JP2010097365A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To guarantee a band of file access of high priority while simultaneously processing a file access request of high priority and a file access request of low priority when two or more file access requests to the same storage device conflict with each other. <P>SOLUTION: Middleware 22, according to a first file access command issued by an application 23, determines regularly whether a file system 21a is performing file access operation of priority higher than that of file access operation related to the first file access command, and if determined affirmatively, issues, to the file system, a second file access command corresponding to the first file access command within a surplus band obtained by subtracting a guaranteed band of file access of high priority from the maximum band based on maximum band data of a storage device. The maximum band of the storage device is repeatedly measured and the maximum band data is updated whenever necessary. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic device including a file storage device (auxiliary storage device), and more particularly to an electronic device in which two or more file accesses compete with the file storage device.

  In the existing file system provided by the operating system, when two or more file access requests for the same storage means from an application conflict, generally, the access operation for the storage means is processed in a time-sharing manner. FIG. 8 shows the state of the file access operation of the file system when two or more file access requests from the application conflict. In the figure, the parts where the access requests are competing are shown as being accessed simultaneously, but in actuality, time division processing is performed.

  In this case, although apparently two or more file access requests are processed in parallel, it can be said that it is suitable for multi-applications. However, as a problem of this parallel processing, the access speed decreases, and the expected performance cannot be exhibited. There is a fear.

  Here, when the image forming apparatus has the above-described configuration, for a file access request related to, for example, a print job that requires real-time performance, the bandwidth is guaranteed to some extent (referred to as “bandwidth guarantee”). In some cases, it is desirable to process a file access request related to, for example, a setting value change, for which real-time property is not required, simultaneously with the file access request that requires the real-time property. The file access bandwidth indicates the access amount (transfer data amount) per unit time to the storage device, and is expressed as, for example, 1.5 Gbps.

In Patent Document 1, when two or more file access requests compete with each other, the bandwidth is guaranteed by preferentially processing the file access requests with high priority, and the file access requests with low priority are also processed. A file system that can be processed simultaneously is disclosed.
JP 2004-104212 A

  However, developing a file system that forms the basis of a computer system of an image forming apparatus has a heavy burden on application vendors. This problem occurs not only in the image forming apparatus but also in other electronic devices provided with a file storage device.

  In view of the above problems, an object of the present invention is to change a file system at all, and when two or more file access requests for the same storage device compete, a high priority file access request and a low priority An object of the present invention is to provide an electronic device capable of guaranteeing a high-priority file access bandwidth while simultaneously processing file access requests.

A first aspect of an electronic apparatus according to the present invention includes a processor, a file storage device that stores a plurality of files, and a program storage device, and has application, middleware, and file access of the storage device to the processor. An existing file system to be operated is an electronic device stored in the program storage device and operated by the processor.
Then, the application causes the processor to issue a first file access command to the middleware in order to access any of the plurality of files.
The middleware responds to the processor in response to this.
When the file system periodically makes a determination as to whether or not the processor is performing a file access operation having a higher priority than the file access operation related to the first file access command, and makes an affirmative determination, the storage device The second file access command corresponding to the first file access command is issued to the file system within the surplus bandwidth obtained by subtracting the guaranteed bandwidth of the file access with high priority from the maximum bandwidth based on the maximum bandwidth data. The maximum bandwidth of the storage device is repeatedly measured to update the maximum bandwidth data.

  In addition, the said application shall include the meaning of a some application or an integrated application.

  According to the present invention, when two or more file access requests for the same storage device compete with each other without changing the existing file system, a high-priority file access request and a low-priority file access request are simultaneously sent. It is possible to guarantee a high-priority file access bandwidth while processing. Even if the maximum bandwidth of the storage device changes over time due to fragmentation or the like, the bandwidth control can be accurately performed because the maximum bandwidth of the storage device is repeatedly measured.

  Other objects, configurations and effects of the present invention will become apparent from the following description.

<1> Hardware Configuration FIG. 3 is a schematic block diagram showing a hardware configuration of the image forming apparatus 10 according to the first embodiment of the present invention. The image forming apparatus 10 is an example of an electronic device.

  The image forming apparatus 10 has a built-in computer. In the image forming apparatus 10, an EEPROM 13 E 1, EEPROM 13 E 2, DRAM 13 D, HDD 14, operation panel 15, scanner 16 S, printer 16 P, NIC 17, facsimile modem 18, and compression / decompression ASIC 19 are coupled to the MPU 11 via an interface 12. In FIG. 3, a plurality of interfaces are shown as one block for simplification. The image forming apparatus 10 according to the first exemplary embodiment is a multifunction peripheral, but may be a single-function image forming apparatus such as a scanner, a printer, or a facsimile transmission / reception apparatus.

