Abstract:
A non-transitory computer-readable medium having embodied thereon a program for implementing functions of managing a recording medium in an electronic device, includes a recording medium management module that includes: an acquisition module configured to acquire an upper limit to the number of recording media registered in the electronic device; and a registering module configured to register the recording medium in which the program is installed in the electronic device such that the acquired upper limit is not exceeded. The recording medium management module may link date and time information to a recording medium identifier identifying the recording medium in which the program is installed, and register the information and the identifier as linked in a management database used to manage the recording medium.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electronic device, a method of managing a recording medium executed by the electronic device, and a program configured to implement the function of managing a recording medium in the electronic device. 
     2. Description of the Related Art 
     Electronic appliances such as mobile game devices and personal digital assistants (PDA) have also been used widely. Recently, multiple-function electronic devices such as smartphones, which is provided with communication functions and in which functions of a cell phone and a PDA are integrated, have become available. These electronic devices are provided with a large-capacity memory and a high-speed processor and allow users to enjoy content without constrained by time and location by transferring content such as a movie created by another device to a recording medium in which the host electronic device can read and write. 
     [patent document No. 1] U.S. Pat. No. 7,558,820 
     To transfer given movie content (e.g., movie content recorded by a device for recording a terrestrial digital broadcast program) to a recording medium, a dedicated application may have to be installed in the recording medium due to the constraints imposed by the standard. In the process of registering and managing recording in the electronic device mediums in which such an application is installed, management will become complicated if an infinite number of recording mediums are allowed to be registered. Therefore, there is a need to manage recording mediums properly. 
     SUMMARY OF THE INVENTION 
     In this background, a purpose of the present invention is to provide a technology of managing a recording medium properly. 
     In order to address the aforementioned challenge, one embodiment of the present invention provides a non-transitory computer-readable medium having embodied thereon a program for implementing functions of managing a recording medium in an electronic device. The program comprises a recording medium management module that comprises: an acquisition module configured to acquire an upper limit to the number of recording media registered in the electronic device; and a registering module configured to register the recording medium in which the program is installed in the electronic device such that the acquired upper limit is not exceeded. 
     Another embodiment of the present invention relates to a method of managing a recording medium executed by a processor of an electronic device. The method comprises acquiring an upper limit to the number of recording media registered in the electronic device; and registering a recording medium in which a designated application program is installed in the electronic device such that the acquired upper limit is not exceeded. 
     Still another embodiment of the present invention relates to an electronic device. The electronic device comprises a management database used to manage a recording medium in which a designated application program is installed; and an application execution unit configured to read the application program from the recording medium and to execute the application program. The application program executed by the application execution unit registers the recording medium in which the application program is installed in the management database such that a predetermined upper limit to the number of recording media registered in the management database is not exceeded. 
     Yet another embodiment of the present invention relates to an electronic device. The electronic device comprises: a management database used to manage a recording medium in which a designated application program is installed such that a predetermined number of recording media is not exceeded; and a database access unit configured to access the management database. The database access unit links date and time information to a recording medium identifier identifying the recording medium in which the application program is installed, and registers the information and the identifier as linked in the management database. 
     Optional combinations of the aforementioned constituting elements, and implementations of the invention in the form of methods, apparatuses, systems, and computer programs may also be practiced as additional modes of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which: 
         FIG. 1  shows an exemplary configuration of an information processing system according to an embodiment; 
         FIG. 2A  shows the front face of the electronic device, and  FIG. 2B  shows the rear face of the electronic device; 
         FIG. 3A  shows the top face of the electronic device, 
         FIG. 3B  shows the bottom face of the electronic device, and 
         FIG. 3C  shows the left side face of the electronic device; 
         FIG. 4  shows the circuit configuration of the electronic device; 
         FIG. 5  schematically shows the functional features of the electronic device according to the embodiment of the present invention; 
         FIG. 6  schematically shows the functional features of the recording medium management module according to the embodiment; 
         FIG. 7  schematically shows the data structure of the management database according to the embodiment; 
         FIG. 8  shows an exemplary screen presented by the unregistration module according to the embodiment before unregistering the memory card; 
         FIG. 9  shows an exemplary screen presented by the registration verification module according to the embodiment; 
         FIG. 10  is another exemplary screen presented by the registration verification module according to the embodiment; 
         FIG. 11  is a flowchart illustrating the flow of steps performed in the electronic device according to the embodiment; and 
         FIG. 12  is a flowchart illustrating the flow of steps of registering a memory card. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention will now be described by reference to the preferred embodiments. This does not intend to limit the scope of the present invention, but to exemplify the invention. 
