Abstract:
A storage medium (computer readable medium) for recording information data in a protective manner such that an easy data processing can hardly succeed correct reproduction of information such as music information. A machine for creating data to be recorded in the storage medium and a machine for restoring the recorded data. Incomplete information data which is obtained by omitting some data in complete information data adapted to provided complete information is recorded in the storage medium. The data creation machine separates the complete information data into the incomplete information data and complementary information data, and writes the incomplete information data into the storage medium. The data restoration machine includes a first storage unit for recording the incomplete information data, and a second storage unit for recording the complementary information data which is the data omitted from the complete information data. The data restoration machine combines the incomplete information data with the complementary information data to create the complete information data.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a storage medium for recording data, an apparatus for creating data to be recorded in the storage medium and an apparatus for restoring the recorded data.  
           [0003]    2. Description of the Related Art  
           [0004]    A so-called e-commerce is spreading nowadays. It allows a client terminal device such as a personal computer to download an information file such as a music information file from a web server over the internet, whereby various information including music (or musical pieces), images, pictures, programs, novels, etc. is bought and sold over the internet.  
           [0005]    The e-commerce is advantageous because a purchaser can immediately obtain desired information such as music without going to a store.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0006]    The size of the information file such as a music file and a picture file is, however, as large as megabyte even after the file is compressed. A terminal device, therefore, requires a considerable amount of time to download the file. An additional time is further needed when the internet is crowded and/or a great amount of data or people access a server. As a result, a user may feel stress during downloading or hesitate to purchase something by the time-consuming downloading.  
           [0007]    In order to cope with this drawback, the information file such as the music file and picture file may be recorded in a storage medium such as a disc and the storage medium may be distributed free. The information file recorded in the storage medium is locked by a so-called electronic key so that correct information cannot be restored when data is read and reproduced directly from the information file. A user is therefore required to access the web server from the terminal device to purchase key information that enables proper restoration when the user wants to utilize desired information among those recorded in the storage medium.  
           [0008]    The key information is, however, a very short data like a password so that it may be leaked from a thoughtless user or unlocked.  
           [0009]    An object of the present invention is to provide a storage medium for recording information data in a protective manner such that easy data processing hardly succeeds correct restoration of information such as music information, an apparatus for preparing data to be recorded in the storage medium, and an apparatus for restoring the recorded data.  
           [0010]    According to one aspect of the present invention, there is provided a storage medium for recording incomplete information data obtained by omitting some data from complete information data which provide complete information.  
           [0011]    According to another aspect of the present invention, there is provided an apparatus for creating recordation data comprising: storage means for storing complete information data adapted to provide complete information; separation means for omitting some data in the complete information to separate the complete information data into incomplete information data and complementary information data; and write means for writing the incomplete information data separated by the separation means into a storage medium.  
           [0012]    According to still another aspect of the present invention, there is provided a data restoration apparatus comprising: first storage means for recording incomplete information data obtained by omitting certain data in complete information data adapted to provide complete information; second storage means for recording the data omitted from the complete information data as complementary information data; and combine means for combining the incomplete information data recorded in the first storage means with the complementary information data recorded in the second storage means to create the complete information data. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a block diagram illustrating a structure of an information providing system according to the present invention;  
         [0014]    [0014]FIG. 2 illustrates part of a structure inside a user terminal device;  
         [0015]    [0015]FIG. 3 illustrates an omitting method for omitting some portions in music data of one-song-worth at constant intervals;  
         [0016]    [0016]FIG. 4 illustrates a structure of an incomplete music file;  
         [0017]    [0017]FIG. 5 illustrates a structure of a complementary music file;  
         [0018]    [0018]FIG. 6 illustrates a block diagram of a structure of a data separation device;  
         [0019]    [0019]FIG. 7 is a flowchart illustrating a data separating operation performed by a control circuit of the data separation device shown in FIG. 6;  
         [0020]    [0020]FIG. 8 is a sequence diagram illustrating an operation of the information providing system shown in FIG. 1;  
         [0021]    [0021]FIG. 9 illustrates contents stored in a database created in an information administration server;  
         [0022]    [0022]FIG. 10 is a flowchart illustrating a combine operation;  
         [0023]    [0023]FIG. 11 is a flowchart illustrating another combine operation suited when a plurality of songs are selected;  
         [0024]    [0024]FIG. 12 is an omitting method for omitting some portions in the music data of one-song-worth at random intervals;  
         [0025]    [0025]FIG. 13 is a block diagram showing a structure of another data separation device;  
         [0026]    [0026]FIG. 14 shows a random number-M-N table;  
         [0027]    [0027]FIG. 15 is a flowchart showing a data separating operation performed by a control circuit of the data separation device shown in FIG. 13;  
         [0028]    [0028]FIG. 16 is a flowchart showing a combine operation applicable to a random number scheme;  
         [0029]    [0029]FIG. 17 illustrates a complementary music file table;  
         [0030]    [0030]FIG. 18 illustrates another complementary music file table;  
         [0031]    [0031]FIG. 19 depicts a random number form data table;  
         [0032]    [0032]FIG. 20 illustrates a structure of music data of TwinVQ scheme;  
         [0033]    [0033]FIG. 21 is a flowchart illustrating a data separating operation carried out by the control circuit when the music data is TwinVQ scheme data;  
         [0034]    [0034]FIG. 22 illustrates a structure of music data of ACC scheme;  
         [0035]    [0035]FIG. 23 illustrates a structure of music data of MP3 scheme;  
         [0036]    [0036]FIG. 24 is a flowchart illustrating a combine operation in case of TwinVQ music data;  
         [0037]    [0037]FIG. 25 is a sequence diagram illustrating another example of an operation carried out by the information providing system shown in FIG. 1;  
         [0038]    [0038]FIG. 26 is a sequence diagram illustrating still another example of an operation carried out by the information providing system shown in FIG. 1;  
         [0039]    [0039]FIG. 27 is a sequence diagram illustrating yet another example of an operation carried out by the information providing system shown in FIG. 1;  
         [0040]    [0040]FIG. 28 is a block diagram illustrating a structure of an information providing system having a kiosk terminal device according to the present invention;  
         [0041]    [0041]FIG. 29 is a block diagram illustrating a structure of a cellar telephone;  
         [0042]    [0042]FIG. 30 is a block diagram illustrating a structure of the kiosk terminal device;  
         [0043]    [0043]FIG. 31 is a flowchart illustrating an operation of a control circuit of the kiosk terminal device;  
         [0044]    [0044]FIG. 32 is a sequence diagram illustrating an operation of the information providing system shown in FIG. 28;  
         [0045]    [0045]FIG. 33 is a block diagram illustrating a structure of another kiosk terminal device;  
         [0046]    [0046]FIG. 34 is a sequence diagram illustrating an operation of the information providing system shown in FIG. 28 that uses the kiosk terminal device of FIG. 33;  
         [0047]    [0047]FIG. 35 depicts a structure of a navigation system;  
         [0048]    [0048]FIG. 36 depicts a structure of a navigation device in the system shown in FIG. 35;  
         [0049]    [0049]FIG. 37 depicts a map data structure;  
         [0050]    [0050]FIG. 38 depicts a concrete structure of a data administrating portion and a data portion in the map data;  
         [0051]    [0051]FIG. 39 depicts relationship between meshes and mesh numbers;  
         [0052]    [0052]FIG. 40 depicts relationship between the mesh numbers and map data addresses;  
         [0053]    [0053]FIG. 41 illustrates a sequence diagram of an operation of the navigation system;  
         [0054]    [0054]FIG. 42 illustrates a sequence diagram of another operation of the navigation system;  
         [0055]    [0055]FIG. 43 illustrates a sequence diagram of still another operation of the navigation system; and  
         [0056]    [0056]FIG. 44 illustrates a sequence diagram of yet another operation of the navigation system. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0057]    Embodiments of the present invention will now be described in detail in reference to the accompanying drawings.  
         [0058]    Referring to FIG. 1, illustrated is a fundamental structure of an information providing system of the present invention.  
         [0059]    The illustrated information providing system includes an information administration server  1 , a financial institute server  2 , a user terminal device  3  and a credit card administration server  4 . The information administration server  1 , financial institute server  2 , user terminal device  3  and credit card administration server  4  are connected to the internet  5 . It should be noted that the information administration server  1  may be connected to the financial institute server  2  and/or the credit card administration server  4  by dedicated lines instead of the internet  5 .  
         [0060]    The information administration server  1  is located in an information administration center of an e-commerce enterprise, and is a server for providing the user terminal device  3  with music information (will be described in detail). The information administration server  1  has a storage device  7  as a database. Although this embodiment only deals with music information providing, the present invention is of course applicable when providing other information such as image information, picture information and atlas data information.  
         [0061]    The financial institute server  2  is a server located in a bank, and functions as a server for cooperation money treatment (will be described) in response to instructions from the information administration server  1 . The credit card administration server  4  is a server situated in a credit card company, and conducts charging in response to instructions from the information administration server  1 .  
         [0062]    The user terminal device  3  is operated by a user who wants to have music delivered. For the sake of clarity and easier understanding of the invention, there is only one user terminal device in this embodiment, but in reality a plurality of terminal devices are connected to the internet  5 . The user terminal device  3  is a personal computer and equipped with a CD-ROM drive  6 . CD-ROM  8  is put on a tray and inserted into the CD-ROM drive  6  of the user terminal device  3 . The user terminal device  3  executes a program written in the CD-ROM  8  as it reads the CD-ROM  8 . This program is a program that enables the terminal device  3  to communicate with the information administration server  1  and reproduce desired music. Specifically, this program is a program for the terminal device  3  to execute a procedure after Step S 22  shown in FIG. 8 (will be described). It should be noted that the program may be stored in a storage device such as a hard disc of the terminal device  3 , and executed upon an operation made by a user.  
         [0063]    It should also be noted that the CD-ROM  8  may be replaced with other storage medium such as DVD-ROM. The storage medium is not limited to the disc; it may be a tape storage medium, a card storage medium, a solid-state memory or the like.  
         [0064]    Referring to FIG. 2, the user terminal device  3  includes a decoder  41  for decoding a complete music file, a D/A converter  42  for converting an output digital signal of the decoder  41  to an analog audio signal, and an amplifier  43  for amplifying the output audio signal of the D/A converter  42  to drive a speaker  44 . The decoder  41  expands a compressed music data, and may be either a hardware element or a software or program executed for that purpose.  
         [0065]    The CD-ROM  8  is, for example, a supplement to a magazine, or the one distributed free or at a very low price. A card having a serial number is attached to the CD-ROM  8  when distributed. It is therefore possible to identify a distribution source and a kind of the disc (recorded contents) from the serial number. The distribution source is an organization such as a store or magazine company that distributes CD-ROMs upon a request from the e-commerce enterprise. The serial number may be recorded on the CD-ROM  8  or printed on a print surface (or a label surface) of the CD-ROM  8 . Recordation of the serial number onto the CD-ROM  8  is automatically made when data such as music data is recorded.  
         [0066]    The music data is incompletely recorded on the CD-ROM  8 . The way of incompletely recording music is, for example as shown in FIG. 3, a simple skipping scheme which misses out some data in the music data at predetermined intervals. The shaded areas indicate the canceled data portions in FIG. 3. The remaining data portions constitute the incomplete music data, and the canceled data portions are complementary (or supplemental) music data.  