  The MPU 11 is an arithmetic processing device that executes processing according to various programs. The EEPROMs 13E1 and 13E2 are rewritable nonvolatile memories, for example, flash memories. The EEPROM 13E1 stores BIOS (Basic Input Output System). The EEPROM 13E2 stores software described later. The DRAM 13D is for work area, and the HDD 14 is for data storage.

  The scanner 16S is used for image input in scanning, copying, and fax transmission. The printer 16P as an image output means includes a print engine, a fixing device, a paper feeding unit, a transport unit, and a paper discharge unit, and generates an electrostatic latent image on the photosensitive drum of the print engine based on the supplied bitmap data. The toner is formed, developed with toner, transferred to a sheet, fixed, and discharged.

  A network interface card (NIC) 17 is coupled to a host computer (not shown) on a network via a cable or a wireless communication medium, and is used for print jobs, electronic mail transmission / reception, and Internet facsimile transmission. The facsimile modem 18 is for facsimile transmission / reception.

  The compression / decompression ASIC 19 is used as a coprocessor of the MPU 11, and has, for example, two ports for image compression and decompression, and can execute up to four in parallel.

<2> Software Configuration FIG. 2 is a schematic block diagram showing a software hierarchical structure of the image forming apparatus 10 according to the first embodiment of the present invention.

  The image forming apparatus 10 includes a device driver group 20, an OS 21, middleware 22, and an application group 23 as software (that is, a computer program).

  The device driver group 20 is located below the OS 21 and includes a plurality of device drivers corresponding to various types of hardware.

  The OS 21 is an operating system such as general-purpose Linux (registered trademark), and provides basic functions to the application 23.

  The middleware 22 is software positioned between the application 23 and the OS 21, and uses various basic functions of the OS 21 via a second API (Application Programming Interface) 24 that is a collection of functions, and is applied to the application 23 more than the OS 21. Functional functions.

  The application group 23 includes, for example, a print application and a copy application, and uses various basic functions of the OS 21 through the second API 24 and uses various application functions of the middleware 22 through the first API 25.

<3> Main Part Configuration FIG. 1 is a diagram showing the main part configuration of the image forming apparatus 10 according to the first embodiment of the present invention.

  In order to implement the bandwidth control of the present invention, the image forming apparatus 10 includes, as software, an HDD device driver 20 a for controlling the HDD 14 in the device driver group 20, an HDD file system 21 a in the OS 21, and middleware 22. The access command distribution unit 22a, the high priority band control unit 22b, the low priority band control unit 22c and the access state management unit 22d are included in the application group 23, and the high priority application 23a and the low priority application 23b are included in the application group 23.

  Further, the image forming apparatus 10 has a file access second API 24a in a function group of the second API 24 and a file access first API 25a in a function group of the first API 25 as callable functions.

  The HDD device driver 20 a is a device driver for controlling the HDD 14.

  The HDD file system 21 a manages files in the HDD 14, receives a file access command for inputting / outputting, creating, or deleting a file from the middleware 22, and responds to the HDD device driver 20 a according to the command. It has a function for requesting a function. It also provides a file protection function with access attributes such as “read / write enabled” and “not writeable” when accessing a file, an access authority check function according to the user, and the like.

  As the file access command from the middleware 22 to the HDD file system 21a, for example, one having an ANSI-C standard file interface (fopen / fread / fwrite) is included, and these are included in the file access second API 24a.

  The access command distribution unit 22a receives a file access command for the middleware 22 from the application group 23, and determines whether to pass the file access command to the high priority bandwidth control unit 22b or the low priority bandwidth control unit 22c according to the priority. To do.

  Examples of file access commands from the application group 23 to the middleware 22 include commands such as “read_Middle” for requesting the middleware 22 to read a file, and “fwrite_Middle” for requesting the middleware 22 to write a file, and these are included in the file access first API 24a. .

  Here, in order to distinguish between a file access command from the application group 23 to the middleware 22 and a file access command from the middleware 22 to the HDD file system 21a, the former will be referred to as a first file access command and the latter as a second. File access command.

  As a method for determining the distribution, for example, a priority is added to the option of the first file access command for the middleware 22, and the access command distribution unit 22a determines the distribution by referring to this option (example of option). The option with high priority is “p” and is used as “read_Middle-p Taro.jpg”.

