JP2004171466A - Image data storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image data storage device capable of actually extending a backup time to a volatile memory without losing data. <P>SOLUTION: This device comprises a volatile memory 10 having a plurality of memory blocks 1, 2, 3, and 4, so that the backup of the individual memory blocks 1, 2, 3 and 4 is performed by the use of a backup power source 610. This device further comprises power supply control means 600, 641, 651, 661, and 671 capable of controlling the power supply to the individual memory blocks. Data are transferred among the memory blocks 1, 2, 3, and 4 so that at least one memory block becomes empty on the basis of reference information obtained from the nonvolatile memory 10. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image data storage device. More specifically, the present invention relates to an image data storage device that includes a volatile memory having a plurality of memory blocks and supplies power to each memory block of the volatile memory.
[0002]
[Prior art]
MFP (abbreviation for Multi Function Peripherals), which refers to a device in which functions such as copying, facsimile, printer, and scanner are integrated into one unit in order to provide efficient office work. An image processing apparatus typified by an image processing apparatus often includes a DRAM (Dynamic Random Access Memory) for storing image data. The DRAM is a volatile memory, and the stored contents are erased unless the refresh is performed periodically. Therefore, even when the main power supply (main switch) of the main body of the image processing apparatus is turned off or the outlet is unplugged, a backup power supply is provided to the DRAM so as to periodically perform a refresh operation to prevent data loss. (This is referred to as “backup”). As this backup power supply, a secondary battery such as nickel cadmium or a primary battery such as a lithium battery is used.
[0003]
Conventionally, for example, in a facsimile apparatus, a method in which a DRAM is divided into a plurality of blocks and backup is stopped for blocks that do not store data (this is called a "first method") or a backup power supply is used. When the voltage drops, there is known a method of stopping backup from a block of lower importance according to the degree (this is called a “second method”) (for example, Patent Document 1). reference.). As a result, even if the power supplies have the same capacity, the backup time for the DRAM is made longer, and the backup time for important data is made longer.
[0004]
[Patent Document 1]
JP-A-5-91225 (page 1, abstract)
[0005]
[Problems to be solved by the invention]
However, according to normal memory management, a memory area in which data is to be stored is secured according to the order in which jobs are received, and the memory area is released upon completion of job execution. Since the order in which the jobs are accepted may be different from the order in which the jobs are completed, the image data is fragmented and stored over all of the plurality of blocks of the DRAM during normal operation. For this reason, in the above-mentioned first method, there is a problem that no block in which the backup can be actually stopped does not occur, and the effect of extending the backup time for the DRAM cannot be obtained. Further, the second method has a problem that part of data is lost in order to lengthen the backup time for the DRAM.
[0006]
Therefore, an object of the present invention is to provide an image data storage device capable of actually extending the backup time for a volatile memory without losing data.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, an image data storage device according to claim 1 is provided.
An image data storage device comprising a volatile memory having a plurality of memory blocks, and performing backup using a backup power supply for each memory block of the volatile memory,
Power supply control means capable of controlling power supply to individual memory blocks of the volatile memory;
Data transfer means for transferring data between the plurality of memory blocks;
Backup control means for controlling the data transfer means such that at least one memory block becomes a free memory block based on reference information obtained from the volatile memory.
[0008]
Note that "backup" means that power is supplied from a backup power supply to the volatile memory to retain the contents stored in the volatile memory. For example, when the main power supply (main switch) of the apparatus is turned off or the outlet is disconnected, or at the time of a power failure, backup is performed to retain the stored contents of the volatile memory.
[0009]
The “memory block” of the volatile memory can take an arbitrary unit as long as power is individually supplied. For example, when a plurality of DRAM chips are mounted on one substrate and power is individually supplied to the DRAM chips, each DRAM chip is a unit. When a plurality of memory units each including a plurality of memory chips mounted on one substrate are provided, and power is individually supplied to each memory unit, each memory unit is a unit.
[0010]
The “empty memory block” means a memory block of the volatile memory, which has no stored data (or has no data corresponding to a backup target described later).
[0011]
In the image data storage device according to the first aspect, the backup control unit controls the data transfer unit based on the reference information obtained from the volatile memory so that at least one memory block becomes a free memory block. The data transfer means transfers data between the plurality of memory blocks of the volatile memory according to the control by the backup control means. Here, the power supply control means can control the power supply to each memory block of the volatile memory. Therefore, when at least one empty memory block is generated by the data transfer by the data transfer unit, the power supply control unit can stop the power supply to the empty memory block.
