Abstract:
An optical disc recording and reproducing apparatus can record data, which is provided in a packet having a fixed length, on an optical disc without waiting for a long time for a completion of a formatting operation. The optical disc is formatted by a formatting process performed as a background process so that another process is acceptable after a start of the formatting process. The formatting process is performed so as to fill at least a predetermined part of a recording area of said optical disc by packets having a fixed length.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to an optical disc recording and reproducing apparatus and, more particularly, to an optical disc recording and reproducing apparatus which records information on a rewritable optical disc such as a CD-RW. 
     2. Description of the Related Art 
     A minimum unit for reproduction of information recorded on a recording area of a compact disc (CD), a recordable optical disc (CD-R) or a rewritable optical disc (CD-RW) is defined as a block of a recording area. Each block can contain information of about 2,048 to 2,352 bytes. 
     A minimum unit for recording information on an optical disc such as a CD-R or a CD-RW is defined as a packet. Each packet comprises at least one user data block, five link blocks preceding the user data block and two link blocks subsequent to the user data block. The five link blocks preceding the user data block include one link block and four run-in blocks. The two link blocks subsequent to the user data block include two run-out blocks. 
     The link blocks are required for interconnecting a plurality of packets when information is recorded on an optical disc such as a CD. The link block does not contain user data. It should be noted that a rule for recording data on a CD is defined by a predetermined standard. Such a rule is referred to as a “linking rule”. 
     There are two methods for recording data on an optical disc such as a recordable compact disc (CD-R) or a rewritable compact disc (CD-RW). One of the methods is referred to as a “track at-once method” and the other is referred to as a “packet write method”. 
     The track at-once method is for recording information on a track all at one time by using a single packet. The user data blocks in the track are consecutive, and there are no link blocks between the user data blocks. A single track constitutes a recording unit, and ninety-nine tracks can be formed on the optical disc at maximum. A start address and an end address of each track are recorded on a separate area of the optical disc as a “table of contents (TOC)”. 
     On the other hand, the packet write method is for recording information on a track by dividing the track into a plurality of packets so that the information is recorded on an individual packet basis. Since this method records information by each individual packet, each user data block is discretely located in a single track and link blocks are provided between adjacent ones of user data blocks. 
     The packet write method is classified into two types, that is, a “fixed packet write method” and a “variable packet write method”. In the fixed packet write method, a number of user data blocks within a track is set to a fixed number. The number of user data blocks within a packet is referred to as a packet length or packet size. On the other hand, in the variable packet write method, packets having various packet lengths are provided in a single track. 
     The Universal Disc format (UDF) is a file system that uses the fixed packet write system. The UDF is used by various devices. The UDF utilizes a recording format that takes advantage of a feature of each device. 
     In a conventional CD-R drive such as one disclosed in Japanese Laid-Open Patent Application No.7-141660, when the recording is performed in accordance with the packet write method, data to be recorded is added to previously recorded packets since only an addition of data is allowed for the CD-R. Accordingly, the UDF uses a variable packet write method referred to as a sequential UDF which can perform a recording only by adding data after the previously recorded data. Thus, there is no need to consider a format. 
     On the other hand, a CD-RW drive is capable of recording data on a CD-RW by overwriting. Thus, the CD-RW drive uses a random UDF which records data by each packet unit and reproduces the data by each block. 
     In order to record and reproduce data at random, the random UDF requires a formatting operation by previously recording packets on the entire recording area or a designated area of the CD-RW, each of the packets having a fixed length, so that the entire recording area or the designated area are filled by the packets. By this formatting operation, data can be randomly recorded on the recording area of the CD-RW, or data recorded on the CD-RW can be randomly reproduced. 
     However, when the above-mentioned formatting operation is performed, it takes a long time to fill the entire recording area or the designated area of the CD-RW by the packets. Thus, there is a problem in that a recording or reproducing operation cannot be performed and completion of the formatting operation data must be waited for when the formatting operation is being performed. 
     The recording capacity of the CD-RW is represented by a time for continuously performing a recording operation. For example, one minute of recording corresponds to 9 megabytes, and data corresponding to about 74 minutes can be recorded on a CD-RW. Thus, it takes about 40 minutes to complete a recording of data including the TOC even if the recording is performed at a double recording speed. This means that one must wait for about 40 minutes until a formatting operation is completed in order to initially use a blank or new CD-RW. 