  When called by the access command distribution unit 22a, the high-priority bandwidth control unit 22b notifies the access state management unit 22d that the file access has started, and reads / writes to / from the HDD file system 21a using a command of the file access second API 24a. Request file access. When the fact that the file access has been completed is received from the HDD file system 21a, the access status management unit 22d is notified of the completion of the file access.

  When called by the access command sorting unit 22a, the low-priority bandwidth control unit 22c acquires the access state of the high-priority bandwidth control unit 22b by the access state management unit 22d, and considers this as described later, and the file access second API 24a Is used to give a file access request such as read / write to the HDD file system 21a.

  The access state management unit 22d manages the access state of the high-priority bandwidth control unit 22b. Upon receiving the file access start notification, the access state management unit 22d receives, for example, F in the shared memory area of the DRAM 13D via the OS 21 and the device driver group 20a. Stores the value = 1. When the file access end notification is received, for example, a value of F = 0 is stored in this area.

  The maximum bandwidth measuring unit 22e repeatedly measures the maximum bandwidth of the HDD 14 and updates the maximum bandwidth data. The maximum bandwidth data is appropriately stored in the EEPROM 13E1, 13E2, DRAM 13D, HDD 14, or the like.

  In the first embodiment, the maximum bandwidth measuring unit 22e periodically measures the maximum bandwidth of the HDD 14. For example, the maximum bandwidth measuring unit 22e measures the maximum bandwidth of the HDD 14 in a predetermined time zone of one day.

  In the first embodiment, the maximum bandwidth measuring unit 22e measures the maximum bandwidth of the HDD 14 at the time of file access based on the first file access command from a predetermined application.

  In the first embodiment, the maximum bandwidth measuring unit 22e measures the maximum bandwidth of the HDD 14 at the time of file access based on the first file access command having a high priority. The maximum bandwidth measuring unit 22e calculates the maximum bandwidth from the amount of data written (or read) at the time of file access and the time required for the file access.

  In the first embodiment, when a first file access command for writing data from the scanner is generated in a predetermined time period, the distribution unit 22a specifies that the file access command is a first file access command having a high priority. Then, the maximum bandwidth measuring unit 22e measures the maximum bandwidth of the HDD 14 at the time of file access based on the first file access command for data writing from the scanner.

  The high priority application 23a is, for example, a scan application, and the application writes image data scanned and generated by the scanner 16S as a file in the HDD 14. The application 23a is determined in advance to be executed with priority, and the priority option (p) is added to the first file access command issued by the application.

  The low priority application 23b is, for example, a setting change application. This application reads a setting file in the HDD 14 and executes a job for changing the setting contents. Note that the program related to the setting change may be included in each application, the operation panel application, or the like, but in the first embodiment, it is assumed that the program exists as a separate application independent of these applications.

<4> Operation of the main part configuration by issuing the first file access command with high priority

  FIG. 4 is a diagram illustrating a flow of operations of the main unit configurations 22a to 22d when the first file access command prioritized from the high priority application 23a to the middleware 22 is issued. In the following, the step identification codes in FIG. 4 are shown in parentheses.

  (Step S1) When the access command distribution unit 22a receives the first file access command and determines that the command option “p” is attached to this command, the access command distribution unit 22a passes this command to the high-priority bandwidth control unit 22b.

  (Step S2) In response to this, the high priority bandwidth control unit 22b notifies (calls) the access state management unit 22d that the file access is started.

  (Step S3) In response to this notification, the access state management unit 22d stores the value of the flag F = 1 in the shared memory area of the DRAM 13D via the OS 21 and the device driver group 20, and gives a high priority to that effect. The bandwidth control unit 22b is notified (returns).

  (Step S4) In response to this, the high priority bandwidth control unit 22b issues a file access request to the HDD file system 21a. That is, a second file access command corresponding to the first file access command from the high priority application 23a is issued.

  (Step S5) In response to the issued second file access command, the HDD file system 21a performs a file access operation according to the command via the HDD device driver 20a.

  (Step S6) When the HDD file system 21a finishes the processing by the second file access command, it notifies the high priority bandwidth control unit 22b to that effect.

  (Step S7) In response to this, the high priority bandwidth control unit 22b notifies the access state management unit 22d of the end of file access.

  (Step S8) In response to this, the access state management unit 22d stores a value of 0 (F = 0) in the flag F in the shared memory area of the DRAM 13D via the OS 21 and the device driver group 20, and To the priority bandwidth control unit.