[0012]
Data transferred between the plurality of memory blocks of the volatile memory is held in the transfer destination memory block. Therefore, no data is lost.
[0013]
As described above, the data storage device of the present invention stores data between the plurality of memory blocks of the volatile memory based on the reference information obtained from the volatile memory such that at least one memory block becomes a free memory block. Forward. Therefore, even when the image data is stored in a fragmented manner over all of the plurality of memory blocks during the normal operation, an empty memory block can be actually generated, and the power supply to the empty memory block is stopped. can do. Therefore, when the backup is started, the backup time for the volatile memory can be actually lengthened even if a limited capacity backup power supply is used.
[0014]
It is desirable that the control by the backup control means and the data transfer by the data transfer means are executed before the start of backup. This is to minimize the consumption of the backup power supply.
[0015]
For example, when the image data storage device is applied to an image processing apparatus such as an MFP, the control by the backup control means and the data transfer by the data transfer means may be performed in a predetermined manner such as a printing failure (toner empty or paper empty). It may be executed when an event occurs.
[0016]
The image data storage device according to claim 2 is the image data storage device according to claim 1, wherein the backup control unit determines whether at least one free memory block is generated by the data transfer by the data transfer unit. It is characterized in that the data transfer means performs data transfer only when at least one free memory block is generated.
[0017]
In the image data storage device according to the second aspect, the backup control means determines whether or not at least one free memory block is generated by data transfer by the data transfer means, and determines whether at least one free memory block is generated. Only causes the data transfer means to execute data transfer. That is, if no empty memory block is generated even when the data transfer by the data transfer unit is performed, the data transfer between the plurality of memory blocks is not performed. Therefore, useless data transfer that does not contribute to lengthening the backup time is not performed, and useless power is not consumed.
[0018]
The image data storage device according to claim 3 is the image data storage device according to claim 1, wherein the reference information is information indicating an amount and a storage position of the data stored in the volatile memory. Features.
[0019]
4. The image data storage device according to claim 3, wherein the volatile memory is configured such that at least one memory block is a free memory block based on information indicating an amount of data stored in the volatile memory and a storage position. Can be transferred between a plurality of memory blocks. Therefore, even when the image data is stored in a fragmented manner over all of the plurality of memory blocks during the normal operation, an empty memory block can be accurately generated.
[0020]
The image data storage device according to claim 4, wherein the reference information is information indicating a type of data stored in the volatile memory, and the backup control unit Is characterized in that, only when the type of data stored in the volatile memory corresponds to a backup target, the data is to be transferred by the data transfer unit.
[0021]
Note that data corresponding to “backup target” is referred to as “backup target data”. For example, image data related to a job received by facsimile (FAX) is often referred to as “backup target data”. On the other hand, image data related to a copy job or a print job is often not considered to be “backup target data” because the user himself can easily designate the same job again.
[0022]
In the image data storage device according to the fourth aspect, only the data to be backed up among the data stored in the volatile memory is to be transferred by the data transfer means. Therefore, the backup target data is held in the transfer destination memory block when transferred, and is held in the original memory block when not transferred. On the other hand, data that does not correspond to backup target data, that is, unnecessary data, is not transferred and remains in the original memory block. If only the “data not applicable to backup target data” is left in this original memory block, this original memory block is treated as a free memory block and this original memory block is The power supply to the block is stopped.
[0023]
As described above, the image data storage device sets only the data to be backed up among the data stored in the volatile memory as the data to be transferred by the data transfer means. No power is consumed.
[0024]
6. The image data storage device according to claim 5, wherein the backup control unit is configured to execute the external data transfer to the plurality of memory blocks when executing the data transfer by the data transfer unit. Is forbidden at least.
[0025]
Note that “external” refers to an element other than the plurality of memory blocks.
[0026]
In the image data storage device according to the fifth aspect, the backup control unit at least prohibits external data writing to the plurality of memory blocks when the data transfer unit executes data transfer. Therefore, for example, data transferred between the plurality of memory blocks and external data are not mixed, and memory management is easily performed.
[0027]
For example, it is assumed that a new job is not accepted when data transfer is performed by the data transfer unit. This effectively prevents data from being externally written to the plurality of memory blocks.