         [0067]    The incomplete music data comprised of a plurality of files is stored in the CD-ROM  8  in a format shown in FIG. 4. Specifically, each file includes a header portion and an incomplete data portion, and the CD-ROM  8  stores a plurality of such files as the incomplete music files, the number of which is the number of songs. The header portion includes information such as the way of making the music data incomplete (simple skipping scheme), a file name of each of the incomplete music files and complementary music files, and a block size of each of the incomplete data portions and complementary data portions.  
         [0068]    The database in the storage device  7  stores the complementary music data in the form of a plurality of files, each having a structure shown in FIG. 5. Specifically, each complementary music file includes a header portion and a complementary data portion, and the database stores a plurality of such files, the number of which is the number of songs. Like the header portion of the incomplete music file, this header portion includes information such as the way of making the music data incomplete (simple skipping), a file name of each of the incomplete and complementary music files, and a block size of each of the incomplete and complementary data portions.  
         [0069]    A structure and an operation of an apparatus for dividing the music data into the incomplete music files and complementary music files will be described below.  
         [0070]    Referring to FIG. 6, the data dividing apparatus includes a control circuit  11 , a music data file storage device  12 , a complementary music file storage device  13  and a disc writer  14 . The music data file storage device  12  stores a plurality of complete music files before divided. The complete music data may be a PCM digital data, and is a compressed data in this embodiment. The compressed data is prepared by a voice compression method such as an MP3 (MPEG-1/Audio Layer 3) method, an AAC (MPEG-2/Advanced Audio Coding (ISO/IEC Standard 13818-7)) method, and an ATRAC (Adaptive Transform Acoustic Coding) 3 method. The decoder  41  can decode this compressed music data.  
         [0071]    The complementary music file storage device  13  is a unit for storing the divided complementary music files. The disc writer  14  is a write device for creating the incomplete music files on a writable disc  15  such as CD-R.  
         [0072]    The control circuit  11  first selects a complete music file worth of one song from a plurality of complete music data files stored in the music data file storage unit  12  as shown in Step S 1  of FIG. 7. The control circuit  11  then sets a file name of a complementary music file in association with the selected complete music file to make and store the complementary music file in the complementary music file storage unit  13  (Step S 2 ). Likewise, the control circuit  11  sets a file name of the incomplete music file in association with the selected complete music file, and instructs the disc writer  14  to write the incomplete music file (Step S 3 ). The disc writer  14  creates the incomplete music file and writes it on the disc  15  in response to the write command. The selected complete music file is referred to as Fcom, the corresponding incomplete music file is Fincom, and the associated complementary or supplemental music file is Fsup in the following description.  
         [0073]    The control circuit  11  prepares a header portion of the complementary music file Fsup associated with the complete music file Fcom and writes it into the complementary music file Fsup of the complementary music file storage unit  13  (Step S 4 ) The control circuit  11  also prepares a header portion of the incomplete music file Fincom associated with the complete music file Fcom and instructs the disc writer  14  to write this header portion additionally into the incomplete music file Fincom (Step S 5 ). Upon receiving the write instructions, the disc writer  14  writes the additional header portion in the incomplete music file Fincom of the disc  15 .  
         [0074]    The control circuit  11  reads N-byte-worth music data from the complete music file Fcom selected from the music data file storage unit  12 , maintains it in an internal buffer B 1  (not shown) (Step S 6 ), and determines whether the reading from the complete music file Fcom is complete (Step S 7 ). If the music data equal to or less than N bytes remains in the complete music file Fcom after reading the N-byte-worth data, the control circuit  11  also reads the remaining data at Step S 6 . In such a case, or if there is no music data left upon completion of the N-byte reading operation at Step S 6 , it is recognized at Step S 7  that the reading of the complete music file Fcom is complete.  
         [0075]    If the complete music file Fcom has not read completely at Step S 7 , the control circuit  11  instructs the disc writer  14  to write the N-byte-worth music data held in the internal buffer B 1  into an incomplete data portion of the incomplete music file Fincom (Step S 8 ). Accordingly, the disc writer  14  writes the N-byte-worth music data into the incomplete data portion of the incomplete music file Fincom of the disc  15  in response to the write instructions.  
         [0076]    After Step S 8 , the control circuit  11  reads music data of M bytes worth from the complete music file Fcom selected from the music data file storage unit  12  and stores it in an internal buffer B 2  (not shown) (Step S 9 ). The control circuit  11  determines whether the reading from the complete music file Fcom is complete or not (Step S 10 ). If the music data equal to or less than M bytes remains in the complete music file Fcom after reading the M-byte-worth data, the control circuit  11  reads both the M bytes of data and the remaining data at Step S 9 . If it is the case, or if there is no music data left upon completion of the M-byte-data reading operation at Step S 9 , then it is recognized at Step S 10  that the reading of the complete music file Fcom is complete. Here, the relationship of N&gt;&gt;M holds true. This is necessary to reduce the size of the complementary music file Fsup to be transmitted. It should be noted, however, that the relationship of N&gt;&gt;M does not necessarily hold true; for example, it may be N&gt;M, or N=M to maintain a copyright.  
         [0077]    If the complete music file Fcom has not been read entirely at Step S 10 , the control circuit  11  writes the M bytes of music data stored in the internal buffer B 2  into a complementary data portion of the complementary music file Fsup of the complementary music file storage device  13  (Step S 11 ). The program returns to Step S 6  after Step S 11  so as to repeat the above described operation.  
         [0078]    When the control circuit  11  determines at Step S 7  that the complete music file Fcom has been read completely, it instructs the disc writer  14  to write the music data equal to or less than N bytes stored in the internal buffer B 1  into an incomplete data portion of the incomplete music file Fincom (Step S 12 ). As a result, the disc writer  14  writes the music data not greater than N bytes into the incomplete data portion of the incomplete music file Fincom of the disc  15  in accordance with the write instructions. Consequently, a single incomplete music file Fincom is created in the disc  15 .  
         [0079]    When the control circuit  11  determines at Step S 10  that the complete music file Fcom has been read completely, it writes the music data not greater than M bytes stored in the internal buffer B 2  into a complementary data portion of the complementary music file Fsup inside the complementary music file storage device  13  (Step S 13 ). By executing Step S 13 , a single complementary music file Fsup is prepared in the complementary music file storage device  13 .  
         [0080]    The above described operation of the data separation device is repeated the number of times equal to the number of the songs to be recorded on the disc  15 . After the writing of the incomplete music file into the disc  15  is repeated the number of times equal to the number of the songs, a file data representing a list of titles of the recorded songs is written into the disc  15  for the recorded incomplete music files. A process program for the terminal device is also written into the disc  15 . This program controls the operation of the terminal device  3 , e.g., downloading of the complementary music file and data combination (will be described). Upon completing the writing operation onto the disc  15 , a plurality of CD-ROMs will be reproduced using the disc  15  as a master disc. One of the reproduced CD-ROMs is the CD-ROM  8  mentioned above.  
         [0081]    An operation of the above described information providing system will now be described.  
         [0082]    As the CD-ROM  8  is placed on the tray (not shown) of the CD-ROM drive  6  of the user terminal device  3 , inserted into the CD-ROM drive  6  together with the tray and the CD-ROM  8  is read, the terminal device  3  then starts its operation.  
         [0083]    As illustrated in FIG. 8, the user terminal device  3  first executes the terminal process program written in the CD-ROM  8  (Step S 21 ). The terminal device  3  retrieves the list of the recorded songs from the CD-ROM  8  when it executes the terminal process program (Step S 22 ). Specifically, the CDROM drive  6  reads the list of the recorded songs (i.e., the recorded song list file) from the CD-ROM  8  and feeds it to the terminal device  3 . The user terminal device  3  then causes a display unit (not shown) to display the recorded song list, which is supplied from the CD-ROM drive  6 , in a display screen in the form of a list (Step S 23 ). The user operates certain keys of the terminal device  3  or a mouse in order to select a song, which the user wants to listen to, from the displayed list of the recorded songs. The terminal device  3  obtains a data representing the song selected by the user&#39;s operating the keys or mouse (Step S 24 ) and starts a trial listening operation to the selected song data (Step S 25 ).  
         [0084]    The user terminal device  3  retrieves an incomplete music file corresponding to the selected song data from the CD-ROM  8  via the CD-ROM drive  6  during the trail listening, and causes the CD-ROM drive  6  to read first N bytes of music data from the data portion of the retrieved incomplete music file, and to feed it to the decoder  41 . The decoder  41  then decodes the supplied N bytes of music data successively and sends the resulting PCM audio signal to the D/A converter  42 . Since the analog audio signal produced by the D/A converter  42  is introduced to the speaker  44  through the amplifier  43 , the user is able to listen to the selected song for a predetermined period. It should be noted that the CD-ROM  8  may have been recorded music data for the trial listening beforehand for each of the songs, and such music data may be taken out for the trail listening. For example, each song may be recorded on the CD-ROM  8  as the complete music data, but with first some tens of seconds of music data being only recorded in a complete form.  
         [0085]    After Step S 25 , it is determined whether the user wants to buy the selected song, i.e., the song listened to for the trial (Step S 26 ). When the user decides to buy the song or not to buy, the user conducts a particular operation. For instance, the display shows a button for YES and a button for NO to buy or decline the song, and the user selects one of these buttons by operating the mouse (not shown). If the user decides not to buy this song, the program returns to Step S 23  such that the user can select another song.  
         [0086]    When the user wants to buy another song(s), the program also returns to Step S 23  such that the user can find out a next song.  
         [0087]    If the user wants to purchase a song, the user terminal device  3  utilizes the display screen to request the user to input a serial number (Step S 27 ). The serial number is written on a card distributed together with the CD-ROM  8  as mentioned above. It is then determined whether the serial number is entered (Step S 28 ). If the serial number is entered, the user terminal device  3  sends a request to the information administration server  1  for authentication of the serial number just entered (Step S 29 ). This authentication request is accompanied with the entered serial number. If the serial number is recorded on the CDROM  8 , the user terminal device  3  may automatically read out it and request the information administration server  1  to authenticate the serial number.  
         [0088]    Upon receiving the request for the serial number authentication, the information administration server  1  uses the database created in the storage device  7  to authenticate the serial number (Step S 30 ).  
         [0089]    The complementary music files are stored in the database of the storage device  7  as described above. As illustrated in FIG. 9, the serial numbers, CD-ROM numbers, groups of complementary music files recorded on the respective CD-ROMs, and distribution sources (including bank account numbers) are associated with each other in the database. As the serial number is obtained from the received authentication request, it is possible to identify a CD-ROM corresponding to that serial number. It is further possible to identify a distribution source of the CD-ROM.  
         [0090]    The information administration server  1  determines at Step S 30  whether the serial number obtained from the authentication request exists in the database. If the information administration server  1  confirms the presence of that serial number, it sends a notice of authentication to the terminal device  3  (Step S 31 ).  
         [0091]    The user terminal device  3  requests, on its display screen, the user to enter credit card information in response to the notice of authentication (Step S 32 ). The credit card information may include a credit card number, a card holder name and an expiration date. If this system accepts a plurality of credit card companies, the credit card information may further include indication of a credit card company which the user uses now. It is then determined whether the credit card information is entered (Step S 33 ). If the answer is yes, the user terminal device sends a request to the information administration server  1  for authentication of the credit card information (Step S 34 ). The authentication request is accompanied with the entered credit card information.  