<5> Operation of main part configuration by issuing low priority first file access command

  FIG. 5 is a diagram showing an operation flow of each main part configuration when a low priority first file access command is issued from the low priority application 23 b to the middleware 22. In the following, the step identification codes in FIG. 5 are shown in parentheses.

  (Step S10) When the access command distribution unit 22a receives the first file access command and determines that the command option “p” is not attached to this command, the access command distribution unit 22a passes this command to the low-priority bandwidth control unit 22c.

  (Step S11) In response to this, when the first file access command is a file read request, for example, the low priority bandwidth control unit 22c is as follows until the end of the file (EOF) is reached. Repeat reading. For example, in the case of writing, writing is repeated as follows until the file size specified by this command is reached.

  (Step S12) The low priority bandwidth control unit 22c requests the access state management unit 22d to return an F value.

  (Step S13) In response to this, the access state management unit 22d reads the F value in the shared memory area of the DRAM 13D via the OS 21 and the device driver group 20, and returns the value to the low priority bandwidth control unit 22c. .

  (Step S14) The low priority bandwidth controller 22c determines whether or not the notified F value is 1, that is, whether or not the high priority bandwidth controller 22b requests the file system 21a for file access. . If a positive determination is made, the process proceeds to the next step S15. If a negative determination is made, the process proceeds to step S16.

  (Step S15) The low priority bandwidth control unit 22c waits for T1 milliseconds.

  (Step S16) The low priority bandwidth control unit 22c makes a file access request to the HDD file system 21a, for example, for only 256 bytes of data in the file specified by the first file access command. That is, a second file access command corresponding to the first file access command is issued.

  Here, the standby time “T1” and the file access amount (corresponding to the access time “T2”) are the bandwidth “Sa that guarantees file access related to the high priority application 23a from the maximum bandwidth“ Smax ”of the HDD 14. "(Hereinafter referred to as guaranteed bandwidth) is determined to be within the surplus bandwidth" Smax-Sa ". The maximum bandwidth “Smax” is the value of the maximum bandwidth data obtained by the maximum bandwidth measuring unit 22e. The file access bandwidth S related to the high priority application 23a can be expressed as S = Smax × T1 / (T1 + T2) ≧ Sa using these values, and S ≧ Sa is established.

  (Step S17) In response to the issued second file access command, the HDD file system 21a performs a file access operation according to the command via the HDD device driver 20a.

  (Step S18) When the HDD file system 21a finishes the processing by the second file access command, the HDD file system 21a notifies the low priority bandwidth control unit 22c to that effect.

  (Step S19) The low-priority bandwidth control unit 22c repeats the processes from Step S12 to Step S16 as long as the repetition condition of S11 is satisfied. If this condition is not satisfied, the process ends.

  FIG. 6 is a diagram showing the state of the file access operation of the HDD file system 21a in the above operation steps S5 and S17. In this figure, the upper row shows the state of file access operation of the HDD file system 21a by the high priority bandwidth control unit 22b, and the lower row shows the state of file access operation of the HDD file system 21a by the low priority bandwidth control unit 22c. A rectangle indicates that an HDD access operation is in progress.

  In this figure, the low-priority bandwidth control unit 22c starts file access first, periodically checks the value of the flag F after the start, and the file access by the high-priority bandwidth control unit 22b is started halfway. It is determined that the F value is 1 and the file access is temporarily interrupted, and the standby for T1 milliseconds and the file access for T2 milliseconds are repeatedly performed. It should be noted that the HDD file system 21a actually performs time-division parallel processing when the file access by the high-priority bandwidth control unit 22b and the low-priority bandwidth control unit 22c in FIG. As a result, the file access by the low-priority bandwidth control unit 22c is also executed within a range that does not violate the guaranteed bandwidth for file access by the high-priority bandwidth control unit 22b.

<6> Effect

  As described above, in the first embodiment, the access command distribution unit 22a as the priority specifying unit specifies the priority of the first file access command. When the priority of the first file access command is high, the bandwidth control unit 22b as the first bandwidth control means holds the file access start information based on the first file access command, and the first file Is the second file access command corresponding to the access command issued to the file system 21a and the bandwidth control unit 22c as the second bandwidth control means holds the start information when the priority of the first file access command is low? If the start information is not held, the second file access command corresponding to the first file access command is issued to the file system 21a to continuously execute the file access. If retained, guaranteed high-priority file access during execution Within the scope of the surplus band other than frequency, the second file access command issued to the file system 21a to execute a file access corresponding to the first file access command. The file system 21a receives the second file access command and performs file access.