[0028]
Note that reading and erasing of data from the outside may be prohibited along with writing of the data from the outside to the plurality of memory blocks. In such a case, memory management is more easily performed.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0030]
FIG. 1 shows a schematic block configuration of an MFP (Multi Function Peripherals) to which the present invention is applied.
[0031]
The MFP 1000 is a device in which functions such as copying, facsimile, printer, and network scanner are integrated into one unit, and each function is realized by using an application program (hereinafter, simply referred to as “application”). Broadly speaking, the MFP 1000 includes an operation panel 700 for a user to operate the device, a CPU (Central Processing Unit) 600 for controlling the entire device, and digital image data obtained by optically reading a document image. A scanner 100 for converting and outputting to a network, an NIC (Network Interface Card) 300 for connecting to a network, a printer 200 for printing out (image forming) digital image data on paper, and performing FAX transmission and reception. FAX board 400, a DRAM (Dynamic Random Access Memory) 10 as a volatile memory for storing data, a memory control unit 500 for managing the memory of the DRAM 10, and a power supply to the DRAM 10 Power supply control means And a control unit 650.
[0032]
The MFP 1000 can transmit and receive data to and from a PC (personal computer) group 800 on a network via the NIC 300. The main data transmitted and received includes scan data transfer to PC 800 when MFP 1000 functions as a network scanner, and printout instructions from PC 800 when MFP 1000 functions as a printer.
[0033]
Further, MFP 1000 can be connected to a telephone line via FAX board 400, and can transmit and receive FAX data and the like to and from other devices via telephone line network 900.
[0034]
The memory control unit 500 includes a scanner input buffer 530 for temporarily storing image data output from the scanner 100, an external I / F input buffer 540 for temporarily storing image data input via the NIC 300, and an input buffer 530. , 540 are provided with a compressor 510 for compressing the data stored therein.
[0035]
The data compressed by the compressor 510 is stored in a copy job, scan job, and print job data area 570 in the DRAM 10. In this example, the copy job, scan job, and print job data do not need to guarantee the data at the time of the power failure, and are handled as not corresponding to the backup target data.
[0036]
The copy job, scan job, and print job data are expanded by the expander 520 according to necessary timing. The data decompressed by the decompressor 520 is temporarily stored in, for example, a printer output buffer 560 depending on the application, and is used for print output by the printer 200. Alternatively, when the data is transferred to the PC 800, the data is temporarily stored in the external I / F output buffer 550 and then transferred to the PC 800 via the NIC 300.
[0037]
On the other hand, FAX reception data received through the telephone line 900 and the FAX board 400 is stored in the FAX job reception data area 580 different from the data area 570 in the DRAM 10. The image data read by the scanner 100 is compressed by the compressor 510 as FAX transmission data when it is to be transmitted by FAX, and then stored in the FAX job transmission data area 590 in the DRAM 10. In this example, these FAX reception data and FAX transmission data are handled as data corresponding to the backup target data because it is necessary to guarantee the data at the time of power failure.
[0038]
Note that the user can easily create the same FAX transmission data again, so that the FAX transmission data may be handled as not corresponding to the data to be backed up. In this case, the user inputs an instruction through the operation panel 700 to limit the backup target data to only the FAX reception data. In this way, by limiting the backup target data to the minimum, the power consumption of the backup power supply can be suppressed when the backup is started. Therefore, the backup time for the DRAM 10 can be lengthened even when a backup power supply having a limited capacity is used.
[0039]
Specifically, the operation of the memory control unit 500 is performed by the CPU 600 controlling the data transfer by performing register setting for a DMA (direct memory access) not shown.
[0040]
Scanner input buffer 530, external I / F input buffer 540, external I / F output buffer 550, printer output buffer 560, copy job, scan job, print job data area 570, FAX job reception data area 580, FAX job transmission data area 590 are all mapped on the DRAM 10.
[0041]
The application for realizing the functions of the above-described copy, facsimile, printer, and network scanner stores compressed data in the DRAM 10 under the control of the memory control unit 500 every time a request based on a user operation or the like occurs. Since the memory control unit 500 stores the image data in the order requested by each application, the DRAM 10 stores the image data for each application in a fragmented and mixed state. Although there is a concept of securing a fixed memory area that is continuous for each application, there is a limitation on the maximum number of jobs that can be processed when a certain application is momentarily biased. Not preferred.
