GB2199684A

GB2199684A - Optical record medium and method of recording control information thereon

Info

Publication number: GB2199684A
Application number: GB08723939A
Authority: GB
Inventors: Takayuki Abe; Akira Matsueda; Yuichiro Akatsuka; Takao Rokutan; Nagahiro Gocho
Original assignee: Olympus Corp; Olympus Optical Co Ltd
Current assignee: Olympus Corp
Priority date: 1986-10-13
Filing date: 1987-10-12
Publication date: 1988-07-13
Anticipated expiration: 2007-10-12
Also published as: DE3734638C2; IT8722244A0; GB2199684B; DE3734638A1; IT1222888B; GB8723939D0

Description

4 cl r OPTICAL RECORD MEDIUM AND METHOD FOR RECORDING CONTROL INFORMATION

THEREOF 2199684 The present invention relates to an optical record medium and a method for recording a control information thereof which is Preferably used for a prepayment system.

As an example of an optical record medium, an optical disc and an optical card disclosed in PCT/US82/00187 have been known.

Fig. 17 is a schematic view showing a construction of a conventional optical card. In this embodiment, an optical card 71 comprises a data record region 72 in which a plurality of tracks each extended along a card longitudinal direction are parallely arranged in a card width direction. The data record region 72 has an ID region 72 in which a track address or a sector address corresponding to. each tracks is previously recorded, and a data region 74 in which data are to be recorded.

In the optical record mediums of write once type mentioned above, since the data is not rewritten, it is necessary to manage the data by means of a control information representing an attribute of the latest recorded data. Various methods for managing the data by means of the control information have been known as f ollows. (1) Record the control information on a rewritable record medium such as a floppy disc in a host computer, and manage the data by means of the control information in the floppy disc. (2) Record the control information on the optical record medium, read the control information into RAM in the host computer, manage the da.ta by means of the control information in the RAM and rewrite the latest control information on the optical record medium at the other region of the previous control information.

However, in the method of (1) mentioned above, if a large amount of optical record mediums are to be managed, it is necessary to use a large amount of memories for the control information and thus the system is made expensive in cost. Moreover, if the host computer is changed into another one, it is necessary to transfer the control information between them and thus an efficiency of using the optical record medium becomes bad.

Further, in the method of (2) mentioned above, since the renewed control information is recorded on the optical record medium at the other region than that of the previous control information, the data record region is decreased every time the control information is renewed. This disadvantage is very serious on the J optical card because an amount of storage of the optical card is relatively small as compared with that of the optical disc.

Moreover, it is required to utilize one optical card for various uses such as bank card, shopping card of department store and medical examination card. However, in the known system using the optical card, the control information such as attribute of track, latest track number etc. is recorded on only one track of the optical card. Therefore, latest tracks of various uses cannot be managed by one optical card.

It is accordingly desirable to provide an optical record medium and a method for recording a control information which performs the data recording and reading operations in an easier and less expensive manner, without decreasing the storage for the data recording region.

It is also desirable to provide an optical record medium and a method for recording a control information which has - various uses.

According to one aspect of the present invention, there is provided an optical record medium comprising a substrate, a first record layer arranged on said substrate and defining a data record 26 region on which data are recorded in an optically readable manner, and a second record layer arranged on said substrate separately from said first record layer and defining a control information record region on which a control information for managing the optical record medium is recorded.

According to another aspect of the present invention, there is provided a method for recording a control information of an optical record medium comprising data record tracks on ahich data are recorded in an optically readable manner and at least one control information record track on which a control information is recorded, which method comprises the steps of:

reading the control information record track to detect a control information of the latest data to be managed, reading the data from the data record track corresponding to the detected control information to renew the data, recording the renewed data on a data record track, and recording a control information of the renewed data on said control information record track.

