Electronic devices, data recovery methods

Abstract

To provide an electronic device and a data recovery method that can suppress the execution of control that differs from the intended control, and that can suppress excessive loss of opportunities to recover control data. [Solution] The image forming apparatus 100 includes a determination processing unit 24 that determines whether the data read from each storage unit provided in a specific sector of the NOR-type flash memory 14 is unchanged when power supply to the RAM 13 is started, and a restoration processing unit 26 that restores the control data that was lost when power supply to the RAM 13 was stopped immediately before, based on the data read from any of the storage units that the determination processing unit 24 determined to be unchanged.

Description

Technical Field

[0001] The present invention relates to an electronic device and a data restoration method.

Background Art

[0002] An electronic device including a backup memory is known (see, for example, Patent Document 1).

[0003] Further, there is known the electronic device that restores control data lost at the previous stop of power supply to the storage unit based on data previously backed up in a flash memory when power supply to a volatile storage unit such as a RAM is started.

[0004] For example, this type of electronic device includes a storage processing unit, an erasure processing unit, and a restoration processing unit. The storage processing unit stores backup data including the control data read from the storage unit into an unused storage unit among a plurality of storage units provided in a predetermined sector of the flash memory each time a predetermined backup timing arrives. The erasure processing unit erases data in the sector when all of the storage units in the sector are used storage units. The restoration processing unit restores the control data lost at the previous stop of power supply to the storage unit based on data read from the sector when power supply to the storage unit is started.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, in the aforementioned electronic device, if the power supply to the electronic device is suddenly interrupted due to a power outage or the like, the data read from the sector may become distorted. If the data read from the sector is different from the original data, and the control data is restored based on that data, there is a risk that the electronic device may execute a control that is different from the original control.

[0007] In contrast, one possible configuration involves reading data from the sector multiple times to determine whether the data read from that sector is immutable or not, and if it is determined that the data read from that sector is not immutable (fluctuates), the restoration of the control data is stopped and the operation of the device is halted.

[0008] However, with the above configuration, the opportunity to recover the control data is excessively lost.

[0009] The object of the present invention is to provide an electronic device and a data recovery method that can suppress the execution of control different from the original control, and suppress excessive loss of opportunities to recover control data. [Means for solving the problem]

[0010] An electronic device according to one aspect of the present invention comprises a storage processing unit, an erasure processing unit, a determination processing unit, and a restoration processing unit. The storage processing unit stores backup data, including control data read from a volatile storage unit, in an unused storage unit among a plurality of storage units provided in a predetermined sector of the flash memory whenever a predetermined backup timing arrives. The erasure processing unit erases the data in the sector if all of the storage units in the sector are used storage units. The determination processing unit determines whether the data read from each storage unit is unchanged when power supply to the storage unit is started. The restoration processing unit restores the control data that was lost when power supply to the storage unit was stopped immediately before, based on the data read from any of the storage units whose read data was determined to be unchanged by the determination processing unit.

[0011] A data recovery method according to another aspect of the present invention is performed on an electronic device comprising: a storage processing unit that stores backup data, including control data read from a volatile storage unit, into an unused storage unit among a plurality of storage units provided in a predetermined sector of a flash memory whenever a predetermined backup timing arrives; and an erasure processing unit that erases the data in the sector if all of the storage units in the sector are used storage units. The method includes a determination step and a recovery step. In the determination step, when power supply to the storage unit is started, it is determined whether the data read from each storage unit is unchanged. In the recovery step, the control data that was lost when power supply to the storage unit was stopped immediately before is recovered based on the data read from any of the storage units whose read data was determined to be unchanged in the determination step. [Effects of the Invention]

[0012] According to the present invention, it is possible to suppress the execution of control that differs from the original control, and to suppress excessive loss of opportunities to recover control data. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a block diagram showing the system configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] Figure 2 shows the configuration of a NOR-type flash memory in an image forming apparatus according to an embodiment of the present invention. [Figure 3] Figure 3 is a flowchart showing an example of backup control processing performed in an image forming apparatus according to an embodiment of the present invention. [Figure 4] Figure 4 is a flowchart showing an example of data recovery processing performed by an image forming apparatus according to an embodiment of the present invention. [Modes for carrying out the invention]

[0014] The embodiments of the present invention will be described below with reference to the attached drawings. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention.