         [0092]    As the information administration server  1  receives the request for the credit card information authentication, it sends a request for reference to the credit card administration server  4  in order to confirm the received credit card information (Step S 35 ).  
         [0093]    The credit card administration server  4  refers to a database (not shown) to determine validity/invalidity of the credit card information in response to the reference request, and sends a reply to the information administration server  1  (Step S 36 ).  
         [0094]    The information administration server  1  determines whether the credit card information is valid or not on the basis of the response from the credit card administration server  4  (Step S 37 ). When the information administration server  1  determines that the credit card information is invalid, it sends a notice of refusal to the terminal device  3  (Step S 38 ). This is the refusal of communication from the terminal device  3  to the information administration server  1  so that the purchase of the selected song becomes impossible.  
         [0095]    If the information administration server  1  determines at Step S 37  that the credit card information is valid, it transmits a notice of purchase acceptance to the terminal device  3  (Step S 39 ).  
         [0096]    Upon receiving this acceptance notice from the information administration server  1 , the terminal device  3  requests the information administration server  1  to send the complementary music file of the selected song (Step S 40 ). The request for the complementary music file includes a file name of the complementary music file that makes a pair with the incomplete music file on the CD-ROM  8  of the selected song.  
         [0097]    As the information administration server  1  receives the request for the complementary music file, it retrieves a complementary music file, which has the same file name as included in the complementary music file request, from the database using the CD-ROM number specified by the already received serial number, and supplies it to a buffer (Step S 41 ). The information administration server  1  then transmits the retrieved complementary music file to the terminal device  3  (Step S 42 ). If a plurality of selected songs are bought, complementary music files for these songs are taken out and sent to the terminal device  3  at Steps S 41  and  42 .  
         [0098]    The terminal device  3  receives the complementary music file and temporarily stores it in the internal storage device  9  (Step S 43 ). Upon successful receiving and storing of the complementary music file, the terminal device  3  instructs the CD-ROM drive  6  to read the incomplete music file of the selected song (Step S 45 ). The CD-ROM drive  6  reads the incomplete music file of the selected song from the CD-ROM  8  on the basis of the file name information of the CD-ROM  8 , and supplies it to the terminal device  3 . The terminal device  3  then combines the incomplete music file data with the complementary music file data to create a complete music file (Step S 47 ). This combine operation will be described in detail below.  
         [0099]    When the combine operation ends, the terminal device  3  sends a notice of data combine completion to the information administration server  1  (Step S 48 ).  
         [0100]    As the information administration server  1  receives the notice of data combine completion, it requests the credit card administration server  4  to start a charging operation on the basis of the already received credit card information (Step S 49 ). The information administration server  1  also requests the financial institute server  2  to transfer a cooperation money to a bank account of a financial institute of a distribution source identified by the serial number (Step S 50 ). Since the bank account number of the distribution source&#39;s bank is stored in the database of the storage device  7  as shown in FIG. 9, the information administration server  1  obtains the band account number from the database and requests the cooperation money transfer.  
         [0101]    The credit card administration server  4  carries out the charging operation on the basis of the credit card information. In the meantime, the financial institute server  2  transfers the cooperation money to the bank account of the distribution source. Accordingly, the CD-ROM manufacturing enterprise has sold a song, which is included in the CD-ROM  8  as the incomplete music file, to the user in a perfectly reproducible manner. The cooperation money is paid as a distribution commission to the distribution source such as a retail store that has actually distributed the CD-ROM  8 .  
         [0102]    It should be noted that the charge request at Step S 49  may be made immediately after completion of Step S 42 , i.e., after the complementary music file transmission to the terminal device  3  is complete.  
         [0103]    When the combine operation is finished, the terminal device  3  starts a reproducing operation (Step S 51 ). The reproducing operation supplies the complete music file prepared by the combining operation to the decoder  41 . The decoder  41  decodes the music data to feed the PCM audio signal to the D/A converter  42 . Since the analog audio signal from the D/A converter  42  is introduced to the speaker  44  through the amplifier  43 , the user can perfectly listen to the song, which he or she bought. When the combine operation is complete, a play button may be displayed on the display screen and the song may be reproduced as the user clicks the play button with the mouse.  
         [0104]    Although the request for the complementary music file to the song which the user has listened to for the trial is sent to the information administration server  1  in this embodiment, it is also satisfactory that the request for the complementary music file of the song selected from the list of the recorded songs is transmitted to the information administration server  1  without giving the user a chance of listening to the song for the trial purpose. In such a case, the program skips to Step S 27  after Step S 24  in the flowchart of FIG. 8. If the user listens to a plurality of songs for the trial, a request for the complementary music files for some of these songs that the user wants to purchase may be sent to the information administration server  1 .  
         [0105]    The combine operation will now be described. For easier understanding, the complementary music file stored in the internal storage device  9  at Step S 43  is referred to as Fsup, the incomplete music file read out from the CD-ROM  8  upon the command at Step S 45  is referred to as Fincom, and the complete music file created by the combine operation is referred to as Fcom in the following description.  
         [0106]    Referring to FIG. 10, the terminal device  3  first sets the file name of the complete music file Fcom to create and store the complete music file in the internal storage device  9  (Step S 61 ). The terminal device then instructs the CD-ROM drive  6  to read the header portion of the incomplete music file Fincom stored in the CD-ROM  8  (Step S 62 ). The CD-ROM drive  6  reads the header portion of the incomplete music file Fincom in response to the read instruction, and feeds it to the terminal device  3 . The terminal device  3 , on the other hand, reads the header portion of the complementary music file Fsup stored in the internal storage device  9  (Step S 63 ). It is then determined whether the header portion of the incomplete music file Fincom matches the header portion of the complementary music file Fsup (Step S 64 ). Specifically, it is determined if there is no discrepancy in various information such as the way of partly omitting the music data, the file names of the incomplete and complementary music files and the block sizes of the incomplete and complementary data portions. If the matching cannot be confirmed in the predetermined aspects of the header portions of the files Fincom and Fsup at Step S 64 , it is determined that one of these files contains an error, and the combine operation is discontinued.  
         [0107]    When the matching between the two files Fincom and Fsup is confirmed at Step S 46 , it means that the incomplete music file Fincom and complementary music file Fsup are derived from the same complete music file. The music data of N bytes are sequentially read out from the incomplete data portion of the incomplete music file Fincom and stored in the internal buffer B 1  (Step S 65 ). It is then determined whether the data portions of both the files Fincom and Fsup are finished by this reading operation applied to the incomplete data portions of the incomplete music file Fincom (Step S 66 ). If data remains less than N bytes upon reading of the incomplete data portion of the incomplete music file Fincom at Step S 66 , it is read together with the music data of N bytes.  
         [0108]    When it is determined at Step S 66  that the reading is not complete, the music data of N bytes held in the internal buffer B 1  is added to the complete music file Fcom inside the internal storage device  9  (Step S 67 ). The music data of M bytes are then read out successively from the complementary data portion of the complementary music file Fsup and stored in the internal buffer B 2  (Step S 68 ). It is then determined whether the data portions of the files Fincom and Fsup have been read by this reading operation applied to the complementary data portion of the complementary music file Fsup (Step S 69 ). If data remains less than M bytes upon reading of the complementary data portion of the complementary music file Fsup at Step S 68 , it is read together with the music data of M bytes.  
         [0109]    If the reading is not complete at Step S 69 , the music data of M bytes held in the internal buffer B 2  is written into the complete music file Fcom inside the internal storage device  9  (Step S 70 ). The program returns to Step S 65  after Step S 70  to repeat the above described procedure.  
         [0110]    If it is determined at Step S 66  that the incomplete data portion of the incomplete music file Fincom has been completely read, the music data not greater than N bytes stored in the internal buffer B 1  is additionally written into the complete music file Fcom of the internal storage device  9  (Step S 71 ). This creates the complete music file Fcom of the selected song in the internal storage device  9 .  
         [0111]    When it is determined at Step S 69  that the complementary data portion of the complementary music file Fsup has been read entirely, the music data not greater than M bytes stored in the inside buffer B 2  is additionally written into the complete music file Fcom of the inside storage device  9  (Step S 72 ). This creates the complete music file Fcom of the selected song in the storage device  9 .  
         [0112]    After Step S 71  or S 72 , the complementary music file Fsup is deleted from the storage device  9  (Step S 73 ). The reason why the complementary music file is deleted at Step S 73  is because it is necessary to prevent an illegal combine operation from occurring by use of the complementary music file remained in the storage device  9 .  
         [0113]    Although the complementary music file Fsup is received to create the complete music file Fcom at the terminal device  3  for a single selected song in the above described combine operation, it is also feasible that a plurality of songs are selected and complementary music files for these songs are received to prepare complete music files for the respective songs at the terminal device  3 .  
         [0114]    The combine operation for a plurality of selected songs will be described below. For the sake of clarity, complementary music files for a plurality of selected songs (Y in number) are in the internal storage device  9  at Step S 43 , these Y complementary music files are referred to as Fsup 1  to FsupY, incomplete music files read out from the CD-ROM  8  upon the instructions at Step S 45  are referred to as Fincom 1  to FincomY, and complete music files formed by the combine operation are referred to as Fcom 1  to FcomY.  
         [0115]    Referring to FIG. 11, the terminal device  3  first sets that a variable X=1 (Step S 81 ), and enters a file name of the complete music file FcomX to create and store the complete music file in the internal storage device  9  (Step S 82 ). The terminal device  3  then instructs the CD-ROM drive  6  to read the header portion of the incomplete music file FincomX stored in the CD-ROM  8  (Step S 83 ). Upon the instructions, the CD-ROM drive  6  reads the header portion of the incomplete music file FincomX and supplies it to the terminal device  3 . In the meantime, the terminal device  3  reads the header portion of the complementary music file FsupX stored in the internal storage device  9  (Step S 84 ). It is then determined whether the header portion of the incomplete music file FincomX corresponds to that of the complementary music file FsupX (Step S 85 ). Specifically, it is determined whether various information such as the way of partly omitting the music data, the file names of the incomplete and complementary music files and the block sizes of the incomplete and complementary data portions are equal to each other. If matching between the files FincomX and FsupX cannot be confirmed in the predetermined aspects of the header portions at Step S 85 , it is determined that one of the files includes an error, and the combine operation is discontinued.  
         [0116]    When the header portion information of the file FincomX matches that of the file FsupX at Step S 85 , it means that the incomplete music file FincomX and complementary music file FsupX have been separated from the same complete music file. The music data of N bytes are therefore successively read out from the incomplete data portion of the incomplete music file FincomX and stored in the internal buffer B 1  (Step S 88 ). It is then determined whether the data portions of the files FincomX and FsupX are both completely read by the reading operation just applied to the incomplete data portion of the incomplete music file FincomX (Step S 89 ). If data remains less than N bytes after the incomplete data portion of the incomplete music file FincomX is read at Step S 88 , it is read together with the N bytes of music data.  
         [0117]    When the reading is not complete at Step S 89 , the music data of N bytes stored in the internal buffer B 1  is additionally written into the complete music file FcomX of the internal storage device  9  (Step S 90 ). The music data of M bytes is further read from the complementary data portion of the complementary music file FsupX successively and stored in the internal buffer B 2  (Step S 91 ). It is then determined whether the data portions of the files FincomX and FsupX are both completely read by the reading operation just applied to the complementary data portion of the complementary music file FsupX (Step S 92 ). If data remains less than M bytes after the complementary data portion of the complementary music file FsupX is read at Step S 90 , it is read together with the M bytes of music data.  
