WO2006001621A1

WO2006001621A1 - Optical disc having plurality of recording layers, and method and apparatus for recordin data thereon

Info

Publication number: WO2006001621A1
Application number: PCT/KR2005/001869
Authority: WO
Inventors: Kyung-Geun Lee; Wook-Yeon Hwang
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2004-06-23
Filing date: 2005-06-17
Publication date: 2006-01-05
Also published as: JP2012155840A; JP5084963B2; EP2109102A1; KR100667755B1; EP1766618A4; CN101819785A; RU2333548C1; US20050286399A1; US8351314B2; MXPA06015185A; CA2571525A1; CN101930762A; MY138702A; CN101930761B; CN101930761A; US20060203671A1; CN1981329B; US20060198266A1; CA2571525C; CN101819785B

Abstract

Provided are an optical disc having a plurality of recording layers, and a method and apparatus for recording data thereon. The optical disc has a plurality of recording layers, each recording layer including: a data area; a connecting area; and a remaining area. The data, connecting, and remaining areas are respectively disposed in a direction from an inner circumference of the optical disc to an outer circumference. An outer boundary of each of the data areas is determined according to an amount of data to be recorded. Locations of the connecting areas and the remaining areas are determined by a recording and/or reproducing apparatus according to the determination of the outer boundary of each of the data areas.