       FIG. 1  shows an exemplary configuration of an information processing system  1  according to an embodiment. An access point (AP)  2  of an information processing system  1  has the functions of a wireless access point and a router. Each electronic device  10  is connected to a network  3  such as the Internet via the AP  2  and a modem (not shown). 
     The electronic device  10  has the function for wireless communication that allows the device  10  to connect to a server  5  on the network  3  via the AP  2  to transmit local data to the server  5  and to receive data of another electronic device  10  from the server  5 . The electronic device  10  may be provided with functions of communicating using a wireless local area network (LAN) system so as to communicate with the server  5  in the infrastructure mode. The device  10  may communicate with the server  5  using a communication scheme employed in cell phones (e.g., the third-generation mobile communication system). In this case, the first electronic device  10  communicates with the server  5  via a base station, which provides a wide area of communication, so that users can use the electronic device  10  outdoors. Each user in the information processing system  1  has a user account that identifies the user and signs in network services provided by the server  5  using a user account. 
     A description will be given of the appearance and circuit configuration of the electronic device according to the embodiment. The electronic device  10  is exemplified by a mobile game device in the following description. However, the electronic device  10  may be a mobile terminal of another type. 
     [Configuration of Front Part] 
       FIG. 2A  shows the front face of the electronic device  10 . The electronic device  10  is formed of an horizontally elongated housing. The left and right areas held by the user have an arc-shaped appearance. A rectangular touch panel  50  is provided on the front face of the electronic device  10 . The touch panel  50  comprises a display device  20  and a transparent front touch pad  21  covering the surface of the display device  20 . The display device  20  is an electro-luminescence panel configured to display images. The display device  20  may be a display means such as a liquid crystal panel. The front touch pad  21  is a multi-touch pad capable of detecting a plurality of simultaneously touched points so that the touch panel  50  is configured as a multi-touch screen. 
     A triangular button  22   a , a circle button  22   b , a cross button  22   c , and a square button  22   d  (hereinafter, may be generically referred to as “user control buttons  22 ”) are provided on the right of the touch panel  50 . On the left of the touch panel  50  are provided an upward key  23   a , a leftward key  23   b , a downward key  23   c , and a rightward key  23   d  (hereinafter, may be generically referred to as “directional keys  23 ”). The user can use the directional key  23  to designate 8 directions, including upward, downward, leftward, rightward directions, and 4 diagonal directions. Below the directional keys  23  is provided a left stick  24   a , and below the user control buttons  22  is provided a right stick  24   b . The user tilts the left stick  24   a  or the right stick  24   b  (hereinafter, may be generically referred to as “analog sticks  24 ”) to input a direction and an amount of movement. At top left and top right of the housing are provided an L button  26   a  and an R button  26   b . The user control buttons  22 , the directional keys  23 , the analog sticks  24 , the L button  26   a , and the R button  26   b  embody user control means used by a user. 
     In the neighborhood of the user control button  22  is provided a front camera  30 . To the left of the left stick  24   a  and to the right of the right stick  24   b  are provided a left speaker  25   a  and a right speaker  25   b  (hereinafter, may be referred to as “speakers  25 ”), respectively, for outputting sound. Below the left stick  24   a  is provided a HOME button  27 , and below the right stick  24   b  are provided a START button  28  and a SELECT button  29 . 
     [Configuration of Rear Part] 
       FIG. 2B  shows the rear face of the electronic device  10 . The rear face of the electronic device  10  is provided with a rear camera  31  and a rear touch pad  32 . Like the front touch pad  21 , the rear touch pad  32  is configured as a multitouch pad. The electronic device  10  is built with two cameras and two touch pads on the front and rear faces. 
     [Configuration of Top Part] 
       FIG. 3A  shows the top face of the electronic device  10 . As already described, the L button  26   a  and the R button  26   b  are provided at the left and right ends of the top face of the electronic device  10 . To the right of the L button  26   a  is provided a power button  33 . The user turns on or turns off power by pressing the power button  33 . The electronic device  10  is provided with power control capabilities that send the device  10  to a suspended state when a predetermined period of time (period of absence of user control) elapses without user control means being used. Once the electronic device  10  enters a suspended state, the user can return the electronic device  10  from a suspended state to an awake state by pressing the power button  33 . 
     A game card slot  34  is a slot where a game card is inserted. The illustration shows the game card slot  34  covered by a slot cover. An LED lamp that flashes when the game card is being accessed may be provided in the vicinity of the game card slot  34 . An accessory terminal  35  is a terminal for connection with a peripheral device (accessory). The illustration shows the accessory terminal  35  covered by a terminal cover. Between the accessory terminal  35  and the R button  26   b  are provided a − button  36   a  and a + button  36   b  for adjusting the volume. 
