part that needs to be replaced can be easily replaced. In addition, leakage of data stored in the NAND flash memory can be surely prevented.

  The reason is that the NAND flash memory consists of multiple NAND flash memory bodies and a controller that writes / reads data to / from multiple NAND flash memory bodies, and replaces at least one of the multiple NAND flash memory bodies. This is because the structure is possible. The information processing device includes a determination unit that determines the state of each NAND flash memory main body, and a NAND flash memory that is replaceable when the determination unit determines that any NAND flash memory main body needs to be replaced. This is because a warning unit for providing a warning for prompting replacement of the main body is provided.

1 is a block diagram illustrating a configuration of an information processing apparatus (image forming apparatus) according to a first exemplary embodiment of the present invention. 1 is a block diagram illustrating a configuration example of a NAND flash memory according to a first embodiment of the present invention. FIG. FIG. 3 is a block diagram illustrating a configuration of a control unit of the information processing apparatus (image forming apparatus) according to the first exemplary embodiment of the present invention. It is a figure which shows typically the replacement | exchange method of the NAND flash memory based on 1st Example of this invention. FIG. 5 is a flowchart illustrating an operation of a control unit of the information processing apparatus (image forming apparatus) according to the first exemplary embodiment of the present invention. It is a block diagram which shows the structural example of the NAND flash memory which concerns on 2nd Example of this invention. It is a figure explaining the wear leveling control of the NAND flash memory which concerns on 3rd Example of this invention. It is a table which shows the data classification preserve | saved at the NAND flash memory which concerns on 4th Example of this invention.

  A flash memory is generally composed of a MOS transistor (cell) whose gate electrode has a two-layer structure, and can be written / read, erased, and rewritten in units of 1 byte (that is, a source line and a bit line in each cell). There are two types: NOR type (connected) and NAND type capable of writing / reading, erasing and rewriting with a plurality of bits (that is, a plurality of cells connected in series between a source line and a bit line). In either case, when a high electric field is applied between the floating gate and the silicon substrate, electrons are tunneled through the gate insulating film and injected into the floating gate, thereby changing the gate voltage (which changes the MOS transistor from the off state to the on state). Information is stored by utilizing the change in the threshold voltage.

  Therefore, when the number of times data is written to the flash memory increases, the gate insulating film deteriorates due to electron tunneling, electrons injected into the floating gate easily escape to the silicon substrate, and the data retention period (data retention) is shortened. In particular, in the NAND flash memory, even when writing to a part of cells in a block, writing is performed in units of blocks. Therefore, the number of times of writing is substantially increased, deterioration of the gate insulating film proceeds, and the data retention period is shortened. Furthermore, with the recent miniaturization of semiconductor manufacturing process rules, the maximum number of times of writing (endurance) and data retention time of the flash memory tend to further decrease.

  Against this background, normally, when writing data to the flash memory, wear leveling is performed so that data writing is not concentrated on the same block, but even if wear leveling is performed, writing / When the number of reads increases, a write error or a read error occurs. Even when nothing is done (when the power is not turned on), a read error occurs due to a decrease in charge retention of the MOS transistor. If such an error occurs above a certain threshold, the error correction function installed in the NAND flash memory replaces the block in which the error occurred with the spare area. When it runs out, it becomes read-only and NAND flash memory needs to be replaced.

  At this time, since the conventional NAND flash memory has an integral structure, the entire NAND flash memory must be replaced, and resources are wasted. Further, it is necessary to take out necessary data from the NAND flash memory taken out from the apparatus, write the data to the new NAND flash memory, and then attach the data to the apparatus, which takes time for the replacement work.

  Also, when replacing, it is necessary to securely erase the data stored in the NAND flash memory, but since NAND flash memory is not erased by overwriting like HDD, it must be physically destroyed. However, physical destruction is not easy with an integrated NAND flash memory. In addition, if there is a part that has not been destroyed, there is a risk that secret information will be leaked.

  This problem occurs in any information processing device that uses NAND flash memory as a storage medium, but it is not easy to replace the NAND flash memory by the user himself, especially in the case of a device with a complicated structure such as an MFP. In order to request replacement by a service person, a proposal of a method by which the service person can easily and surely replace the NAND flash memory is required. In addition, there is a need for a proposal of a method that can suppress wasteful consumption of resources in a device such as an MFP that requires cost reduction.