     SUMMARY OF THE INVENTION 
     It is a general object of the present invention to provide an improved and useful optical disc recording and reproducing apparatus in which the above-mentioned problems are eliminated. 
     A more specific object of the present invention is to provide an optical disc recording and reproducing apparatus which can record data, which is provided in a packet having a fixed length, on an optical disc without waiting for a long time for a completion of a formatting operation. 
     Another object of the present invention is to provide a formatting method for formatting a rewritable optical disc without delaying a recording operation or a reproducing operation performed on the optical disc. 
     In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention an optical disc recording and reproducing apparatus, comprising: 
     recording means for recording data on a rewritable optical disc by using a fixed packet write method; 
     reproducing means for reproducing data recorded on the optical disc by the recording means; and 
     background formatting means for formatting the optical disc by a formatting process performed as a background process so that another process is acceptable after a start of the formatting process, the formatting process being performed so as to fill at least a predetermined part of a recording area of the optical disc by packets having a fixed length. 
     According to the above-mentioned invention, since the formatting process is performed as a background process so that another process can be accepted when the formatting operation is being performed, execution of a recording operation or a reproducing operation may be performed without waiting until the formatting process is completed. 
     In the optical disc recording and reproducing apparatus according to the present invention, the background formatting means may include end-of-process notifying means for notifying completion of the formatting process before the formatting process is completed. Accordingly, a host computer connected to the optical disc recording and reproducing apparatus can accept another process to be performed by the optical disc recording and reproducing apparatus. 
     Additionally, in the optical disc recording and reproducing apparatus according to the present invention, the background formatting means may include means for interrupting the formatting process when a request for recording user data is made, recording the user data on the optical disc and thereafter resuming the formatting process. Accordingly, a recording operation of data can be started at any time even when the formatting process is being performed. 
     Additionally, in the optical disc recording and reproducing apparatus according to the present invention, the background formatting means may include means for resuming the formatting process by excluding an area in which the user data has been recorded from among areas to be formatted when the packets having a fixed length are not yet recorded in the area in which the user data has been recorded. Accordingly, the user data recorded while the formatting process is being performed is not erased by overwriting with the packets having the fixed length when the formatting process is resumed. 
     In the optical disc recording and reproducing apparatus according to the present invention, the background formatting means may include means for interrupting the formatting process when a request for reproducing data recorded in a designated area is made, reproducing the data and thereafter resuming the formatting process. Accordingly, a reproducing operation can be started at any time even when the formatting process is being performed. 
     Additionally, in the optical disc recording and reproducing apparatus according to the present invention, the background formatting means may include means for outputting previously prepared information as a result of attempted reproduction of data recorded in the designated area when the packets having the fixed length are not yet recorded in the designated area by execution of the formatting process. Accordingly, a reproducing operation can be substitutionally performed when a reproducing operation cannot be performed since the area of which data is to be reproduced has not been formatted. 
     Additionally, in the optical disc recording and reproducing apparatus according to the present invention, the background formatting means may include means for prohibiting ejection of the optical disc when a request for ejecting the optical disc is made during an execution of the formatting process. Accordingly, the optical disc is not ejected when the formatting process is being performed. Thus, the optical disc is prevented from being incompletely formatted. 
     Additionally, there is provided according to another aspect of the present invention a formatting method for formatting a rewritable optical disc, data being recorded on the optical disc by using a fixed packet write method, the formatting method comprising the steps of; 
     starting a formatting process for the optical disc as a background process, the formatting process being performed so as to fill a recording area of the optical disc by packets having a fixed length; 
     enabling execution of another process while the formatting process is being performed; and 
     ending the formatting process after the recording area to be formatted has been filled by the packets having the fixed length. 
     According to the above-mentioned invention, since the formatting process is performed as a background process so that another process can be accepted when the formatting operation is being performed, execution of a recording operation or a reproducing operation may be performed without waiting until the formatting process is completed. 
     In the formatting method according to the present invention, the step of enabling may comprise the step of notifying of completion of the formatting process before the formatting process is completed. 
     Accordingly, a host computer connected to the optical disc recording and reproducing apparatus can accept another process to be performed by the optical disc recording and reproducing apparatus. 