         [0118]    When the reading is not complete at Step S 92 , the music data of M bytes stored in the internal buffer B 2  is additionally written into the complete music file FcomX of the internal storage device  9  (Step S 93 ). The program returns to Step S 88  after Step S 93  to repeat the above described procedure.  
         [0119]    When it is determined at Step S 89  that the incomplete data portion of the incomplete music file FincomX has been read entirely, the music data not greater than N bytes stored in the internal buffer B 1  is additionally written into the complete music file FcomX of the internal storage device  9  (Step S 94 ). Consequently, the complete music file FcomX of the selected song is formed in the internal storage device  9 .  
         [0120]    If it is determined at Step  92  that the complementary data portion of the complementary music file FsupX has been read entirely, the music data not greater than N bytes stored in the internal buffer B 2  is additionally written into the complete music file FcomX of the internal storage device  9  (Step S 95 ). The complete music file FcomX of the selected song is therefore formed in the internal storage device  9 .  
         [0121]    The complementary music file FsupX is deleted from the internal storage device  9  after Step S 94  or S 95  (Step S 96 ).  
         [0122]    After the deletion of the complementary music file FsupX at Step S 96 , one is added to the variable X (Step S 97 ). It is subsequently determined whether the variable X is greater than a variable Y (Step S 98 ). If X≦Y, the program returns to Step S 82  to repeat the above described procedure. If, on the other hand, X&gt;Y, it means that the Y complete music files Fcom 1  to FcomY, which the user has decided to purchase, are formed in the internal storage device  9 . A series of combine operations are therefore complete.  
         [0123]    The way of making the music data incomplete shown in FIG. 3 is dropping a portion of the music data at predetermined intervals consistently, but it is also satisfactory for the music data to have missing portions of random lengths at random intervals as shown in FIG. 12. The shaded portions represent the missing portions in FIG. 12. The remaining music data is the incomplete music data, and the data of the missing portions is the complementary music data.  
         [0124]    Referring to FIG. 13, a data separation device for causing the music data to have the missing portions at random intervals includes a random number sequence generator  16 . This data separation device also includes a control circuit  11 , a music data file storage device  12 , a complementary music file storage device  13  and a disc writer  14 , like the one illustrated in FIG. 6.  
         [0125]    The random number sequence generator  16  generates a random number sequence, made up of the numbers  0  to  9 , at a period of 2 32  as it is given an unspecified (non-specific) random number generation instructing value from the control circuit  11 . When the random number generation instructing value is defined, the random number sequence generator  16  produces a corresponding random number sequence. “M” of the M bytes of the complementary music data and “N” of the N bytes of the incomplete music data to be taken out from the complete music data are determined on the basis of the respective random numbers in the random number sequence. The relationship of N&gt;&gt;M is established in this embodiment. It should be noted, however, that the relationship of N&gt;M is also acceptable, and the relationship of N=M is still satisfactory in order to maintain a copyright, as mentioned above.  
         [0126]    The relationship among the random number, “M” of the M bytes of complementary music data and “N” of the N bytes of incomplete music data is stored, in the form of a random number-M-N table as shown in FIG. 14, in an internal memory (not shown) of the control circuit  11 . The control circuit  11  separates the data of the complete music file, using the random number-M-N table, to prepare the incomplete music file and complementary music file.  
         [0127]    The file structures of the incomplete and complementary music files created by the random number scheme using this random number-M-N table are those shown in FIGS. 4 and 5 as in the case of simple skipping scheme. The header contents of the incomplete music file, however, include the way of making the music data incomplete (random number scheme) and the file names of the incomplete and complementary music files, and the header contents of the complementary music file include the way of making the music data incomplete (random number scheme), the file names of the incomplete and complementary music files and the random number generation instructing value R.  
         [0128]    The reason the random number generation instructing value R is not recorded in the incomplete music file is that a tendency or system of the random numbers is assumable if this value R is recorded in a disc distributed free. There is a risk that the complementary music data would be reproduced in an improper manner.  
         [0129]    Referring to FIG. 15, the control circuit  11  of the data separation device shown in FIG. 13 first selects a complete music file of one song worth from a plurality of complete music data stored in the music data file storage device  12  (Step S 101 ). The control circuit then sets the file name of the complementary music file relative to the selected complete music file to create and store the complementary music file in the complementary music file storage device  13  (Step S 102 ). Likewise, the control circuit sets the file name of the incomplete music file to the selected complete music file and instructs the disc writer  14  to write the incomplete music file (Step S 103 ). The disc writer  14  creates the incomplete music file and writes it on the disc  15  in response to the write command. The selected complete music file is referred to as Fcom, the corresponding incomplete music file is referred to as Fincom and the corresponding complementary music file is referred to as Fsup in the following description as in the foregoing description.  
         [0130]    The control circuit  11  sets the random number generation instructing value R (Step S 104 ), and supplies it to the random number sequence generator  16  (Step S 105 ). The random number generation value R is randomly determined from  0  to  9 . As the random number sequence generator  16  is given the random number generation instructing value R, it is brought into an initial condition to successively produce random numbers in a random number sequence in compliance with the random number generation instructing value R. The control circuit  11  sequentially reads the random numbers of this sequence as mentioned in Step S 108  (will be described). The random number sequence generator  16  issues a random number as the control circuit  11  reads a preceding random number.  
         [0131]    The control circuit  11  makes a header portion of the complementary music file Fsup to the complete music file Fcom and additionally writes it in the complementary music file Fsup in the complementary music file storage device  13  (Step S 106 ). The control circuit  11  also creates a header portion of the incomplete music file Fincom to the complete music file Fcom and instructs the disc writer  14  to write the header portion into the incomplete music file Fincom (Step S 107 ). The disc writer  14  additionally writes the header portion to the incomplete music file Fincom of the disc  15  in response to the write command.  
         [0132]    The control circuit  11  reads a random number for the random number sequence generator  16  (Step S 108 ) and retrieves “M” and “N” of the above mentioned M and N bytes in correspondence with the random number from the random number-M-N table (Step S 109 ).  
         [0133]    The control circuit reads music data of N bytes from the complete music file Fcom selected from the complementary music file storage device  13  and stores it in an internal buffer B 1  (not shown) (Step S 110 ). The control circuit then determines whether the complete music file Fcom has been read completely (Step S 111 ). If data less than N bytes remains in the complete music file Fcom at Step S 110 , it is read together with the music data of N bytes. If it is the case or no music data remains after reading the music data of N bytes at Step S 110 , it is determined at Step S 111  that the complete music file Fcom has been read completely.  
         [0134]    When Step S 111  determines that all the complete music file Fcom is not read entirely, the control circuit instructs the disc writer  14  to write the music data of N bytes stored in the internal buffer B 1  into the incomplete data portion of the incomplete music file Fincom (Step S 112 ). Accordingly, the disc writer  14  additionally writes the music data of N bytes into the incomplete data portion of the incomplete music file Fincom of the disc  15  on the basis of the write command.  
         [0135]    After Step S 112 , the control circuit  11  reads the music data of M bytes from the complete music file Fcom selected from the complementary music file storage device  13  and stores it in an internal buffer B 2  (not shown) (Step S 113 ). The control circuit then determines whether the complete music file Fcom has been read completely (Step S 114 ). If music data less than M bytes remains in the complete music file Fcom at Step S 113 , it is read together with the music data of M bytes. If it is the case or no music data remains after reading the music data of M bytes at Step S 113 , it is determined at Step S 114  that the complete music file Fcom has been read completely.  
         [0136]    When Step S 114  determines that the reading operation applied to the complete music file Fcom is not complete, the control circuit writes the music data of M bytes stored in the internal buffer B 2  into the complementary data portion of the complementary music file Fsup inside the complementary music file storage device  13  (Step S 115 ). The program returns to Step S 108  after Step S 115  to repeat the above described procedure in accordance with the next random number.  
         [0137]    If it is determined at Step S 111  that the reading operation to the complete music file Fcom is finished, the control circuit instructs the disc writer  14  to write the music data not greater than N bytes stored in the internal buffer B 1  into the incomplete data portion of the incomplete music file Fincom (Step S 116 ). The disc writer  14  additionally writes the music data not larger than N bytes into the incomplete data portion of the incomplete music file Fincom of the disc  15  on the basis of the write instructions. As a result, a single incomplete music file Fincom is formed inside the disc  15 .  
         [0138]    When it is determined at Step S 114  that the reading operation applied to the complete music file Fcom is complete, the control circuit additionally writes the music data not larger than M bytes stored in the internal buffer B 1  into the complementary data portion of the complementary music file Fsup inside the complementary music file storage device  13  (Step S 117 ). Execution of Step S 117  results in a single completed complementary music file Fsup formed in the complementary music file storage device  13 .  
         [0139]    The above described operation of the data separation device in accordance with the random number scheme is repeatedly performed the number of times which corresponds to the number of the songs to be recorded on the disc  15 . When such repetitive writing of the incomplete music files onto the disc  15  is finished, a list of recorded songs in the form of file is also written onto the disc  15 . A process program for the terminal device is further written on the disc  15 . As the writing onto the disc  15  is complete, a plurality of copied CD-ROMs are fabricated using the disc  15  as a master disc. One of these CD-ROMs is the above mentioned CD-ROM  8 .  
         [0140]    The combine operation employed in the random number scheme will be described. Like in the foregoing description, the complementary music file stored in the internal storage device  9  at Step S 43  is referred to as Fsup, the incomplete music file read from the CD-ROM  8  in response to the instructions at Step S 45  is referred to as Fincom, and the complete music file created by the combine operation is referred to as Fcom.  
         [0141]    A random number sequence generator (not shown) identical to the described random number sequence generator  16  is incorporated in the terminal device  3 . This random number sequence generator may be a program software recorded in the incomplete music file. In order to prevent a structure of the random number sequence generator from being investigated, this software may be transmitted over the network together with the complementary music file.  
         [0142]    Referring to FIG. 16, the terminal device  3  first sets a file name of the complete music file Fcom, and creates and stores the complete music file in the internal storage device  9  (Step S 121 ). The terminal device  3  then instructs the CD-ROM drive  6  to read the header portion of the incomplete music file Fincom stored in the CD-ROM  8  (Step S 122 ). The CD-ROM drive  6  reads the header portion of the incomplete music file Fincom in response to the read instructions, and supplies it to the terminal device  3 . The terminal device  3  also reads the header portion of the complementary music file Fsup stored in the internal storage device  9  (Step S 123 ). It is then determined whether the header portion of the incomplete music file Fincom matches the header portion of the complementary music file Fsup (Step S 124 ). Specifically, it is determined whether information such as the scheme of making the music data incomplete, and the file names of the incomplete and complementary music files matches between the incomplete and complementary music files. If it is not confirmed at Step S 124  that the header portion information of the file Fincom matches that of the file Fsup, it is assumed that one of the files has an error, and the combine operation is terminated.  
         [0143]    If the coincidence of the header information is confirmed between the two files Fincom and Fsup at Step S 124 , it means that the incomplete music file Fincom and complementary music file Fsup are separated from the same complete music file. The terminal device therefore reads the random number generation instructing value R from the header portion of the complementary music file Fsup (Step S 125 ). The terminal device then supplies the random number generation instructing value R to the built-in random number sequence generator (Step S 126 ). Upon receiving the random number generation instructing value R, the random number sequence generator is brought into an initial condition to produce random numbers successively in a sequence on the basis of the random number generation instructing value R. The terminal device  3  reads the random numbers of this sequence in turn. The random number sequence generator issues a random number as a preceding random number is read.  