Reference will now be made, by wa-,,, of example, to the accompany-inq drawings, wherein:

Fig. 1 is a schematic view showing an embodiment of an optical record medium according to the present invention; Fig. 2 is a schematic view illustrating an embodi ment of a record format of the optical record medium - t p according to the present invention; Fig. 3 is a schematic view showing another embodiment of the record format according to the present invention; Figs. 4 and 5 are schematic views depicting still another embodiment of the optical record medium according to the present invention, respectively; Figs. 6 and 7 are schematic-views showing control information for.use in an embodiment of the present invention; Fig. 8 is a schematic view illustrating control information for use in an embodiment of the present invention; Fig. 9 is a block diagram depicting a main construction of a.read/write apparatus for an optical card embodying the present invention; Figs. 10A and 10B are schematic views showing waveforms of readout signal and detection signal, respectively; 20 Fig. 11 is a schematic view illustrating still another embodiment of the optical record medium according to the present invention; Figs. 12A and 12B are schematic views for use in explaining a method for recording the control information embodying another aspect of the present invention; Figs. 13A and 13B are schematic views for use in explaining a method for recording the control information embodying another aspect of the present invention; Figs. 14 and 15 are schematic views illustrating still another embodiment of the optical record medium according to the present invention; Figs. 16A and 16B are schematic views depicting an embodiment of data to be managed, respectively; and Fig. 17 is a schematic vieK showing a known optical card.

Fig. 1 is a schematic view showing an embodiment of an optical record mediu-n according to the present invention. In this embodiment, a record layer 2 having tracks for recording data and extended in a longitudinal direction of an optical card 1 is stuck to a substrate of the optical card 1. The record layer 2 comprises ID portions 3A and 3B in which data representing track addresses are previously recorded, a data record region 4 for recording desired data, and a control information record region 5 shown by a hatched area for recording a control information of the optical card. The ID portions 3A and 3B are arranged at both ends of the optical card by being extended in a perpendicular direction with respect to the longitudinal direction of the optical card 1. In Fig. 1, a scanning operation is performed from left to right in the ID portion 3A and from right to left in the ID portion 3B so as to read 7 v 1 the track address. The data record region.4 and the control information record region 5 each having a plurality of tracks are arranged between the ID regions 3A and 3B.

Fig. 2 is a schematic view showi ng an embodiment of a record format of the optical card according to the present invention. In Fig. 2, the control information record region,5 comprises a plurality of record portions 7 divided by prerecord regions 6, and the control information of the optical card are successively recorded in these record portions 7.

As for the control information, use is made of, for example, the latest address of the data recorded on the data record region 4, when the data is to be added successively in the optical record medium of write-once type and a referring frequency of the data is not so high. In a prepayment card system, the balance can be known by reading out the data on the data record region 4 corresponding to the latest address recorded on the record portion 7 of the control information record region 5. Then, a result of current dealings is recorded on the data record region 4 and the latest address corresponding to the current dealings is recorded on the next record portion 7 of the control information record region 5. In this manner, an effective prepayment card system can be realized.

It should be noted that a search of the latest address on the control information record region 5 can be performed by various known method such as dichotomizing search.

Fig. 3 is a schematic view showing another embodiment of the record format of the optical card according to the present invention. In this embodin-ent, the latest address to be renewed is recorded successively to the last address 8 just previously recorded on the control information record region 5 without arranging the prerecord region of Fig. 2. In this case, it is possible to manage the latest address without changing the prerecord portion of the known optical card.

Fig. 4 is a schematic view showing another embodiment of the optical record medium according to the present invention. In this embodin-ent, a record layer 12 having tracks for recording data and extended in a longitudinal direction of an optical card 11 is arranged on a substrate of the optical card 11. The record layer 12 comprises an ID portion 13 in which data representing track addresses are previously recorded by means of patterns each having different reflectivity, and a data record region 14 for recording desired data.

