APPARATUS FOR RECORDING AN INFORMATION SIGNAL

Abstract: The invention relates to an apparatus (1) for recording an information signal on a record carrier (7). The apparatus comprises a memory (13) for storing at least the information which gives an indication about the position on the record carrier of the beginning or the end of the recorded information signal. The apparatus (1) is provided with means for recording this indication information in an intermediate storage area (4) on the record carrier (7).

Description: Apparatus for recording an information signal. The invention relates to an apparatus for recording an information signal on a record carrier, said apparatus comprising a memory for storing at least information which gives an indication about the position on the record carrier of the beginning or the end of the recorded information signal. The invention also relates to a record carrier which is suitable for use in such an apparams and to a method of recording an information signal. An apparams of the type described in the opening paragraph is known from, for example European patent specification EP 0 029 946. The apparams described in this document comprises means for recording a table of contents of the information signals on a record carrier. The apparams is provided with a memory in which information is temporarily stored, which information indicates the position on the record carrier of the end of the recorded information signal. This information is not stored in the table of contents until after the end of the recording session the record carrier has been rewound to the position of the table of contents and before the record carrier is removed from the apparams. The table of contents may be present at the beginning or the end of the record carrier described in said European patent specification. It is also known per se to provide the table of contents in the middle of the record carrier. This has the advantage that it can be more rapidly accessed from most positions on the record carrier than in the case where the table of contents would be present at the beginning or the end of the record carrier. A drawback of the apparatus described in said European patent specification is that, after the information signal has been recorded and the information about this signal is stored in this temporary memory of the apparams, the information related to the recorded information signal must be retained in the temporary memory for a relatively long time, irrespective of the position of the table of contents on the record carrier, so that there is a relatively great risk of losing this information. This will be the case, for example when there is a power failure of the apparams or when the record carrier is removed prematurely from the apparams. It is an object of the present invention to provide an apparams in which the above-mentioned drawbacks are obviated. To this end, the apparams according to the invention is characterized in that the apparams is provided with means for recording said indication information in an intermediate storage area on the record carrier. The apparams may be, for example, a video disc recorder or a video tape recorder or a PC. An intermediate storage area is herein understood to mean a storage site on the record carrier which is outside the site reserved for storing a table of contents. The intermediate storage areas may be created, for example on the spot, when an information signal has been recorded completely, or on any other spot where it might be useful to have an intermediate storage possibility. The positions of the intermediate storage areas are preferably defined in advance. This saves time when retrieving these spaces. The presence of intermediate storage areas on the record carrier allows temporary storage of indication information in a non- volatile way. At a later stage, when the record carrier is at the suitable position or before the record carrier is removed from the apparams, this information will be added to the table of contents on the record carrier. Consequently, when an information signal recording session has been finished, no time is lost whenever the record carrier is wound to the position of the table of contents, but a short positioning time to the closest intermediate storage area is sufficient if the intermediate storage areas have been defined in advance. If the intermediate storage areas are created during recording, no winding time is required. Moreover, the indication information will still be retained when there is an interruption in the system before this indication information has been stored in the table of contents. The intermediate storage areas thus ensure a non-volatile storage of the indication information. A preferred embodiment of the apparams according to the invention is characterized in that the apparams is provided with means for seeking a predefined intermediate storage area on the record carrier where the indication information is stored when an information signal recording session has been completed. The indication information-of a recorded information signal is thus stored in an intermediate storage area but may also be ' stored in the memory. The most recent intermediate storage area comprises all indication information to be updated in the table of contents of at least the last-recorded information signal and possibly one or more previously recorded information signals. The table of contents on the record carrier will be updated regularly, either with reference to the information in the memory or with reference to the information in the intermediate storage areas. Updating with reference to information in the memory is a quicker process because the memory is more rapidly accessible. Both the intermediate storage areas and the table of contents on the record carrier may be provided with an indicator in such a way that it indicates which intermediate storage area comprises the most recent indication information, or how far the table of contents on the record carrier has been updated. When the indicator of the most recent