[0015] [Configuration of the image forming apparatus 100] First, the configuration of the image forming apparatus 100 according to an embodiment of the present invention will be described with reference to Figures 1 and 2.

[0016] The image forming apparatus 100 is a multifunction device having multiple functions, including a scanning function for reading an image from a document, a printing function for forming an image based on the image data, a fax function, and a copy function. The image forming apparatus 100 is an example of the electronic device of the present invention. The present invention may also be applied to electronic devices such as scanners, printers, fax machines, copiers, televisions, microwave ovens, washing machines, and refrigerators.

[0017] As shown in Figure 1, the image forming apparatus 100 comprises an ADF (Auto Document Feeder) 1, an image reading unit 2, an image forming unit 3, a paper feeding unit 4, an operation display unit 5, a storage unit 6, and a control unit 7.

[0018] The ADF 1 conveys a document whose image is to be read by the image reading unit 2. The ADF 1 includes a document setting section, a plurality of conveyance rollers, a document presser, and a paper discharge section.

[0019] The image reading unit 2 implements the scan function. The image reading unit 2 includes a document platen, a light source, a plurality of mirrors, an optical lens, and a CCD (Charge Coupled Device). The image reading unit 2 reads an image from a document conveyed by the ADF 1, and outputs image data including the read image. Further, the image reading unit 2 reads an image from a document placed on the document platen, and outputs image data including the read image.

[0020] The image forming unit 3 implements the print function. Specifically, the image forming unit 3 forms an image on a sheet supplied by the paper feed unit 4 by an electrophotographic method. For example, the image forming unit 3 includes a plurality of image forming units, an optical scanning device, an intermediate transfer belt, a secondary transfer roller, a fixing device, and a paper discharge tray. Note that the image forming unit 3 may form an image on the sheet supplied by the paper feed unit 4 by another image forming method such as an inkjet method.

[0021] The paper feed unit 4 supplies sheets to the image forming unit 3. The paper feed unit 4 includes a paper feed cassette and a plurality of conveyance rollers.

[0022] The operation display unit 5 is a user interface of the image forming apparatus 100. The operation display unit 5 includes a display unit and an operation unit. The display unit displays various types of information in response to a control instruction from the control unit 7. Specifically, the display unit is a display device such as a liquid crystal display. The operation unit inputs various types of information to the control unit 7 in accordance with a user's operation. Specifically, the operation unit is an operation device including operation keys and a touch panel.

[0023] The storage unit 6 is a nonvolatile storage device. For example, the storage unit 6 is an SSD (Solid State Drive) or an HDD (Hard Disk Drive).

[0024] The control unit 7 comprehensively controls the image forming apparatus 100. As shown in Figure 1, the control unit 7 comprises a CPU 11, ROM 12, RAM 13, and NOR-type flash memory 14. The CPU 11 is a processor that performs various arithmetic operations. The ROM 12 is a non-volatile memory device in which information such as control programs for causing the CPU 11 to perform various operations is pre-stored. The RAM 13 is a volatile memory device used as a temporary storage memory (work area) for various operations performed by the CPU 11. The NOR-type flash memory 14 is a non-volatile memory device. The NOR-type flash memory 14 includes multiple sectors 30 (see Figure 2). A sector 30 is the smallest unit for data erasure and is also called a block. In the control unit 7, various control programs pre-stored in the ROM 12 are executed by the CPU 11. In this way, the control unit 7 comprehensively controls the image forming apparatus 100.