  Therefore, in one embodiment of the present invention, the NAND flash memory is composed of a plurality of NAND flash memory bodies and a controller for writing / reading data to / from the plurality of NAND flash memory bodies, and the plurality of NAND flash memory bodies At least one of the NAND flash memory main bodies is configured to be replaceable. Then, it is predicted in advance that a spare area to be replaced with a block in which an error has occurred, and a warning is issued based on the prediction result to prompt the user to replace the NAND flash memory body. After that, the service person saves the data stored in the NAND flash memory to be replaced, then removes the NAND flash memory to be replaced and installs a new NAND flash memory to transfer the data. And physically destroy the removed NAND flash memory. As a result, it is possible to ensure both the life of the entire NAND flash memory (data retention period) and safe disposal. Note that, instead of physically destroying the removed NAND flash memory body, a data erase process (Secure Erase) for erasing stored data can be performed on the removed NAND flash memory body.

  In the case of an apparatus that is left in the warehouse for a long time, a program for operating the apparatus is stored in a replaceable NAND flash memory main body, and the NAND flash memory main body storing the program is attached when the apparatus is installed. As a result, it is possible to prevent problems such as a start-up error at the time of arrival or problems such as a printing failure and a reading error from occurring.

  In addition, the replaceable NAND flash memory can be replaced when the data retention period becomes relatively short, so the data write frequency to the replaceable NAND flash memory can be made relatively high or rewritten frequently. Data stored in the NAND flash memory body that can be exchanged. Thereby, the lifetime of the whole NAND flash memory can be extended.

  In order to describe the above-described embodiment of the present invention in more detail, the information processing apparatus, flash memory replacement support method, and replacement support program according to the first embodiment of the present invention will be described with reference to FIGS. I will explain. FIG. 1 is a block diagram illustrating a configuration of an information processing apparatus according to the present embodiment, FIG. 2 is a block diagram illustrating a configuration example of a NAND flash memory, and FIG. 3 is a block diagram illustrating a configuration of a control unit of the information processing apparatus. FIG. FIG. 4 is a diagram schematically showing the NAND flash memory replacement method of this embodiment, and FIG. 5 is a flowchart showing the operation of the information processing apparatus of this embodiment.

  The information processing apparatus according to the present exemplary embodiment is an image forming apparatus such as an MFP, for example. The image forming apparatus includes a main controller 100, an image reading unit 120, an image processing unit 130, and an image forming unit 140 as illustrated in FIG. The operation display unit 150 and the like.

  The main controller 100 includes a RAM (Random Access Memory) 101, a ROM (Read Only Memory) 102, a CPU (Central Processing Unit) 103, a NAND flash memory 104, and the like.

  The CPU 103, the ROM 102, and the RAM 101 constitute a control unit. The control unit accepts a user operation from the operation display unit 150, and the image reading unit 120, the image processing unit 130, the image forming unit 140, and the operation display unit 150 are operated. To execute predetermined control. In addition, a command for writing / reading data to / from the NAND flash memory 104, monitoring the use state of the NAND flash memory 104, and giving a warning prompting replacement based on the use state determination result (details) Will be described later.)

  As shown in FIG. 2, the NAND flash memory 104 includes a plurality of NAND flash memory bodies (four in the figure) for storing data and a NAND flash memory for writing / reading data to / from the plurality of NAND flash memory bodies. And a controller 105. The NAND flash memory main body is configured to be detachable from the NAND flash memory controller 105, and includes a NAND flash memory (referred to as a removable NAND flash memory main body 107) used as a spare area for error correction. The NAND flash memory main body includes a NAND flash memory (referred to as a fixed NAND flash memory main body 106) that is configured integrally with the NAND flash memory controller 105 (that is, configured so as not to be detachable) as necessary. . FIG. 2 shows a case where a plurality of NAND flash memory bodies are composed of two fixed NAND flash memory bodies 106 and two detachable NAND flash memory bodies 107. At least one (including all) of them may be the removable NAND flash memory main body 107.