     [Configuration of Bottom Part] 
       FIG. 3B  shows the bottom face of the electronic device  10 . A memory card slot  37  is a slot where a memory card is inserted. The illustration shows the memory card slot  37  covered by a slot cover. On the bottom face of the electronic device  10  are provided a sound input and output terminal  38 , a microphone  39 , and a multiuse terminal  40 . 
     The Multiuser Terminal  40  is Compatible with Universal Serial 
     Bus (USB) and provides connection with other devices via a USB cable. 
     [Configuration of Left Side Part] 
       FIG. 3C  shows the left side face of the electronic device  10 . On the left side face of the electronic device  10  is provided a SIM card slot  41  where a SIM card is inserted. 
     [Circuit Configuration of Electronic Device] 
       FIG. 4  shows the circuit configuration of the electronic device  10 . The illustrated blocks are connected to each other via a bus  92 . A wireless communication module  71  comprises a wireless LAN module compatible with a communication standard such as IEEE802.11b/g and connects to an external network via an AP 2 . The wireless communication module  71  may be provided with communication capabilities compatible with the Bluetooth (registered trademark) protocol. A mobile telephone module  72  is compatible with the 3rd generation digital mobile telephone scheme compliant with the International Mobile Telecommunication 2000 (IMT-2000) standard established by the International Telecommunication Union (ITU) and connects to a mobile telephone network  4 . A SIM card  74  in which a unique ID identifying the telephone number of the cell phone is recorded is inserted in the SIM card slot  41 . By inserting the SIM card  74  into the SIM card slot  41 , the mobile telephone module  72  becomes capable of communicating with the mobile telephone network  4 . 
     A central processing unit (CPU)  60  executes a program loaded into a main memory  64 . A graphics processing unit (GPU)  62  executes computation necessary for image processing. The main memory  64  is implemented by a random access memory (RAM) and stores a program or data used by the CPU  60 . A storage  66  comprises, for example, a NAND-type flash memory and is used as a built-in auxiliary storage device. 
     A motion sensor  67  detects the motion of the electronic device  10  and a geomagnetic sensor  68  detects geomagnetism in the directions of three axes. A GPS control unit  69  receives a signal from a GPS satellite and computes a current position. The front camera  30  and the rear camera  31  capture an image to collect image data. The front camera  30  and the rear camera  31  comprise a complementary metal oxide semiconductor (CMOS) image sensor. 
     The display device  20  is an organic electro-luminescence display device and is provided with light-emitting elements that emit light by applying a voltage to the cathode and the anode. In the power-saving mode, the voltage applied between the electrodes is lowered so that the display device  20  is placed in a diminished light state and power consumption is reduced. The display device  20  may be a liquid crystal panel display device provided with a backlight. In the power-saving mode, the amount of light from the backlight is reduced so that the liquid crystal panel display device is placed in a diminished light state and power consumption is reduced. 
     A user control unit  70  of an interface  90  includes various user control means in the electronic device  10 . More specifically, the user control unit  70  includes user control buttons  22 , the directional keys  23 , the analog stick  24 , the L button  26   a , the R button  26   b , the HOME button  27 , the START button  28 , the SELECT button  29 , the power button  33 , the − button  36   a , and the + button  36   b . The front touch pad  21  and the rear touch pad  32  are multi-touch pads. The front touch pad  21  is arranged to be superimposed on the surface of the display device  20 . The speaker  25  outputs sound generated by various functions of the electronic device  10 , and the microphone  39  picks up sound around the electronic device  10 . The sound input and output terminal  38  receives stereo sound from an external microphone and outputs the stereo sound to, for example, an external headphone. 
     A game card  76  in which a game file is recorded is inserted in the game card slot  34 . The game card  76  is provided with a data write enabled area. When the game card  76  is seated in the game card slot  34 , the media drive writes/reads data. A memory card  78  is inserted into the memory card slot  37 . Once the memory card  78  is seated in the memory card slot  37 , the memory card  78  is used as an external auxiliary storage device. The multiuse terminal  40  can be used as a USB terminal. A USB cable  80  may be connected to the multiuse terminal  40  to transmit and receive data to and from other USB devices. A peripheral device is connected to the accessory terminal  35 . 
     [Embodiment] 
     A summary of the embodiment of the invention will be given. The electronic device  10  according to the embodiment reads a designated application from the memory card  78  in which it is installed and executes the application. The designated application executed by the electronic device  10  registers the memory card  78  in which it is installed in the electronic device  10  such that a predefined upper limit to the number of applications is not exceeded. A plurality of memory cards  78  may be registered and managed in the electronic device  10  such that a predetermined upper limit to the number of cards is not exceeded. In each memory card  78 , the designated application downloaded by the electronic device  10  is installed. 
