Apparatus and method for recording and erasing user data on a recordable optical disc

An information recording apparatus includes: a first memory which stores synchronization data for updating data on a recordable optical disc and/or adding data to the recordable optical disc; a second memory which stores erasure information indicating data to be erased; and a controller which controls addition, update, and erasure of data on the optical disc. The controller records the synchronization data onto the optical disc. After recording the synchronization data, the controller records, onto the optical disc, management information indicating the state of the optical disc on which the synchronization data has been recorded and the state of the optical disc resulting from erasure according to the erasure information. Subsequently, the controller closes the session. After closing the session, the controller physically erases the data to be erased which has been recorded on the optical disc.

BACKGROUND

1. Technical Field

The present disclosure relates to a method and apparatus for erasing data recorded on a recordable optical disc.

2. Description of the Related Art

Recordable optical discs such as digital versatile discs recordable (DVD-R) and Blu-ray discs recordable (BD-R) are recording media on which recording marks that have been recorded once are not rewritable. Unexamined Japanese Patent Publication No. 2017-033621 discloses an information recording and reproducing apparatus which erases data recorded on a recordable optical disc.

The information recording and reproducing apparatus disclosed in Unexamined Japanese Patent Publication No. 2017-033621 includes: a memory storing a database for managing data recorded on an optical disc and history data related to said data; and a controller which controls data recording, update, and erasure on the optical disc. The history data is data that has not yet been updated in the case where data recorded on the optical disc is updated. When erasing subject data recorded on the optical disc, the controller determines whether or not there is at least one piece of history data related to the subject data, and when there is at least one piece of history data related to the subject data, erases, on the optical disc, the subject data and the history data related to the subject data. With this configuration, not only data to be erased, but also history data related thereto, are automatically detected and erased. This improves user convenience in the erasure process.

SUMMARY

One aspect of the present disclosure is an information recording apparatus capable of erasing user data recorded on a recordable optical disc. The information recording apparatus includes: a first memory which stores synchronization data for updating user data on the optical disc and/or adding user data to the optical disc; a second memory which stores erasure information indicating user data to be erased; and a controller which controls addition, update, and erasure of user data on the optical disc. The controller records the synchronization data onto the optical disc. After recording the synchronization data, the controller records, onto the optical disc, management information indicating the state of the optical disc on which the synchronization data has been recorded and the state of the optical disc resulting from erasure according to the erasure information. Subsequently, the controller closes the session. After closing the session, the controller physically erases the data to be erased which has been recorded on the optical disc.

One aspect of the present disclosure is a data erasure method for erasing user data recorded on a recordable optical disc. According to the data erasure method, synchronization data for updating user data on the optical disc and/or adding user data to the optical disc is generated, and erasure information indicating user data to be erased is generated. Furthermore, the synchronization data is recorded onto the optical disc. After the synchronization data is recorded, management information indicating the state of the optical disc on which the synchronization data has been recorded and the state of the optical disc resulting from erasure according to the erasure information is recorded onto the optical disc. Subsequently, the session is closed. After the session is closed, the data to be erased which has been recorded on the optical disc is physically erased.

According to the information recording apparatus and the erasure method in the present disclosure, after a session is closed, the process of physically erasing data is performed on data to be erased. Thus, even when an erasure operation is interrupted due to malfunctioning of a drive during physical data erasure, the subsequent recording and reproducing operations for the optical disc are possible because the session has been closed.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments will be described in detail with reference to the drawings as necessary. However, there are instances where overly detailed description is omitted. For example, detailed description of well-known matter, overlapping description of substantially identical elements, etc., may be omitted. This is to prevent the subsequent description from becoming unnecessarily redundant, and thus facilitate understanding by a person having ordinary skill in the art.

Note that the inventor(s) provides the accompanying drawings and the subsequent description so that a person having ordinary skill in the art is able to sufficiently understand the present disclosure, and is not intended to limit the scope of the subject matter recited in the claims.