     The formatting method according to the present invention may further comprise the steps of: 
     interrupting the formatting process when a request for recording user data is made; 
     recording the user data on said optical disc; and 
     resuming the formatting process after the user data has been recorded. 
     Accordingly, a recording operation of data can be started at any time even when the formatting process is being performed. 
     Additionally, in the formatting method according to the present invention, the step of resuming may include the step of excluding an area in which the user data has been recorded from among areas to be formatted when the packets having the fixed length are not yet recorded in the area in which the user data has been recorded. 
     Accordingly, the user data recorded while the formatting process is being performed is not erased by overwriting with the packets having the fixed length when the formatting process is resumed. 
     Additionally, the formatting method according to the present invention may further comprise the steps of: 
     interrupting the formatting process when a request for reproducing data recorded in a designated area is made; 
     reproducing the data in the designated area; and 
     resuming the formatting process after the data recorded in the designated area has been reproduced. 
     Accordingly, a reproducing operation of data can be started at any time even when the formatting process is being performed. 
     Additionally, in the formatting method according to the present invention, the step of reproducing may include the step of outputting previously prepared information as a result of attempted reproduction of the data recorded in the designated area when the packets having the fixed length are not yet recorded in the designated area by execution of the formatting process. 
     Accordingly, a reproducing operation can be substitutionally performed when a reproducing operation cannot be performed since the area of which data is to be reproduced has not been formatted. 
     Additionally, the formatting method according to the present invention may further comprise the step of prohibiting ejection of the optical disc when a request for ejecting the optical disc is made during an execution of the formatting process. 
     Accordingly, the optical disc is not ejected when the formatting process is being performed. Thus, the optical disc is prevented from being incompletely formatted. 
     Additionally, there is provided according to another aspect of the present invention a processor readable medium storing program codes causing an optical disc recording and reproducing apparatus to perform the above-mentioned formatting methods. 
     Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an optical disc recording apparatus according to a first embodiment of the present invention; 
         FIG. 2  is an illustration for explaining a track and a format of a packet used in a fixed packet write method; 
         FIG. 3  is an illustration for explaining a format of a recording area of an optical disc which has been formatted by the optical disc recording and reproducing apparatus shown in  FIG. 1 . 
         FIG. 4  is a flowchart of a formatting process performed by the optical disc recording and reproducing apparatus shown in  FIG. 1 , the formatting process being performed as a background process; 
         FIG. 5  is a flowchart of a formatting process performed by the optical disc recording and reproducing apparatus shown in  FIG. 1  when a request for recording data on the optical disc is made while the formatting process is being performed as a background process; 
         FIG. 6  is a flowchart of a formatting process performed by the optical disc recording and reproducing apparatus shown in  FIG. 1  so as to prevent a recording area from being formatted, user data having been recorded in the recording area, while the formatting process is being performed as a background process; 
         FIG. 7  is a flowchart of a formatting process performed by the optical disc recording and reproducing apparatus shown in  FIG. 1  when a request for reproducing data recorded on the optical disc is made while the formatting process is being performed as a background process; 
         FIG. 8  is a flowchart of a formatting process performed by the optical disc recording and reproducing apparatus shown in  FIG. 1  when reproduction is performed on an unformatted recording area while the formatting operation is being performed as a background process; and 
         FIG. 9  is a flowchart of a formatting process performed by the optical disc recording and reproducing apparatus shown in  FIG. 1  when a request for ejecting the optical disc is made while the formatting process is being performed as a background process. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A description will now be given of a first embodiment of the present invention.  FIG. 1  is a block diagram of an optical disc recording and reproducing apparatus according to the first embodiment of the present invention. 
     The optical disc recording and reproducing apparatus shown in  FIG. 1  records information on an optical disc  1  such as a CD-RW by providing a train of pits spirally formed on the optical disc. The optical disc recording and reproducing apparatus reads the information on the optical disc  1  by information units referred to as user data blocks. The optical disc recording apparatus according to the present embodiment uses the above-mentioned fixed packet write method to record information on the optical disc  1 . 