       FIG. 5  schematically shows the functional features of the electronic device  10  according to the embodiment of the present invention. The electronic device  10  according to the embodiment includes an arithmetic unit  100 , a storage  66 , a memory card slot  37 , and a memory card  78 . 
       FIG. 5  depicts functional features of the electronic device  10  according to the embodiment that implement the function of managing recording mediums so that the other features are omitted from the illustration. The elements depicted in  FIG. 5  as functional blocks for performing various processes are implemented by hardware such as a CPU, a main memory, or other LSI&#39;s, and by software such as a programs etc., loaded into the main memory. Therefore, it will be obvious to those skilled in the art that the functional blocks may be implemented in a variety of manners by hardware only, software only, or a combination of thereof. 
     As described above, the storage  66  comprises, for example, a NAND-type flash memory and is used as a built-in auxiliary storage device of the electronic device  10 . In the electronic device  10  according to the embodiment, the storage  66  stores a management database  150 . The details of the management database  150  will be described later. 
     The memory card slot  37  is an interface for reading and writing in the memory card  78 , which functions as an external recording medium of the electronic device  10 . The memory card  78  stores a system database  120 , a data storage area  130 , and an application  140 . 
     The arithmetic unit  100  controls the operation of the electronic device  10  in a centralized manner. For example, the arithmetic unit  100  can be implemented by using the CPU  60  to execute the operating system program loaded into the main memory  64 . The arithmetic unit  100  further includes a system control unit  102 , a database access unit  104 , a data writing unit  106 , an application execution unit 108 , and an application registration unit  110 . 
     The application registration unit  110  installs in the memory card  78  (recording medium) an application program for implementing an application (hereinafter, “an application program for implementing an application” will simply be referred to as “application” in the specification). The application registration unit  110  downloads an application from the server  5  via the network  3  and then installs the downloaded application in the memory card  78 . 
     The application execution unit  108  reads and executes the application stored in the memory card  78 . The application registration unit  110  can install in the memory card  78  any application permitted to be installed in the memory card. The application execution unit  108  can execute any program installed in the memory card  78 . 
     The database access unit  104  is an interface for the electronic device  10  to access the management database  150  so as to, for example, update the management database. Under the control of, for example, the designated application executed by the application execution unit  108 , the database access unit  104  registers the memory card  78  in which the application is installed in the management database  150  such that a predefined upper limit to the number of applications is not exceeded. The term “designated application” as used in the embodiment refers to an application required to be installed in a portable recording medium such as the memory card  78  due to the constraints imposed by the standard. 
     Specific examples of designated applications include an application designed to transfer content recorded by a recording device for recording a terrestrial digital broadcast program to the memory card  78 . Examples of the standard imposing the constraints include but are not limited to Embedded Memory with Playback and Recording function (EMPR). The management database  150  described above is used to manage the memory card  78  in which the designated application is installed. The memory card  78  not registered in the management database  150  cannot be accessed from applications run on the electronic device  10 , including the designated application. 
     A content transfer application  140  for transferring content recorded by a recording device for recording a terrestrial digital broadcast program to the memory card  78  will be explained below by way of example of the designated application. 
     The content transfer application  140  includes an area creation module  142  for creating the data storage area  130  for storing content in the memory card  78  in which the content transfer application  140  is installed. The content transfer application  140  also includes a loopback module  144  configured to publish the data storage area  130  created by the area creation module  142  to a device outside the electronic device  10  as an independent recording medium. The content transfer application  140  further includes a recording medium management module  146  for registering the recording medium in which the content transfer application  140  is installed in the electronic device  10 . 
     The area creation module  142  creates the data storage area  130  by creating a file in a free area in the memory card  78  and formatting the file with the File Allocation Tables (FAT) file system. The loopback module  144  publishes the data storage area  130  formatted by the area creation module  142  to a device outside the electronic device  10  as if the data storage area  130  appears as a block mass storage such as a hard disk drive. 
     The user may be able to select from several options the size of the data storage area  130  created by the area creation module  142  within the constraints of the free area in the memory card  78 . The user can create a file size necessary to transfer data handled by the content transfer application  140  in the memory card  78 , and use the remaining area to store other data such as save data of the game. Therefore, the memory card  78  can be used efficiently. 
     Given that the electronic device  10  is designed to store data used for system management of the electronic device  10  in the system database  120  in the memory card  78 , the aforementioned approaches allows the area in the memory card  78  used by the content transfer application  140  to be fully isolated from the area used by the electronic device  10  so that the system security is improved. Examples of data stored in the system database  120  include an electronic device identifier that uniquely identifies the electronic device  10 . The database access unit  104  stores in the system database  120  the electronic device identifier of the electronic device  10  used to install the designated application in the memory card  78 . 