First Exemplary Embodiment

FIG. 1illustrates a configuration of information recording system100according to the present exemplary embodiment. InFIG. 1, information recording system100includes information recording apparatus20and storage apparatus40. The information recording system100is connected to client apparatus10via network200.

Client apparatus10is a computer which uses functions, data, etc., provided by information recording system100according to input from a user. According to the user input, client apparatus10issues various commands to information recording system100. For example, client apparatus10issues a command for recording a file (user data) to storage apparatus40, a command for reading a file recorded on storage apparatus40, and a command for erasing a file recorded on storage apparatus40.

Information recording apparatus20records data onto a recording medium (optical disc) in storage apparatus40or reads data from the recording medium, for example, by controlling storage apparatus40according to the command received from client apparatus10.

Information recording apparatus20includes: controller21which controls the whole operation of information recording apparatus20; display23which displays various information; inputter24which receives user input; and data memory22in which data and a program are stored. Furthermore, information recording apparatus20includes: communication interface26which allows connection of an external device; and network interface25which allows connection to network200.

Display23is, for example, a liquid-crystal display or an organic electroluminescent (EL) display. Inputter24includes various members which are operated by a user such as a keyboard, a mouse, a touch pad, a touch panel, and a button.

Communication interface26is a circuit (module) for connecting storage apparatus40to information recording apparatus20. Communication interface26performs communication in accordance with communication standards such as serial attached SCSI (SAS).

Network interface25is a circuit (module) for connecting information recording apparatus20to a network, for example, a local area network (LAN) or a wide area network (WAN), via a wired or wireless communication line. Network interface25performs communication complying with communication standards such as IEEE802.3, IEEE802.11a/11b/11g/11ac, and WiFi.

Data memory22is a recording medium which stores a parameter, data, a control program, and the like necessary for providing a predetermined function, and is in the form of hard disk drive (HDD). Data memory22may be in the form of a solid-state device (SSD). As described later, data memory22operates as a memory which stores erasure list33(refer toFIG. 2) and cache34(refer toFIG. 2) which temporarily stores data to be recorded onto optical disc101and data read from optical disc101.

Controller21includes a central processing unit (CPU) or a microprocessor (MPU) and provides a predetermined function by executing a control program (software). The control program is stored, for example, in data memory22or read-only memory (ROM) (not illustrated in the drawings).

Furthermore, information recording apparatus20includes random-access memory (RAM) (not illustrated in the drawings) including a semiconductor device such as dynamic random-access memory (DRAM) or static random-access memory (SRAM). The RAM temporarily stores data and functions as a working area for controller21.

Storage apparatus40stores optical disc101, which is a recording medium, and records and reproduces data on optical disc101according to a control of information recording apparatus20. Storage apparatus40includes controller42, changer44, and optical disc drive46Controller42controls the whole operation of storage apparatus40. Controller42includes CPU or MPU and provides a predetermined function by executing a control program (software). Alternatively, the functions of controller42may be provided by controller21. Optical disc drive46writes data onto optical disc101and reads data from optical disc101. Changer44loads optical disc101into optical disc drive46. Optical disc101is a recordable optical disc such as DVD-R or BD-R.

FIG. 2illustrates a function configuration of information recording apparatus20according to the present exemplary embodiment. Each element (function) of information recording apparatus20illustrated inFIG. 2is provided by controller21executing a control program.

Client apparatus10receives user input through a Web browser, such as the Internet Explorer developed by Microsoft Corporation, as a graphical user interface (GUI). A user can input (instruct) recording, transfer, and/or reproduction of user data on optical disc101to information recording system100via such GUI. In this case, client apparatus10transmits information based on the hypertext transfer protocol (HTTP) to information recording system100. Furthermore, client apparatus10can instruct data recording, erasure, etc., to information recording system100(optical disc101) using a user interface (GUI) for file system (FS) access. In this case, client apparatus10transmits a command based on a common internet file system (CIFS) or a network file system (NFS) to information recording apparatus20.

