JP2000066947A - Data recording apparatus and method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable storage of free space information even when the power supply of an apparatus is cut off, and to reduce power and processing time spent for maintaining free space information of a medium or checking free space. I do. In a data recording apparatus capable of recording data on a removable storage medium, it is determined whether or not a mounted device is usable when power is turned on. If the device is usable, the data is stored in an EEPROM. The available free space data is loaded into the DRAM 7. Then, the free space data on the DRAM 7 is updated according to the recording or erasing of the data. When the power is turned off, the remaining memory data stored in the DRAM 7 is stored in the EEPROM 8. When the attachment / detachment of the device 10 for recording data is detected, the remaining memory data on the DRAM 7 is rewritten with the changed remaining memory capacity of the storage medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording apparatus using a removable storage medium and a method therefor.

[0002]

2. Description of the Related Art Conventionally, in a data recording apparatus using a removable storage medium, it is performed to check the free space of a medium to obtain free space information. The obtained free space information is maintained by continuing the power-on state of the data recording device. For this reason, every time the power of the data recording device is turned off, the free space information of the storage medium is lost, and it is necessary to check the free space of the storage medium every time the power is turned on again.

In this type of data recording apparatus,
The following two methods have been known as methods for taking out a storage medium. That is, (1) floppy disk (3.5
(inch, 5.25 inch, etc.) as a storage medium, employs a mechanical mechanism, and uses a display means for indicating a state during recording to prevent removal of the medium during recording. 2) This method employs a loading method, as shown in a data recording device using a magneto-optical disk or the like as a storage medium, and uses a display means for indicating a state during recording to prevent ejection.

[0004]

However, as described above, if the information indicating the free space of the storage medium is held by continuing the power supply of the data recording apparatus, the power consumption becomes remarkable. Further, if the power of the apparatus is turned off and the free space is checked every time the power is turned on again, time is consumed for detecting the free space, and it takes time to start up the apparatus.

In the above-described storage medium removal methods (1) and (2), the storage medium can be removed at any time when it is desired to remove the storage medium. However, if the storage medium is removed by mistake during the recording operation, Fatal data destruction on the storage medium could be caused. In the worst case, all data in the storage medium may not be able to be read.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and enables the storage of free space information even when the power of the apparatus is cut off. To reduce the power and processing time spent on

It is another object of the present invention to more effectively protect data when a storage medium is attached and detached.

[0008]

A data recording apparatus according to one embodiment of the present invention for achieving the above object includes, for example, the following steps. That is, a data recording device capable of recording data on a removable storage medium, a load unit for loading remaining memory data stored in a non-volatile memory into a volatile memory when power is turned on, and a data recording device. Or updating means for updating the remaining memory data on the non-volatile memory in response to erasing; and storing means for storing the remaining memory data stored in the volatile memory in the non-volatile memory when power is turned off. Rewriting means for rewriting the remaining memory data in the volatile memory with the changed remaining memory capacity of the storage medium when the change of the storage medium for recording data is detected.

According to another aspect of the present invention, there is provided a data recording method realized by the data recording apparatus. Further, according to another aspect of the present invention, there is provided a storage medium for storing a control program for causing a computer to implement the data recording method.

[0010]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a control configuration of the electronic camera according to the present embodiment. In the present embodiment, as an example of a data recording device, an electronic camera that converts a subject image into an electric signal to generate image data, and records the image data in a removable storage medium or a built-in storage medium will be described. .

In FIG. 1, 1 is a lens, 2 is a shutter, and 3 is an image sensor. Reference numeral 4 denotes a first signal processing circuit which performs various correction processing, clamp processing, and the like on an image signal output from the image sensor 3. Reference numeral 5 denotes an A / D converter, which performs analog-digital conversion of an image signal output from the first signal processing circuit 4. Reference numeral 6 denotes a second signal processing circuit which performs processing such as compression on digital image data output from the A / D converter 5.

Reference numeral 7 denotes a DRAM for temporarily storing at least one image data. Reference numeral 8 denotes an electrically erasable and writable EEPROM such as a flash memory for storing at least one image data.