     The data writing unit  106  of the arithmetic unit  100  writes data in the data storage area  130  published by the loopback module  144  to the device outside the electronic device  10 . More specifically, the data writing unit  106  transfers data hosted by an external device such as a terrestrial digital recorder, connected to the electronic device  10  via the multiuse terminal  40 , to the data storage area  130 . A movie player application (not shown) of the electronic device  10  can directly read and write data in the data storage area  130  without mediation by the loopback module  144 , but the loopback module  144  may be used to read data from the data storage area  130  to play back content such as a movie stored in the data storage area  130 . 
     The system control unit  102  of the arithmetic unit  100  manages the operation of the recording medium management module  146 , the data writing unit  106 , the application execution unit  108 , and the application registration unit  110  in a centralized manner. 
     Management of the memory card  78  by the recording medium management module  146  will be explained in further detail below. 
       FIG. 6  schematically shows the functional features of the recording medium management module  146  according to the embodiment. The recording medium management module  146  according to the embodiment includes a registration verification module  202 , a recording medium registration module  204 , a registration restriction module  206 , an unregistration module  208 , a registration information updating module  210 , and a management and control module  200  that manages these blocks in a centralized manner. 
     The recording medium registration module  204  registers date and time information and the recording medium identifier uniquely identifying the memory card  78  in the management database  150 , linking the information to the identifier to each other. More specifically, the recording medium registration module  204  executed by the application execution unit  108  registers the information and the identifier in the management database  150  via the system control unit  102  and the database access unit  104 . It will be assumed hereinafter that access from the application executed by the application execution unit  108  to the management database  150  takes place via the system control unit  102  and the database access unit  104 , so that a description thereof will be omitted. 
     The “date and time information” represents information related to the date and time of generation, update, etc. of the data storage area  130  in the memory card  78 . For example, the recording medium registration module  204  registers, in the management database  150 , the creation date and time information indicating the date and time when the area creation module  142  newly created the data storage area  130  in the memory card  78 , linking the recording medium identifier to the information. 
     When the data writing unit  106  updates data in the data storage area  130  already created in the memory card  78 , the registration information updating module  210  registers, in the management database  150 , the recording medium identifier of the memory card  78  and the date and time information indicating the date and time of update of data, linking the identifier to the information. An access information updating unit (not shown) may be provided in the recording medium management module  146  so as to register, in the management database  150 , the date and time that the application (e.g., a movie player application) last accessed data in the data storage area  130  as the last access date and time information. 
     The recording medium registration module  204  also links the recording medium identifier to the electronic device identifier that uniquely identifies the electronic device  10  and stores the identifiers in the management database  150  accordingly. More specifically, when the area creation module  142  in the memory card  78  inserted into the memory card slot  37  of the electronic device  10  creates a new data storage area  130  in the memory card  78 , the recording medium registration module  204  links the electronic device identifier to the recording medium identifier and stores the identifies in the management database  150  accordingly. 
     As described above, by linking the date and time information to the recording medium identifier and registering the information and the identifier in the management database  150 , it is possible to analyze the status of use (e.g., a period of time used) of the memory card  78  identified by the recording medium identifier. The electronic device  10  that created the data storage area  130  in the memory card  78  identified by the recording medium identifier can be identified by referring to the electronic device identifier stored in the system database  120  in the memory card  78 . 
     As described above, a designated application may have to be installed in a portable recording medium such as the memory card  78  due to, for example, the constraints from the standard. Installation of the content transfer application  140  in the memory card  78  will be explained by way of example. Desirably, an upper limit to the number of memory cards  78  registered in the electronic device  10  is defined. The “upper limit to the number registered” may be determined experimentally by allowing for the capacity of the storage  66  of the electronic device  10  or the assumed mode of use. By way of example, the upper limit is 4. The upper limit to the number registered is stored in, for example, the storage  66 . 
       FIG. 7  schematically shows the data structure of the management database  150  according to the embodiment. As shown in  FIG. 7 , the management database  150  stores the recording medium identifier, the electronic device identifier, the creation date and time information, the update date and time information, and the last access date and time information, linking these types of information to the recording medium identifier.  FIG. 7  shows a case where the upper limit to the number registered is 4. In this case, the management database  150  shown in  FIG. 7  stores 4 recording medium identifiers and information linked thereto. 
     Reference is made back to  FIG. 6 . The registration restriction module  206  in the recording medium management module  146  acquires the upper limit to the number of cards registered that is stored in the management database  150 . The registration restriction module  206  verifies whether the number of memory cards  78  registered in the management database reaches the acquired upper limit. If the number of memory cards  78  registered in the management database reaches the upper limit, the unregistration module  208  selects a candidate of the memory card  78  that should be unregistered from the management database  150  before the recording medium registration module  204  additionally registers the memory card  78  in the management database  150 . More specifically, the unregistration module  208  refers to the date and time information registered in the management database 150  as being linked to the recording medium identifier so as to select a candidate of the memory card  78  that should be unregistered. 