HTTP module31is a function which receives the information transmitted from client apparatus10according to the HTTP protocol. CIFS module32is a function which receives the command, data, etc., based on the CIFS from client apparatus10. For example, an erasure command for erasing a file may be received via HTTP module31, and a command for updating (rewriting) a file may be received via CIFS module32. In the case of using the NFS, the same or similar functions are obtained by replacing CIFS module32with an NFS module.

Cache34is a means which temporarily stores data to be written onto optical disc101. Cache34is provided using data memory22.

Virtual management information35is a file system which manages a virtual state of a file when the data stored in cache34is reflected in optical disc101. In other words, virtual management information35is a file system which logically manages the state of a file on optical disc101that is to be modified according to an instruction from client apparatus10, but has not yet been actually modified.

In contrast, management information37is a file system which manages the file (data) recorded on optical disc101loaded in optical disc drive46. In other words, management information37indicates an actual state of a file (data) on optical disc101. By referring to management information37, information recording apparatus20can recognize the position of data recorded on optical disc101and the position of the terminal end of a data recorded area. Virtual management information35and management information37are for managing the file recorded on optical disc101in accordance with the ISO 9660 standard as described later (details will be described later).

Web application36is a function which provides a main operation of information recording apparatus20, which will be described later.

Scheduler38is a function which performs a file synchronization process (details will be described later) on optical disc101according to a schedule. The schedule is set, for example, by a manager. In the schedule, a time slot (start and end points in time) in which the synchronization process is performed on optical disc101is set. In accordance with the set schedule, a synchronization process for reflecting, in optical disc101, virtual management information35and the data stored in cache34is performed on optical disc101. Information recording apparatus20according to the present exemplary embodiment performs a file physical erasure process after this synchronization process.

Erasure list33(one example of erasure information) is for managing a file to be erased.FIG. 3illustrates a configuration example of erasure list33. Erasure list33is for managing a file ID, a file name, and a path indicating a file storage location, of a file to be erased.

Optical disc101according to the present exemplary embodiment is a recordable recording medium.FIG. 4illustrates a logical configuration (area) of optical disc101. Optical disc101, which has the shape of a circular plate, includes at least one recording layer on which information can be recorded and reproduced. This recording layer includes: grooves (pits) formed spirally from the center; and physical tracks in either the grooves (pits) or lands (areas between the grooves). Each of the physical tracks includes a plurality of finely divided blocks403. The grooves (pits) of the physical tracks are formed by wobbling which includes address information (physical address) indicating a specific position on the disc. Note that the physical tracks may be provided on both the grooves and the lands to record information so that the recording density improves.

The width (track pitch) of each of the physical tracks is 0.32 μm, for example, on a Blu-ray disc (BD) (registered trademark).

Block403is a unit of error correction and is the minimum unit of data on which recording and reproduction operations are performed. The size of block403is 32 Kbyte on a DVD (registered trademark) and 64 Kbyte (=1 cluster) on a BD, for example. When a sector (2 Kbyte), which is the minimum unit of data on optical disc101, is used as notation, 1 cluster equals 32 sectors. Note that “cluster” and “block” will be hereinafter used with the same meaning.

Optical disc101includes data area405formed spirally from the inner perimeter toward the outer perimeter. Data is continuously recorded in this data area405from the inner perimeter toward the outer perimeter. In optical disc101according to the present exemplary embodiment, data is recorded in compliance with the ISO 9660 format. Specifically, in data area405, management information60for managing the file recorded on optical disc101and file data (hereinafter referred to as “user data”)50are recorded in each session, as illustrated inFIG. 5.

Management information60includes system area61, volume descriptor set62, path table63, and directory record64. System area61is a 16-sector region from the beginning and is prepared for the system. Volume descriptor62holds volume-related information (such as a volume or creator name, the position of path table63or a root directory, and boot information). Path table63is a table in which information of the entire directory in the volume (such as a directory name, a directory position, and a parent directory) is arranged in the breadth first search order. Directory record64holds information about a file, a subdirectory, and the like (such as a file name, a file position, and a size), as in a general file system.