  When two or more file accesses from the application group 23 compete, the low-priority bandwidth control unit 22c in the middleware 22 performs the bandwidth control as described above, so that the high-priority file is not changed without changing the existing file system. The access and the low-priority file access can be processed simultaneously, and the high-priority file access bandwidth can be guaranteed.

  In a general image forming apparatus, it is impossible to change a set value during scanning by a scanner. However, due to the above, it is possible to change a set value without delaying processing of the job during scanning by a scanner. Is possible.

  The maximum bandwidth measuring unit 22e repeatedly measures the maximum bandwidth of the HDD 14 and updates the maximum bandwidth data. Since bandwidth control is performed based on the maximum bandwidth data, even if the maximum bandwidth of the HDD 14 changes with time due to fragmentation of the HDD 14, accurate bandwidth control is performed at each time point.

  In the image forming apparatus according to the second embodiment of the present invention, three levels of priority “high”, “medium” and “low” file access commands are processed. Other configurations and operations of the image forming apparatus according to the second embodiment are the same as those in the first embodiment. Hereinafter, band control in the image forming apparatus according to the second embodiment will be described.

  In the image forming apparatus according to the second embodiment, the distribution unit 22a determines that the first file access command has the priority “high”, the priority “medium”, and the priority “low” based on the type of application or the command option described above. The first file access command with the priority “high” is passed to the bandwidth control unit 22b, and the first file access command with the priority “medium” and “low” is specified. It is passed to the bandwidth controller 22c.

In the image forming apparatus according to the second embodiment,
(A) When writing data from the scanner 16S, a file access command with a high priority is issued,
(B) A file access command with a priority “medium” is issued when data is read from the printer 16P and when data is written from the facsimile modem 18 at the time of facsimile reception.
(C) A file access command with a priority “low” is issued at the time of other file access (for example, data read / write required in processing of the operation panel 15, NIC 17, etc.)

  For example, in the case of copy processing, data writing from the scanner is performed by a file access command having a high priority, and data reading to the printer is performed by a file access command having a high priority. For this reason, data writing from the scanner is preferentially executed.

  FIG. 7 is a diagram illustrating a state of a file access operation of the HDD file system 21a in accordance with the three priorities in the second embodiment.

  The control of the middleware 22 by the “high” priority file access command is the same as the processing shown in FIG. That is, the bandwidth controller 22b processes this command.

  The control of the middleware 22 by the file access command having the “medium” priority is the same as the processing shown in FIG. That is, the bandwidth controller 22c processes this command. However, before step S11, the access start is notified to the access state management unit 22d in the same manner as in step S2 shown in FIG. In response to this, the access state management unit 22d sets 1 to a flag FF different from the flag F, for example. Note that the value of the flag FF is continuously set to 1 only during the period from the start to completion of the file access based on this file access command.

  Regarding the control of the middleware 22 by the “low” priority file access command, if the bandwidth control unit 22c (a) the flag is F = 0 and FF = 0, the bandwidth control is not performed and the access request is directly sent to the HDD file system. If the flag is F = 1 and FF = 0 or F = 0 and FF = 1, the same processing as the processing shown in FIG. 5 is performed. However, in step S14, it is further determined whether or not FF = 1, and if an affirmative determination is made, the process proceeds to step S15. (C) If the flag is F = 1 and FF = 1, the bandwidth controller 22c performs the same processing as the processing shown in FIG. However, by waiting for longer than “T1” in step S15 or by making an access request in step S16 so as to be shorter than the access time “T2” in step S17, “high” and “medium” priorities are set. Guarantees file access bandwidth.

  In the second embodiment, the maximum bandwidth measurement unit 22e repeatedly measures the maximum bandwidth of the HDD 14 and updates the maximum bandwidth data when the file access command has a priority of “high”.

  The above-described embodiments of the present invention are examples for explaining the present invention, and are not intended to limit the scope of the present invention only to those embodiments. Various modifications can be made without departing from the gist of the present invention.

  For example, the present invention can be applied to electronic devices other than the image forming apparatus. That is, the present invention can be applied by providing the above-described application group 23, middleware 22, file system 21a, device driver 20a, and HDD 14 in an electronic device.

  Further, the bandwidth control target (file access target) according to the present invention is not limited to the HDD 14, and can be applied to an auxiliary storage device such as an MO or a flash memory.

  Furthermore, in the first and second embodiments, the case where priority is added for each application has been described. However, priority may be added for each job.