intermediate storage area corresponds to that of the table of contents, this means that the table of contents on the record carrier has been fully updated. The memory may be either a volatile or a non-volatile memory. An advantage of a non-volatile memory is that the information in the memory is not lost in the case of power failure. An additional advantage of an apparams with a non-volatile memory such as, for example a hard disc, is that the same record carrier can be written and/or read in more than one apparams while maintaining the correct references for the indication information in the memory of the apparams with respect to the indication information on the record carrier. If the memory is a non-volatile memory, the table of contents of at least one record carrier can be stored in this memory. The table of contents in the non-volatile memory is preferably provided with a third indicator. In this way it can be checked whether the table of contents in the memory is updated with respect to the table of contents on the record carrier. When the indicator of the table of contents on the record carrier and the indicator of the table of contents in the memory do not correspond, this means that the table of contents in the memory is still lagging behind the table of contents on the record carrier. Consequently, recent information will have to be added from an intermediate storage area to the tables of contents. Relatively short information signals are preferably recorded proximate to the table of contents. In this way, recorded short -information signals are accessible in a relatively rapid manner, while there is sufficient space left to record longer information signals without interruptions such as, for example video signals. These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter. In the drawings: Fig. 1 shows an embodiment of an apparams according to the invention; Figs. 2(a), 2(b), 2(c) and 2(d) show some embodiments of a record carrier according to the invention, in which the table of contents is each time present at a different position on the record carrier and in which a number of intermediate storage areas are shown; Figs. 3(a) and 3(b) show two embodiments of a helical scan tape provided with intermediate storage areas; Figs. 4(a) and 4(b) show two embodiments of a longitudinal record carrier according to the invention, on which a possible distribution of short and long information signals is shown; and Figs. 5(a), 5(b) and 5(c) show some embodiments of a disc-shaped record carrier provided with intermediate storage areas. Fig. 1 shows diagrammatically an embodiment of an apparams 1 for recording an information signal in one or more tracks on a record carrier as shown in, for example, Figs. 2(a) to 2(d). Figs. 2(a), 2(b), 2(c) and 2(d) show diagrammatically a longitudinal record carrier 7 throughout its length. The beginning of the record carrier 7 is denoted by BOT (begin-of-tape) and the end is denoted by EOT (end-of-tape). The area which is available for recording information signals comprises a plurality of tracks t j , as is shown in Fig. 2(a). The apparams 1 has an input 3 for receiving the information signal. The input 3 is connected to the input of a formatter 5 which ensures that the input signal is converted to the format suitable for recording this signal on a record carrier 7. The output of the formatter 5 is coupled to a write unit 9 which comprises a read/write head 11. The formatted information signal is applied to the write unit 9 and recorded in the tracks t j of the record carrier 7. The apparams 1 also comprises a memory 13 in which information can be stored, giving an indication about the position on the record carrier of the end of the information signal which is being recorded, and means 15 for storing this information in the memory 13. These means 15 may be, for example a position detector which picks up the indication information. Tue indication information may consist of the position in the longitudinal direction on the record carrier and the track number. Subsequently, the indication information is stored in the memory 13. This is effected at an instant which is indicated by a control unit 17 which is driven by drive means 19. The drive means 19 may be, for example a keyboard or the operating section of a video recorder. When the end of recording an information signal has been reached, which end is determined either manually or via the programming of the apparams, the control unit 17 will ensure that the position of the record carrier detected at that instant by the position detector can be recorded in the memory. Similarly as in the European patent specification mentioned in the opening paragraph, the longimdinal record carrier 7 may have a table of contents (TOC). Such a table of contents should be updated regularly with information about newly recorded information signals. The table of contents may be present at different positions on the record carrier, as is illustrated in the Figures. In Fig. 2(a), the table of contents is present at the beginning of the record carrier 7, in Fig. 2(c), it is present in the middle and in Fig. 2(d) at the end. Another way of providing the table of contents on the record carrier is shown in Fig. 2(b). The table of contents covers only a part of the width of the record carrier but extends through a greater length. This mode may of course be used in the middle or at the end of the record carrier 7. The information which is to be recorded in the table of contents is not complete until an information signal has been recorded completely. However, the position of a record carrier 7 with respect to the read/write head 11 at the instant when the information signal has been recorded completely generally does not coincide with the position of the table of contents on the record carrier. This means that the record carrier will have to be wound or rewound to the position of the table of contents. This takes a relatively long time. Moreover, there is a risk that, during winding, the indication information is lost because of, for example