  The structure that can be detached from the NAND flash memory controller 105 is, for example, a structure in which a terminal is fitted in a socket or the like provided in the NAND flash memory 104, and does not include a structure that can be removed / attached by soldering. Further, the plurality of NAND flash memory main bodies may have the same storage capacity, or each NAND flash memory main body may have a different storage capacity. Further, the fixed NAND flash memory main body 106 and the detachable NAND flash memory main body 107 may have the same recording structure or different recording structures (SLC / MLC / TLC, etc.). For example, since the fixed NAND flash memory body 106 is not replaced, the SLC has a relatively high reliability, and the removable NAND flash memory body 107 can be replaced, so that the MLC / TLC has a relatively low reliability. Can do.

  As shown in FIG. 3, the control unit that controls the NAND flash memory 104 having the above configuration also functions as a write control unit 108, a flash memory state determination unit 109, a notification unit 110, and the like.

  The write control unit 108 instructs the NAND flash memory controller 105 of the NAND flash memory 104 to write / read data.

  The flash memory state determination unit 109 monitors the usage state of the NAND flash memory body over time (frequency of data writing / reading to the NAND flash memory body, usage time, etc.). It is determined whether or not a predetermined state has been established. This predetermined state includes a state in which the life of the removable NAND flash memory main body 107 is shortened so that it cannot be used as a spare area, and an error occurrence block in the fixed NAND flash memory main body 106 increases and the spare area of the removable NAND flash memory main body 107 It can be considered that the situation is insufficient.

  Regarding the former, the flash memory state determination unit 109 calculates the remaining life of the detachable NAND flash memory body 107, and the calculated remaining life becomes less than a predetermined ratio with respect to the life of the detachable NAND flash memory body 107 ( That is, when it is predicted that the area cannot be used as a spare area, it is determined that the predetermined state has been reached. For example, when the lifetime depends on the number of data writes, the number of data writes to the detachable NAND flash memory body 107 is integrated, and the accumulated number of data writes is predetermined with respect to the maximum number of writes of the detachable NAND flash memory body 107. It is determined that the predetermined state has been reached when the ratio is exceeded. If the lifetime depends on the data retention period, the usage time of the removable NAND flash memory main body 107 is accumulated, and the accumulated usage time is set to a predetermined ratio with respect to the data retention period of the removable NAND flash memory main body 107. If it exceeds, it is determined that a predetermined state has been reached. When the NAND flash memory controller 105 has a function of outputting information on the usage status of the removable NAND flash memory main body 107 as a report, the flash memory state determination unit 109 outputs the report output from the NAND flash memory controller 105. Based on the information, it is determined whether or not the removable NAND flash memory main body 107 is in a predetermined state.

  Regarding the latter, the flash memory state determination unit 109 calculates the number of error-occurring blocks in the fixed NAND flash memory main body 106, and the calculated number of blocks represents a predetermined ratio with respect to the size of the spare area in the removable NAND flash memory main body 107. When it exceeds (that is, when the spare area is predicted to be exhausted), it is determined that the predetermined state has been reached. For example, when the number of error-occurring blocks depends on the number of data writes, the number of data writes to the fixed NAND flash memory main body 106 is integrated, and the total number of data writes is the maximum number of writes to the fixed NAND flash memory main body 106. On the other hand, when the predetermined ratio is exceeded, it is determined that the predetermined state has been reached. When the number of error-occurring blocks depends on the data holding period, the usage time of the fixed NAND flash memory main body 106 is accumulated, and the accumulated usage time is predetermined with respect to the data holding period of the fixed NAND flash memory main body 106. It is determined that the predetermined state has been reached when the ratio is exceeded. Further, when the NAND flash memory controller 105 has a function of outputting information on the usage status of the fixed NAND flash memory main body 106 as a report, the flash memory state determination unit 109 outputs the report output from the NAND flash memory controller 105. Based on the information, it is determined whether or not the fixed NAND flash memory main body 106 is in a predetermined state.

  In the above, the case of comparing the number of data writes and the maximum number of writes of the NAND flash memory main body and the case of comparing the usage time and the data retention period of the NAND flash memory main body are illustrated, but both are compared. It can also be determined whether or not a predetermined state has been reached.

  When the flash memory state determination unit 109 determines that the NAND flash memory main body is in a predetermined state (a state in which the spare area is predicted to be depleted), the notification unit 110 detachable NAND flash memory main body 107 By displaying information on the operation display unit 150 on the screen of the operation display unit 150, outputting information from a speaker provided in advance in the image forming apparatus, or blinking a lamp provided in advance in the image forming apparatus. Notify

  Note that the write control unit 108, the flash memory state determination unit 109, and the notification unit 110 may be configured as hardware, and the control unit includes at least the write control unit 108, the flash memory state determination unit 109, and the notification unit 110. It may be configured as a flash memory replacement support program that functions as one, and the CPU 103 may execute the flash memory replacement support program.