     As shown in  FIG. 1 , the optical disc recording and reproducing apparatus is provided with a spindle motor  2 , an optical pickup  3  and a coarse adjustment motor  4 . The spindle motor  2  rotates the optical disc  1 . The optical pickup  3  has a semiconductor laser which projects a laser beam L onto a recording area of the optical disc  1 . The coarse adjustment motor  4  moves the optical pickup  3  in a radial direction of the optical disc  1  in cooperation with a seek motor (not shown in the figure) provided in the optical pickup  3 . 
     The optical disc recording and reproducing apparatus further includes a rotation control system  5 , a coarse adjustment motor control system  6 , an optical pickup control system  7  and a signal processing system  8 . The rotation control system  5  controls operation of the spindle motor  2 . The coarse adjustment motor control system  6  controls operation of the coarse adjustment motor  4 . The optical pickup control system  7  controls operation of the optical pickup  3 . The signal processing system  8  transmits information read by the optical pickup  3  and receives information to be recorded on the optical disc  1  by the optical pickup  3 . 
     The optical disc recording apparatus is further provided with a controller  9  and an interface  10 . The controller  9  controls the above-mentioned rotation control system  5 , the coarse adjustment motor control system  6 , the optical pickup control system  7  and the processing system  8 . The interface  10  enables communication with an external host computer. 
     In the thus-constructed optical disc recording and reproducing apparatus, the optical pickup  3  is moved in the radial direction of the optical disc  1  while the optical disc  1  is rotated by the spindle motor  2  so as to record or read information by projecting the laser beam L from the semiconductor laser of the optical pickup  3  onto the recording area of the optical disc  1 . 
     When the optical disc recording and reproducing apparatus shown in  FIG. 1  records information, the controller  9  moves the optical pickup  3  in a radial direction of the optical disc  1  while the optical disc  1  is rotated. The laser beam L is projected from the optical pickup  3  onto the recording area of the optical disc  1  at a recording power level so as to record the information on the optical disc  1 . 
     Additionally, when the optical disc recording and reproducing apparatus shown in  FIG. 1  reproduces information recorded on the optical disc  1 , the controller  9  moves the optical pickup  3  while the optical disc  1  is rotated. The laser beam L is projected from the optical pickup  3  onto the recording area of the optical disc  1  at a reproducing power level so as to read the information recorded on the optical disc  1 . The reproduced information is transferred to the host computer via the interface  10 . 
     In the optical disc recording and reproducing apparatus, the controller  9  controls a recording and reproducing operation of data in each track on the optical disc  1  according to the fixed packet write method. The controller  9  also controls a formatting operation for the optical disc  1  in a background process. That is, the controller  9  serves as means for recording data on the rewritable optical disc  1  by the fixed packet write method and reproducing the recorded data. Additionally, the controller  9  sends a notification to notify of a completion of a formatting operation immediately after the formatting operation has started when the optical disc  1  is formatted. Thereafter, the controller  9  serves as background formatting means for formatting the optical disc  1  in a background process so as to record fixed packets in the entire recording area or a designated area of the optical disc  1 . 
     Further, the controller  9  serves to interrupt the formatting operation when a request is made for recording user data during the formatting operation in the background process and restart the formatting operation after the user data has been recorded. Additionally, the controller  9  serves to resume the formatting operation, after the formatting operation is restarted while preventing the area in which the user data is recorded from being formatted. 
     Additionally, the controller  9  serves to interrupt the formatting operation when a request is made for reproducing user data recorded in a designated area during the formatting operation in the background process and restart the formatting operation after the user data recorded in the designated area has been reproduced. Further, the controller  9  serves to output predetermined information as a result of attempted reproduction of data in a designated area when the fixed packets are not yet recorded in the designated area by the formatting operation. Additionally, the controller  9  serves to prohibit the optical disc  1  from being ejected when a request is made to eject the optical disc  1  while the formatting operation is performed as the background process. 
     A description will now be given of the fixed packet write method used by the optical disc recording and reproducing apparatus shown in  FIG. 1 . A description will also be given of a format of a packet used in the fixed packet write method.  FIG. 2  is an illustration for explaining a track and a format of a packet recorded on the optical disc  1  in a fixed packet write method. 
     According to the fixed packet write method, a plurality of tracks are formed in a recording area of the rewritable optical disc  1 . Each of the tracks is divided into a plurality of packets each having the same number of user data blocks so that information is recorded for each individual packet at once. 