power failure of the apparams or premature removal of the record carrier from the apparams. The present invention proposes to provide the record carrier with a plurality of intermediate storage areas. Intermediate storage areas are sites on the record carrier in which temporary indication information indicating the position on the record carrier of the end of the recorded information signals can be recorded separately from the site which is reserved for the table of contents. All information which must still be stored in the table of contents is preferably present in the most recent intermediate storage area. Thus, it is not necessary to reposition the record carrit: and the write/read head with respect to each other to arrive at the position of the table of contents before the end of an information signal has been reached. Moreover, since the information is stored in the intermediate storage areas in a non- volatile manner, the risk of unwanted loss of indication information is reduced considerably. To this end, the apparams 1 of Figure 1 is provided with means which ensure that the indication information indicating the position on the longimdinal record carrier at the end of a recording session of an information signal is stored in one of the intermediate storage areas. These means also make use of the information about the position of the record carrier, detected by the position detector 15. This information is not only stored in the memory 13 but also in the relevant intermediate storage area. To this end, the motor transport unit 21 is activated, so that the record carrier is wound to the intermediate storage area which is closest to the position of the end of the information signal on the record carrier. The record carrier may be, for example a longimdinal multi-track magnetic record carrier. In that case, a plurality of juxtaposed tracks are situated longitudinally on the record carrier. The intermediate storage areas are situated in one of the longimdinal tracks, preferably the lower track, as is shown in Figs. 2(a) to 2(d). The intermediate storage areas may be alternatively provided in the upper track or in the other tracks. The last-mentioned tracks are, however, preferably left free for recording long information signals such as, for example video signals. The record carrier may be alternatively, for example a helical scan tape. In that case, the parallel tracks extend from the bottom left to the top right obliquely across the record carrier. Also such a record carrier always has a longimdinal track. Figs. 3(a) and 3(b) show two embodiments of a helical scan tape which is also provided with a plurality of intermediate storage areas 4. In Fig. 3(a), the intermediate storage areas are situated in the longimdinal track and in Fig. 3(b), the intermediate storage areas are situated in the oblique tracks on the tape. Thusfar, in the apparams described the record carrier was supposed to be a longimdinal record carrier such as a tape. -However, the record carrier may also be a disc. In a preferred embodiment the disc is an optical disc. Although the access time of a position on an optical disc is much lower than the access time for a position on a tape, the same risk as described for a longimdinal record carrier occurs in case the record carrier is disc-shaped, especially in case that a high data rate signal has to be recorded. It might then be impossible to update the table of contents during recording. The time which is needed for the apparams to bring the write/read head to the position of the table of contents while the recording session is not finished yet might be too short, so that the time between two updates of the table of contents becomes too long. The present invention proposes also for this kind of record carriers the use of intermediate storage areas. Figs. 5(a), 5(b) and 5(c) show schematically a few embodiments of a disc 25, for example, an optical disc, comprising intermediate storage areas 4. In practice, the geometry of the disc is much more complicated. In each of the embodiments shown in Figure 5, the table of contents is located in the centre of the disc 25, but different possible locations for the intermediate storage areas are shown. The information which is to be recorded in the table of contents and in the intermediate storage areas can be various. In any case, when recording is started, the title and the code with which the recording session will be indicated in the intermediate storage areas have to be registered. Supplementary information may be added, if wanted. Figures 5(a), 5(b) and 5(c) show different possibilities for the location of the intermediate storage areas 4. The difference in shading in the drawing makes clear the length of a recorded fragment or the length of still free regions to be filled with signals to be recorded. An example of the recording procedure for a disc-shaped record carrier is described here below. Free blocks are searched for in the table of contents. During recording said free blocks are filled in a predefined sequence. For example, at the beginning of a block, it is noted for which fragment the block concerned is used. After the recording session has been terminated, the table of contents is updated. In the meanwhile, when an intermediate storage area is reached, information about the signal being recorded is already stored in said area. In an apparams for recording information on an optical disc, the record carrier should not be wound, but the read/ write head may be displaced over the disc. The apparams for recording an information signal, independent of the type of record carrier, is provided with means for seeking the table of contents after recording an information signal. This is preferably the case when, subsequent to completing the information signal recording session, the next-information signal is not recorded within a given time interval, thus allowing the table of contents to be updated. To this end, for a longimdinal record carrier, the control unit 17 is connected to a motor transport unit 21. By driving the motor transport