[0025] Here, RAM 13 stores count data. For example, the count data is data indicating the cumulative number of sheets printed by the image forming apparatus 100. In this case, the count data is incremented each time a sheet with an image formed by the image forming apparatus 100 is output. The count data is also used to determine whether or not it is time to replace the components of the image forming unit 3. The count data is an example of the control data of the present invention. RAM 13 is an example of the volatile storage unit of the present invention. The count data may also be data indicating the cumulative operating time of the image forming apparatus 100. Furthermore, the control data of the present invention is not limited to the count data, but may be any data used to control the image forming apparatus 100.

[0026] Furthermore, the NOR-type flash memory 14 is used to back up the count data. The NOR-type flash memory 14 is an example of the flash memory of the present invention.

[0027] Specifically, the NOR-type flash memory 14 includes two backup sectors 31 (see Figure 2). Two predetermined sectors 30 out of a plurality of sectors 30 constitute the two backup sectors 31. The backup sectors 31 are an example of predetermined sectors according to the present invention.

[0028] As shown in Figure 2, each backup sector 31 includes multiple storage units 41. Each storage unit 41 is a memory area used for storing backup data, which will be described later.

[0029] [Functional configuration of control unit 7] Next, the functional configuration of the control unit 7 will be described with reference to Figures 1 and 2.

[0030] As shown in Figure 1, the control unit 7 includes a storage processing unit 21, a switching processing unit 22, an erase processing unit 23, a determination processing unit 24, an identification processing unit 25, and a restoration processing unit 26.

[0031] Specifically, the ROM 12 of the control unit 7 contains pre-stored operation control programs that enable the CPU 11 to function as each of the aforementioned processing units. The CPU 11 then functions as each of the aforementioned processing units by executing the operation control programs stored in the ROM 12.

[0032] The operation control program may be recorded on a computer-readable recording medium such as a CD, DVD, or flash memory, and may be read from the recording medium and stored in a non-volatile storage device such as the storage unit 6. Furthermore, some or all of the processing units included in the control unit 7 may be composed of electronic circuits. Also, the operation control program may be a program that causes multiple processors to function as individual processing units included in the control unit 7.

[0033] The storage processing unit 21 stores the backup data, including the count data read from the RAM 13, in one of the unused storage units 41 provided in the backup sector 31 of the NOR-type flash memory 14 whenever a predetermined backup timing arrives. The unused storage unit 41 is a storage unit 41 that is writable (i.e., has no data written to it).

[0034] For example, the backup timing is the timing when the count data is incremented. The backup timing may also occur at a predetermined interval.

[0035] For example, the backup data includes the count data read from RAM 13 and an error detection code. For example, the error detection code is a checksum. The backup data is generated based on the count data read from RAM 13 when the backup timing arrives. Note that the error detection code is not limited to the checksum.

[0036] For example, the storage processing unit 21 stores the backup data in an unused storage unit 41 of a pre-configured specific sector among the two backup sectors 31. The specific sector is identified by the identification processing unit 25.

[0037] For example, the storage processing unit 21 stores the backup data in the storage unit 41 with the smallest address among the unused storage units 41 included in the specific sector. Alternatively, the storage processing unit 21 may store the backup data in the storage unit 41 with the largest address among the unused storage units 41 included in the specific sector.

[0038] The switching processing unit 22 switches the specific sector to one of the two backup sectors 31 that is not the specific sector if all of the storage units 41 within the specific sector are used storage units 41. Used storage units 41 are storage units 41 that cannot have data written to them (data has been written to them).

[0039] The erasure processing unit 23 erases the data in the backup sector 31 if all of the storage units 41 within the backup sector 31 are already used. This makes it possible to repeatedly use the backup sector 31 as a storage location for backup data in a NOR-type flash memory 14 where data cannot be overwritten.