         [0144]    The terminal device  3  reads the random numbers from the random number sequence generator (Step S 127 ), and retrieves the “M” and “N” corresponding to the obtained random number from the random number-M-N table (Step S 128 ). The terminal device  3  then successively reads music data of N bytes worth from the incomplete data portion of the incomplete music file Fincom and stores them in the internal buffer B 1  (Step S 129 ). The terminal device determines whether the data portions of the files Fincom and Fsup are completely read by this reading operation applied to the incomplete data portion of the incomplete music file Fincom (Step S 130 ). If data less than N bytes remains in the incomplete data portion of the incomplete music file Fincom at Step S 129 , it is read together with the data of N bytes.  
         [0145]    If the reading is not complete at Step S 130 , the music data of N bytes stored in the buffer B 1  is additionally written into the complete music file Fcom of the storage device  9  (Step S 131 ). The music data of M bytes is also successively read from the complementary data portion of the complementary music file Fsup and stored in the buffer B 2  (Step S 132 ). It is then determined whether the data portions of both of the files Fincom and Fsup are entirely read by this reading operation applied to the complementary data portion of the complementary music file Fsup (Step S 133 ). If data less than M bytes remains in the complementary data portion of the complementary music file Fsup at Step S 132 , it is read together with M bytes of music data.  
         [0146]    If the reading is not complete at Step S 133 , the music data of M bytes stored in the buffer B 2  is additionally written into the complete music file Fcom of the storage device  9  (Step S 134 ). The program returns to Step S 127  after Step S 134 , and obtains a new random number to iterate the above described operation.  
         [0147]    If it is determined at Step S 130  that the incomplete data portion of the incomplete music file Fincom has been read completely, the music data not greater than N bytes stored in the buffer B 1  is additionally written into the complete music file Fcom of the storage device  9  (Step S 135 ). As a result, the complete music file Fcom of the selected song is completely formed in the storage device  9 .  
         [0148]    If it is determined at Step S 133  that the complementary data portion of the complementary music file Fsup has been read completely, the music data not greater than M bytes stored in the buffer B 2  is additionally written into the complete music file Fcom of the storage device  9  (Step S 136 ). As a result, the complete music file Fcom of the selected song is completely formed in the storage device  9 .  
         [0149]    After Step S 135  or S 136 , the complementary music file Fsup is deleted from the storage device  9  (Step S 137 ).  
         [0150]    In the data separation and combine operations under the random number scheme, the random number generation specifying value R is constant with respect to the same song so that the random number, M and N obtained in turn are also constant with respect to the same song. In the storage device  7  of the information administration server  1 , therefore, a complementary music file table is stored in which a random number generation specifying value R and a complementary music file are associated with each of the songs as shown in FIG. 17.  
         [0151]    It should be noted, however, that a plurality of different random number generation specifying values R may be associated with each song. In this case, the storage device  7  of the information administration server  1  stores a complementary music file table having a plurality of songs, each of which is accompanied with a plurality of random number generation specifying values R and corresponding complementary music files, as shown in FIG. 18, for example. The header portion of the incomplete music file includes the random number generation specifying value R as well as the way of partly omitting the music data (random number scheme) and the file names of the incomplete and complementary music files, like the header portion of the complementary music file. The terminal device  3 , therefore, sends the random number generation specifying value R together with the complementary music file name when it requests the complementary music file at Step S 40 . The information administration server  1  retrieves a complementary music file from the database and sends it to the buffer at Step S 41  using the CD-ROM number specified by the already received serial number, the song having the complementary music file name carried with the complementary music file request, and the random number generation specifying value R. The information administration server  1  then transmits the retrieved complementary music file to the terminal device  3  at Step S 42 .  
         [0152]    In order to prevent the relationship between the random number generation specifying value R, M and N from being easily analyzed, the storage device  7  of the information administration server  1  may store a data table of random number forms that indicates the relationship between “i” (for example, twenty) random number forms T 1  to Ti and the random number generation specifying values R as shown in FIG. 19. In such a case, a type of random number T (i.e., one of T 1  to Ti) corresponding to the random number generation specifying value R obtained at Step S 104  is randomly selected from the random number form data table, and ordered to be written into the incomplete music file Fincom when the header portion is ordered to be written into the incomplete music file Fincom at Step S 107 . The terminal device  3  sends the random number type T along with the complementary music file name when it sends the complementary music file request at Step S 40 . The information administration server  1  first acquires the random number generation specifying value R corresponding to the random number type T from the random number type data table, and retrieves a complementary music file from the database to send it to the buffer at Step S 41  using the CD-ROM number specified by the already received serial number, the song having the complementary music file name carried with the complementary music file request, and the random number generation specifying value R. The information administration server  1  then transmits the retrieved complementary music file to the terminal device  3  at Step S 42 .  
         [0153]    A music data separation method according to a music data compression scheme may also be employable in addition to the above described simple skipping and random number scheme.  
         [0154]    Referring to FIG. 20, illustrated is a structure of the music data when an MPEG 4 Audio Twin VQ method is utilized as the compression method. This is a structure in which a header, window information, spectrum envelope and quantization information, MDCT coefficient and quantization index, and other information are repeated. The data separation apparatus causes the TwinVQ music data to lose the spectrum envelop and quantization information so as to prepare an incomplete music file and a complementary music file.  
         [0155]    The data separation apparatus for the Twin VQ music data has the same structure as that shown in FIG. 6. The music data file storage device  12  stores a plurality of complete music files compressed in accordance with the Twin VQ method.  
         [0156]    A data separation operation will be described in which the data compressed by the Twin VQ method is divided by the control circuit  11  of the data separation device. The file structures of the incomplete and complementary music files resulting from this data separation are those shown in FIGS. 4 and 5 respectively, as in the case of the simple skipping scheme. The incomplete and complementary music files have the same header portion contents; the way of partly omitting the music data (Twin VQ based scheme) and the file names of the incomplete and complementary music files are the same.  
         [0157]    Referring to FIG. 21, the control circuit  11  first selects a complete music file of one song worth from a plurality of complete music file stored in the music data file storage device  12  (Step S 141 ). The control circuit then sets the file name of the complementary music file relative to the selected complete music file to create and store the complementary music file in the complementary music file storage device  13  (Step S 142 ). Likewise, the control circuit sets the file name of the incomplete music file to the selected complete music file and instructs the disc writer  14  to write the incomplete music file (Step S 143 ). The disc writer  14  creates the incomplete music file and writes it on the disc  15  in response to the write command. The selected complete music file is here referred to as Fcom, the corresponding incomplete music file is referred to as Fincom and the corresponding complementary music file is referred to as Fsup.  
         [0158]    The control circuit  11  prepares a header portion of the complementary music file Fsup to the complete music file Fcom and additionally writes it in the complementary music file Fsup inside the complementary music file storage device  13  (Step S 144 ). The control circuit  11  also creates a header portion of the incomplete music file Fincom to the complete music file Fcom and instructs the disc writer  14  to write the header portion into the incomplete music file Fincom (Step S 145 ). The disc writer  14  additionally writes the header portion to the incomplete music file Fincom of the disc  15  in response to the write command.  
         [0159]    The control circuit analyzes the data structure inside the complete music file Fcom selected from the complementary music file storage device  13 , and decides the “N” bytes to be read (Step S 146 ). The control circuit determines based on the result of this analysis whether the complete music file Fcom has been read completely (Step S 147 ).  
         [0160]    If it is determined at Step S 147  that the complete music file Fcom has not been read entirely, the control circuit reads N bytes of data from the complete music file Fcom and stores it in the buffer B 1  (Step S 148 ). The control circuit then determines whether the data stored in the buffer B 1  is the spectrum envelope and quantization information (Step S 149 ). If it is not the spectrum envelope and quantization information, the control circuit instructs the disc writer  14  to write the N bytes of data stored in the buffer B 1  into the incomplete data portion of the the incomplete music file Fincom (Step S 150 )  
         [0161]    Accordingly, the disc writer  14  additionally writes the N bytes of data into the incomplete data portion of the incomplete music file Fincom of the disc  15  on the basis of the write command. If the data stored in the buffer B 1  is the spectrum envelope and quantization information, the control circuit additionally writes the N bytes of data stored in the buffer B 1 , i.e., the spectrum envelope and quantization information, into the complementary data portion of the complementary music file Fsup inside the complementary music file storage device  13  (Step S 151 ). The program returns to Step S 146  after Step S 150  or S 151  to iterate the above described procedure.  
         [0162]    When Step S 147  determines that the reading operation applied to the complete music file Fcom is complete, it means that a single incomplete music file Fincom is complete to the complete music file Fcom of the TwinVQ format inside the disc  15  and a single complementary music file Fsup is complete inside the complementary music file storage device  13 . The control circuit  11  therefore terminates the data separation operation.  
         [0163]    The reason the spectrum envelope and quantization information is only removed from the single incomplete music file Fincom to the complete music file Fcom of the TwinVQ format is because it is not possible at all to reproduce a song from the information that does not have the spectrum envelope and quantization information. For the trial listening purpose, the CD-ROM  8  records reproducible music data (complete music data) of several songs worth, which would last several tens of seconds, and these music data are read out for the trail listening at Step S 25 .  
         [0164]    Alternatively, some portions may be omitted in the window information and/or MDCT coefficient quantization index information if degrading the music information is satisfactory, rather than completely disabling the music information from being reproduced as described above.  
         [0165]    The frame structures of the data compressed by the above mentioned compression methods, i.e., ACC method and MP3 method, are shown in FIGS. 22 and 23 respectively. The AAC method shown in FIG. 22 causes the Huffman table selection information to miss as the complementary music data. The MP3 method shown in FIG. 23 causes the Huffman table selection information, which is included in the side information, to miss as the complementary music data. Alternatively, the entire side information may be missed as the complementary music data.  
         [0166]    The combine operation to regenerate the complete music file of the TwinVQ format will be described. Like in the foregoing description, the complementary music file stored in the internal storage device  9  at Step S 43  is referred to as Fsup, the incomplete music file read from the CD-ROM  8  in response to the instructions at Step S 45  is referred to as Fincom, and the complete music file created by the combine operation is referred to as Fcom.  
         [0167]    Referring to FIG. 24, the terminal device  3  first sets a file name of the complete music file Fcom, and creates and stores the complete music file in the internal storage device  9  (Step S 161 ). The terminal device  3  then instructs the CD-ROM drive  6  to read the header portion of the incomplete music file Fincom stored in the CD-ROM  8  (Step S 162 ). The CD-ROM drive  6  reads the header portion of the incomplete music file Fincom in response to the read instructions, and supplies it to the terminal device  3 . The terminal device  3  also reads the header portion of the complementary music file Fsup stored in the internal storage device  9  (Step S 163 ). It is then determined whether the header portion of the incomplete music file Fincom matches the header portion of the complementary music file Fsup (Step S 164 ). Specifically, it is determined whether information such as the scheme of making the music data incomplete and the file names of the incomplete and complementary music files matches between the incomplete and complementary music files. If it is not confirmed at Step S 164  that the header portion information of the file Fincom matches that of the file Fsup, it is assumed that one of the files has an error, and the combine operation is terminated.  