Reference numeral 10 denotes a card-type device called a PC card conforming to the well-known PCMCIA standard, and has a 68-pin connector for connection. In this apparatus, a hard disk, a FLASH memory, an SRAM, a DRAM for recording or reading image data are mainly used.
A removable card type storage medium such as the above is used. However, since the shape of the connector is common and standardized, other types of PC cards (for example, modem, SC
SI. LAN, a card for sound, etc.) can also be connected.

Reference numeral 9 denotes a device control I / F, which exchanges data with the device 10. A timing generator 13 outputs various timing signals to the image sensor 3 and the A / D converter 5. An external I / O 14 transmits image data to an external computer or the like (not shown).
Section F. 11 is an overall control unit for controlling the entire apparatus,
Reference numeral 12 denotes a RAM for storing various data in the overall control unit 11, and reference numeral 15 denotes a display unit for displaying a state of the apparatus. The overall control unit 11, the second signal processing circuit 6, and D
RAM 7, EEPROM 8, device control I / F unit 9,
The external I / F units 14 are connected by a bus 16 respectively.

FIG. 2 is an external view of the electronic camera body according to the present embodiment as viewed from the rear side. In FIG. 2, reference numeral 20 denotes an electronic camera main body, and reference numeral 21 denotes a release switch for instructing image capture. Reference numeral 22 denotes an opening for inserting the card-type device 10, and reference numeral 23 denotes an eject switch for taking out the device 10. Reference numeral 24 denotes a detection switch, which detects opening and closing of the lid 25. 25 is the opening 2
2. A cover that covers the eject switch 23 and the detection switch 24. When the cover 25 is opened and closed, the detection switch 24 is opened.
Are turned on and off, and this can be detected by the overall control unit 11. Reference numerals 26, 27, and 28 denote displays for displaying the status of the electronic camera, which are an LCD display, a green lamp, and a red lamp, respectively.

In the above configuration, the data configuration of the EEPROM 8 and the data configuration of the storage medium when the storage medium is mounted as the device 10 will be described. FIG. 3 is a diagram illustrating the data configuration of the storage medium according to the present embodiment.

As shown in FIG. 3, the storage medium 10 is divided into a management area and a file area. This set of management area and file area is called a drive, and one or a plurality of drives can be created for one storage medium. 1
One drive has a unique identification number and a unique identification name (referred to as volume serial number and volume label, respectively). The management area has a reserved area for managing files, a file allocation table (hereinafter, referred to as
FAT) and a root directory.

In the file area, actual data of the file is recorded. The access unit of the file area is called a cluster, and each file is composed of a number of clusters (one or a plurality of clusters) according to the data size.

The FAT has an entry corresponding to each cluster, and the value of the entry corresponding to a continuous cluster is recorded in each entry. If there is no continuing entry (the entry corresponding to the last cluster of the file), a value indicating that is recorded. In the directory, a file name, a file size, a value of a head entry of the file, a date, and the like are recorded.

Further, the FAT is often recorded in a plurality of locations in an overlapping manner. This is because if the data of the FAT becomes unreadable, the information recorded on the storage medium becomes unreadable, so that the reliability is ensured by duplicate recording. It should be noted that, even when the duplicate recording is not adopted, some means for basically ensuring the reliability of the FAT is often taken.

The above recording method is well-known, so that a more detailed description is omitted here.

Next, the initial operation of the electronic camera according to the present embodiment will be described. 4 and 5 are flowcharts illustrating the initial operation of the electronic camera according to the present embodiment. This process is always executed when the power is turned on.

When the device 10 is inserted into the electronic camera body, first, power is turned on to the electronic camera body except the device 10 (step S300). Then, the overall control unit 11 detects two predetermined states of the 68 pins via the device control I / F unit 9. Based on this state, the power supply voltage is determined to be 3.3 V or 5 V (the determination method is publicly known), and the determined power is supplied to the device 10 (step S301).

Next, data in a device information ROM (not shown) provided in the device 10 is read out,
It is determined whether or not the device can be used by the electronic camera. The data read from the device information ROM includes information about the device, and includes, for example, the speed, type, size, interface, power supply, access space, IRQ, and other items of the device. Since the format of this information is known in the PCMCIA standard, a detailed description is omitted.