[0040] For example, the erase processing unit 23 erases the data in the backup sector 31, which does not include the unused storage section 41, immediately after the first storage of the backup data after the specific sector has been switched by the switching processing unit 22. Compared to a configuration in which there is a time interval between the first storage of the backup data after the specific sector has been switched by the switching processing unit 22 and the data erasure, one of the two backup sectors 31 is almost always in an unused state (a state that does not include the used storage section 41). Therefore, the specific sector can be identified based on the state of each backup sector 31. Also, compared to a configuration in which the data is erased before the first storage of the backup data after the specific sector has been switched by the switching processing unit 22, it is always possible to leave one or more of the backup data in the NOR-type flash memory 14.

[0041] When power supply to RAM13 is started, the restoration processing unit 26 restores the count data that was lost when power supply to RAM13 was stopped immediately before, based on the data read from the specific sector.

[0042] Incidentally, in the image forming apparatus 100, if the power supply to the image forming apparatus 100 is suddenly stopped due to a power outage or the like, the data read from sector 30 may become distorted. If the data read from the specific sector is different from the original data, and the count data is restored based on that data, there is a risk that the image forming apparatus 100 will execute a control that is different from the original control.

[0043] In contrast, one possible configuration involves reading data from the specified sector multiple times to determine whether the data read from that sector is constant or not, and if it is determined that the data read from that sector is not constant (fluctuates), the restoration of the count data is stopped and the operation of the device is halted.

[0044] However, with the above configuration, the opportunity to recover the count data is excessively lost.

[0045] In contrast, the image forming apparatus 100 according to the embodiment of the present invention can suppress the execution of control that differs from the original control, as described below, and can also suppress excessive loss of opportunities to recover the count data.

[0046] When power is supplied to the RAM 13, the determination processing unit 24 determines whether the data read from each storage unit 41 included in the two backup sectors 31 is unchanged.

[0047] For example, the determination processing unit 24 determines that the data read from the storage unit 41 is immutable if two pieces of data read from the storage unit 41 at different times match.

[0048] Furthermore, the determination processing unit 24 may determine that the data read from the storage unit 41 is unchanged if three or more pieces of data read from the storage unit 41 at different timings are identical.

[0049] The identification processing unit 25 identifies the specific sector based on the data of the backup sector 31, which does not include the storage unit 41 (hereinafter sometimes referred to as the "abnormal storage unit") whose read data has been determined by the determination processing unit 24 to be non-mutable.

[0050] Specifically, the identification processing unit 25 determines whether the backup sector 31 is unused based on the data read from the backup sector 31 that does not include the abnormal storage unit. The identification processing unit 25 only needs to determine that the backup sector 31 is unused if the data read from the backup sector 31 that does not include the abnormal storage unit consists only of "1".

[0051] The identification processing unit 25 then determines that if a backup sector 31 that does not include the abnormal storage unit is unused, a backup sector 31 different from that backup sector 31 is the specified sector. Furthermore, if a backup sector 31 that does not include the abnormal storage unit is not unused, the identification processing unit 25 determines that the backup sector 31 is the specified sector.

[0052] In the image forming apparatus 100, the identification information for identifying the specific sector may be stored in a non-volatile storage unit different from the NOR-type flash memory 14, such as the storage unit 6. In this case, the storage processing unit 21, the switching processing unit 22, the erase processing unit 23, and the restore processing unit 26 only need to identify the specific sector based on the identification information. The determination processing unit 24 only needs to determine whether the data read from each storage unit 41 included in the specific sector identified based on the identification information is unchanged. Furthermore, the control unit 7 does not need to include the identification processing unit 25.

[0053] The restoration processing unit 26 restores the count data that was lost when power was cut off to the RAM 13 immediately prior to the restoration, based on data read from one of the storage units 41 included in the specific sector that the determination processing unit 24 has determined to have unchanged read data (hereinafter sometimes referred to as "normal storage unit"), and which does not have any errors detected based on the error detection code.

[0054] For example, the restoration processing unit 26 determines whether each piece of data read from the normal storage unit contains an error based on the portion of the data corresponding to the error detection code. The restoration processing unit 26 then restores the count data based on the data that has been determined to be error-free, where the value of the portion corresponding to the count data is different from the specified value and is the largest. The specified value is the value of the portion of the data read from the unused storage unit 41 that corresponds to the count data. The restoration processing unit 26 may also restore the count data based on the data that has been determined to be error-free, where the address of the source storage unit 41 is the largest.