Description

OPTICALDISCHAVINGPLURALITYOFRECORDING

LAYERS,ANDMETHODANDAPPARATUSFORRECORDING

DATATHEREON Technical Field [1] The present invention relates to an optical disc, and more particularly, to an optical disc on which data can be recorded quickly and on which an exclusive region for a specified purpose can be selectively allocated at the outer circumference thereof, and a method of and an apparatus for recording data thereon. Background Art [2] Optical discs are used as data storage media of optical pickup devices for recording and reproducing data without contact. Two types of optical discs are compact discs (CDs) and digital versatile discs (DVDs), which differ according to recording capacity. Some are recordable, such as the 650MB CD-R, 650MB CD-RW, 4.7GB DVD+R/RW, 4.7GB DVD-RAM, and DVD-R/RW. Others are read-only, such as the 650MB CD and 4.7GB DVD-ROM. Furthermore, a next generation DVD whose recording capacity is over 15GB is under development. [3] Presently, the only type of conventional recordable DVD is a 4.7 GB single layer disc. However, DVD-ROMs are available in 8.5GB dual layer discs. In order to backup these 8.5GB discs, an 8.5GB recordable DVD is required. However, in this case, the recording time roughly doubles, which can be a disadvantage for the user. Although the recording speed can theoretically be improved, this would require im¬ provements in disc technology and therefore, a method of effectively recording data at a conventional speed is required to immediately introduce the 8.5GB recordable DVD to the market. [4] FIG. IA illustrates the structure of a conventional rewritable optical disc. FIG. IB illustrates the structure of a conventional read-only optical disc. The structure of a lead-out area of the rewritable optical disc shown in FIG. IA is almost the same as the structure of a lead-in area. [5] FIGS. 2A and 2B illustrate conventional methods of recording data on a dual recording layer disc. FIG. 2A shows the case where the recording direction is an opposite track pass (OTP), and FIG. 2B shows the case where the recording direction is a parallel track pass (PTP). [6] As shown in FIGS. 2A and 2B, user data is recorded on a recording layer Ll, and then the remaining user data is recorded on a recording layer L2. Pattern data having a lead-out attribute is recorded on an area on which the user data cannot be recorded, in the recording layer L2. Commonly, the area connecting data storage layers to each other is called a connecting area, to discriminate from the lead-out area and the lead-in area. The recording methods shown in FIGS. 2A and 2B can be applied to read-only and rewritable discs. [7] FIGS. 3A and 3B illustrate other conventional methods of recording data on a dual recording layer disc. FIG. 3A shows the case where the recording direction is an optical path track (OTP), and FIG. 3B shows the case where the recording direction is a parallel track pass (PTP). As shown in FIGS. 3A and 3B, if the total amount of data to be recorded is less than the total capacity of the two recording layers Ll and L2, then in order to record the same amount of data on each of the two recording layers Ll and L2, data is recorded up to a specified position before the lead-out area on each recording layer, and pattern data having the lead-out attribute is recorded on the remaining area. In particular, the pattern data having the lead-out attribute is recorded on to the outermost circumference of the disc. [8] FIGS. 4 A and 4B illustrate other conventional methods of recording data on a dual recording layer disc. FIG. 4A shows the case where the recording direction is the OTP, and FIG. 4B shows the case where the recording direction is the PTP. Like the recording methods shown in FIGS. 3A and 3B, the data recording methods shown in FIGS. 4A and 4B show the case where data is recorded up to a specified position before the lead-out area on each recording layer in order to record the same amount of data on each of the two recording layers Ll and L2, and pattern data having the lead- out attribute is recorded on the remaining area, when the total amount of data to be recorded is less than the total capacity of the two recording layers Ll and L2. However, unlike the recording methods shown in FIGS. 3 A and 3B which record the pattern data having the lead-out attribute on to the outermost circumference of the disc, the data recording methods shown in FIGS. 4 A and 4B record data only as far as necessary, and do not record the data on to the outermost circumference of the disc. [9] According to the conventional data recording methods described above, additional data recording time is required to record the pattern data having the lead-out attribute on the area on which user data cannot be recorded. [10] In the case of a recordable optical disc, a test area to record data for testing is allocated to the optical disc in order to record actual data at an optimum recording power before the actual data is recorded on the optical disc. However, in the case of an optical disc having a plurality of recording layers, since recording characteristics vary according to which recording layer data is recorded on first, the test area must be allocated considering the recording characteristics when the test area for an optimum power control (OPC) is allocated to the optical disc. In particular, when the test area is allocated to the outer circumference area of the optical disc, the characteristics of the outer circumference area must be considered. Also, the process is complicated by the fact that in an optical disc having a plurality of recording layers, the recording charac¬ teristics of the outer circumference area are worse than in an optical disc having a single recording layer. Furthermore, when the test area and an area having another purpose are allocated to the outer circumference