  As shown in FIG. 1, the image reading unit 120, the image processing unit 130, and the image forming unit 140 are controlled by the main controller 100 and provide a function as an image forming apparatus.

  Specifically, the image reading unit 120 is a part that optically reads image data from a document placed on a document table, and converts a light source that scans the document and light reflected by the document into an electrical signal. An image sensor such as a charge coupled device (CCD) and an A / D converter that A / D converts an electrical signal are output to the main controller 100.

  The image processing unit 130 performs image processing such as edge enhancement processing, smoothing processing, and color conversion processing on the image data of the document read by the image reading unit 120. In addition, when the image processing unit 130 acquires print data described in PDL (Page Description Language) represented by PostScript or PCL (Printer Control Language) from another device, each page included in the print data Is rasterized to generate image data for each page, and the image processing is performed on the generated image data. Then, the image data after image processing is output to the main controller 100.

  The image forming unit 140 performs a printing process on a sheet based on the image data subjected to the image processing by the image processing unit 130. Specifically, in the case of an electrophotographic system, an electrostatic latent image is formed by irradiating light corresponding to an image from an exposure device onto a photosensitive drum charged by a charging device, and toner charged by a developing device is used. The toner image is attached and developed, and the toner image is primarily transferred to the transfer belt, secondarily transferred from the transfer belt to the paper, and further, the fixing device fixes the toner image on the paper.

  The operation display unit 150 includes a touch panel in which an operation unit such as a touch sensor including a grid-like transparent electrode is disposed on a display unit such as an LCD (Liquid Crystal Display), a hard key, and the like, and an operation screen of the image forming apparatus. , And receives an operation from the user, and outputs a signal corresponding to the operation to the main controller 100. In this embodiment, in particular, a screen for notifying information from the notification unit 110 is displayed to prompt the user to replace the removable NAND flash memory main body 107.

  In this embodiment, the information processing apparatus is an image forming apparatus such as an MFP and includes the image reading unit 120, the image processing unit 130, the image forming unit 140, and the like. However, these components are not essential. A single-function printer that does not have the image reading unit 120, a printer controller that does not have the image reading unit 120 or the image forming unit 140, a RIP (Raster Image Processor) controller, or the like, or a facsimile apparatus that has a communication function via a telephone line And so on.

  Next, a method for replacing the removable NAND flash memory main body 107 with the NAND flash memory 104 having the above configuration will be described with reference to the schematic diagram of FIG. 4 and the flowchart of FIG. In the image forming apparatus, the CPU 103 executes a program stored in the ROM 102 or the NAND flash memory 104, thereby realizing the processing of each step shown in the flowchart of FIG. In FIG. 4, the NAND flash memory 104 includes four NAND flash memory bodies, two of which are fixed NAND flash memory bodies 106 and the other two are detachable NAND flash memory bodies 107. There may be a plurality of NAND flash memory bodies, and at least one NAND flash memory body 107 may be the removable NAND flash memory body 107.

  When the user turns on the power switch and turns on the power to the image forming apparatus in the power-off state (S101), the main controller 100 executes an apparatus initialization process (S102). When the apparatus initialization process is completed, the main controller 100 displays a user interface screen on the operation display unit 150 so that the user can operate the image forming apparatus.

  Next, the main controller 100 (flash memory state determination unit 109) determines the usage status of the NAND flash memory 104 (detachable NAND flash memory body 107 and fixed NAND flash memory body 106) mounted on the image forming apparatus over time. Monitoring (S103), it is determined whether the removable NAND flash memory main body 107 and / or the fixed NAND flash memory main body 106 has reached a predetermined state (a state in which the spare area is predicted to be exhausted) (S104). .