         [0168]    If the coincidence of the header information is confirmed between the two files Fincom and Fsup at Step S 164 , it means that the incomplete music file Fincom and complementary music file Fsup are separated from the same complete music file. The terminal device therefore analyzes the data structure of the incomplete data portion of the incomplete music file Fincom and decides how many bytes should be read from the incomplete data portion (Step S 165 ). If the music data to be read next time is the data of the incomplete data portion in the incomplete music file Fincom, the “N” of N bytes of data will have a predetermined value. If, on the other hand, the music data of the complementary music file Fsup should be read next time, i.e., the spectrum envelope and quantization information should be read, “N” bytes will be zero byte.  
         [0169]    After Step S 165 , the terminal device determines whether the data portions of the files Fincom and Fsup are completely read, depending upon the data structure analysis performed at Step S 165  (Step S 166 ). If the data reading is not complete, it is then determined whether this reading is applied to the incomplete data portion of the incomplete music file Fincom (Step S 167 ). If the answer is yes, the terminal device successively reads the N bytes of data from the incomplete data portion of the incomplete music file Fincom and additionally writes them into the complete music file Fcom of the storage device  9  (Step S 168 ).  
         [0170]    If it is then determined that the reading is applied to the complementary data portion of the complementary music file Fsup, the terminal device analyzes the data structure of the complementary data portion of the complementary music file Fsup and decides the M bytes to be read from the complementary data portion (Step S 169 ). The bytes of a pair of spectrum envelope and quantization information is determined to be M, for example. The terminal device then reads the M bytes of data from the complementary data portion of the complementary music file Fsup and additionally writes them into the complete music file Fcom of the storage device  9  (Step S 170 ). After Step S 168  or S 170 , the program returns to Step S 165  to repeat the above described procedure.  
         [0171]    If it is determined at Step S 166  that the data portions of the files Fincom and Fsup have been read completely, it means that the complete music file Fcom having the TwinVQ form of the selected song is completely formed in the storage device  9 . In this case, the complementary music file Fsup is deleted from the storage device  9  (Step S 171 ).  
         [0172]    Referring to FIG. 25, another example of the operation of the information providing system, which is different from that shown in FIG. 8, will be described below.  
         [0173]    In FIG. 8, the user terminal device  3  executes the terminal process program written in the CD-ROM  8  at Step S 21  and retrieves the list of the songs recorded in the CD-ROM  8  at Step S 22 . Alternatively, the user terminal device  3  may obtain and display the list of the recorded songs from the information administration server  1  as shown in FIG. 25. In other words, the user terminal device  3  may activate the browser software to look at the web pages and access a predetermined URL (Uniform Resource Locator) of the information administration server  1  after Step S 21  (Step S 181 ). In response to this access, the information administration server  1  sends the data of the recorded song list, which may be an HTML file stored in the predetermined URL, to the terminal device  3  (Step S 182 ). This URL is stored in the CD-ROM  8 . It is included in, for instance, the terminal process program stored in the CD-ROM  8 .  
         [0174]    Upon receiving the recorded song list, the user terminal device  3  displays it in a browser screen on the display (Step S 183 ). The subsequent procedure is the same as that after Step S 23  in FIG. 8.  
         [0175]    It should be noted here that the incomplete music file corresponding to the song selected at Step S 24  may not exist in the CD-ROM  8  in the procedure of FIG. 25. If it is the case, the user terminal device may display a message such as “Please load No. X disc” to the user such that the user will replace the current CD-ROM by another one that contains the incomplete music file corresponding to the selected song. This is significantly effective when a plurality of CD-ROMs are distributed.  
         [0176]    Referring to FIG. 26, illustrated is still another example of the operation of the information providing system. After Step S 21 , the user terminal device  3  activates the web browser to access a predetermined URL of the information administration server  1  (Step S 191 ). In response to this access, the information administration server  1  sends the serial number entry request display data, which is stored in the predetermined URL, to the terminal device  3  (Step S 192 ). Upon receiving this data, the user terminal device  3  displays the serial number entry request in a browser screen on the display (Step S 193 ). The user then enters the serial number printed on the card distributed together with the CD-ROM  8  by operating the keys as described above. The terminal device  3  determines whether or not the entry of the serial number is made (Step S 194 ). If the serial number is input, the terminal device requests the information administration server  1  to authenticate the serial number (Step S 195 ). The authentication request carries the serial number input by the user.  
         [0177]    As the information administration server  1  receives the serial number authentication request, it uses the database formed in the storage device  7  to authenticate the serial number (Step S 196 ). This authentication process is similar to that at Step S 30 . The information administration server  1  determines at Step S 196  whether the same serial number as received upon the authentication request exists in the database. If the information administration server  1  confirms the presence of the same serial number, it sends the data of songs recorded in the CD-ROM having this serial number (Step S 197 ). The terminal device receives the recorded song list data, and displays it in the browser screen of the display (Step S 198 ). The subsequent procedure is the same as that after Step S 23  in FIG. 8.  
         [0178]    It should be noted that the serial number authentication is already complete when the selected song is purchased at Step S 26  in the flowchart of FIG. 26 so that the program may immediately proceed to Step S 32  as illustrated, so as to request the user to enter the credit card information using the display.  
         [0179]    The terminal device  3  may ask the information administration server  1  to send the complementary music data for the trail listening such that the user can listen the selected song for the trail purpose. As illustrated in FIG. 27, for example, when the terminal device  3  obtains the selected song data at Step S 24 , it displays the serial number entry request to the user (Step S 200 ). If the serial number is entered (Step S 201 ), the terminal device requests the information administration server  1  to authenticate that serial number (Step S 202 ).  
         [0180]    As the information administration server  1  receives the serial number authentication request, it utilizes the database formed in the storage device  7  to conduct the authentication process (Step S 203 ). When the information administration server confirms the presence of the same serial number in the authentication process, it sends the complementary music data for the trail listening, which is stored in the database created in the storage device  7 , to the terminal device  3  (Step S 204 ). This complementary music data may be data for all the songs recorded on the CD-ROM  8  or for the song selected at Step S 24 . If the complementary music data for the selected song is only sent, the serial number authentication request at Step S 202  includes the data of the selected song. As the terminal device  3  receives the complementary music data for the trail listening, it combines the incomplete music file with the complementary music file for the trail to create the complete music file for the trail (Step S 205 ; combine operation). After the combine operation, the user terminal device commences the trail listening with the trail complete music file (Step S 206 ). The subsequent procedure is the same as that after Step S 25  in FIG. 26.  
         [0181]    It should be noted that the information management server  1  may send first some tens of seconds of the complete music data of the selected song in order to dispense with the necessity of the combine operation for the trail listening.  
         [0182]    Referring to FIG. 28, illustrated is an information providing system equipped with a kiosk terminal device according to the present invention. This information providing system includes an information administration server  21  of a cellar telephone company, a cellar telephone  22  and a kiosk terminal device  23 . Electric waves received by and sent from the cellar telephone  22  are caught by a communication relay device (repeater)  24 . A communication line or network  26  connects the communication relay device  24  with the information administration server  21 . A high-speed dedicated line  27  connects the information administration server  21  with the kiosk terminal device  23 .  
         [0183]    The information administration server  21  is, for example, located in an information administration center of the cellar telephone company, and is a server for supplying music information to the cellar telephone  22  (will be described in detail). The information administration server  21  has a storage device  28  as a database. Inside the database of the storage device  28 , stored are a plurality of complementary music data having a structure shown in FIG. 5 in the form of a plurality of files. The complementary music files are allotted song numbers respectively.  
         [0184]    The cellar telephone  22  is used by a user who wants to have a song distributed. Although there is only one cellar telephone in this embodiment for the sake of easier understanding, a plurality of cellar telephones are present in reality.  
         [0185]    Referring to FIG. 29, the cellar telephone  22  includes a transmission/reception part  31  for wireless telephone and data communication, a music reproducing part  32  for decoding music data to reproduce it as an analog audio signal, a memory controller  33  for writing into and reading from a memory card  25  such as a flash memory, a display unit  34 , an operation unit  35 , and a control circuit  36  constituted by CPU. The control circuit  36  is connected to the transmission/reception part  31 , music reproducer  32 , memory controller  33 , display part  34  and operation part  35  to control the overall operations of the cellar telephone  22 . The transmission/reception part  31  has a microphone  37  for telephone talking and a speaker  38  for listening as well as an antenna  31   a . The music reproducing part  32  possesses a structure as shown in FIG. 2. It should be noted, however, that this music reproducing part  32  is not provided with a speaker; instead, it is equipped with a jack  39  for connection to a pair of headphones (not shown).  
         [0186]    A memory support  40  is attached to the memory controller  33  to removably support the memory card  25 . The memory card  25  obtains and stores incomplete music file of a desired song from the kiosk terminal device  23 , and loads the incomplete music file into the cellar telephone  22 . The memory card  25  is inserted into the memory support  40  by the user from an insert opening (not shown) formed in a lateral face of the cellar telephone  22 . The memory card  25  fitted and supported in the memory support  40  can be removed by pulling away the memory card from the memory support  40 .  
         [0187]    The kiosk terminal device  23  is installed at a store such as a convenience store. As illustrated in FIG. 30, the kiosk terminal device  23  includes a communication unit  51  connected to a communication network  26  and a high speed dedicated line  27 , a storage device  52  constituted by a hard disc, a memory controller  53  for writing data into the memory card  25 , a display unit  54 , an operation unit  55  and a control circuit  56  constituted by CPU. The control circuit  56  is connected to the communication unit  51 , storage device  52 , memory controller  53 , display unit  54  and operation unit  55 , and controls the overall operations of the kiosk terminal device  23 . The memory controller  53  is equipped with a memory support  57  to removably support the memory card  25 . The memory card  25  is inserted into the memory support  57  by the user from an insert opening  23   a  formed in a surface of the kiosk terminal device  23 . The memory card  25  can be pushed out by an eject button (not shown) or automatically.  
         [0188]    The storage device  52  of the kiosk terminal device  23  stores a plurality of incomplete music files. Each of these incomplete music files has a structure shown in FIG. 4, which is prepared by the above described data separation apparatus beforehand. The incomplete music files are received by the communication unit  51  over the high speed dedicated line  27  and written into the storage device  52  under the control of the control circuit  56 . Since data about song lists are transmitted together with the incomplete music files, they are also written into the storage device  52 . The song list data indicate the relationship between the song titles and incomplete music files. The control circuit  56  causes the display unit  54  to list the song titles. A user can select a song in the list by operating a cursor and/or buttons using the operation unit  55 .  
         [0189]    A user of the cellar telephone  22  inserts the memory card  25  into the memory support  57  from the insertion slot  23   a  if he or she finds a desired song title among those displayed in the screen  54  of the kiosk terminal device  23 .  
         [0190]    As illustrated in FIG. 31, the control circuit  56  of the kiosk terminal device  23  determines via the memory controller  53  whether the memory card  25  is inserted in the memory support  57  (Step S 251 ). If the control circuit  56  confirms the inserted memory card  25 , it detects a song selected by a user through the operations made at the operation unit  55  (Step S 252 ). The user moves a cursor to a position of a desired one of the songs listed in the display  54  by using the operation unit  55 , and presses a selection button. Then that song is selected. The control circuit determines which song has is selected, on the basis of the cursor position. After Step S 252 , the control circuit reads an incomplete music file corresponding to the selected song from the storage device  52  (Step S 253 ), and supplies it to the memory controller  53  together with a write command (Step S 254 ). The memory controller  53  writes the incomplete music file into the memory card  25  in response to the write command.  