area of the optical disc, the charac¬ teristics of the outer circumference area must also be considered. Disclosure of Invention Technical Solution [11] An embodiment of the present invention provides an optical disc having a plurality of recording layers on which data can be recorded quickly and on which an exclusive area for a specified purpose can be selectively allocated at the outer area. [12] An embodiment of the present invention also provides a data recording method and apparatus for recording data on an optical disc having a plurality of recording layers quickly, and selectively allocating an exclusive area for a specified purpose to the outer area. Advantageous Effects [13] According to an embodiment of the present invention, exclusive areas can be se¬ lectively allocated for a specified purpose, to allow data to be recorded quickly, and to allow data to be recorded reliably on the outer area of the optical disc. Description of Drawings [14] These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings of which: [15] FIG. IA illustrates the structure of a conventional rewritable optical disc; [16] FIG. IB illustrates the structure of a conventional read-only optical disc; [17] FIGS. 2 A and 2B illustrate conventional methods of recording data on a dual recording layer disc; [18] FIGS. 3A and 3B illustrate other conventional methods of recording data on a dual recording layer disc; [19] FIGS. 4A and 4B illustrate other conventional methods of recording data on a dual recording layer disc; [20] FIG. 5 illustrates the structure of an optical disc according to an embodiment of the present invention; [21] FIG. 6 illustrates a zone of a recording layer Ll affected by a beam focused on a recording layer L2 of the optical disc of FIG. 5; and [22] FIG. 7 is a block diagram of a data recording/reproducing apparatus according to an embodiment of the present invention. Best Mode [23] According to an aspect of the present invention, there is provided an optical disc having a plurality of recording layers, each recording layer including: a data area; a connecting area; and a remaining area. The data, connecting, and remaining areas are respectively disposed in a direction from an inner circumference of the optical disc to an outer circumference. An outer boundary of each of the data areas is determined according to an amount of data to be recorded. Locations of the connecting areas and the remaining areas are determined according to the determination of the outer boundary of each of the data areas . [24] According to another aspect of the present invention, there is provided an apparatus for recording/reproducing data, including: a write/read unit which transfers data with respect to an optical disc having a plurality of recording layers; and a controller which determines an outer boundary of a data area of each recording layer according to an amount of data to be recorded and which determines corresponding locations of a connecting area and a remaining area of each recording layer according to the de¬ termination of the outer boundary of each of the data areas . [25] According to another aspect of the present invention, there is provided a method of recording data on a plurality of recording layers, the method including: determining an outer boundary of a data area of each recording layer according to an amount of data to be recorded; and determining locations of a connecting area and a remaining area of each recording layer according to the determination of the outer boundary of each of the data areas. [26] According to another aspect of the present invention, there is provided a computer readable medium having recorded thereon a computer readable program for performing a method of recording data on a plurality of recording layers, the method including: determining an outer boundary of a data area of each recording layer according to an amount of data to be recorded; and determining locations of a connecting area and a remaining area of each recording layer according to the de¬ termination of the outer boundary of each of the data areas. [27] Additional and/or other aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the de¬ scription, or may be learned by practice of the invention. Mode for Invention [28] Reference will now be made in detail to an embodiment of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiment is described below in order to explain the present invention by referring to the figures . [29] FIG. 5 illustrates the structure of an optical disc according to an embodiment of the present invention. The optical disc shown in FIG. 5 is a dual layer rewritable optical disc having two recording layers Ll and L2. The recording layer Ll includes a lead-in area 110, a first data area 120, a first connecting area 130, a first non-usage area 140, a first buffer area 150, a first exclusive area 160, and a first non-recording area 170. The recording layer L2 includes a lead-out area 210, a second data area 220, a second connecting area 230, a second exclusive area 240, a second buffer area 250, a second non-usage area 260, and a second non-recording area 270. [30] A non-limiting example of the detailed structure of the lead-in area 110 is the structure shown in FIG. 1. The structure of the lead-out area 210 is similar to the structure of the lead-in area 110. However, it is to be understood that other structures can be used. [31] The first data area 120 and the second data area 220 are areas on which to record user data. Data having a specified pattern indicating the end of the first or second data area 120 or 220 is recorded on the first connecting area 130 and the second connecting area 230, respectively. A data recording/reproducing apparatus (such as that shown in FIG. 7) recognizes the respective first or second connecting area 130 or 230 after the first or second