  When it is determined that the NAND flash memory 104 is not in the predetermined state (No in S104), the process returns to S103 and periodically monitors the usage status of the NAND flash memory 104. On the other hand, when it is determined that the removable NAND flash memory main body 107 and / or the fixed NAND flash memory main body 106 has reached a predetermined state (Yes in S104), the main controller 100 (notification unit 110) The user is notified by displaying information for prompting replacement, outputting from the speaker, or blinking the lamp (S105). The notification content is not particularly limited, but since the spare area is predicted to be depleted, use of the image forming apparatus should be refrained until the service person replaces the removable NAND flash memory main body 107. Information such as prompting the user may be added.

  In response to this notification, when the user calls a serviceman, as shown in FIG. 4A, the serviceman is stored in the removable NAND flash memory main body 107 to be replaced (the removable NAND flash memory main body 107a in the figure). Data stored in another NAND flash memory main body (fixed NAND flash memory main body 106 or other removable NAND flash memory main body 107), the RAM 101 of the main controller 100, an HDD built in or externally attached to the image forming apparatus (S106) ).

  Thereafter, as shown in FIG. 4B, the service person removes the removable NAND flash memory main body 107 to be replaced from the NAND flash memory 104 (S107), and replaces the removable NAND flash memory main body 107 (removable NAND flash memory in the figure). The main body 107b) is attached to the NAND flash memory 104 (S108).

  Then, the service person physically destroys the detached detachable NAND flash memory main body 107a by crushing or cutting it (S109), and ends a series of NAND flash memory main body replacement operations.

  In this way, the NAND flash memory 104 is composed of a plurality of NAND flash memory bodies and a NAND flash memory controller, and at least one NAND flash memory body that can be used as a spare area in the plurality of NAND flash memory bodies can be replaced. If the spare area is predicted to be exhausted, a warning prompting the user to replace the NAND flash memory is issued. Can be replaced appropriately. Further, since the removed NAND flash memory main body can be easily physically destroyed, it is possible to prevent leakage of data stored in the NAND flash memory main body and to safely discard the NAND flash memory main body.

  Next, an information processing apparatus, flash memory replacement support method, and replacement support program according to a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration example of the NAND flash memory of this embodiment.

  In the first embodiment, the case where the detachable NAND flash memory main body 107 is used as a spare area for error correction has been described. However, in this embodiment, the detachable NAND flash memory main body 107c is used to operate the device. Store the program. Then, the detachable NAND flash memory main body 107 c storing the program is incorporated into the NAND flash memory 104 when the apparatus is installed.

  As a result, even for devices such as MFPs that are stored in a warehouse for a long time and then installed at the user's site, the MOS transistor's charge retention is reduced, causing problems such as startup errors at the time of arrival. It is possible to prevent problems such as occurrence and troubles such as printing defects and reading errors.

  Next, an information processing apparatus, flash memory replacement support method, and replacement support program according to a third embodiment of the present invention will be described with reference to FIG. FIG. 7 is a diagram illustrating wear leveling in the NAND flash memory according to the present embodiment.

  In normal wear leveling control, as shown in FIG. 7A, the NAND flash memory 104 as a whole is controlled so that the writing frequency is uniform, and the data holding period is extended to extend the life. Thus, in the case of a structure having a plurality of NAND flash memory bodies in the NAND flash memory 104, changing the write frequency in each NAND flash memory body may prolong the life of the NAND flash memory 104 as a whole. it can.

  Specifically, as shown in FIG. 7B, the control unit (write control unit 108) of the main controller 100 controls the NAND flash memory controller 105 of the NAND flash memory 104, and the fixed NAND flash memory main body 106. And wearable / removable NAND flash memory main body 107 are subjected to wear leveling control under different conditions. For example, since the fixed NAND flash memory main body 106 is not replaced, it is necessary to extend the data holding period as much as possible. Therefore, wear leveling control (first wear leveling control in the figure) is performed under the condition that the writing frequency is low. On the other hand, since the removable NAND flash memory body 107 can be replaced as appropriate, wear leveling control (second wear leveling control in the figure) is performed under the condition that the writing frequency is high. Thus, by appropriately replacing the detachable NAND flash memory main body 107, the data retention period of the entire NAND flash memory 104 can be extended, and the life of the apparatus can be extended.