[0042]
On the other hand, the image data (compressed data) stored in the DRAM 10
When copying, when copying is completed,
When the scan data transfer is completed for a network scanner,
When printing is completed for a printer,
In the case of facsimile transmission, when fax data transmission is completed,
When facsimile reception, when fax reception data printing is completed
Then, since it is no longer necessary to hold them, they are erased.
[0043]
Normally, data relating to a copy job and a print job are erased without remaining in the memory for a long time when the prunita engine is in a printable state. Similarly, the data relating to the scan job is deleted without remaining in the memory for a long time as long as there is a transmission partner. On the other hand, data related to FAX transmission / reception is often retained in the memory for a long time because communication with the transmission destination cannot be established or batch transmission of memory or a confidential print function is instructed. As a result, the order of writing on the memory and the order of erasing are different. Therefore, if the MFP 1000 operates for a while, the DRAM 10 has an empty area where no data is stored between the areas where the image data for each application is fragmented and stored (for example, FIG. 5B-1). (A region shown by a blank in (C-1)). This is a steady state.
[0044]
FIG. 2 shows the configuration of the power supply control unit 650 as power supply control means.
[0045]
The DRAM 10 is divided into a plurality (four in this example) of memory blocks 1, 2, 3, and 4, and can operate independently for each memory block. Switches 641, 651, 661, and 671 controlled by the CPU 600 are connected in series to the memory blocks 1, 2, 3, and 4, respectively.
[0046]
A commercial power supply 620 is commonly connected to the series-connected memory block 1 and the switch 641, the memory block 2 and the switch 651, the memory block 3 and the switch 661, and the memory block 4 and the switch 671. A backup battery (eg, nickel cadmium battery) 610 as a power supply and a normally-on type relay switch 630 are commonly connected.
[0047]
During normal operation, the relay switch 630 is turned off and the switches 641, 651, 661, 671 are turned on under the control of the CPU 600. Thus, power is supplied from the commercial power supply 620 to the individual memory blocks 1, 2, 3, and 4.
[0048]
On the other hand, when the commercial power supply 620 is turned off or the outlet is disconnected, or when power supply from the commercial power supply 620 cannot be received due to a power failure, the relay switch 630 is turned on. Under the control of the CPU 600, the switches 641, 651, 661, 671 are individually turned on and off. Thus, power can be supplied from the backup battery 610 to the individual memory blocks 1, 2, 3, and 4. The power failure state is notified to the CPU 600 by a power failure detection sensor (not shown).
[0049]
Further, the CPU 600 can access each of the memory blocks 1, 2, 3, and 4 via an address bus and a data bus. The CPU 600 functions as a data transfer means and can freely transfer data between the memory blocks 1, 2, 3, and 4 (specifically, data transfer is performed via a DMA, but here, The explanation of is omitted.).
[0050]
Further, the CPU 600 functions as backup control means and controls data transfer based on reference information obtained from the DRAM 10 so that at least one of the memory blocks 1, 2, 3, and 4 becomes a free memory block.
[0051]
FIG. 3 shows a specific control flow (main routine) performed by the CPU 600.
[0052]
i) First, it is checked whether an event causing a backup start such as a power failure or printing failure has occurred (S1). "Print disabled" means that the printer engine has been disabled for printing due to some cause such as an engine status change (for example, paper empty, toner empty, trouble, warming up, sleeping, etc.). It should be noted that what kind of event is the cause of the backup start can be changed by an instruction from the operation panel 700 according to the user's needs.
[0053]
If an event has not occurred (NO in S2), the state of waiting for the event is maintained.
[0054]
ii) On the other hand, if an event occurs and there is a processing request (YES in S2), the state of the DRAM 10 is referred to, and a data transfer determination process is performed based on the obtained reference information (S3).
[0055]
In this example, the "reference information" obtained from the DRAM 10 indicates the amount, storage position, and type of data stored in the DRAM 10, that is, in each of the memory blocks 1, 2, 3, and 4.
[0056]
Depending on the “type” of the data, it is determined whether the data is “backup target data”. In this example, FAX reception data and FAX transmission data relating to a facsimile (FAX) job correspond to backup target data as described above. On the other hand, copy job, scan job, and print job data do not correspond to backup target data.
[0057]
As will be described in detail later, in the "data transfer determination process", it is determined whether or not at least one empty memory block is generated by data transfer between the memory blocks 1, 2, 3, and 4. By making a determination based on the above-mentioned reference information, an empty memory block can be generated accurately.