[0055] The backup data does not necessarily have to include the error detection code. In this case, the restoration processing unit 26 can restore the count data that was lost when power was cut off to the RAM 13 immediately prior to the error detection code, based on the data read from one of the normal storage units among the storage units 41 included in the specific sector.

[0056] [Backup control processing] The following describes an example of the backup control process performed by the control unit 7 in the image forming apparatus 100, with reference to Figure 3. Here, steps S11, S12, etc., represent the processing procedure (step) numbers performed by the control unit 7.

[0057] <Step S11> First, in step S11, the control unit 7 determines whether or not the backup timing has arrived.

[0058] If the control unit 7 determines that the backup timing has arrived (Yes in S11), it proceeds to step S12. If the backup timing has not arrived (No in S11), the control unit 7 waits for the backup timing to arrive in step S11.

[0059] <Step S12> In step S12, the control unit 7 performs a backup process to back up the count data stored in the RAM 13. The process in step S12 is performed by the storage processing unit 21 of the control unit 7.

[0060] Specifically, the control unit 7 reads the count data from the RAM 13. The control unit 7 also generates the backup data based on the read count data. The control unit 7 then stores the generated backup data in the storage unit 41 with the smallest address among the one or more unused storage units 41 included in the specific sector of the NOR-type flash memory 14. The specific sector is identified in advance when power is supplied to the control unit 7 (see step S32 described later).

[0061] <Step S13> In step S13, the control unit 7 determines whether the processing in step S12 was the first processing after the specific sector was switched.

[0062] Here, if the control unit 7 determines that the process in step S12 was the first process after the specific sector was switched (Yes side of S13), it moves the process to step S14. If the process in step S12 is not the first process after the specific sector was switched (No side of S13), the control unit 7 moves the process to step S15.

[0063] <Step S14> In step S14, the control unit 7 erases the data in the backup sector 31 that does not include the unused storage section 41. The process in step S14 is performed by the erase processing unit 23 of the control unit 7.

[0064] <Step S15> In step S15, the control unit 7 determines whether or not the switching conditions for the specific sector are met.

[0065] Specifically, the control unit 7 determines that the switching condition is satisfied when all of the storage units 41 within the specified sector are used storage units 41.

[0066] If the control unit 7 determines that the switching condition is met (Yes in S15), it proceeds to step S16. If the switching condition is not met (No in S15), the control unit 7 proceeds to step S11.

[0067] <Step S16> In step S16, the control unit 7 switches the specific sector to the other of the two backup sectors 31. The process in step S16 is performed by the switching processing unit 22 of the control unit 7.

[0068] [Data recovery process] Next, with reference to Figure 4, the data recovery method of the present invention will be described along with an example of the procedure for data recovery processing performed by the control unit 7 in the image forming apparatus 100. Note that the data recovery processing is performed when power supply to the control unit 7 is initiated.

[0069] <Step S21> First, in step S21, the control unit 7 reads data from one of the two backup sectors 31 (hereinafter sometimes referred to as the "first sector").

[0070] <Step S22> In step S22, the control unit 7 reads data from the first sector.

[0071] <Step S23> In step S23, the control unit 7 performs a first determination process to determine whether the data read from each storage unit 41 included in the first sector is unchanged, based on the data obtained in step S21 and the data obtained in step S22. The process in step S23 is an example of the determination step of the present invention and is performed by the determination processing unit 24 of the control unit 7.

[0072] In the first determination process, if two pieces of data read from any of the storage units 41 included in the first sector match, it is determined that the data read from that storage unit 41 is unchanged.

[0073] <Step S24> In step S24, the control unit 7 determines whether the first sector includes the abnormal storage unit based on the result of the execution of the first determination process.