  Further, when a plurality of the detachable NAND flash memory main bodies 107 are provided, wear leveling control can be performed under different conditions for each detachable NAND flash memory main body 107 as shown in FIG. For example, when data with relatively high confidentiality is stored in the removable NAND flash memory main body 107d and data with relatively low confidentiality is stored in the removable NAND flash memory main body 107e, the removable NAND flash memory main body 107d has On the other hand, wear leveling control (second wear leveling control in the figure) is performed under the condition that the writing frequency is low, and wear leveling control (first figure in the figure is performed on the removable NAND flash memory body 107e under the condition that the writing frequency is high. 3 wear leveling control). As a result, the lifetime of the device can be extended and the risk of leakage of confidential information can be reduced because the removable NAND flash memory main body 107e storing relatively insensitive data can be replaced. It becomes.

  The removable NAND flash memory body 107d uses a relatively large or relatively expensive storage capacity, and the removable NAND flash memory body 107e has a relatively small storage capacity or a relatively expensive price. When a lower one is used, wear leveling control (second wear leveling control in the figure) is performed on the detachable NAND flash memory main body 107d under the condition that the writing frequency is low, and for the detachable NAND flash memory main body 107e. Wear leveling control (third wear leveling control in the figure) is performed under the condition that the writing frequency is high. As a result, it is possible to reduce the replacement cost of the removable NAND flash memory main body 107.

  Next, an information processing apparatus, flash memory replacement support method, and replacement support program according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a table showing data types stored in the NAND flash memory of this embodiment.

  In the first embodiment described above, the block data in which an error has occurred is stored in the removable NAND flash memory main body 107, and in the second embodiment, a program for starting the device is stored. By adjusting the type of data stored in the main body 106 and the removable NAND flash memory main body 107, the lifetime of the entire apparatus can be extended.

  For example, in an image forming apparatus such as an MFP, there are many types of data to be handled, including frequently updated information (for example, job history information and counter information), and frequently written / readed information (for example, Image data), information with low writing frequency (for example, program and font data, display data displayed on the operation display unit 150, language data used for printing and display), and the like. The NAND flash memory main unit that stores frequently updated information or frequently written / read information has a shorter data holding period, and the NAND flash memory main unit that stores information that is read only has a data holding period. become longer.

  Therefore, in this embodiment, as shown in the table of FIG. 8, information with low writing frequency is stored in the fixed NAND flash memory main body 106 to suppress a decrease in the data holding period, and frequently updated information or frequently written information is stored. / Information to be read is stored in the removable NAND flash memory main body 107 and exchanged when the data holding period becomes short.

  As a result, even if the data retention period of the removable NAND flash memory main body 107 is reduced and the lifetime is shortened, the lifetime of the entire image forming apparatus can be extended by repeating the replacement as a consumable item.

  In addition, this invention is not limited to the said Example, The structure and control method can be changed suitably, unless it deviates from the meaning of this invention.

  For example, in the above-described embodiment, the image forming apparatus is exemplified as the information processing apparatus. However, the information processing apparatus is not limited to the image forming apparatus, and the present invention is not limited to an arbitrary apparatus using the NAND flash memory 104 as a storage medium. The flash memory structure and replacement method can be applied as well.

  The present invention can be used for an information processing apparatus that uses a flash memory as a storage medium, a method for supporting replacement of a flash memory, a program for supporting replacement, and a recording medium on which the program is recorded.

100 Main controller 101 RAM
102 ROM
103 CPU
DESCRIPTION OF SYMBOLS 104 NAND flash memory 105 NAND flash memory controller 106 Fixed NAND flash memory main body 107, 107a-107e Detachable NAND flash memory main body 108 Write control part 109 Flash memory state determination part 110 Notification part 120 Image reading part 130 Image processing part 140 Image formation part 150 Operation display section

Claims (14)