[0058]
iii) Only when the data transfer determination processing has the effect of extending the backup time (YES in S4) and it is determined that data transfer is necessary (YES in S5), the memory blocks 1, 2, and Data transfer between 3 and 4 is started (S6). When the data transfer is completed (YES in S7), at least one of the memory blocks 1, 2, 3, and 4 is a free memory block because the effect of extending the backup time is obtained. Therefore, under the control of the CPU 600, the switch (one of the switches 641, 651, 661, 671) corresponding to the empty memory block is turned off, and the power supply to the empty memory block is stopped (S8). Therefore, when the backup is started, the backup time for the DRAM 10 can be actually lengthened even if the backup battery 610 having a limited capacity is used.
[0059]
iv) On the other hand, if it is determined by the data transfer determination processing (S3 in FIG. 3) that there is no effect of extending the backup time (NO in S4), the process returns to step S1 and waits for the occurrence of an event.
[0060]
v) In the data transfer determination process (S3 in FIG. 3), the backup time can be extended (YES in S4), but when it is determined that data transfer is not necessary (NO in S5), Even if the transfer is not performed, at least one of the memory blocks 1, 2, 3, and 4 is already a free memory block. Then, under the control of the CPU 600, the switch (at least one of the switches 641, 651, 661, 671) corresponding to the empty memory block is turned off, and the power supply to the empty memory block is stopped (S8). Therefore, when the backup is started, the backup time for the DRAM 10 can be actually lengthened even if the backup battery 610 having a limited capacity is used.
[0061]
It is desirable that the processing in FIG. 3 be executed before the actual backup starts. This is to minimize the consumption of the backup battery 610.
[0062]
FIG. 4 shows the flow of the above-described data transfer determination processing (S3 in FIG. 3) in detail. This processing will be described next with reference to the memory map of FIG.
[0063]
i) First, the capacity of the data to be backed up is calculated (S11). That is, the total capacity of the data stored in the memory blocks 1, 2, 3, and 4 corresponding to the data to be backed up (hereinafter referred to as "data capacity to be backed up") is calculated.
[0064]
ii) Next, it is determined whether the number of memory blocks to be backed up can be reduced based on the backup target data capacity (S12). For example, it is assumed that each of the memory blocks 1, 2, 3, and 4 has a capacity of 1 MB, and that four memory blocks can store a maximum of 4 MB of data. In this case, if the backup target data capacity is 3 MB or less, at least one memory block can be made a free memory block, and the number of memory blocks to be backed up can be reduced.
[0065]
iii) In step S12, for example, as shown in FIG. 5D-1, if the data volume to be backed up exceeds 3 MB, the number of memory blocks to be backed up cannot be reduced. It is determined that there is no effect (S19). Then, the process returns to the main routine. In this case, as shown in FIG. 5D-2, data transfer is not performed, and power supply to all the memory blocks 1, 2, 3, and 4 is maintained. If it is determined that the reduction has no effect, data transfer between a plurality of memory blocks is not performed. Therefore, useless data transfer that does not contribute to lengthening the backup time is not performed, and useless power is not consumed.
[0066]
iv) On the other hand, in step S12, if the data size of the data to be backed up is 3 MB or less, the number of memory blocks to be backed up can be reduced, so it is determined that the reduction is "effective" (S13).
[0067]
v) Subsequently, the arrangement (storage position) of data in the memory blocks 1, 2, 3, and 4 is checked (S14), and it is determined whether or not data transfer is necessary to generate an empty memory block. (S15).
[0068]
vi) In this step S15, for example, as shown in FIG. 5A-1, the backup target data exists only in the memory blocks 1, 2, and 3, and the memory block 4 is a free memory block at this time. In this case, it is determined that data transfer is unnecessary (S17). Then, the process returns to the main routine. In this case, the power supply to the memory block 4 can be stopped as shown in FIG. 5A-2 without performing the data transfer (the memory block to which the power supply is stopped is indicated by a broken line). The same applies hereinafter.). Therefore, when the backup is started, the backup time for the DRAM 10 can be actually lengthened even if the backup battery 610 having a limited capacity is used. Moreover, if the power supply to the memory blocks 1, 2, 3 is maintained, the data to be backed up is not lost.
[0069]
vii) On the other hand, in step S15, as shown in, for example, FIG. 5 (B-1) and FIG. 5 (C-1), the backup target data capacity is 3 MB or less (actually 2 MB or less) and the data is backed up. If the number of memory blocks to be reduced can be reduced, it is determined that data transfer is necessary (S16).