[0074] If the control unit 7 determines that the first sector includes the abnormal storage unit (Yes side of S24), it proceeds to step S25. If the first sector does not include the abnormal storage unit (No side of S24), the control unit 7 proceeds to step S26.

[0075] Furthermore, if the control unit 7 determines that the first sector includes the abnormal storage unit (Yes side of S24), it may, instead of proceeding to step S25, proceed to step S22 until the number of times the first sector has been determined to include the abnormal storage unit reaches a predetermined number of times.

[0076] <Step S25> In step S25, the control unit 7 performs a first replacement process in which it replaces the data read from the abnormal storage unit among the data acquired in step S21 with data consisting only of "0". This makes it possible to identify the data read from the abnormal storage unit among the data acquired in step S21.

[0077] <Step S26> In step S26, the control unit 7 reads data from the backup sector 31 that is different from the first sector (hereinafter sometimes referred to as the "second sector").

[0078] <Step S27> In step S27, the control unit 7 reads data from the second sector.

[0079] <Step S28> In step S28, the control unit 7 performs a second determination process to determine whether the data read from each storage unit 41 included in the second sector is unchanged, based on the data obtained in step S26 and the data obtained in step S27. The process in step S28 is an example of the determination step of the present invention and is performed by the determination processing unit 24 of the control unit 7.

[0080] In the second determination process, if two pieces of data read from any of the storage units 41 included in the second sector match, it is determined that the data read from that storage unit 41 is unchanged.

[0081] <Step S29> In step S29, the control unit 7 determines whether the second sector includes the abnormal storage unit based on the result of the execution of the second determination process.

[0082] If the control unit 7 determines that the second sector includes the abnormal storage unit (Yes in S29), it proceeds to step S30. If the second sector does not include the abnormal storage unit (No in S29), the control unit 7 proceeds to step S31.

[0083] Furthermore, if the control unit 7 determines that the second sector includes the abnormal storage unit (Yes side of S29), it may, instead of proceeding to step S30, proceed to step S27 until the number of times the second sector has been determined to include the abnormal storage unit reaches a predetermined number of times.

[0084] <Step S30> In step S30, the control unit 7 performs a second replacement process in which it replaces the data read from the abnormal storage unit among the data acquired in step S26 with data consisting only of "0". This makes it possible to identify the data read from the abnormal storage unit among the data acquired in step S26.

[0085] <Step S31> In step S31, the control unit 7 determines whether or not the specific sector can be identified.

[0086] Specifically, the control unit 7 determines that the specific sector is identifiable if either or both of the first sector and the second sector do not contain the abnormal storage unit. Conversely, the control unit 7 determines that the specific sector is not identifiable if both the first sector and the second sector contain the abnormal storage unit.

[0087] If the control unit 7 determines that the specific sector can be identified (Yes in S31), it proceeds to step S32. If the specific sector cannot be identified (No in S31), the control unit 7 proceeds to step S34.

[0088] <Step S32> In step S32, the control unit 7 identifies the specific sector. The processing in step S32 is performed by the identification processing unit 25 of the control unit 7.

[0089] Specifically, the control unit 7 determines whether the first sector is unused based on the data obtained in step S21, if the first sector does not contain the abnormal storage unit. If the first sector is unused, the control unit 7 determines that the second sector is the specified sector. If the first sector is not unused, the control unit 7 determines that the first sector is the specified sector.

[0090] Furthermore, if the second sector does not contain the abnormal storage unit, the control unit 7 determines whether the second sector is unused based on the data obtained in the process of step S26. If the second sector is unused, the control unit 7 determines that the first sector is the specified sector. If the second sector is not unused, the control unit 7 determines that the second sector is the specified sector.

[0091] Furthermore, the control unit 7 stores the identification result of the specific sector in a predetermined storage area of ​​the RAM 13. This allows the storage processing unit 21, switching processing unit 22, erase processing unit 23, and restore processing unit 26 to recognize the specific sector.

[0092] <Step S33> In step S33, the control unit 7 restores the count data that was lost when power to the RAM 13 was stopped immediately before, based on the data read from the specific sector.