     For example, the unregistration module  208  refers to the date and time information in the management database  150  to select a memory card  78  in which the data storage area  130  was created on the earliest date and time as the candidate of unregistration. The memory card  78  in which the data storage area  130  was created on an early date and time is likely to be left unused by the user in many cases. Therefore, by presenting such a memory card  78  to the user, the user is relieved of the trouble of selecting a card to be unregistered. 
     By way of another example, the unregistration module  208  selects a memory card  78  in which the data in the data storage area  130  was updated on the earliest date and time as the candidate of unregistration. The term “update of data” should encompass the first instance of data transfer performed after the data storage area  130  is created. The memory card  78  in which the data is updated on an early date and time is likely to be left unused by the user in many cases. Therefore, by presenting such a memory card  78  to the user, the user is relieved of the trouble of selecting a card to be unregistered. 
     By way of still another example, the unregistration module  208  selects a memory card  78  in which the data in the data storage area  130  was accessed on the earliest date and time as the candidate of unregistration. The memory card  78  in which the data is last accessed on an early date and time is likely to be left unused by the user in many cases. Therefore, by presenting such a memory card  78  to the user, the user is relieved of the trouble of selecting a card to be unregistered. 
     If the user accepts unregistration of the memory card  78 , the unregistration module  208  unregisters the memory card  78  registered in the management database  150 . 
     The algorithm for selecting a candidate of unregistration presented by the unregistration module  208  to the user is not limited to the one described above. A skilled person would appreciate that a variety of algorithms would be possible. For example, if two items of creation date and time information registered in the management database  150  indicate events of creation close in time, the memory card  78  in which the data is updated on the earliest date and time may be selected as a candidate of unregistration. 
       FIG. 8  shows an exemplary screen presented by the unregistration module  208  according to the embodiment before unregistering the memory card  78 . The screen is stored in a data area in the content transfer application  140  installed in the memory card  78  or in the storage  66  of the electronic device  10 . The screen is displayed by the GPU  62  on the touch panel  50 . To accept unregistration of the memory card  78 , the user taps “Yes” on the touch panel  50 . To refuse unregistration of the memory card  78 , the user taps “No” on the touch panel  50 . In this way, the unregistration module  208  can prompt the user whether to accept or refuse unregistration of the memory card  78 . 
     Reference is made back to  FIG. 6 . When the memory card  78  is inserted into the memory card slot  37 , the registration verification module  202  in the recording medium management module  146  verifies whether the recording medium identifier of the memory card  78  is found in the management database  150 . If the recording medium identifier of the memory card  78  is not found in the management database  150 , the registration verification module  202  transmits information indicating as such to the system control unit  102 . 
     If the memory card  78  is not registered in the management database  150 , the content transfer application  140  cannot access the memory card  78 . Thus, when the memory card  78  is inserted into the memory card slot  37 , whether the content transfer application  140  can access the memory card  78  inserted into the memory card slot  37  can be verified only by referring to the management database  150 . 
     If the recording medium identifier of the memory card  78  is found in the management database  150 , the registration verification module  202  verifies whether the electronic device identifier stored in the management database  150  linked to the recording medium identifier matches the electronic device identifier stored in the system database  120  of the memory card  78 . If the electronic device identifier stored in the management database  150  linked to the recording medium identifier differs from the electronic device identifier stored in the system database  120  of the memory card  78 , the registration verification module  202  causes the recording medium registration module  204  to suspend registration of the memory card  78  in the management database  150 . 
     Generally, the memory card  78  can be removed from the electronic device  10  and carried with the user as desired. Therefore, if the data storage area  130  created in the memory card  78  is open to access by another electronic device  10 , the data stored in the data storage area  130  may be distributed at will, which could possibly cause a legal problem or a problem in terms of conformity with the standard. In this regard, it is desired that the data storage area  130  created by a given electronic device  10  in the memory card  78  be prevented from being accessed by other electronic devices  10 . 
     This is addressed by ensuring that the data storage area  130  is created from scratch in order to allow the memory card  78  in which the data storage area  130  is created by a given electronic device  10  to be used by the content transfer application  140  in another electronic device  10 . As a result, the data transferred by another electronic device  10  to the memory card  78  cannot be used. Therefore, if the recording medium identifier stored in the system database  120  in the memory card  78  differs from the electronic device identifier of the electronic device  10 , the registration verification module  202  causes the recording medium registration module  204  to suspend registration of the memory card  78  in the management database  150  and to indicate that the existent data in the memory card  78  cannot be used if the registration is continued. 