Operations of information recording system100having the above-described configuration will be described. When receiving user input for recording, reproduction, etc., of a file on information recording system100, client apparatus10transmits, to information recording apparatus20, information (hereinafter referred to as a “command”) indicating said input. Information recording apparatus20in information recording system100receives the command from client apparatus10. According to the received command, controller21in information recording apparatus20provides an instruction to storage apparatus40. Storage apparatus40(controller42) records, reproduces, etc., data on optical disc101according to the instruction from information recording apparatus20.

[1-2-1. Recording of Management Information and User Data]

With reference toFIGS. 6A and 6B, recording the management information and the user data onto optical disc101will be described.

In the case of recording the user data onto optical disc101first, management information60afor managing the user data (file set) to be recorded onto optical disc101is recorded in an area starting from lead position P0of a data area of optical disc101, as illustrated inFIG. 6A. Subsequently, user data50a(including data of at least one file) is recorded in an area continuing from the area in which management information60ais recorded. When recording of user data50ais completed, information indicating position P1of the terminal end of the data recorded area on optical disc101(hereinafter referred to as a “session end position”) is recorded in management information60a. In the case ofFIG. 6A, the information indicating position P1of the terminal end of the area in which management information60aand user data50ahave been recorded is recorded in management information60a. In this way, the session end position is recorded in management information60a; thus, the session is closed.

Thereafter, in the case of adding new data, last session end position P1is recognized with reference to management information60aand, as illustrated inFIG. 6B, new management information60bis recorded in the area continuing from last session end position P1, and user data50bis recorded following management information60b. When recording of user data50bis completed, information indicating new session end position P2is recorded in management information60b. Thus, the new session is closed.

In this way, the management information and the user data are sequentially recorded every time data is added (or updated). Thus, the management information and the data are recorded in each session. At this time, information in the volume descriptor of the last session is merged with volume descriptor62of the latest session. Information in path table63and directory record64of the last session is also merged with the latest information. A file is accessed with reference to volume descriptor62, path table63, and directory record64all recorded in the latest session. Information indicating the lead position, that is, the starting address, of the latest session is recorded in a predetermined area on the inner perimeter or the outer perimeter of optical disc101. By referring to this information, it is possible to recognize the lead position of the latest session.

In the case of adding a new file or rewriting (updating) a part of a file on optical disc101according to the command from client apparatus10, information recording system100first records, onto cache34, data to be added or update data (hereinafter referred to as “synchronization data”) before adding, etc., the file to optical disc101.

In other words, cache34stores synchronization data which is data to be added and/or an update data portion that have been received from client apparatus10. Thereafter, according to the command received from client apparatus10, file addition or update is performed using the synchronization data on cache34. The file on cache34is managed according to virtual management information35.

Controller21performs a process of reflecting, in optical disc101, the state of virtual management information35and the data on cache34. Furthermore, management information37is updated so that the management state of the updated file is managed. A series of these processes is called “the synchronization process”. Through the synchronization process, the state of the file (data) stored on cache34which is managed according to virtual management information35is reflected in the physical data recorded on optical disc101. Optical disc101is placed in the state where the file addition, update, or the like has been performed according to the command from client apparatus10. After the synchronization process, controller21causes storage apparatus40to modify (specifically, physically erase) the file (data) to be eased on optical disc101into the state where the data is unreadable.

In this way, when receiving the command from client apparatus10, information recording system100performs data update or the like on cache34first. Subsequently, the synchronization process is performed on optical disc101so that the content on cache34is reflected in optical disc101. Thus, even when more than one command is received and the data on cache34is updated more than one time, processes corresponding to more than one command can be reflected in optical disc101through one synchronization process. Accordingly, the frequency of loading optical disc101into optical disc drive46can be reduced, and the efficiency of the process of recording onto optical disc101can be increased. In particular, when the number of optical discs101on which data may be recorded is large relative to the number of optical discs on which data can be simultaneously written by optical disc drive46, the frequency of loading optical disc101into optical disc drive46is reduced.

With reference to the flowchart inFIG. 7, the flow of a file update process in information recording apparatus20upon reception of an update command will be described.