[0093] Specifically, when the first sector is the specified sector, the control unit 7 determines whether there is an error in each of the data read from the normal storage unit among the data acquired in step S21, based on the portion of the data corresponding to the error detection code contained in that data. Then, the control unit 7 restores the count data based on the data in which the value of the portion corresponding to the count data is different from the specified value and is the largest among the data determined to be error-free.

[0094] Furthermore, if the second sector is the specified sector, the control unit 7 determines whether there is an error in each of the data read from the normal storage unit among the data acquired in step S26, based on the portion of the data corresponding to the error detection code contained in that data.Then, the control unit 7 restores the count data based on the data in which the value of the portion corresponding to the count data is different from the specified value and is the largest among the data determined to be error-free.

[0095] <Step S34> In step S34, the control unit 7 notifies the system of the occurrence of an error and stops the operation of the device.

[0096] Specifically, the control unit 7 displays an error screen on the operation display unit 5, which includes a message indicating that an error has occurred.

[0097] Thus, in the image forming apparatus 100, when power supply to the RAM 13 is started, it is determined whether the data read from each storage unit 41 included in the specific sector is unchanged. Then, based on the data read from one of the normal storage units among the storage units 41 included in the specific sector, and based on the data for which no error is detected based on the error detection code, the count data that was lost when power supply to the RAM 13 was stopped immediately before is restored. This makes it possible to suppress the execution of control that is different from the original control. Furthermore, compared to a configuration in which the restoration of the count data is stopped and the operation of the apparatus is stopped if the data read from the specific sector is not unchanged, it is possible to suppress excessive loss of opportunities to restore the count data.

[0098] Note that the backup sector 31 included in the NOR-type flash memory 14 may be just one.

[0099] In this case, the control unit 7 does not need to include the switching processing unit 22.

[0100] Furthermore, if the backup timing has arrived and all of the storage units 41 in the backup sector 31 are already used, the erase processing unit 23 may erase the data in the backup sector 31 before the storage processing unit 21 stores the backup data.

[0101] Furthermore, when power supply to the RAM 13 is started, the determination processing unit 24 only needs to determine whether the data read from each storage unit 41 included in the backup sector 31 is unchanged.

[0102] Furthermore, the backup sectors 31 included in the NOR-type flash memory 14 may be three or more.

[0103] Furthermore, the storage unit 6 may be a flash memory. In this case, the flash memory of the present invention may be the storage unit 6.

[0104] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0105] <Note 1> An electronic device comprising: a storage processing unit that, each time a predetermined backup timing arrives, stores backup data including control data read from a volatile storage unit into an unused storage unit among a plurality of storage units provided in a predetermined sector of the flash memory; an erasure processing unit that erases the data in the sector if all of the storage units in the sector are used storage units; a determination processing unit that determines whether the data read from each storage unit is immutable when power supply to the storage unit is started; and a restoration processing unit that restores the control data that was lost when power supply to the storage unit was stopped immediately before, based on the data read from any of the storage units whose read data has been determined by the determination processing unit to be immutable.

[0106] <Note 2> The electronic device according to Appendix 1, wherein the storage processing unit stores the backup data in an unused storage unit of a predetermined specific sector among a plurality of sectors, the electronic device includes a switching processing unit that switches the specific sector to another sector if all of the storage units in the specific sector are used storage units, and the erasure processing unit erases the data in the sector that does not include the unused storage units after the first storage of the backup data after the specific sector has been switched by the switching processing unit.

[0107] <Note 3> The electronic device according to Appendix 2, wherein the specified sector is one of the two sectors, the erase processing unit erases the data in the sector that does not include the unused storage unit immediately after the first storage of the backup data after the specified sector has been switched by the switching processing unit, the determination processing unit determines whether the data read from each of the storage units included in the two sectors is immutable, and the electronic device includes an identification processing unit that identifies the specified sector based on the data in the sector that does not include the storage unit for which the determination processing unit has determined the read data is not immutable.