     Accordingly, in the fixed packet write method, each of the packets  12  in a single track  11  in the recording area of the optical disc  1  has the same packet length, and each of the packets  12  has the same number of the user data blocks. 
     The packet  12  includes a plurality of user data blocks  15  which can be reproduced. Additionally, the packet  12  includes five link blocks preceding the user data blocks  15 . The five link blocks consist of one link block  13  and four run-in blocks  14 . The packet  12  further includes two link blocks subsequent to the user data blocks  14 . The two link blocks consist of two run-out blocks  16 . These link blocks are used for connecting the packets  12  to each other when data is recorded in the user data blocks  15  of the packets  12  in the track  11  of the optical disc  1 . 
       FIG. 3  is an illustration for explaining a format of the recording area of the optical disc which is formatted by the optical disc recording and reproducing apparatus shown in  FIG. 1 . As shown in  FIG. 3 , when the entire recording area or a designated area of the optical disc  1  is subjected to the formatting operation according to the fixed packet recording method, the entire recording area or the designated area is filled by the fixed packets. 
     A description will now be given of a formatting process performed as a background process in the optical disc recording and reproducing apparatus shown in  FIG. 1 .  FIG. 4  is a flowchart of the formatting process performed by the optical disc recording and reproducing apparatus shown in  FIG. 1 . 
     Immediately after the formatting process for the optical disc  1  is started, the controller  9  outputs, in step S 1 , a message to a host computer so as to notify a user (the host computer) that the formatting process has been completed. Then, in step S 2 , an actual formatting operation is performed as a background process of the host computer. In the formatting operation, the entire area or a designated area of the optical disc  1  is filled by packets having a fixed length. It is determined, in step S 3 , whether or not the area to be formatted is filled by the packets. If the area is not filled by the packets, the routine returns to step S 2 . If it is determined that the entire area is filled by the packets, the routine is ended. 
     In the above-mentioned formatting process, since the actual formatting operation is performed as a background process, recording or reproduction of data can be accepted by the host computer while the formatting operation is being progressed. Thus, the host computer dose not wait for a long time to accept the recording or reproduction of data even when the formatting process is being performed. 
     A description will now be given of a case in which a request for recording data on the optical disc  1  is made during the above-mentioned formatting process.  FIG. 5  is a flowchart of the formatting process performed as a background process when a request for recording is made during the formatting process. 
     Immediately after the formatting process for the optical disc  1  is started, the controller  9  outputs, in step S 11 , a message to a host computer so as to notify a user (the host computer) that the formatting process has been completed. Then, in step S 12 , an actual formatting operation is performed as a background process of the host computer. In the formatting operation, the entire area or a designated area of the optical disc  1  is filled by packets having a fixed length. It is then determined, in step S 13 , whether or not a request for recording is sent from the host computer. 
     If it is determined, in step S 13 , that a request for recording is not sent from the host computer, the routine proceeds to step S 15 . On the other hand, if it is determined, in step S 13 , that a request for recording is sent from the host computer, the routine proceeds to step S 14 . In step S 14 , the formatting operation is temporarily stopped so as to record a user data packet. After the recording of the user data packet is completed, the routine proceeds to step S 15 . 
     In step S 15 , it is determined whether or not the area to be formatted is filled by the packets. If the area is not filled by the packets, the routine returns to step S 12 . If it is determined that the entire area to be formatted is filled by the packets, the routine is ended. 
     According to the above-mentioned formatting process, a recording operation can be performed any time the formatting operation is being progressed. 
     However, if the data is recorded in an unformatted area where the fixed packets are not yet recorded by the formatting process being performed, it is possible that fixed packets are overwritten on the recorded data after the formatting process is restarted. This results in erasure of the recorded data. In order to avoid such a problem, the optical disc recording and reproducing apparatus according to the present invention performs a formatting process shown in  FIG. 6 . 
       FIG. 6  is a flowchart of the formatting process for preventing a data recorded area from being formatted. 
     Immediately after the formatting process for the optical disc  1  is started, and before an background formatting operation of step S23, the controller  9  outputs, in step S 21 , a message to a host computer so as to notify a user (the host computer) that the formatting process has been completed. It is then determined, in step S 22 , whether or not a user data packet has been recorded. If it is determined that the user data packet has been recorded, the routine proceeds to step S 24 . On the other hand, if it is determined that the user data packet has not been recorded, the routine proceeds to step S 23 . In step S 23 , an actual formatting operation is performed as a background process of the host computer. In the formatting operation, the entire area or a designated area of the optical disc  1  is filled by packets having a fixed length. 