       FIG. 9  shows an exemplary screen presented by the registration verification module  202  according to the embodiment. Like the screen presented by the unregistration module  208 , the screen is also stored in a data area in the content transfer application  140  installed in the memory card  78  or in the storage  66  of the electronic device  10 . The screen is displayed by the GPU  62  on the touch panel  50 . To accept continuation of registration of the memory card  78 , the user taps “Yes” on the touch panel  50 . To refuse unregistration of the memory card  78 , the user taps “No” on the touch panel  50 . In this way, the recording medium registration module  204  can prompt the user whether to accept or refuse registration of the memory card  78  being used by another electronic device  10 . This prevents the data from being inadvertently deleted, to the advantage of the user not desiring the data to become unusable. The data stored in the memory card  78  can continue to be used in the electronic device  10  that has registered the memory card  78   
     If the recording medium identifier of the memory card  78  is not found in the management database  150  and if the electronic device identifier stored in the system database  120  of the memory card  78  matches the electronic device identifier of the electronic device executing the content transfer application  140 , the registration verification module  202  also causes the recording medium registration module  204  to suspend registration of the memory card  78  in the management database  150 . In this case, the memory card  78  attempted to be registered in the management database  150  is considered to be registered in the management database  150  in the past but unregistered subsequently. Thus, the registration verification module  202  notifies the user that re-registration is necessary in order to use the memory card  78 . 
       FIG. 10  is another exemplary screen presented by the registration verification module  202  according to the embodiment. As in the case shown in  FIG. 9 , the screen is also stored in a data area in the content transfer application  140  installed in the memory card  78  or in the storage  66  of the electronic device  10 . The screen is displayed by the GPU  62  on the touch panel  50 . To accept re-registration of the memory card  78 , the user taps “Yes” on the touch panel  50 . To refuse unregistration of the memory card  78 , the user taps “No” on the touch panel  50 . 
       FIG. 11  is a flowchart illustrating the flow of steps performed in the electronic device  10  according to the embodiment. The application registration unit  110  downloads an application that should be installed in the memory card  78  to the main memory  64  of the electronic device  10  via the network  3  (S 2 ). 
     The application registration unit  110  installs the application downloaded to the main memory  64  in the memory card  78  (S 4 ). Examples of applications installed by the application registration unit  110  in the memory card  78  include the content transfer application  140 . The recording medium registration module  204  in the recording medium management module  146  registers the memory card  78 , i.e., the recording medium, inserted into the memory card slot  37 , in the management database  150  (S 6 ). 
     The application execution unit  108  executes the area creation module  142  in the content transfer application  140  and creates the data storage area  130  in a free area in the memory card  78  (S 8 ). Further, the application execution unit  108  publishes the data storage area  130  created by the area creation module  142  to a device outside the electronic device  10  as a mass storage, by executing the loopback module  144  in the content transfer application  140  (S 10 ). 
     The multiuse terminal  40  connects to an external recording device such as a terrestrial digital recorder via USB (S 12 ). The external recording device, which hosts the data, recognizes the data storage area  130  as an independent recording medium. The data writing unit  106  transfers the data stored in the external recording device to the data storage area  130  (S 14 ). When the multiuse terminal  40  disables USB connection to the external recording device (S 16 ), the loopback module  144  closes the data storage area  130  (S 18 ). 
     When the loopback module  144  closes the data storage area  130 , the content transfer application  140  transmits meta data including creation date and time information and update date and time information (S 20 ) and the application execution unit  108  receives the meta data (S 22 ). The recording medium management module  146  updates the management database  150  according to the meta data acquired by the application execution unit  108  (S 24 ). By repeating the above steps, the electronic device  10  is capable of managing registration of the memory card  78  which is inserted into the memory card slot  37  and in which a designated application is installed. 
     Update of the management database  150  by the recording medium management module  146  may not be timed to occur after the loopback module  144  closes the data storage area  130 . For example, the recording medium management module  146  may update the management database  150  when the data writing unit  106  completes transferring the data to the data storage area  130 . 
       FIG. 12  is a flowchart illustrating the flow of steps of registering a memory card  78  according to the embodiment. The steps of the flowchart is started when the memory card  78  is inserted into the memory card slot  37 . 
     The management and control module  200  in the recording medium management module  146  learns that the memory card  78  is inserted into the memory card slot  37  (S 30 ). The registration verification module  202  verifies whether the memory card  78  is already registered by verifying whether the recording medium identifier of the memory card  78  inserted into the memory card slot  37  is found in the management database  150 . 