Controller21in information recording apparatus20receives an update command from client apparatus10(S11). In the update command, the file name of a file to be updated, the position of data to be updated, the length of the data to be updated, and the data to be updated are designated. Controller21updates cache34and virtual management information35by updating the file according to the update command (S12, S13). Specifically, controller21adds, to cache34, the new file updated according to the update command (S12). When the update is performed, the file before the update is deleted, and the file after the update is recorded on the disc, in an area different from where the file before the update is located. Therefore, controller21updates virtual management information35so that virtual management information35indicates the state of the file after the update (S13).

Subsequently, the synchronization process (S14) is performed to synthesize (match) the logical state of optical disc101which is managed according to virtual management information35and the actual physical state of optical disc101. The file update is reflected in optical disc101through the synchronization process. The synchronization process may be performed at the timing freely designated by a user or may be performed sequentially after an update-related process on virtual management information35or may be performed at a preset point in time by the function of scheduler38.

Processes on optical disc101upon the file update through the synchronization process will be described. Since optical disc101is a recordable optical disc, data that has been once recorded on optical disc101cannot be updated (rewritten) in the same physical position on the disc. Thus, upon the file update, a file is recorded onto optical disc101as follows.

With reference toFIGS. 8A and 8B, the processes performed on optical disc101upon updating (rewriting) the file already recorded in a user data area of optical disc101(hereinafter referred to as a “subject file”) will be described in detail.

Assume that as illustrated inFIG. 8A, management information60aand user data50ahave already been recorded in the data area of optical disc101. The case where user data50aincludes data of a plurality of files and one file51aamong them is updated will be described as an example.

In the case of updating file51a, as illustrated inFIG. 8B, management information60bfor managing the state of a file on optical disc101after file update and data of updated file51bgenerated by updating file51aare recorded in the free space in the data area of optical disc101.

Specifically, updated file51bis generated by updating (rewriting) file51aaccording to the update command. This updated file51bis recorded at a location different from where original file51abefore the update is recorded. Accordingly, the content of management information60afor managing files on optical disc101is rewritten, and new management information60bis generated. New management information60bis recorded in the area continuing from last session end position P1. Subsequently, updated file51bis recorded following management information60b.

Note that since original file51afor updated file51bis erased, management information60bis generated in such a way as to manage the state after original file51has been erased.

In this way, new entity data of the updated file is recorded on optical disc101.

With reference toFIG. 9, file erasure by information recording system100will be described.FIG. 9is a flowchart showing the flow of logical file erasure.

When receiving an erasure command from client apparatus10(S31), information recording apparatus20in information recording system100logically erases the file to be erased. Specifically, controller21erases the file on virtual management information35(S32) and registers the file to be erased in erasure list33(S33). Thus, the file to be erased is logically erased. Mere logical erasure of the file means that the entity data of the file is still effectively present on optical disc101and thus, the data of said file can be reproduced (read).

Subsequently, controller21identifies the file to be erased with reference to erasure list33, and physically erases the identified file (S34). The physical erasure means rewriting the data of the file to be erased so that the file is physically unreadable. The data of the erased file cannot be reproduced (read) after the physical erasure.

As described above, when the erasure command is received, the file to be erased is erased in virtual management information35and is registered in erasure list33. In this state, the file to be erased is merely logically erased in virtual management information35; the content of the file can be read. Subsequently, controller21physically erases the file to be erased which has been registered in erasure list33. Thus, the data of the file is physically erased (made unreadable).

The physical erasure is achieved by placing the file to be erased in an unreadable state. For example, at least part of the data of the file to be erased is rewritten with a predetermined erasure pattern to make the file unreadable. Specifically, the file to be erased is made unreadable by rewriting at least one of the entity data of the file to be erased, the synchronization data, and data for error correction with the predetermined erasure pattern. Rewriting is performed, for example, by deforming, in the recording layer of optical disc101, a recording mark included in the data of the file to be erased so that an elongated recording mark is used, as illustrated inFIG. 10. As a result of deformation of the recording mark, the file is unreadable afterward, which substantially means that the file has been physically erased.