  Further, although the image forming apparatuses according to the first and second embodiments are equipped with multi-applications, they may be equipped with integrated applications capable of executing a plurality of jobs with one application.

  Further, the application itself may have the functions of the middleware 22 according to the first and second embodiments.

  Further, in the first and second embodiments, user authentication is performed at the start of use of the image forming apparatus, and the priority of the file access command is changed according to the user in use or the user group to which the user belongs. Also good.

1 is a diagram illustrating a configuration of main parts of an image forming apparatus according to Embodiment 1 of the present invention. 1 is a schematic block diagram illustrating a software hierarchical structure of an image forming apparatus according to Embodiment 1 of the present invention. 1 is a schematic block diagram illustrating a hardware configuration of an image forming apparatus according to Embodiment 1 of the present invention. It is a figure which shows the flow of operation | movement of each principal part structure when the high priority 1st file access command is issued. It is a figure which shows the flow of operation | movement of each principal part structure when the low priority 1st file access command is issued. It is a figure which shows the state of the file access operation of the HDD file system according to the priority of "high" and "low". FIG. 10 is a diagram illustrating a state of a file access operation of an HDD file system according to priorities of “high”, “medium”, and “low” in the second embodiment. It is a figure which shows the state of the file access operation of a file system when two or more file access requests from an application compete.

Explanation of symbols

10 Image forming device (electronic equipment)
11 MPU (processor)
13E2 EEPROM (program storage device)
14 HDD (file storage device, storage means)
16S Scanner 16P Printer 18 Facsimile modem (facsimile transceiver)
21a File system 22 Middleware 22a Access command distribution unit (priority specifying means)
22b High priority bandwidth control unit (first bandwidth control means)
22c Low-priority bandwidth control unit (second bandwidth control means)
22e Maximum bandwidth measuring unit (maximum bandwidth measuring means)
23 Application Group (Application)

Claims (6)

A program storage device including a processor, a file storage device for storing a plurality of files, and a program storage device, and an application, middleware, and an existing file system that causes the processor to operate file access of the storage device An electronic device stored in a device and operated by the processor,
The application causes the processor to issue a first file access command to the middleware in order to access any of the plurality of files.
The middleware responds to the first file access command to the processor.
When the file system periodically makes a determination as to whether or not the processor is performing a file access operation having a higher priority than the file access operation related to the first file access command, and makes an affirmative determination, the storage device A second file access command corresponding to the first file access command is issued to the file system within a surplus bandwidth obtained by subtracting the guaranteed bandwidth of the high-priority file access from the maximum bandwidth based on the maximum bandwidth data of Repeatedly measuring the maximum bandwidth of the storage device and updating the maximum bandwidth data;
An electronic device characterized by that. Storage means for storing a plurality of files;
Priority specifying means for specifying the priority of the first file access command issued to access any of the plurality of files;
When the priority of the first file access command is high, the file access start information based on the first file access command is held, and the second file access command corresponding to the first file access command is sent to the file system. First bandwidth control means for issuing;
When the priority of the first file access command is low, it is determined whether or not the start information is held. When the start information is not held, a second corresponding to the first file access command is determined. When a file access command is issued to the file system to continuously execute the file access and the start information is held, the guaranteed bandwidth of the file access with high priority being executed is set to the maximum of the storage device. Second bandwidth control means for issuing a second file access command corresponding to the first file access command to execute file access within a surplus bandwidth subtracted from a maximum bandwidth based on bandwidth data;
A file system that receives the second file access command and performs file access to the storage means;
Maximum bandwidth measuring means for repeatedly measuring the maximum bandwidth of the storage device and updating the maximum bandwidth data;
An electronic device comprising:   3. The electronic apparatus according to claim 2, wherein the maximum bandwidth measuring unit periodically measures the maximum bandwidth of the storage device.   3. The electronic apparatus according to claim 2, wherein the maximum bandwidth measuring unit measures the maximum bandwidth of the storage device when accessing a file based on the first file access command from a predetermined application.   3. The electronic device according to claim 2, wherein the maximum bandwidth measuring unit measures the maximum bandwidth of the storage device when accessing a file based on the first file access command having a high priority. Equipped with a scanner,
The priority specifying means specifies the first file access command for data writing from the scanner as a first file access command having a high priority,
3. The electronic apparatus according to claim 2, wherein the maximum bandwidth measuring unit measures the maximum bandwidth of the storage device at the time of file access based on the first file access command for data writing from the scanner.

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