unit 21, it is possible to wind the record carrier into one of the two directions denoted by the arrow 23. As already stated, the control unit 17 then also receives the required signal from the drive means 19. The intermediate storage areas are marked with a first indicator indicating which intermediate storage area comprises the most recent information and is thus relevant for updating the table of contents. The indicator may have, for example a serial number or an instant. The table of contents is provided with a second indicator upon each update. If the first and the second indicator correspond to each other, this means that the table of contents on the record carrier has been updated completely. The memory 13 in the apparams 1 may be a volatile memory such as, for example a RAM, or a non-volatile memory such as, for example a hard disc. In both cases, a copy of the table of contents of the record carrier can be stored in the memory. In this way, the table of contents on the record carrier can be updated with reference to the information in the memory. This is a faster process than that carried out via the intermediate storage areas, because the memory is more rapidly accessible than the record carrier. In this case, the intermediate storage areas only have a security function for the indication information. A non-volatile memory has the additional advantage that, when the same record carrier is read and/or written in different apparams, the record carrier is recognizable in each apparams and a reference is present for the indication information of the inserted record carrier. In the case of a non-volatile memory, a survey of the tables of contents of a number of record carriers may also be stored. The apparams may then be provided with means for notifying the user which record carrier must be inserted into the apparams so as to read the relevant information signal. The table of contents in the non- volatile memory is preferably provided with a third indicator. It can be deduced from the comparison of the third indicator with the second indicator on the record carrier in how far the table of contents in the memory has been updated with the information in the table of contents on the record carrier. When the second and third indication do not correspond to each other, this means that there is still recent information in at least one of the intermediate storage areas which must still be added to the two tables of contents. In this case, the-first and the second indicator will not correspond to each other. This is the case, for example when the record carrier had been removed from the apparams before the table of contents on the record carrier was updated. It can be ascertained by means of the third indicator whether the contents of a record carrier have been modified when the record carrier is used in another apparams. The exchange of record carriers between different apparams is recognizable in this way. The non- volatile memory can thus be used to recognize the use of a given record carrier in another apparams and to match the table of contents of this record carrier comprising the information added to the record carrier in the other apparams with the table of contents of this record carrier in the memory. Each apparams should thus be provided with its own, third indicator. If there is a copy of the table of contents in the memory, the indication information of a new information signal can also be applied to the memory. Then, it is not necessary to first look up the table of contents on the record carrier. This saves time. When many different information signals have been recorded on a record carrier, the tables of contents of all record carriers may be stored in a compressed form. Figs. 4(a) and 4(b) show two embodiments of a record carrier 7 on which short and long information signals have been distributed in an advantageous manner. Recording of an information signal may start at any position on the record carrier. When, for example recording is started at the beginning of the record carrier (BOT), the full track can be written from the left to the right. When the track is full, the recording session may be continued in a subsequent track by inverting the transport direction of the record carrier and recording the information signal from the right to the left. The start position of recording the information signal does not have to be at the beginning of the record carrier. Consequently, it is possible, for example subsequent to an information signal which has ended halfway the record carrier, to start recording the next information signal. This facility allows distribution of short and long information signals such as, for example video signals, to be distributed optimally on the record carrier. An optimal distribution is understood to mean that short information signals start in the proximity of the table of contents and are thus accessible in a relatively rapid way, while there is sufficient space left for recording long information signals without too many interruptions. In Figs. 4(a) and 4(b), information signals are also present in the track in which the intermediate storage areas 4 are situated. The way in which the recorded fragments are stored on the record carrier may be determined by indices allocated by the system. The kind of indices may be twofold. On the one hand, already existing indices may be used such as the length of the file, the name of the file, read-only or archive indicatives. These are so-called attributes. On the other hand the type of file may be used as index, such as for example real time or back up. This kind of indexing allows organized storage of files in accordance with the user's preferences. The present invention has been elucidated by means of the end of the recorded information signal, but also applies to the registration of the beginning of an information signal to be recorded. Consequently, neither at the beginning of recording of an information signal nor at the end of recording an information signal, the position of the table of contents has to be seeked for.