[0108] <Note 4> The electronic device according to any one of the appendices 1 to 3, wherein the backup data includes the control data and an error detection code, and the restoration processing unit restores the control data that was lost when power was stopped to the storage unit immediately before, based on data read from any of the storage units whose read data has been determined by the determination processing unit to be unchanged and which does not have an error detected based on the error detection code.

[0109] <Note 5> A data recovery method performed on an electronic device comprising: a storage processing unit that stores backup data, including control data read from a volatile storage unit, in an unused storage unit among a plurality of storage units provided in a predetermined sector of a flash memory whenever a predetermined backup timing arrives; and an erasure processing unit that erases the data in the sector if all of the storage units in the sector are used storage units, the data recovery method comprising: a determination step that determines whether the data read from each storage unit is immutable when power supply to the storage unit is started; and a recovery step that restores the control data that was lost when power supply to the storage unit was stopped immediately before, based on the data read from any of the storage units whose read data was determined to be immutable by the determination step. [Explanation of Symbols]

[0110] 1 ADF 2 Image reading unit 3 Image forming unit 4 Paper feed section 5 Operation display section 6 Memory section 7 Control Unit 11 CPU 12 ROM 13 RAM 14. NOR flash memory 21 Storage Processing Unit 22 Switching Processing Unit 23 Erasure Processing Unit 24. Determination Processing Unit 25 Identification Processing Unit 26. Recovery Processing Unit 31 Backup sectors 41 Storage Unit 100 Image forming apparatus

Claims

1. A storage processing unit that, each time a predetermined backup timing arrives, stores backup data, including control data read from a volatile memory unit, in an unused storage unit among a plurality of storage units provided in a predetermined sector of the flash memory, If all of the storage units within the sector are used storage units, an erasure processing unit is provided to erase the data within the sector. When power supply to the storage unit is started, a determination processing unit determines whether the data read from each storage unit is unchanged, A restoration processing unit restores the control data that was lost when power to the storage unit was immediately cut off, based on the data read from any of the storage units that the determination processing unit has determined to be unchanged. Electronic devices equipped with these features.

2. The storage processing unit stores the backup data in an unused storage unit of a predetermined specific sector among a plurality of sectors. The aforementioned electronic device is The system includes a switching processing unit that switches the specific sector to another sector if all of the storage units within the specified sector are already in use. The erasure processing unit erases data in the sectors that do not include unused storage units after the first storage of the backup data following the switching of the specific sector by the switching processing unit. The electronic device according to claim 1.

3. The aforementioned specific sector is one of the two aforementioned sectors, The erasure processing unit erases the data in the sector that does not include the unused storage unit immediately after the first storage of the backup data after the specific sector has been switched by the switching processing unit. The determination processing unit determines whether the data read from each of the storage units included in the two sectors is unchanged, The aforementioned electronic device is The system includes an identification processing unit that identifies a specific sector based on the data of the sector, excluding the storage unit, which the determination processing unit has determined is not immutable. The electronic device according to claim 2.

4. The backup data includes the control data and the error detection code. The restoration processing unit restores the control data that was lost when power was stopped to the storage unit immediately prior to the determination processing unit, based on data read from any of the storage units whose read data is determined to be unchanged by the determination processing unit and which does not have any errors detected based on the error detection code. The electronic device according to any one of claims 1 to 3.

5. A data recovery method performed on an electronic device comprising: a storage processing unit that, each time a predetermined backup timing arrives, stores backup data including control data read from a volatile memory unit into an unused storage unit among a plurality of storage units provided in a predetermined sector of flash memory; and an erasure processing unit that erases the data in the sector if all of the storage units in the sector are used storage units, When power supply to the storage unit is started, a determination step is made to determine whether the data read from each storage unit remains unchanged. A restoration step is performed to restore the control data that was lost when power to the storage unit was immediately stopped, based on the data read from any of the storage units that the read data is determined to be unchanged by the determination step, Data recovery methods including...

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