In an information processing apparatus that uses NAND flash memory as a storage medium,
The flash memory includes a plurality of flash memory bodies that store data, and a controller that writes / reads data to / from the plurality of flash memory bodies,
The plurality of flash memory bodies include at least one first flash memory body that is detachable from the controller,
The control unit for controlling the flash memory is
A flash memory state determination unit that determines whether any one of the plurality of flash memory main bodies is in a predetermined state;
An information processing apparatus comprising: a notification unit that issues a warning prompting replacement of the first flash memory main body when it is determined that any one of the flash memory main bodies is in the predetermined state .   The information processing apparatus according to claim 1, wherein the plurality of flash memory main bodies include a second flash memory main body that cannot be attached to and detached from the controller.   The information processing apparatus according to claim 2, wherein the first flash memory main body is used as a spare area for replacing an error occurrence block of the second flash memory main body.   The information processing apparatus according to claim 2, wherein the first flash memory main body is used as a storage medium that stores a program for operating the information processing apparatus.   The flash memory state determination unit calculates the number of the error occurrence blocks of the second flash memory main body, and the calculated number of blocks corresponds to the size of the spare area of the first flash memory main body. 4. The information processing apparatus according to claim 3, wherein when the predetermined ratio is exceeded, it is determined that the second flash memory main body is in the predetermined state.   The flash memory state determination unit calculates a remaining lifetime of the first flash memory body, and the calculated remaining lifetime is less than a predetermined ratio with respect to a predetermined lifetime of the first flash memory body. 5. The information processing apparatus according to claim 3, wherein the information processing apparatus determines that the first flash memory main body is in the predetermined state when it becomes. The control unit further includes:
A write control unit for instructing the controller to write data so that a data write frequency to the first flash memory main body is higher than a data write frequency to the second flash memory main body; The information processing apparatus according to any one of claims 2 to 6. In an information processing apparatus that uses NAND flash memory as a storage medium,
The flash memory includes a plurality of flash memory bodies that store data, and a controller that writes / reads data to / from the plurality of flash memory bodies,
The plurality of flash memory bodies include a first flash memory body that can be attached to and detached from the controller, and a second flash memory body that cannot be attached to and detached from the controller.
The control unit for controlling the flash memory is
A write control unit for instructing the controller to write data so that a data write frequency to the first flash memory main body is higher than a data write frequency to the second flash memory main body; Information processing apparatus.   When the plurality of flash memory main bodies include a plurality of first flash memory main bodies, the write control unit sends data to the controller so that the frequency of data writing to each of the first flash memory main bodies is different. The information processing apparatus according to claim 7, wherein writing is instructed. The information processing apparatus is an image forming apparatus;
The data written to the first flash memory body includes one selected from job history information, counter information, and image data,
10. The data written in the second flash memory main body includes one selected from language data among programs, font data, and display data. The information processing apparatus described. A flash memory replacement support method in an information processing apparatus using NAND flash memory as a storage medium,
The flash memory includes a plurality of flash memory bodies that store data, and a controller that writes / reads data to / from the plurality of flash memory bodies,
The plurality of flash memory bodies include at least one first flash memory body that is detachable from the controller,
The information processing apparatus includes:
Determining whether any one of the plurality of flash memory bodies is in a predetermined state,
A flash memory replacement support method, wherein, when it is determined that any one of the flash memory bodies is in the predetermined state, a warning is given to prompt replacement of the first flash memory body. A flash memory replacement support method in an information processing apparatus using NAND flash memory as a storage medium,
The flash memory includes a plurality of flash memory bodies that store data, and a controller that writes / reads data to / from the plurality of flash memory bodies,
The plurality of flash memory bodies include a first flash memory body that can be attached to and detached from the controller, and a second flash memory body that cannot be attached to and detached from the controller.
The information processing apparatus includes:
Instructing the controller to write data so that the data writing frequency to the first flash memory body is higher than the data writing frequency to the second flash memory body. Exchange support method. A flash memory replacement support program that operates on an information processing device that uses a NAND flash memory as a storage medium,
The flash memory includes a plurality of flash memory bodies that store data, and a controller that writes / reads data to / from the plurality of flash memory bodies,
The plurality of flash memory bodies include at least one first flash memory body that is detachable from the controller,
In the information processing apparatus,
A flash memory state determination process for determining whether any one of the plurality of flash memory bodies is in a predetermined state,
A flash memory replacement, wherein a notification process for issuing a warning prompting replacement of the first flash memory body is executed when it is determined that any one of the flash memory bodies is in the predetermined state. Support program. A flash memory replacement support program that operates on an information processing device that uses a NAND flash memory as a storage medium,
The flash memory includes a plurality of flash memory bodies that store data, and a controller that writes / reads data to / from the plurality of flash memory bodies,
The plurality of flash memory bodies include a first flash memory body that can be attached to and detached from the controller, and a second flash memory body that cannot be attached to and detached from the controller.
In the information processing apparatus,
Causing the controller to execute a write control process for instructing data write so that the data write frequency to the first flash memory body is higher than the data write frequency to the second flash memory body. Feature flash memory replacement support program.

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