The timing for the physical erasure may be freely designated by a user or may be scheduled in advance or may be in parallel with the synchronization process.

[1-2-5. Physical Erasure Associated with Synchronization Process]

Hereinafter, physical file erasure in the case where the synchronization process is performed at the scheduled timing will be described.FIG. 11AtoFIG. 11Cillustrate the physical file erasure in the case where the synchronization process is performed at the scheduled timing. Assume that as illustrated inFIG. 11A, files52a,52b, and52chave been logically erased as the files to be erased. Specifically, this is a situation in which although the state of files52a,52b, and52cmanaged according to virtual management information35indicates that these files have been erased, the physical data on optical disc101have not been erased. When the synchronization process is performed in this situation, synchronization data53ais added so that the state of the files managed according to virtual management information35is reflected in optical disc101. Thus, prior to recording of synchronization data53a, management information60bfor managing the new file state is added. Management information60bis for managing the state of optical disc101after files52a,52b, and52chave been erased and synchronization data53ahave been reflected. Subsequently, when files52a,52b, and52care physically erased on optical disc101, the data of files52a,52b, and52care made unreadable on optical disc101.

FIG. 12is a flowchart showing the synchronization process which is performed at the scheduled timing and the physical erasure associated with the synchronization process. Hereinafter, the synchronization process which is performed at the scheduled timing and the physical erasure which is performed in association with the synchronization process will be described with reference toFIG. 12.

Controller21determines, by the function of scheduler38, whether or not the current time has reached a point in time at which the synchronization process starts (S61). When determining that the current time has reached the synchronization process start time (S61), controllers21starts the synchronization process.

First, controller21checks with storage apparatus40whether or not optical disc101is in the online state (in other words, whether or not optical disc101has been loaded in optical disc drive46) (S62). When optical disc101is not in the online state, controller21instructs storage apparatus40to load optical disc101into optical disc drive46(S66).

Subsequently, controller21performs the synchronization process on optical disc101according to virtual management information35and cache34(S63). In the synchronization process, controller21adds, modifies, etc., a file (entity data), management information, or the like on optical disc101so that the state of the data which is managed according to virtual management information35is reflected in optical disc101. For example, as illustrated inFIG. 11B, management information60bfor managing the state after the synchronization is newly recorded onto optical disc101.

After the end of the synchronization process, controller21closes the session (S64). When the session is closed, the session end position, that is, the position of the terminal end of the area in which the data has been recorded on optical disc101(for example, position P2inFIG. 11B) is fixed. Controller21instructs storage apparatus40to record, in the management information (for example, management information60b), information indicating the session end position. Thus, the information indicating the session end position is recorded in the management information. Upon recording data onto optical disc101next, the data recording start position of the next session can be identified with reference to the information indicating session end position P2recorded in management information60b.

As described earlier, regarding the file erasure, when the synchronization process is performed and the content of virtual management information35is reflected, the file to be erased is merely logically erased (files52a,52b, and52cinFIG. 11B). Thus, after the session is closed, controller21physically erases the file to be erased (S65). Specifically, with reference to erasure list33, controller21searches for the file to be erased and instructs storage apparatus40to physically erase the file (S65). According to the instruction from controller21in information recording apparatus20, controller42in storage apparatus40physically erases, on optical disc101, the file indicated in the instruction (files52a,52b, and52cinFIG. 11C). The physically erased file is unreadable.

If the physical erasure is performed before the session is closed, the following problem may arise. When the physical erasure fails to be normally completed due to a device trouble or the like during the physical erasure, the session cannot be closed, and the information of the session end position is not recorded in the management information. Therefore, the session end position cannot be recognized; thus, no data can be added to optical disc101afterward though data reading (reproduction) is possible. In contrast, when the physical erasure is performed after the session is closed as in the present exemplary embodiment, the information of the session end position is recorded in the management information before the physical erasure. Therefore, even when the physical erasure fails to be normally completed, the information of the session end position can be read from the management information; thus, subsequent data reading and addition are possible.