data area 120 or 220 by reading the data having the specified pattern. In general, data having a lead-out attribute is recorded as the data having the specified pattern. [32] The first exclusive area 160 and the second exclusive area 240 are used for a specific purpose by the data recording/reproducing apparatus. For example, the first exclusive area 160 and the second exclusive area 240 are test areas for an optimum power control (OPC). The OPC means that an optimum recording power is determined in the data recording/reproducing apparatus through a preliminary test, before the user data is recorded on the rewritable disc. However, the first exclusive area 160 and the second exclusive area 240 may be used for at least another purpose. For example, the first exclusive area 160 and the second exclusive area 240 may be used to record data indicating the time of recording and the type of data recording/reproducing apparatus. The data recording/reproducing apparatus determines the size of the first exclusive area 160 and the second exclusive area 240 and whether or not they are allocated. [33] When data is recorded on an optical disc having a plurality of recording layers, if the amount of user data to be recorded is less than the total recordable capacity of the optical disc, and if the amount of user data to be recorded is known to a data recording/ reproducing apparatus in advance, then the data recording/reproducing apparatus determines the size of each of the data areas 120 and 220 to record the same amount of user data on each of the plurality of recording layers. [34] Since the beginning locations of the data areas 120 and 220 are specified, then if the size of each of the data areas 120 and 220 is determined, the ending locations of the data areas 120 and 220 are also determined. If the locations of the data areas 120 and 220 are determined, the locations of the connecting areas 130 and 230 having a specified size are determined. Finally, it is determined whether or not to allocate the first exclusive area 160 and the second exclusive area 240. The size of each of the first exclusive area 160 and the second exclusive area 240 is determined by the data recording/reproducing apparatus later according to the usage frequency of the exclusive area 160 or 240. Since the beginning locations of the first exclusive area 160 and the second exclusive area 240 are specified, then if the size of each of the exclusive areas 160 and 240 is determined, ending locations of the exclusive areas 160 and 240 are also determined. [35] Various methods may be used to determine whether or not to allocate the first exclusive area 160 and the second exclusive area 240. For example, if the size of the first data area 120 and the second data area 220 are determined, then the locations of the connecting areas 130 and 230 having a specified size are determined. If the locations of the connecting areas 130 and 230 are determined, the size of each of remaining areas from the outer boundaries of the connecting areas 130 and 230 to the outermost circumference is calculated. The data recording/reproducing apparatus allocates the first exclusive area 160 or the second exclusive area 240 to the optical disc when the size of each of remaining areas is larger than a specified standard value. As a non-limiting example, 3% of the total amount of data that can be recorded on one recording layer Ll or L2 may be used as the specified standard value. However, it is to be understood that other amounts can be used. [36] When the first exclusive area 160 or the second exclusive area 240 is allocated, data indicating the fact is recorded on a specified area, e.g., the lead-in area 110. [37] The directions of the first exclusive area 160 and the second exclusive area 240 are opposite to each other, and the direction of each exclusive area 160 or 240 is opposite to that of the data area 120 or 220 in the recording layer Ll or L2 in which that exclusive area 160 or 240 exists. Referring to FIG. 5, the direction of the first data area 120 in the recording layer Ll is outward, and the direction of the first exclusive area 160 is inward. On the other hand, the direction of the second data area 220 in the recording layer L2 is inward, and the direction of the second exclusive area 240 is outward. [38] The first non-usage area 140 and the second non-usage area 260 are completely unused. In an optical disc having a plurality of rewritable recording layers, recording characteristics vary according to which recording layer is recorded first. In particular, the recording characteristics of the outer area of the optical disc are worse than in the inner area. Therefore, no data is recorded by designating an area of the recording layer L2 located at the same location with the first exclusive area 160 as the second non- usage area 260. Likewise, no data is recorded by designating an area of the recording layer Ll located at the same location with the second exclusive area 240 as the first non-usage area 140. [39] The first buffer area 150 and the second buffer area 250 are prepared considering influences caused by eccentricity of the optical disc and a beam focused on another recording layer. Like the first non-usage area 140 and the second non-usage area 260, no data is recorded on the first buffer area 150 and the second buffer area 250. [40] FIG. 6 illustrates a zone of the recording layer Ll affected by a beam focused on the recording layer L2. Referring to FIG. 6, when a beam 400 is focused on a specific position of the recording layer L2 through an objective lens 300 of a data recording/ reproducing apparatus, a zone of the recording layer Ll corresponding to a radius y is affected by the beam 400. The first buffer area 150 and the second buffer area 250 are allocated to a proper size considering the influence of the beam 400 radiated to