         [0191]    The control circuit  56  determines whether the writing to the memory card  25  is complete (Step S 255 ). If complete, the program returns to Step S 251 . If there is another desired song, the above described procedure will be repeated to write an incomplete music file of the next song into the memory card  25 .  
         [0192]    When, for example, the memory card  25  is discharged from the kiosk terminal device  23  upon pressing an eject button on the operation unit  55 , Step S 252  and subsequent steps will not be executed by the control circuit  56 .  
         [0193]    As the incomplete music file is written into the memory card  25 , the user loads the memory card  25  into the memory support  40  from a slot of the cellar telephone  22 .  
         [0194]    As shown in FIG. 32, the control circuit  36  of the cellar telephone  22  determines via the memory controller  33  whether the memory card  25  is inserted in the memory support  25  (Step S 261 ). If the control circuit detects the insertion of the memory card  25 , it then determines whether the incomplete music file is stored in the memory card  25  (Step S 262 ). If the incomplete music file is stored in the memory card  25 , the control circuit sends a request for subscriber authentication to the information administration server  21  to purchase a song (Step S 263 ). The subscriber authentication request carries user identification information such as a telephone number and an identification code written in the internal memory  30  of the cellar telephone  22 . The user identification information is given from the cellar telephone company. It should be noted that the user may also enter another user identification information such as a password using the operation unit  35  at Step S 263 , and that information may be included in the subscriber authentication request. The cellar telephone  22  and information administration server  21  communicate with each other via the communication repeater  24  and communication network  26 .  
         [0195]    As the information administration server  21  receives the subscriber authentication request, it conducts the authentication using the database formed in the storage unit  28  (Step S 264 ).  
         [0196]    The database in the storage device  28  stores the complementary music file as described above. It also stores the user identification information of all the subscribers. When the information administration server  21  confirms that the user identification information included in the received subscriber authentication request exists in the database, it sends a notice of approval to the cellar telephone  22  (Step S 265 ).  
         [0197]    As the cellar telephone  22  receives the approval notice, it sends a request for complementary music file to the information administration server  21  (Step S 266 ). The complementary music file request includes a predetermined song number. The information administration server  21  can specify the requested complementary music file from the song number.  
         [0198]    If incomplete music files of plural songs are recorded in the memory card  25  and the user wants to request the information administration server  21  to send complementary music files that mate with incomplete music files for some of the songs, then a list of songs recorded in the memory card  25  is indicated on the display unit  34  immediately before execution of Step S 266  and a request for selection of one song from the list is also made to the user through the display unit  34 . A request for the complementary music file of the song selected by the user is made at Step S 266 .  
         [0199]    As the information administration server  21  receives the complementary music file request, it retrieves the complementary music file specified by the song number included in the complementary music file request from the database and sends it to the buffer (Step S 267 ) This complementary music file is then transmitted to the cellar telephone  22  (Step S 268 ). When the user wants to buy a plurality of songs, complementary music files of these songs are read and sent to the cellar telephone  22  at Steps S 267  and S 268 .  
         [0200]    The cellar telephone  22  receives the complementary music file and temporarily stores it in the internal memory  30  (Step S 269 ). Upon completing the reception of the complementary music file, the cellar telephone  22  instructs the memory controller  33  to read the incomplete music file from the memory card  25  (Step S 271 ). The memory controller  33  reads the incomplete music file from the memory card  25  and supplies it to the cellar telephone  22 . The cellar telephone  22  performs a combine operation; it combines the incomplete music file with the complementary music file to create a complete music file (Step S 272 ). This combine operation is the same as that described above. As a result of the combine, the complete music file is written in the memory card  25  via the memory controller  33 , and the incomplete music file stored in the memory card  25  is deleted.  
         [0201]    When the combine is successfully complete, the cellar telephone  22  sends a notice of data combine completion to the information administration server  21  and terminates the communication (Step S 273 ).  
         [0202]    Upon receiving the data combine completion notice, the information administration server  21  conducts a charging operation (Step S 274 ). The bill is charged to the user together with a cellar telephone fee by this charging operation.  
         [0203]    As the combine operation is finished, the cellar telephone  22  starts a replay operation (Step S 275 ). In this replay operation, the complete music file created by the combine operation is read from the memory card  25  and fed to the music replay part  32  via the memory controller  33  and control circuit  36 . The music replay part  32  decodes the music data successively, D/A converts a PCM audio signal to an analog audio signal, and supplies it to a headphone set via the amplifier. The user therefore can completely listen to a song which he or she has purchased.  
         [0204]    In case of the memory card  25  recording the complete music file, it is possible to replay a song with an equipment other than the cellar telephone, such as a personal computer or a music reproducer incorporating a semiconductor memory.  
         [0205]    Although the memory card  25  is employed in the above embodiments, it is satisfactory that an incomplete music file of a desired song is recorded in CD-R at the kiosk terminal device  23 , and a terminal device such as a personal computer, not the cellar telephone  22 , utilizes the CD-R and asks the information administration server to send a complementary music file of the desired song in accordance with the procedure shown in FIG. 3 in order to create a complete music file. In this case, the kiosk terminal device  23  has an insertion slot for the CD-R and a write device for the CD-R.  
         [0206]    It is also satisfactory that the information such as the incomplete music file is wireless transmitted between the kiosk terminal device  23  and cellar telephone  22  in accordance with, for example, B 1 uetooth, not via the memory card  25 . Alternatively, the information may be exchanged between the kiosk terminal and cellar telephone by wire or cable.  
         [0207]    The kiosk terminal device  23  may also be equipped with a data separation function. In such case, the kiosk terminal device  23  includes a decoder  61 , a D/A converter  62 , an amplifier  63  and a speaker set  64  as shown in FIG. 33 as well as the elements shown in FIG. 30. The data separation is performed as shown in FIG. 7, but it should be noted that the incomplete music file Fincom to the complete music file Fcom is written in the memory card  25  inside the kiosk terminal device  23 , and the complementary music file Fsup is temporarily stored in the storage device  52 .  
         [0208]    A plurality of complete music files are recorded in the memory device  52  of the kiosk terminal device  23 . As illustrated in FIG. 34, these complete music files are transmitted from the information administration server  21  (Step S 281 ), received at the communication unit  51  via the high speed dedicated line  27 , and written in the memory device  52  under the control of the control circuit  56  (Step S 282 ). Since a song list data is transmitted together with the complete music files, it is also written in the memory device  52 . The song list data represents the relationship between the song titles and the complete music files. The control circuit  56  causes the screen  54  to display the song titles in the form of list (Step S 283 ). A song can be selected from the list displayed on the screen  54  of the operation unit  55  by using the cursor and selection button.  
         [0209]    The user operates keys on the operation unit  55  when he or she selects a desired song from the displayed song list. Specifically, the user moves the cursor to the desired one of the songs present in the display  54  and presses the selection button in order to select that song. The selected song can be specified from the cursor position. The kiosk terminal device  23  obtains a song number data of the selected song from the key operations made to the operation unit  55  (Step S 284 ), and starts a trial listening operation in accordance with the song number data (Step S 285 ).  
         [0210]    The kiosk terminal device  23  retrieves a complete music file corresponding to the song number data from a plurality of complete music files in the memory device  52  during the trial listening, reads first S bytes of music data from the retrieved complete music file, and feeds it to the decoder  61 . The decoder  61  successively decodes the S bytes of music data and issues a PCM audio signal to the D/A converter  62 . An analog audio signal produced from the D/A converter  62  is supplied to the speaker set  64  via the amplifier  63  so that the user can listen to the selected song for a prescribed period for the trail listening purpose.  
         [0211]    If the user of the cellar telephone  22  wishes to purchase the song which the user just listened to, the user inserts the memory card  25  into the memory support  57  from the insertion slot  23   a . The user may operate the operation unit  55  instead of inserting the memory card  25 .  
         [0212]    The control circuit  56  of the kiosk terminal device  23  uses the memory controller  53  to determines whether the memory card  25  is loaded into the memory support  57  (Step S 286 ). Unless the loading of the memory card  25  is detected, the program may be terminated as shown in FIG. 34. Alternatively, a message urging the user to load the memory card  25  into the insertion slot  23   a  may be indicated in the display  54 , and the program may execute Step S 286  again.  
         [0213]    If the control circuit  56  detects the memory card loading, on the other hand, it performs the data separation operation to the complete music file of the selected song (Step S 287 ).  
         [0214]    In the data separation operation, the incomplete music file corresponding to the complete music file of the selected song is written into the memory card  25 , and the complementary music file is temporarily stored in the memory device as described above. The header portions of the incomplete and complementary music files include various information such as the song number, the way of making the song incomplete, the file names of the incomplete and complementary music files, and the block sizes of the incomplete and complementary data portions respectively.  
         [0215]    The control circuit  56  of the kiosk terminal device  23  supplies the just separated incomplete music file to the memory controller  53  and instructs the writing (Step S 288 ). The memory controller  53  writes the incomplete music file in the memory card  25  in response to this write command.  
         [0216]    The control circuit  56  determines whether the writing to the memory card  25  is complete (Step S 289 ). If the writing is complete, the control circuit reads the just separated complementary music file from the memory device  52  and sends it to the information administration server  21  (Step S 290 ). Upon receiving the complementary music file, the information administration server  21  stores it in the database of the memory device  28  (Step S 291 ).  
         [0217]    The control circuit  56  of the kiosk terminal device  23  returns to Step S 283  after Step S 290 . If there is another desired song, the above described procedure will be repeated to write the incomplete music file corresponding to this song in the memory card  25 .  
         [0218]    When, for instance, the eject button on the operation unit  55  is operated to discharge the memory card  25  from the kiosk terminal device  23 , the control circuit  56  does not execute the process following Step S 284 .  
         [0219]    When the incomplete music file is written in the memory card  25 , the user loads the memory card  25  into the insertion slot of the cellar telephone  22  such that the memory card is supported in the memory support  40 . The user then obtains the complementary music file from the information administration server  21  using the cellar telephone  22 , and combines it with the incomplete music file so that the user can replay the song. This procedure is the same as shown in FIG. 32 so that the redundant description is omitted here. If there are a plurality of different data separation schemes, one of them is specified when the complementary music file is requested.  
         [0220]    Although the kiosk terminal device  23  does not conduct the combine operation in the above described embodiment, the kiosk terminal device  23  may be equipped with a combiner (not shown) for the combine operation so that a person who does not have a cellar telephone or personal computer is able to buy a disc such as CD-R and MD or a cassette tape for recording the complete music file or analog music signal.  
         [0221]    The incomplete file of music data which includes a missing part and the complementary file are prepared in the above embodiments, but the present invention is not limited in this regards. The present invention is, for example, applicable to data carrying other information such as images and pictures. If MPEG image data is utilized as the image data, I frame data may be lacking. The reason the I frame is lacking is because an original image cannot be reproduced without the I frame. The above described TwinVQ method can be employed in the image data separation machine and combine operation.  
         [0222]    If there is a demand that the information should be divided into two for the sake of copy right, P frame and/or B frame may be missing.  
         [0223]    If a home server is available at home, a server such as the above mentioned information administration server of a center arbitrarily broad-distributes incomplete music file at night or other time. When a user finds a desired song, the user obtains a complementary music file and a billing operation is conducted. It is preferred to automatically delete those incomplete music files for which the user does not request complementary music files within several days if the incomplete music files are arbitrarily distributed.  