Based on the information obtained from the device information ROM as described above, it is determined whether or not the device is a device that can be used in the electronic camera. This criterion depends on the hardware / software of the electronic camera. That is, in terms of hardware, the speed, size, interface, power supply, access space,
An item such as IRQ determines whether the electronic camera has an environment necessary for operating the device. On the software side, it is determined from the item such as the type of the device whether or not a program necessary for operating the device exists in the electronic camera (step S302).

If it is determined that the device can be used by the determination of both hardware and software, the display unit 15
The green lamp 27 is blinked twice (OK display) to notify that it can be used (step S303). On the other hand, if it is determined in step S302 that it is unusable,
The red lamp 28 of the display unit 15 flashes rapidly for 2 seconds (N
G display), and the fact that it is unusable is notified (FIG. 5, step S313).

When the device 10 is a usable storage medium and can operate at both the power supply voltage of 3.3 V / 5 V, the present electronic camera can supply before the operation of the device 10. A high power supply voltage, that is, 5 V is supplied.

Next, in step S304, the EEP
The free space data recorded in the ROM 8 is stored in a DRAM.
7 (or RAM 12), and sets a flag (valid flag) indicating that the free space data in the DRAM 7 is valid. The valid flag is reset when the lid 25 or the lid that covers a battery (not shown) that is a power supply of the apparatus is opened and closed. In the process at the time when the device 10 is newly attached, the lid 25 that covers the storage medium 10 is used.
Is opened and closed, and the valid flag indicating that the free space data in the DRAM 7 is valid is reset.

Next, the format information is read from the attached storage medium. That is, the information in the management area described with reference to FIG.
(Or the RAM 12) and verify data reliability (whether or not there is a format error) (this verification method is not specified) (step S305).

If an error (such as a read error) due to a format error or a medium failure is detected, an error relating to the medium is displayed on the LCD display 26 of the display unit 15, and the medium and the electronic camera body are detected. Turn off the power. Then, until the medium is removed from the electronic camera, the photographing operation as the camera is prohibited. Even more safely, the photographing operation may be prohibited until the medium is removed from the electronic camera and the lid is closed (steps S311, S31).
2).

On the other hand, as a result of the format check, if there is no problem in the data, a flag indicating that the data is valid (media mount completion flag) is set (step S306). Then, it is determined whether a valid flag indicating that the free space data in the DRAM 7 is valid is set (step S307). If the valid flag is reset, the management area of the medium is searched to calculate the free space (step S307). S308). Free space is FA
Each entry in the T area is searched to detect whether or not each entry is unused, and it can be known by adding them. And this free space data is transferred to DRAM
7 (or RAM 12). Furthermore, this DR
A valid flag indicating that the free space data on the AM 7 is valid is set. Note that these mount completion flags and valid flags are held in a DRAM state.

Then, the fact that the storage medium inserted into the electronic camera body is valid is displayed on the display device, and the free space is displayed on the LCD display 26 of the display unit 15 (step S309). Thereafter, the free space data in the DRAM 7 is copied to the EEPROM 8, and the power of the medium and the main body of the electronic camera is turned off (step S310).

If it is determined in step S302 that the device 10 is unusable, an NG display is performed in step S313, and the format information is read from the EEPROM 8. That is, the EEPROM
8, the information in the management area shown in FIG. 3 is read out, and data necessary for medium control is stored in the DRAM 7 (or RAM 1).
2) and verify data reliability (whether or not there is a format error) (this verification method is not specified) (step S314).

Here, if the format is abnormal or E
Abnormality due to failure of EPROM 8 (Read error, etc.)
Is detected, an error relating to the medium is displayed on the display device, and the power of the electronic camera body is turned off. Until the EEPROM 8 is formatted in the electronic camera, the photographing operation as the camera is prohibited (steps S319 and S320).

On the other hand, if there is no problem with the above data,
A flag indicating that the data is valid (media mount completion flag) is set (step S315).
Then, the free space of the medium is searched. Free space is F
It is possible to find out by searching each entry of the AT area, detecting whether each entry is unused and adding them. And this free space data is transferred to DRAM
7 (or RAM 12) and DRA
A flag indicating that the free space data on M7 is valid (a free space search completed flag) is set (step S).
316). Then, the fact that the storage medium in the electronic camera is valid is displayed on the display device, and the free space is displayed on the LCD display 26 of the display unit 15 (step S31).
7). After that, the free space data in the DRAM 7 is
The data is copied to the PROM 8, and the power of the medium and the electronic camera is turned off (step S318).