In the present exemplary embodiment, the physical erasure is performed in association with the synchronization process as described above. Thus, in the state where optical disc101is loaded in optical disc drive46for the synchronization process, the physical exposure can be continuously performed. Therefore, it is not necessary to load optical disc101separately for the erasure process, and thus the waiting time for loading, the loading frequency, etc., can be reduced; the efficiency of the process of updating optical disc101can be improved as a whole.

As described above, information recording apparatus20according to the present exemplary embodiment is capable of erasing a file (that is, user data) recorded on recordable optical disc101. Information recording apparatus20includes: cache34or data memory22(an example of the first memory) which stores synchronization data (34) for updating user data on optical disc101and/or adding user data to optical disc101; data memory22(an example of the second memory) which stores erasure list33(an example of the erasure information) indicating user data to be erased; and controller23(an example of the controller) which controls addition, update, and erasure of user data on optical disc101. Controller21records the synchronization data onto optical disc101. After recording the synchronization data, controller21records, onto optical disc101, management information60a,60bindicating the state of optical disc101on which the synchronization data has been recorded and the state of optical disc101resulting from erasure according to erasure list33(S63). Subsequently, controller21closes the session (S64). After closing the session, controller21physically erases the data to be erased which has been recorded on optical disc101(S65). Furthermore, controller21erases the synchronization data stored in cache34or data memory22(an example of the first memory).

In the present exemplary embodiment, the data to be erased is physically erased after the session is closed. Thus, even when the physical erasure is interrupted due to malfunctioning of information recording apparatus20during the physical erasure of the data to be erased, since the closure of the session has been completed, recording and reproduction on the optical disc continue to be possible afterward.

When the session is closed, controller21may record, in management information60a,60bon optical disc101, the information indicating the position (P1, P2) of the terminal end of the data recorded area on optical disc101. Thus, even when the physical erasure is interrupted due to malfunctioning of information recording apparatus20during the physical erasure of the data to be erased, the position of the terminal end of the data recorded area on optical disc101can be recognized with reference to management information60a,60b.

Management information60a,60bmay be for managing, in compliance with the ISO 9660 standard, the data recorded on optical disc101.

FIG. 13AtoFIG. 13Gillustrate an example of the operation in which information recording apparatus20modifies the user data on optical disc101.

Assume that inFIG. 13A, client apparatus10provides, to information recording apparatus20, input for updating Data A, which is user data of File A recorded on optical disc101, to Data A′. Information recording apparatus20temporarily holds, in cache34, Data A′ as synchronization data corresponding to File A. When generating Data A′ to be held in cache34, information recording apparatus20may use Data A, which is data read from optical disc101. Furthermore, information recording apparatus20manages the state of File A using virtual management information35.

FIG. 13Billustrates the operation in which, after the input inFIG. 13A, client apparatus10provides input for reading File A to information recording apparatus20. Information recording apparatus20transfers, to client apparatus10, data corresponding to File A, on the basis of the synchronization data held in cache34, which is Data A′, with reference to virtual management information35. Thus, even in the state where the user data corresponding to File A on optical disc101has not yet been updated to Data A′, client apparatus10can obtain Data A′ as the user data corresponding to File A.

FIG. 13Cillustrates an example of the operation in which client apparatus10provides input for deleting File B to information recording apparatus20. Virtual management information35is for managing information indicating that File B on the optical disc has been deleted. For example, when client apparatus10provides input for reading File B to information recording apparatus20, information recording apparatus20notifies client apparatus10that File B is unreadable on optical disc101. Thus, even in the state where File B on optical disc101has not been physically erased, information recording apparatus20can perform substantially the same operation as in the case where File B has been deleted.

FIG. 13Dillustrates the operation performed when client apparatus10provides, to information recording apparatus20, input for updating the user data corresponding to File A from Data A′ to Data A″. With reference to virtual management information35, information recording apparatus20confirms that cache34is holding the synchronization data corresponding to File A. Information recording apparatus20updates Data A′, which is the synchronization data held in cache34that corresponds to File A, to Data A″. Thus, information recording apparatus20can virtually update File A without accessing optical disc101.