         [0224]    In case of arbitrary incomplete music file broad distribution, the user may register favorite music information in the center beforehand. That is, the user can register what kind of music he or she wishes to listen to, such as western music, Japanese music, popular songs, enka songs, and the music files may automatically be broad distributed in compliance with the registered information.  
         [0225]    It is necessary to prevent the complementary music file from being copied illegally. One of the methods is deleting the complementary music file from the storage device when the complete music file is created at the terminal device as described above. Another method is only allowing a registered terminal device to perform the combine operation. Specifically, when the complementary music file is requested to the server of the information administration center from the terminal device, an identification number of the terminal device is sent. The information administration server appends the identification number to the complementary music file and sends the complementary music file to theterminal device. The combine operation is enabled at the terminal device only when it is confirmed that the identification number of the terminal device itself coincides with the received identification number. It is also feasible for the information administration server to specify a plurality of terminal devices that are allowed to perform the combine operation when the information administration server sends the complementary music file. The complementary music file may have an expiration date or an upper limit number of use.  
         [0226]    Referring to FIG. 35, illustrated is a basic configuration of a navigation system which adopts the information providing system of the present invention. This navigation system includes a navigation terminal device  71 , a communication relay device (repeater)  72 , a gateway device  73  and an information administration server  74 . The navigation terminal device  71  wireless communicates with the communication relay device  72 . The communication relay device  72  is connected to the gateway device  73  via a dedicated line  75 . The gateway device  73  is connected to the information administration server  74  over the internet  76 .  
         [0227]    The information management server  74  manages map data used in the navigation terminal device  71 .  
         [0228]    As illustrated in FIG. 36, the navigation terminal device  71  has a navigation device  81  and a mobile phone  82  as its major components, and is installed on a vehicle. The navigation device  81  is connected to the mobile phone  82 . Information transmission between the navigation device  81  and mobile phone  82  may be made using a short distance wireless communication scheme such as the above mentioned Bluenote. The navigation device  81  includes a GPS device  88  and a control circuit  89 , and the GPS device  88  can detect a current location of the vehicle. The navigation device  81  also includes a DVD-ROM drive  84  for reading data (map data) recorded in the DVD-ROM  83  so that it can read from DVD-ROM  83  map data including the current vehicle location or map data of a desired area decided by the user operating the operation unit  86 , and display a map of the map data in the screen  87 .  
         [0229]    The communication relay device  72  is owned by an enterprise of the mobile phone  82 , i.e., a telephone company. A user of the navigation terminal device  71  contracts the telephone company regarding use of the mobile telephone  82 . Since complementary map data of the map data is packet transmitted, an amount of packet transmission is subjected to the charging by the telephone company.  
         [0230]    Like the above described music data, the map data is divided into an incomplete map file and a complementary map file with respect to each of a plurality of areas (each area is a box of a map mesh or grid) by the simple skipping scheme or random number scheme, and CD-ROM including incomplete map files for the areas is distributed. A user terminal device has a complementary map file of a desired area transmitted from the information administration server and combines it to the incomplete map file to reconstruct an original map file.  
         [0231]    The map data can also be treated as described below.  
         [0232]    As illustrated in FIG. 37, the map data has a structure comprised of an administration portion and a map data portion. A map data including the administration portion and map data portion is a complete map data. The map data portion records map data representing respective map meshes. Specifically, as shown in FIG. 38, the administration portion is divided into a level 0 mesh data group, a level 1 mesh data group, . . . . Each mesh data group includes a plurality of map data. The number of the meshes is the number of the map data in the mesh data group. Each mesh represents an area resulting from dividing a map such as a map of Japan into a grid after enlarging, as shown in FIG. 39. The administration portion includes, as shown in FIG. 38, address regions representing front addresses of the respective mesh administration information, and a mesh administration information group representing the respective mesh administration information. The mesh (map) data address of the administration information group is information indicating at which location the mesh is recorded in DVD-ROM  83 . If the mesh data address is unknown, a desired map data cannot be read from DVD-ROM  83 . The mesh data address (content surrounded by the single-dot chain line in FIG. 38) is therefore missing from DVD-ROM  83 , and is stored as the complementary map data in a database of a storage device  77  of an information administration server  74 . In the storage device  77 , stored is a data table indicating the relationship between the mesh numbers and the map data address numbers as shown in FIG. 40.  
         [0233]    DVD-ROM  83  without the mesh map data address that is prepared in the above described manner is distributed free or at an extremely low price. It should be noted that the incomplete map data that does not have the mesh map data address may be recorded in a hard disc (not shown) inside the navigation device  81 .  
         [0234]    It is also satisfactory that neither a free disc nor hard disc data is provided when the navigation device  81  is purchased; instead, the incomplete map data is broad distributed at the time of first initialization and recorded in the hard disc. In this case, the current location detected by the GPS device  88  is transmitted to the information administration server of the center, and the incomplete map data of an area including the current location is sent to the navigation terminal device  71  from the information administration server.  
         [0235]    Referring to FIG. 41, as the navigation terminal device  71  is activated (Step S 310 ), the mobile phone  82  sends an access signal to the information administration server  74  (Step S 311 ). The access signal reaches the communication relay device  72  as the wireless signal, becomes a wire signal and advances to the information administration server  74  via the gateway device  73  and internet  76 . When transmitted from the information administration server  74  to the navigation terminal device  71 , the signal proceeds the above route in the opposite direction.  
         [0236]    When the information administration server  74  receives the access signal, it performs user authentication (Step S 312 ). If the received access signal is an access signal from a registered user, the information administration server issues a response signal to the navigation terminal device  71  (Step S 313 ). If the information providing service is only available to pre-registered users, a user identification data needed for user authentication is included in the access signal. If the information providing service is available to unnamed persons, the user authentication at Step S 312  is dispensed with.  
         [0237]    After the navigation terminal device  71  receives the response signal, an area is selected in accordance with the operation conducted at the operation unit  86  (Step S 314 ). This area selection is made by, for example, entering a latitude and a longitude, a station name, or a town name. The mobile phone  82  transmits to the information administration server  82  a request for the complementary map data having the mesh number of the selected area (Step S 315 ).  
         [0238]    As the information administration server  74  receives the complementary map data request, it retrieves and reads the map data address corresponding to the mesh number indicated by the complementary map data request from the database of the storage device  77  (Step S 316 ). The map data address is then sent to the navigation terminal device  71  from the information administration server  74  as the complementary map data (Step S 317 ).  
         [0239]    As the navigation terminal device  71  receives the complementary map data, the mobile phone  82  terminates the communication (Step S 318 ). Upon termination of the communication, the telephone company starts the charging operation. Although not shown, a request for cooperation fee transfer may be made to a bank account of a company that distributes the free DVD-ROM or the like.  
         [0240]    The navigation terminal device then instructs the DVD-ROM drive  84  to read the map data corresponding to the map data address indicated by the received complementary map data (Step S 319 ). The DVD-ROM drive  84  reads the map data of the area specified by the map data address from DVD-ROM  83 , and supplies it to the navigation device  81  (Step S 320 ). The display unit  87  displays the map derived from the map data (Step S 321 ).  
         [0241]    The relationship between the received map data address and the mesh number is stored in a memory of the navigation device  81 .  
         [0242]    In order to prevent a third party from illegally utilizing the complementary map data, the complementary map data may have an expiration date or an upper limit number of usage.  
         [0243]    It should be noted that as shown in FIG. 42 the current vehicle location may be obtained from the GPS device  88  (Step S 314   a ) instead of Step S 314 , and the complementary map data corresponding to the mesh number of the area including the current vehicle location may be sent to the information administration server  74  at Step S 315 .  
         [0244]    In case of FIG. 42, the control circuit  89  of the navigation device  81  determines whether the current vehicle location reaches the outer boundary of the displayed map as the vehicle further moves (Step S 331 ). If so, the program may return to Step S 315  to repeat the above described procedure to obtain another map data, which is suitable for displaying the current vehicle location in the displayed map, from the information administration server  74 .  
         [0245]    After Step S 321 , the program may return to Step S 314  upon elapsing of a predetermined period to newly acquire a suitable map data from the information administration server  74  to indicate the current vehicle position in the displayed map.  
         [0246]    When the information administration server  74  receives the complementary map data request, Step S 316  may retrieve not only the map data address corresponding to the mesh number carried with the complementary map data request but also map data addresses corresponding to mesh numbers before and after the mesh number from the database of the storage device  77 . Step S 317  may send these map data addresses to the navigation terminal device  71  from the information administration server  74  as the complementary map data.  
         [0247]    The navigation terminal device  71  may operate as shown in FIG. 43 after it receives the response signal. Specifically, the control circuit  89  of the navigation module  81  retrieves a route from the current vehicle location to a desired destination in accordance with the operation made to the operation unit  86  by the user (Step S 341 ) and selects at least one area including that route (Step S 342 ). After Step S 342 , the program proceeds to Step S 315  so that the mobile phone  82  transmits to the information administration server  74  a request for the complementary map data corresponding to the mesh number of the selected area.  
         [0248]    In case of FIG. 43, if a plurality of areas are selected at Step S 342 , a request for complementary map data representing the relationship between a plurality of mesh numbers and a plurality of map data addresses is sent at Step S 343  as shown in FIG. 44. As the information administration server  74  receives the complementary map data request, it reads a plurality of map data addresses corresponding to a plurality of mesh numbers indicated by the complementary map data request from the database of the storage device  77  at Step S 344 . The information administration server  74  transmits the relationship between these map data addresses and mesh numbers to the navigation terminal device  71  as the complementary map data at Step S 345 .  
         [0249]    When the navigation terminal device  71  receives the complementary map data representing the relationship between the mesh numbers and map data addresses, it stores this relationship in a built-in memory of the navigation device  81  (Step S 346 ), and the mobile phone  83  discontinues the communication (Step S 347 ). The navigation terminal device then obtains the vehicle current location from the GPS device (Step S 348 ), reads the map data address corresponding to the mesh number allotted to the area including the current location from the built-in memory (Step S 349 ), and instructs the DVD-ROM drive  84  to read the map data specified by the map data address (Step S 350 ). The DVD-ROM drive  84  reads the map data of the area specified by the map data address from DVD-ROM  83  and feeds it to the navigation module  81  (Step S 351 ). The display unit  87  displays the map together with the current vehicle location based on the map data (Step S 352 ). After that, steps S 348  to S 352  are repeated.  
         [0250]    As understood from the foregoing, there is an advantage that a user is only required to purchase necessary map data if the present invention is applied to the navigation system.  
         [0251]    It should be noted that the complete information data is referred to as the complete music data or the complete map data, and the complete information file derived from the complete information data is referred to as the complete music file or the complete map file in the above described embodiments. Further, the incomplete information data is referred to as the incomplete music data or the incomplete map data, and the incomplete information file derived from the incomplete information data is referred to as the incomplete music file or the incomplete map file. Likewise, the complementary information data is referred to as the complementary music data or the complementary map data, and the complementary information file derived from the complementary information data is referred to as the complementary music file or the complementary map file.  
         [0252]    As described above, the present invention does not require a long time in downloading the information data such as music and image even if the information data size is large. A user therefore does not feel stresses in downloading. This also promotes the information data purchasing.  
         [0253]    This application is based on a Japanese Patent Application No. 2000-195024 which is hereby incorporated by reference.