Note that the same operation as described above can be performed even if the storage medium 10 is inserted in the electronic camera body in advance and the battery is inserted later. Also, since the mounting is performed every time the power is turned on, it is not necessary to copy the mounting completion flag into the EEPROM. In addition, the camera body is attached to the medium (or the lid is closed).
The valid flag is always cleared by the interrupt of, or if a medium is present in advance when the battery is mounted, an interrupt for mounting the medium (or closing the lid) similarly occurs, and the valid flag is always cleared. Therefore, there is no need to copy the valid flag to the EEPROM.

Next, the operation at the time of photographing will be described with reference to the flowchart of FIG. FIG. 6 is a flowchart showing a process at the time of shooting in the electronic camera of the present embodiment.

When an imaging / recording command from the release switch 21 is instructed to the overall control unit 11 (or an imaging / recording instruction command from an external computer or the like (not shown) is input via the external I / F unit 14). And) the electronic camera body is powered on (step S400). Then, the free space data in the EEPROM 8 is copied to the DRAM 7 (or the RAM 12), and a flag indicating that the free space data in the DRAM 7 is valid is set (step S401).

After that, the overall control section 11 executes an image recording operation. That is, exposure is performed by driving the shutter 2,
The image signal is read from the image sensor 3 (Step S402). This image signal is subjected to color correction and various processes by the first signal processing circuit 4 (step S403). Thereafter, analog-digital conversion is performed by the A / D converter 5 to become digital image data (step S40).
4) The data is temporarily stored in the DRAM 7 as a buffer memory via the second signal processing circuit 6. After this, the DRAM 7
Is compressed by the second signal processing unit 6 and then stored again in the DRAM 7 (step S405).

Here, the analog-to-digital converter 5
The digitally converted image data is subjected to real-time compression processing by the second signal processing circuit 6 and then subjected to DR processing.
You may make it memorize | store in AM7. Further, a configuration in which the compression process is not performed may be adopted.

Next, the image data is transferred to the external storage medium 10.
(Or EEPROM 8). Hereinafter, description will be given on the assumption that recording on the external storage medium 10 is performed. When recording image data, a directory is first created via the medium control I / F unit 9 (step S406). Then, the image data once stored in the DRAM 7 is recorded in the storage medium 10 for each block of a predetermined size, and the file size and date in the directory are also updated (step S407).

When the number of clusters being recorded becomes insufficient during recording, the value of the FAT in the storage medium 10 is determined as needed, and an unused entry is added to the cluster chain to continue recording. At the same time, DRAM
7 (or RAM 12) is also updated. That is, the FAT associated with the recording on the storage medium 10
The free space data is reduced by the amount of the consumed entries.

The above-mentioned block is a unit for dividing image data into one compression, or one line of image data, a unit of memory secured in the DRAM 7 for processing, and other various processing. The unit is divided for the purpose, and details thereof are not limited here.

When all the image data is recorded (step S408), the free space data in the DRAM 7 is copied to the EEPROM 8, and then the power of the medium and the electronic camera is turned off (step S409).

Next, the above photographing operation is performed, and while the image data is being recorded on the storage medium 10 (S406, 407), the cover 2
The operation when 5 is opened will be described. FIG. 7 is a flowchart illustrating processing when the lid of the medium mounting unit is opened in the electronic camera of the present embodiment. Note that the processing in FIG. 7 is started by interruption.

When the detection switch 24 detects that the lid 25 has been opened, the overall control unit 11 stops executing a new file access to the storage medium 10 thereafter (step S410). Next, recording of the block being executed at that time or other file access being executed is completed (step S411).

Then, the DRAM 7 (or the RAM 12)
The above flag (media mounting completion flag) indicating that the format information necessary for medium control read from the storage medium 10 is valid is reset (step S41).
2). After this, while continuing the file access to the storage medium 10 stopped in the above step S410,
Further, it operates to accept execution of a new file access. (Step S413). However, since the format information has already been invalidated (unmounted) in step S412, all file accesses operate to return an error. After a lapse of a predetermined time, the power of the medium and the power of the electronic camera body are turned off (step S414). Resetting the mount completion flag is equivalent to the absence or invalidity of a medium, and thus an access error occurs. That is, resetting the mount completion flag is the simplest method for causing an access error unconditionally.