Claims: CLAIMS: 1. An apparams for recording _n information signal on a record carrier, said apparams comprising a memory for storing at least information which gives an indication about the position on the record carrier of at least the beginning or the end of the recorded information signal, characterized in that the apparams is provided with means for recording said indication information in an intermediate storage area on the record carrier. 2. An apparams as claimed in Claim 1, characterized in that the record carrier is a longimdinal record carrier. 3. An apparams as claimed in Claim 2, characterized in that the record carrier is a magnetic record carrier. 4. An apparams as claimed in Claim 1, characterized in that the record carrier is disc-shaped. 5. An apparams as claimed in Claim 4, characterized in that the record carrier is an optical disc. 6. An apparams as claimed in one of the previous Claims, characterized in that the apparams is provided with means for seeking a predefined intermediate storage area on the record carrier where the indication information is stored when an information signal recording session has been completed. 7. An apparams as claimed in one of the previous Claims, characterized in that the apparams is provided with means for storing the indication information in the memory after the relevant information signal recording session has been completed. 8. An apparams as claimed in one of the previous Claims, wherein the record carrier has a location for storing a table of contents of the recorded information signals, characterized in that the apparams is adapted to find the position of the table of contents after the relevant information signal recording session has been completed, and to update the table of contents on the record carrier. 9. An apparams as claimed in one of the previous Claims, characterized in that the apparams comprises means for updating the table of contents on the record carrier with reference to the information in intermediate storage areas. 10. An apparams as claimed in one of the Claims 1 to 8, characterized in that the apparams comprises means for updating the-table of contents on the record carrier with reference to the information in the memory. 11. An apparams as claimed in one of the previous Claims, characterized in that the apparams comprises means for providing intermediate storage areas in a track of the record carrier. 12. An apparams as claimed in Claim 9 or 11, characterized in that the intermediate storage areas are provided with a first indicator indicating which intermediate storage area comprises the most recent indication information. 13. An apparams as claimed in any one of Claims 1 to 12, characterized in that the table of contents on the record carrier is provided with a second indicator which, in combination with the first indicator, indicates how far the table of contents has been updated. 14. An apparams as claimed in any one of the preceding Claims, characterized in that the memory is a volatile memory. 15. An apparams as claimed in any one of Claims 1 to 13, characterized in that the memory is a non-volatile memory and comprises a survey of the table of contents of at least one magnetic record carrier. 16. An apparams as claimed in Claim 15, characterized in that the nonvolatile memory is provided with a third indicator indicating in how far the table of contents in the memory has been updated for a given record carrier. 17. An apparams as claimed in any one of the preceding Claims, characterized in that relatively short information signals are present in the proximity of the table of contents on the magnetic record carrier. 18. A method of recording an information signal in a track on a record carrier on which a table of contents of the recorded information signals is stored, and in which the apparams is further provided with a memory in which at least the information is stored which gives an indication about the position on the record carrier of the beginning or the end of the relevant recorded information signal, characterized in that said indication information is at least recorded in an intermediate storage area on the record carrier. 19. A record carrier having a location for storing a table of contents, characterized in that the record carrier further has at least one intermediate storage area for storing indication information indicating the position on the record carrier of the beginning or the end of the recorded information signal.

Inventors: DENISSEN ADRIANUS JOHANNES MAR, MONTIE EDWIN ANDRE, TOL RONALD MARCEL, DENISSEN, ADRIANUS, JOHANNES, MARIA, MONTIE, EDWIN, ANDRE, TOL, RONALD, MARCEL
Applicants: DENISSEN ADRIANUS JOHANNES MAR, KONINKL PHILIPS ELECTRONICS NV, MONTIE EDWIN ANDRE, PHILIPS SVENSKA AB, TOL RONALD MARCEL, DENISSEN, ADRIANUS, JOHANNES, MARIA, KONINKLIJKE PHILIPS ELECTRONICS N.V., MONTIE, EDWIN, ANDRE, PHILIPS AB, TOL, RONALD, MARCEL
Application year: 1998
Main classification: G11B27
IPC codes: G11B5, G11B7, G11B15, G11B20, G11B27