     If the recording medium identifier is registered in the management database  150  (Y in S 32 ), the application execution unit  108  displays the content of data stored in the data storage area  130  in the memory card  78  (S 34 ). If the recording medium identifier is not registered in the management database  150  (N in S 32 ), the recording medium registration module  204  displays a message on the touch panel  50 , prompting the user whether to register the memory card  78  from scratch. 
     If the user selects registering the memory card  78  from scratch (Y in S 36 ), the registration verification module  202  verifies whether the memory card  78  is used by another electronic device  10 . More specifically, the registration verification module  202  verifies whether the electronic device identifier linked to the recording medium identifier is the same as the electronic device  10  uniquely identifying the electronic device  10 . 
     If the memory card  78  is not registered by another electronic device (N in S 38 ), the registration restriction module  206  verifies whether there is vacancy for registration in the management database  150 . If there is no vacancy for registration in the management database  150  (N in S 40 ), the unregistration module  208  displays a message on the touch panel  50 , prompting the user whether to unregister one of the memory cards  78  already registered in the management database  150 . 
     When the user selects unregistering one of the memory cards  78  already registered in the management database  150  (Y in S 42 ), the unregistration module  208  unregisters the memory card  78  selected as the candidate of unregistration (S 44 ). 
     If the memory card  78  is already registered by another electronic device (Y in S 38 ), the registration verification module  202  displays a message on the touch panel  50 , prompting the user whether to delete the data storage area  130  created by another electronic device  10 . When the user selects deleting the data storage area  130  created by another electronic device (Y in S 46 ), the area creation module  142  creates a data storage area  130  from scratch. This deletes the data storage area  130  created by another electronic device (S 48 ). 
     If there is vacancy for registration in the management database  150  (Y in S 40 ), or if the data storage area  130  created by another electronic device  10  is deleted, the recording medium registration module  204  registers the recording medium identifier of the memory card  78  in the management database  150  from scratch (S 50 ). More specifically, the recording medium identifier of the memory card  78  is registered in the management database  150  in response to the creation of the data storage area  130  by the area creation module  142 . 
     If the application execution unit  108  displays the content of data stored in the data storage area  130  or if the user does not select registering the memory card  78  from scratch (N in S 36 ), if the user does not select unregistering one of the memory cards  78  already registered in the management database  150  (N in S 42 ), if the user does not select deleting the data storage area  130  created by another electronic device (N in S 46 ), or if the recording medium registration module  204  registers the recording medium identifier of the memory card  78  in the management database  150  from scratch, the steps in the flowchart are completed. 
     As described above, according to the electronic device of the embodiment, the memory card  78  (recording medium) can be managed properly. 
     Described above is an explanation based on an exemplary embodiment. The embodiment is intended to be illustrative only and it will be obvious to those skilled in the art that various modifications to constituting elements and processes could be developed and that such modifications are also within the scope of the present invention. 
     The recording medium identifier and the electronic device identifier are described above as being separately stored in the management database  150 . Instead, the recording medium management module  146  may manage these types of information, by using a Hash value generated according to the recording medium identifier, the electronic device identifier, and the data stored in the data storage area  130 . For example, this can be implemented by a Hash value defined in the EMPR standard mentioned above. In this case, the recording medium registration module  204  may generate a Hash value when the area creation module  142  creates the data storage area  130 , and register the value in the management database  150 . Similarly, the registration information updating module  210  may generate a Hash value when the data writing unit  106  updates the data in the data storage area  130 , and register the value in the management database  150 . 
     If a device such as a PC different from the electronic device  10  is used to rewrite the data in the data storage area  130 , the Hash value stored in the management database in the electronic device  10  should not be updated. Therefore, by comparing the Hash value stored in the management database with the Hash value generated according to the recording medium identifier, the electronic device identifier, and the data stored in the data storage area  130 , verification can be made as to whether the data in the data storage area  130  is generated or updated by the electronic device  10 . For example, this can prevent the content copied to the memory card  78  by illegal means from being used by unauthorized means. 
     The description given above concerns management of the memory card  78  in which a designated application is installed. As described above, the electronic device  10  is capable of writing/reading in the game card  76  as well as the memory card  78  so that a designated application may be installed in the game card  76 . In this case, the recording medium management module  146  may link the game card identifier capable of uniquely identifying the game card  76  to the date and time information, and register and manage the identifier and the information in the management database  150 . 
     As described above, it is desirable that the data storage area  130  created in the memory card  78  by a given electronic device be prevented from being accessed by another electronic device  10 . Therefore, the movie player application (not shown) of the electronic device  10  may verify whether the recording medium identifier stored in the system database  120  in the memory card  78  matches the electronic device identifier of the electronic device  10  before reading or writing data in the data storage area  130  and, if the identifiers do not match, the movie player application may suspend playing back the movie. This allows the determination as to whether the memory card  78  is fit for use in the electronic device  10 .