Although the operation when the lid 25 is opened while image data is being recorded on the storage medium 10 has been described here, the power supply voltage may be lower than a predetermined value while the electronic camera is operating with a battery (not shown). The above-mentioned operation may be started when the detection of is performed.

Next, the operation at the time of erasing will be described with reference to the flowchart of FIG. FIG. 8 is a flowchart illustrating a file erasing procedure in the electronic camera according to the present embodiment.

When an erasing command is issued to the overall control unit 11 by a switch or the like (not shown) (or an erasing command from an external computer or the like, not shown) is sent to the external I / O.
First, the power is turned on to the electronic camera body (step S500). Then, the free space data in the EEPROM 8 is copied to the DRAM 7 (or the RAM 12), and a flag indicating that the free space data in the DRAM 7 is valid is set.

Thereafter, the overall control unit 11 executes an erasing operation of the designated data file. That is, the storage medium 1
0 for the specified data file.
First, the directory is deleted via the F section 9 (step S501). Then, from the value of the first entry of the file in the directory, all entries of the file are made unused according to the cluster chain in the FAT area. Furthermore, at the same time, D
The free space data on the RAM 7 (or RAM 12) is updated. That is, the free space data is increased by an amount corresponding to the release of the FAT entry in accordance with the erasure of the data in the storage medium 10 (step S502).

After the predetermined data file is erased (step S503), the free space data in the DRAM 7 is copied to the EEPROM 8, and then the power of the medium and the electronic camera is turned off (step S504).

As described above, according to the above-described embodiment, in a data recording apparatus using a removable storage medium, it is possible to clearly know whether or not the attached device is a storage medium. Even when the medium is not a medium, data can be recorded on a storage medium built in the recording apparatus. Further, it is possible to clearly know the medium format abnormality or the medium abnormality.

Further, since the free space of the medium is checked once when the storage medium is mounted and recorded in the EEPROM, it is not necessary to check again even if the apparatus is turned on again. For this reason, power and time for detecting the free space can be significantly reduced.

Further, information for medium control is read from the storage medium, and the storage medium is controlled based on the information. Then, when it is detected that the lid covering the storage medium has been opened, or when it is detected that the power supply voltage has become lower than or equal to a predetermined value during operation with the battery, the information for reading the storage medium is read out. Perform invalidation. For this reason, processing at the time of error can be simplified, and the amount of programs for error processing can be reduced.

Furthermore, even if the storage medium is erroneously removed during recording, or if the battery output drops during recording, there is no possibility of causing fatal data destruction to the storage medium. Further, since the storage medium can be taken out whenever it is desired to take it out, the storage medium can be taken out even while data is being recorded, and it can be mounted on another device. This has the effect of improving usability (handling ease) more than before. is there.

Further, a plurality of power supply voltages can be supplied to the removable storage medium, and when a storage medium operable with a plurality of power supply voltages is inserted, of the operable power supply voltages of the storage medium, Since the highest possible power supply voltage is supplied, access to the medium can be made faster and the recording time can be reduced.

An object of the present invention is to supply a storage medium storing program codes of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU) of the system or the apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0064]

As described above, according to the present invention,
Even when the power of the apparatus is cut off, the free space information can be held, and the power and processing time spent for maintaining the free space information of the medium or checking the free space can be reduced.

Further, according to the present invention, data protection at the time of attaching / detaching the storage medium can be more effectively performed.

[0066]

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a control configuration of an electronic camera according to an embodiment.

FIG. 2 is an external view of the electronic camera main body as viewed from the rear side as in the embodiment.

FIG. 3 is a diagram illustrating a data configuration of a storage medium according to the present embodiment.

FIG. 4 is a flowchart illustrating an initial operation of the electronic camera according to the embodiment.

FIG. 5 is a flowchart illustrating an initial operation of the electronic camera according to the embodiment.

FIG. 6 is a flowchart illustrating a photographing process performed by the electronic camera according to the embodiment.