record data on another recording layer and the eccentricity of the optical disc. [41] The first non-recording area 170 and the second non-recording area 270 are located on the outmost circumference of the disc and are designated as areas on which data is not recorded to compensate for bad recording characteristics. However, the first non- recording area 170 and the second non-recording area 270 may not be allocated. [42] An exemplary optical disc having dual recording layers has been described above. However, it is to be understood that the present invention is not limited to this example. Indeed, it is contemplated that the present invention may be applied to optical discs having more than two recording layers. [43] FIG. 7 is a block diagram of a data recording/reproducing apparatus according to an embodiment of the present invention. Referring to FIG. 7, the apparatus includes a write/read unit 1, a controller 2, and a memory 3. An optical disc 100 has the structure shown in FIG. 5 according to an embodiment of the present invention. [44] The write/read unit 1 records data on the optical disc 100 or reads the recorded data, under the control of the controller 2. User data to be recorded on the optical disc 100 is temporarily stored in the memory 3 under the control of the controller 2. Also, data read from the optical disc 100, or various kinds of control data generated during recording or reproducing, is stored in the memory 3. [45] Referring to FIGS. 5 and 7, the controller 2 determines the size and location of each area of the optical disc 100 as described above. In particular, the controller 2 determines the allocation and location of the first exclusive area 160 and the second exclusive area 240. [46] The operation of the controller 2 will now be described in more detail. The controller 2 determines the size of the first data area 120 and the second data area 220, to record the same amount of user data on each of a plurality of recording layers when the amount of user data to be recorded on the optical disc 100 is less than the total recordable capacity of the optical disc 100. [47] Since the beginning (i.e., start) locations of the data areas 120 and 220 are specified, then if the size of each of the data areas 120 and 220 is determined, the ending locations of the data areas 120 and 220 are determined. If the locations of the data areas 120 and 220 are determined, the locations of the connecting areas 130 and 230 having a specified size are automatically determined. [48] The controller 2 determines whether or not to allocate the exclusive areas 160 and 240 of the recording layers Ll and L2 according to a specified standard. For example, if the sizes of the first data area 120 and the second data area 220 are determined, and if the locations of the connecting areas 130 and 230 having a specified size are determined, the controller 2 can calculate the size of each of the remaining areas from the outer boundaries of the connecting areas 130 and 230 to the outermost cir¬ cumference. The controller 2 allocates the first exclusive area 160 or the second exclusive area 240 to the optical disc 100 when the size of each of remaining areas is larger than a specified standard value. As a non-limiting example, 3% of the total amount of data that can be recorded on one recording layer Ll or L2 may be used as the specified standard value. [49] When the first exclusive area 160 or the second exclusive area 240 is allocated, the controller 2 controls the write/read unit 1 to record data indicating that the first exclusive area 160 or the second exclusive area 240 has been allocated on a specified area, e.g., the lead-in area 110. [50] As described above, the directions of the first exclusive area 160 and the second exclusive area 240 are opposite to each other, and the direction of each exclusive area 160 or 240 is opposite to the direction of the data area 120 or 220 in the recording layer Ll or L2 in which that exclusive area 160 or 240 exists. [51] In an optical disc having a plurality of rewritable recording layers, the recording characteristics vary according to which recording layer is recorded first, and the recording characteristics of the outer area of the optical disc are worse than in the inner area. Therefore, the controller 2 designates an area of the recording layer L2 at the same location as the first exclusive area 160 as the second non-usage area 260. Likewise, the controller 2 designates an area of the recording layer Ll at the same location as the second exclusive area 240 as the first non-usage area 140. [52] The controller 2 allocates the first buffer area 150 and the second buffer area 250 considering influences caused by eccentricity of the optical disc and a beam focused on another recording layer. While described in terms of a recording/reproducing apparatus, it is to be understood that the apparatus need not perform both recording and reproduction. [53] Aspects of the present invention may be embodied in a general-purpose or a specific -purpose computer by running a program from a computer readable medium, including but not limited to storage media such as magnetic storage media (ROMs, RAMs, floppy disks, magnetic tapes, etc.), optically readable media (CD-ROMs, DVDs, etc.), and carrier waves (transmission over the internet). The present invention may be embodied as a computer readable medium having a computer readable program code unit embodied therein for causing a number of computer systems connected via a network to effect distributed processing. [54] Although a few embodiments of the present invention have been shown and described, the present invention is not limited to the described embodiments. Instead, it would be appreciated by those skilled in the art that changes may be made to these em¬ bodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents .

Claims

Claims [1] 1. An optical disc having a plurality of recording layers, each recording layer comprising: a data area; a connecting area; and a remaining area, wherein the data, connecting, and remaining areas are respectively disposed in a direction from an inner circumference of the optical disc to an outer cir¬ cumference, wherein an outer boundary of each of the data areas is determined according to an amount of data to be recorded, and wherein locations of the connecting areas and the remaining areas are determined by a recording and/or reproducing apparatus according to the determination of the outer boundary of each of the data areas. [2] 2. The optical disc of claim 1, wherein each recording layer comprises an exclusive area for a specified purpose, the exclusive area being in the remaining area of each recording layer when the size of the remaining area is larger than a specified size. [3] 3. The optical disc of claim 2, wherein data indicating that the exclusive areas have been allocated is recorded on a specified area of the optical disc. [4] 4. The optical disc of claim 2, wherein an end position of each of the exclusive areas varies on the basis of a using direction of the exclusive areas. [5] 5. The optical disc of claim 2, wherein respective usage directions of exclusive areas allocated to two adjacent recording layers among the plurality of recording layers are opposite to each other. [6] 6. The optical disc of claim 2, wherein each recording layer comprises an unused area at a position corresponding to the location of an exclusive area allocated to an adjacent recording layer. [7] 7. The optical disc of claim 2, wherein the remaining area of each recording layer includes a buffer area to compensate for an influence of eccentricity of the optical disc and a beam focused on another recording layer. [8] 8. The optical disc of claim 2, wherein respective usage directions of the data area and the exclusive area allocated to each recording layer are opposite to each other. [9] 9. The optical disc of claim 2, wherein the exclusive area is a test area usable to determine optimum recording conditions. [10] 10. An apparatus for recording/reproducing data, comprising: a write/read unit which transfers data with respect to an optical disc having a plurality of recording layers; and a controller which determines an outer boundary of a data area of each recording layer according to an amount of data to be recorded and which determines cor¬ responding locations of a connecting area and a remaining area of each recording layer according to the determination of the outer boundary of each of the data areas. [11] 11. The apparatus of claim 10, wherein the controller allocates an exclusive area for a specified purpose to the remaining area of each recording layer when the size of the remaining area is larger than a specified size. [12] 12. The apparatus of claim 11, wherein the controller controls the write/read unit to record data indicating that the exclusive area has been allocated on a specified area of the optical disc. [13] 13. The apparatus of claim 11, wherein the controller uses the exclusive area from a beginning position of the exclusive area and determines an ending position of the exclusive area. [14] 14. The apparatus of claim 11, wherein , when data is recorded on the exclusive areas allocated to two adjacent recording layers among the plurality of recording layers, the respective recording directions are opposite to each other. [15] 15. The apparatus of claim 31, wherein each recording layer includes an unused area at a position corresponding to the location of an exclusive area allocated to an adjacent recording layer. [16] 16. The apparatus of claim 11, wherein the remaining area of each recording layer includes a buffer area to compensate for an influence of eccentricity of the optical disc and a beam focused on another recording layer. [17] 17. The apparatus of claim 11, wherein the controller controls the usage directions of the data area and the exclusive area allocated to each recording layer so that the usage directions are opposite to each other. [18] 18. The apparatus of claim 11, wherein the exclusive area is a test area usable to determine optimum recording conditions. [19] 19. A method of recording data on a plurality of recording layers, comprising: determining an outer boundary of a data area of each recording layer according to an amount of data to be recorded; and determining locations of a connecting area and a remaining area of each recording layer according to the determining of the outer boundary of each of the data areas. [20] 20. The method of claim 19, further comprising: allocating an exclusive area for a specified purpose to the remaining area of each recording layer, when the size of the remaining area is larger than a specified size. [21] 21. The method of claim 20, wherein allocating the exclusive area includes recording data indicating that the exclusive area has been allocated on a specified area of the optical disc. [22] 22. The method of claim 20, further comprising: using the exclusive area from a beginning position of the exclusive area according to a specified purpose and determining an ending position of the ex elusive area. [23] 23. The method of claim 20, wherein respective usage directions of exclusive areas allocated to two adjacent recording layers among the plurality of recording layers are opposite to each other. [24] 24. The method of claim 20, wherein an area of a recording layer at a location corresponding to an exclusive area allocated to an adjacent recording layer is not used. [25] 25. The method of claim 20, wherein respective usage directions of the data area and the exclusive area allocated to each recording layer are opposite to each other. [26] 26. The method of claim 20, wherein the exclusive area is a test area usable to determine optimum recording conditions. [27] 27. The method of claim 19, wherein data having a specified pattern indicating the end of the data area is recorded in the connecting area of each recording layer. [28] 28. The method of claim 27, wherein the data having the specified pattern includes a lead-out attribute. [29] 29. The method of claim 20, wherein the specified purpose is as a test area to determine for an optimum power control (OPC) or to record data indicating the time of recording and the type of data recording/reproducing apparatus used. [30] 30. The method of claim 19, wherein, when an amount of user data to be recorded is less than a total recordable capacity of the optical disc, and when an amount of user data to be recorded is known in advance, a size of each of the data areas is determined and equal amounts of user data are recorded on each of the plurality of recording layers. [31] 31. The method of claim 20, wherein a size of each of the exclusive areas is determined based on a usage frequency of the exclusive area. [32] 32. The method of claim 20, wherein the specified size is 3% of the total amount of data recordable on one recording layer of the optical disc. [33] 33. A computer readable medium having recorded thereon a computer readable program implemented by a computer for performing a method of recording data on a plurality of recording layers, the method comprising: determining an outer boundary of a data area of each recording layer according to an amount of data to be recorded; and determining locations of a connecting area and a remaining area of each recording layer according to the determination of the outer boundary of each of the data areas.