[0070]
For example, in the example of FIG. 5 (B-1), as shown in FIG. 5 (B-2), data to be backed up is collected in the memory block 3 with a policy of collecting data e, Processing for obtaining the transfer source address and the transfer destination address of the data f is performed. When such a simple policy is adopted, the process of obtaining an address can be simplified.
[0071]
On the other hand, in the example of FIG. 5 (C-1), the process of obtaining the transfer source address and the transfer destination address is performed with a policy of minimizing the data transfer in order to minimize the power consumption required for the data transfer. In order to minimize the amount of data transfer, the backup target data capacity is calculated for each memory block, and as shown in FIG. What is necessary is just to transfer to a large memory block (that is, a memory block with a small free space). In this example, data a and b are transferred from the memory block 1 to the memory block 2. In this case, the process of obtaining an address is repeatedly performed until a target free space can be secured.
[0072]
viii) Finally, the data transfer source address and the data transfer destination address are calculated, and information for executing the data transfer is prepared (S18). Thereafter, the process returns to the main routine of FIG.
[0073]
As a result of the data transfer, for example, the state changes from FIG. 5 (B-1) to FIG. 5 (B-2), and the state changes from FIG. 5 (C-1) to FIG. 5 (C-2). In this case, the number of memory blocks to be backed up can be reduced to two. Therefore, when the backup is started, the backup time for the DRAM 10 can be actually lengthened even if the backup battery 610 having a limited capacity is used. In addition, the backup target data transferred between the memory blocks is held in the transfer destination memory block. Therefore, data to be backed up is not lost.
[0074]
When data transfer is performed between the memory blocks 1, 2, 3, and 4, it is desirable to prohibit externally writing, reading, and erasing data to and from the memory blocks 1, 2, 3, and 4. For example, it is assumed that a new job is not accepted when executing data transfer between the memory blocks 1, 2, 3, and 4. As a result, it is possible to effectively prevent data from being externally written to the memory blocks 1, 2, 3, and 4. In such a case, data transferred between the memory blocks 1, 2, 3, and 4 and data from the outside are not mixed, and memory management is easily performed.
[0075]
In this embodiment, an example has been described in which a DRAM is backed up as a volatile memory. However, the present invention is not limited to this. The present invention can be similarly applied to, for example, a case of backing up an SRAM (Static Random Access Memory).
[0076]
【The invention's effect】
As apparent from the above, according to the image data storage device of the present invention, the backup time for the volatile memory can be actually lengthened without losing data.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of an MFP to which an image data storage device according to an embodiment of the present invention is applied.
FIG. 2 is a diagram illustrating a configuration of a power supply control unit of the MFP.
FIG. 3 is a diagram showing a flow of control (main routine) by a CPU of the MFP.
FIG. 4 is a diagram showing a flow (subroutine) of a data transfer determination process in the main routine.
FIG. 5 is a diagram schematically illustrating handling of data in a memory block.
[Explanation of symbols]
1,2,3,4 memory block
10 DRAM
500 Memory control unit
600 CPU
610 Backup battery
641,651,661,671 switch
650 Power supply control unit

Claims (5)

An image data storage device comprising a volatile memory having a plurality of memory blocks, and performing backup using a backup power supply for each memory block of the volatile memory,
Power supply control means capable of controlling power supply to individual memory blocks of the volatile memory;
Data transfer means for transferring data between the plurality of memory blocks;
An image data storage device, comprising: backup control means for controlling the data transfer means such that at least one memory block becomes a free memory block based on reference information obtained from the volatile memory. The image data storage device according to claim 1,
The backup control means determines whether or not at least one free memory block is generated by the data transfer by the data transfer means, and executes the data transfer to the data transfer means only when at least one free memory block is generated. An image data storage device, wherein The image data storage device according to claim 1,
The image data storage device, wherein the reference information is information indicating an amount and a storage position of data stored in the volatile memory. The image data storage device according to claim 1,
The reference information is information indicating the type of data stored in the volatile memory,
The image data storage device, wherein the backup control unit sets the data to be transferred by the data transfer unit only when the type of data stored in the volatile memory corresponds to a backup target. The image data storage device according to claim 1,
The image data storage device, wherein the backup control means at least prohibits writing of external data to the plurality of memory blocks when data transfer is performed by the data transfer means.

Images