FIG. 7 is a flowchart illustrating processing when a lid of a medium mounting unit is opened in the electronic camera of the embodiment.

FIG. 8 is a flowchart illustrating a file erasing procedure in the electronic camera according to the present embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lens 2 shutter 3 image sensor 4 first signal processing circuit 5 A / D converter 6 second signal processing circuit 7 DRAM 8 EEPROM 9 device control I / F unit 10 device 11 overall control unit 12 RAM 13 timing generation unit 14 external I / F section

Claims (11)

[Claims] 1. A data recording apparatus capable of recording data on a removable storage medium, comprising: loading means for loading remaining memory data stored in a non-volatile memory into a volatile memory when power is turned on; Updating means for updating the remaining memory data in the volatile memory in accordance with recording or erasing of data; and storing the remaining memory data stored in the volatile memory in the nonvolatile memory when power is turned off. Storage means, and rewriting means for rewriting the remaining memory data on the volatile memory with the changed remaining memory capacity of the storage medium when a change in the storage medium for recording data is detected. Data recording device. 2. The method according to claim 1, wherein the rewriting means rewrites the remaining memory data using the newly mounted storage medium as a changed storage medium when the mounting of the new storage medium is detected. The data recording device according to claim 1. 3. The device is capable of recording data on a removable storage medium or a built-in nonvolatile memory, and the rewriting means is configured to rewrite the built-in nonvolatile memory when the removable storage medium is removed. 2. The data recording apparatus according to claim 1, wherein the remaining memory data is rewritten as a storage medium after the change. 4. A power supply to a device, comprising: a determination unit for determining whether a removable storage medium is usable; and, when the determination unit determines that the storage medium is unusable, using the built-in nonvolatile memory. 4. The data recording apparatus according to claim 3, further comprising control means for controlling recording of data. 5. When the failure of the storage medium or the format error is detected even though the determination unit determines that the storage medium is usable, at least the storage medium is removed. 5. The data recording apparatus according to claim 4, further comprising a first prohibition unit for prohibiting recording of new data until the first prohibition unit. 6. When a failure or a format error of the built-in nonvolatile memory is detected in the use of the built-in nonvolatile memory determined to be unusable by the determining means, at least until the error is cleared. The data recording apparatus according to claim 5, further comprising a second prohibition unit for prohibiting recording of new data. 7. The loading means loads the medium control information stored in the non-volatile memory together with the memory remaining amount data into the volatile memory when the power is turned on, and detects that the lid covering the medium is opened. Or, if a preliminary detection means for detecting in advance the attachment / detachment of the medium is detected,
2. The data recording apparatus according to claim 1, further comprising invalidating means for invalidating the medium control information. 8. When the invalidation unit detects that the power supply voltage has become equal to or lower than a predetermined value during operation on a battery,
The data recording apparatus according to claim 7, wherein the medium control information is invalidated. 9. A power supply unit capable of supplying a plurality of power supply voltages to the removable storage medium, and a storage medium operable when a storage medium operable with a plurality of power supply voltages is inserted. 2. The data recording apparatus according to claim 1, further comprising: a power supply control unit that controls the power supply unit so as to supply the highest power supply voltage that can be supplied. 10. A data recording method capable of recording data on a removable storage medium, comprising: a loading step of loading remaining memory data stored in a nonvolatile memory into a volatile memory when power is turned on; An updating step of updating the remaining memory data on the volatile memory in accordance with recording or erasing of data; and storing the remaining memory data stored in the volatile memory in the nonvolatile memory when power is turned off. A storage step; and a rewriting step of, when a change of the storage medium for recording data is detected, rewriting the remaining memory data on the volatile memory with the changed remaining memory capacity of the storage medium. Data recording method. 11. A storage medium for storing a control program for causing a computer to control data recording on a removable storage medium, wherein the control program is stored in a nonvolatile memory when power is turned on. A code for a load step of loading remaining data into the volatile memory; a code for an update step of updating remaining memory data on the volatile memory in accordance with recording or erasing of data; A code of a storage step of storing the remaining memory data stored in the memory in the nonvolatile memory; and, if a change in the storage medium for recording the data is detected, the remaining memory capacity of the changed storage medium is used. A code for a rewriting step of rewriting the remaining memory data on the volatile memory.