FIG. 13E,FIG. 13F, andFIG. 13Gillustrate the operation in which information recording apparatus20performs the synchronization process and the physical erasure on optical disc101.

As illustrated inFIG. 13E, information recording apparatus20opens a session for writing information onto optical disc101. With reference to virtual management information35, information recording apparatus20records, onto optical disc101, the synchronization data after update held in cache34. For example, Data A″, which is the user data corresponding to File A, is recorded onto optical disc101.

As illustrated inFIG. 13F, information recording apparatus20records the management information onto optical disc101with reference to virtual management information35. The management information includes information indicating the position of File A after update and information indicating that File B is not referable. After recording the management information onto optical disc101, information recording apparatus20closes the session. Thus, even in the state where the user data on optical disc101has not been physically erased, when optical disc101is reproduced by an ordinary method, update of the user data can be assumed to have been completed. This means that even if some failure occurs after the session is closed, it is possible to avoid damage to the logical data on optical disc101.

InFIG. 13G, data on optical disc101is physically erased with reference to erasure list33. Specifically, data on optical disc101that has been logically erased, but has not been physically erased is physically erased. Consequently, it becomes difficult to reproduce the erased information and the user data before update even when an unordinary method is used in an attempt to reproduce the data on optical disc101.

After closing the session inFIG. 13F, information recording apparatus20erases synchronization data that has been recorded on optical disc101among the synchronization data held in cache34(FIG. 13G).

As described above, information recording apparatus20according to the flowcharts inFIG. 7andFIG. 12is capable of reducing the possibility of damage to the logical data on optical disc101due to a failure occurring during physical erasure of the data on optical disc101.

Other Exemplary Embodiments

The first exemplary embodiment has been described above by way of example of techniques disclosed in the present application. The techniques according to the present disclosure, however, are not limited to the foregoing exemplary embodiment, and can also be applied to exemplary embodiments obtained by carrying out modification, substitution, addition, omission, etc. Furthermore, it is also possible to obtain a new embodiment by combining respective structural elements described in the above first exemplary embodiment.

In the above-described exemplary embodiments, the physical file erasure is performed at the time of execution of the synchronization process, but the physical erasure may be performed independently of the synchronization process. In other words, the physical erasure may be performed at any timing, i.e., not in association with the synchronization process.

In the above-described exemplary embodiments, the file system complying with the ISO 9660 standard is used as the management information for optical disc101, but the management information may be another file system. For example, the universal disk format (UDF) may be used.

In the above-described exemplary embodiments, erasure list33is used as the erasure information, the erasure information is not limited to erasure list33. Any information with which the file to be erased can be identified may be used as the erasure information.

In the above exemplary embodiments, controllers21and52are described as CPUs or MPUs which provide the predetermined functions in cooperation with software. However, dedicated electronic circuits designed to provide the predetermined functions may be used as controllers21and52. Specifically, CPUs, MPUs, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), and the like can be used as controllers21and52.

In the above exemplary embodiments, storage apparatus40including only one optical disc101is described in order to simplify description, but storage apparatus40may be configured to store more than one optical disc and switch, by changer44, the optical disc to be loaded into optical disc drive46.

Furthermore, in the above-described exemplary embodiments, the data to be erased is exemplified by a file, but an object that has been increasingly used in Swift or the like may become the subject to be erased.

The exemplary embodiments have been described above by way of example of techniques of the present disclosure. To this extent, the accompanying drawings and detailed description are provided.

Thus, the structural elements set forth in the accompanying drawings and detailed description may include not only structural elements essential to solve the problems but also structural elements unnecessary to solve the problems for the purpose of illustrating the above techniques. Thus, those unnecessary structural elements should not be deemed essential due to the mere fact that they appear in the accompanying drawings and the detailed description.

The above-described exemplary embodiments illustrate the techniques of the present disclosure, and thus various modifications, substitutions, additions, omissions, etc., are possible in the scope of the appended claims and the equivalents thereof.

The present disclosure is applicable to an apparatus capable of erasing data from a recordable optical disc.