     It is then determined, in step S 24 , whether or not a request for recording is sent from the host computer. If it is determined, in step S 24 , that a request for recording is not sent from the host computer, the routine proceeds to step S 27 . On the other hand, if it is determined, in step S 24 , that a request for recording is sent from the host computer, the routine proceeds to step S 25  in which the formatting operation is temporarily stopped so as to record a user data packet. After the recording of the user data packet is completed, the routine proceeds to step S 26 . In step S 26 , the formatting operation is restarted and an address of the area in which the user data packet has been recorded is stored, and the routine proceeds to step S 27 . 
     In step S 27 , it is determined whether or not the area to be formatted is filled by the packets having a fixed length. If the area is not filled by the packets, the routine returns to step S 22  so as to determine whether or not the user data packet has been recorded based on the address stored in step S 26 . If the user data packet has been recorded, the formatting process is continued while excluding the recorded area from being formatted. If the user data packet has not been recorded, the fixed packets are recorded. Accordingly, the process of steps S 22  to S 26  is repeated, and the routine is ended after the entire area to be formatted is filled by the fixed packets. 
     According to the above-mentioned formatting process, the fixed packets are not overwritten on the data which has been recorded while the formatting process is being performed. Thus, the recorded data is prevented from being undesirably erased after the formatting process is restarted. 
     A description will now be given of a case in which a request for reproduction of data is made while the formatting operation is being performed.  FIG. 7  is a flowchart of a process when a request for reproduction of data is made while the formatting operation is being performed as a background process in the optical disc recording and reproducing apparatus shown in  FIG. 1 . 
     In the process shown in  FIG. 7 , immediately after the formatting process for the optical disc  1  is started, the controller  9  outputs, in step S 31 , a message to a host computer so as to notify a user (the host computer) that the formatting process has been completed. Then, in step S 32 , an actual formatting operation is performed as a background process of the host computer. In the formatting operation, the entire area or a designated area of the optical disc  1  is filled by packets having a fixed length. It is then determined, in step S 33 , whether or not a request for reproducing data is sent from the host computer. 
     If it is determined, in step S 33 , that a request for reproducing data is not sent from the host computer, the routine proceeds to step S 35 . On the other hand, if it is determined, in step S 33 , that a request for reproducing data is sent from the host computer, the routine proceeds to step S 34 . In step S 34 , the formatting operation is temporarily stopped so as to reproduce data recorded on a designated area. After the reproduction of the data is completed, the routine proceeds to step S 35 . 
     In step S 35 , it is determined whether or not the area to be formatted is filled by the fixed packets. If the area is not filled by the fixed packets, the routine returns to step S 32  so as to repeat the process of steps S 32  to S 34 . If it is determined that the entire area to be formatted is filled by the fixed packets, the routine is ended. 
     According to the above-mentioned formatting process, a reproducing operation can be performed any time the formatting operation is being progressed. 
     If the fixed packets have not yet been recorded in the designated area in which the user data to be reproduced is recorded in the formatting operation performed as a background process, a reproducing operation cannot be performed since there is no packet to be reproduced. However, in order to have the user be unconscious of the formatting process being performed as a background process, it is better to reproduce data recorded in an unformatted area. Accordingly, in the optical disc recording and reproducing apparatus according to the present embodiment, data recorded in the unformatted area can be also reproduced while the formatting operation is being performed. 
       FIG. 8  is a flowchart of a process for performing a reproducing operation with respect to an unformatted area while the formatting operation is being performed as a background process. 
     In the process shown in  FIG. 8 , immediately after the formatting process for the optical disc  1  is started, the controller  9  outputs, in step S 41 , a message to a host computer so as to notify a user (the host computer) that the formatting process has been completed. Then, in step S 42 , an actual formatting operation is performed as a background process of the host computer. In the formatting operation, the entire area or a designated area of the optical disc  1  is filled by packets having a fixed length. It is then determined, in step S 43 , whether or not a request for reproducing data is sent from the host computer. 
     If it is determined, in step S 43 , that a request for reproducing data is not sent from the host computer, the routine proceeds to step S 47 . On the other hand, if it is determined, in step S 43 , that a request for reproducing data is sent from the host computer, the routine proceeds to step S 44 . It is then determined, in step S 44 , whether or not a packet has been recorded in the area (designated area) from which data is requested to be reproduced. 
     If it is determined, in step S 44 , that the packet has been recorded, the routine proceeds to step S 45  so as to reproduce the data from the recorded packet, and the routine proceeds to step S 47 . On the other hand, if it is determined that the packet has not been recorded, the routine proceeds to step S 46 . In step S 46 , pseudo-data such as ALL-0 (all zero data) which is previously stored in a memory is reproduced, and the routine proceeds to step S 47 . 
     As mentioned above, if data has not been recorded in the packet from which data is requested to be reproduced, the pseudo-data is reproduced and output so as to enable a reproducing operation as if the formatting process has ended. 
     In step S 47 , it is determined whether or not the area to be formatted is filled by the fixed packets. If the area is not filled by the fixed packets, the routine returns to step S 42  so as to repeat the process of steps S 42  to S 46 . If it is determined that the entire area to be formatted is filled by the fixed packets, the routine is ended. 
     According to the above-mentioned formatting process, if data has not been recorded in the packet from which data is requested to be reproduced while the formatting operation is being performed, a reproducing operation can be performed by using the pseudo-data. Thus, the reproducing operation can be performed without the user being conscious of the formatting process being performed as a background process. 
     Additionally, when the fixed packets have not been recorded in the designated area by the formatting process, previously prepared information is output as a result of reproduction. Accordingly, a reproducing operation can be substitutionally performed even when a reproducing operation cannot be performed due to the fact that the formatting operation on the area subjected to the reproduction by interrupting the formatting process has not ended. 
     A description will now be given of a process when an instruction for ejection of the optical disc is provided while the formatting operation is being performed in the optical disc recording and reproducing apparatus according to the present embodiment. 
     If the optical disc  1  is ejected while the formatting process is being progressed, the formatting process cannot be continued. Additionally, the formatting of the ejected optical disc is incomplete and a recording and reproducing operation cannot be performed on the optical disc. 
     Accordingly, in the optical disc recording and reproducing apparatus according to the present embodiment, the optical disc  1  is prevented from being ejected when the formatting process is being performed. 
       FIG. 9  is a flowchart of a process when an instruction for ejecting an optical disc is provided during the formatting operation in the optical disc recording and reproducing apparatus according to the present embodiment. 
     In the process shown in  FIG. 9 , immediately after the formatting process for the optical disc  1  is started, the controller  9  outputs, in step S 51 , a message to a host computer so as to notify a user (the host computer) that the formatting process has been completed. Then, in step S 52 , an actual formatting operation is performed as a background process of the host computer. In the formatting operation, the entire area or a designated area of the optical disc  1  is filled by packets having a fixed length. It is then determined, in step S 53 , whether or not a request for ejecting the optical disc is sent from the host computer. 
     If it is determined, in step S 53 , that a request for ejecting the optical disc is not sent from the host computer, the routine proceeds to step S 55 . On the other hand, if it is determined, in step S 53 , that a request for ejecting the optical disc is sent from the host computer, the routine proceeds to step S 54 . In step S 54 , the formatting operation is continued without ejecting the optical disc  1  and an error message is output to the host computer, and the routine proceeds to step S 55 . 
     In step S 55 , it is determined whether or not the area to be formatted is filled by the fixed packets. If the area is not filled by the fixed packets, the routine returns to step S 52  so as to repeat the process of steps S 52  to S 54 . If it is determined that the entire area to be formatted is filled by the fixed packets, the routine is ended. 
     As mentioned above, the optical disc  1  is not ejected when the formatting operation is being performed so that a recording and reproducing operation is prevented from not being performed due to the incomplete formatting. 
     It should be noted that the above-mentioned formatting process may be performed in accordance with programs stored in a memory provided in the controller  9 . The program data may be stored in a CD-ROM which is readable by the optical disc recording and reproducing apparatus, or may be supplied from the host computer via the interface  10 . 
     The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from the scope of the present invention. 
     The present application is based on Japanese priority application No.9-227921 filed on Aug. 25, 1997, the entire contents of which are hereby incorporated by reference.