A data recording operation into the data record region 14 is performed in such a manner that an inner layer having low reflectivity is exposed by irradiating 9 a laser beam modulated by the data information to be.recorded. Moreover, a data reading operation is performed by detecting a difference in reflectivity as is the same as the data reading operation of the ID portion 13. ' - In this embodiment, a magnet ic tape 15 is stuck to the substrate of the optical card 11 as the control information record region apart.from the record layer 12. Therefore, the control information of the optical card 11 can be recorded on the magnetic tape 15 in a rewritable manner.

As for the control information, use-is made of, for example, the latest track address of the data recorded on the data'record region 14. In this case, the data is recorded at first on a first track of the data record region 14, and then a magnetic pattern "1" representing the latest track address is recorded on the magnetic tape 15. When the data are to be renewed, the data representing the latest track address just previously recorded on the magnetic tape 15 are read out -rack address is rewritten and confirmed, and the latest on the magnetic tape 15 by a value adding "1" to the number of the latest track address thus read out. Finally, the data to be renewed is recorded on the latest track address. After that, the same operation mentioned above is repeated.' In this manner, since the latest track address is always recorded on the magnetic tape 15, an effective system can be realized.

Fig. 5 is a schematic view showing still another embodin-ent of the optical record n-ediun according to the present invention. In Fig. 5, a record layer 22 having tracks for recording data and extended in a longitudinal direction of an optical card 21 is arranged on a substrate of the optical card 21. The record layer 22 comprises an ID portion 23 in which data representing track addresses are previously recorded, and a data record region 24 for recording desired data. A data recording operation into the data record region 24 is performed in such a manner that an inner layer having low reflectivity is exposed by irradiating a laser beam modulated by the data information to be recorded. Moreover, a data reading operation is performed by detecting a difference in reflectivity. In the ID portion 23, ID data such as track addresses are recorded by patterns each having different reflectivity and formed by a printing method etc.

In this embodiment shown in Fig..5, a predetermined track among a plurality of tracks of the optical card 21, for example, a first track is used for a control information record track 25, and the other tracks are used for the data record track. In the control information record track 25, predetermined 1 prerecord marks 26 are formed by the printing method etc. by an interval corresponding to an information unit such as a track or a sector in the track. In order to detect the prerecord mark 26 from the other portions, the prerecord mark 26 is formed by patterns each having different reflectivity or by specific patterns.

Every time the data is reccrded on the data record tracks, a laser write mark 27 representing an attribute of the data thus recorded is recorded on a record portion having.the prerecord mark 26 corresponding to an address of the data thus recorded. In order to detect the laser write mark 27 from the other portions, the laser write mark 27 is formed by patterns utilizing the number of record pits, interval of pits, length of pit, reflectivity of pit etc. Figs. 6 and 7 are schematic views showing an embodiment of the control information such that the number of pits is used for the laser write mark 27, respectively. Fig. 8 is a schematic view illustrating another embodiment of the control information such that the length of pit is used for the laser light mark 27. As for the attribute of data to be recorded, use is made of variogs information such as whether or not respective information units are recorded, whether or not the corresponding track can be used, or a mark and a class for search. In this mannerr the attribute of the information unit can be recorded by recording the laser write mark 27 on the record portion defined by the prerecord marks 26 corresponding to the information unit to be managed.

Fig. 9 is a block diagram showing a main construction of a read/write apparatus for the optical card which performs the laser write mark recording operation. In this embodiment, the read/write apparatus comprises a prerecord mark detector 31 for detecting the prerecord mark 26 from a readout signal of the control information record track 25 in the optical card 21, a laser write mark detector 32 for detecting the laser write mark 27 from the readout signal, a counter 33 for counting a detection signal of the prerecord mark supplied from the prerecord mark detector 31, a laser write mark recorder 34 for recording the laser write mark 27, and a controller 35 for supplying a mark record command-signal to the laser write mark recorder 34 on the basis of a count signal of the counter 33 and for detecting the attribute of the information unit on the basis of a detection signal of the laser write mark supplied from the laser write mark detector 32.

Hereinafter, an operation of recording the laser write mark 27 will be explained. Prior to a recording of the laser write mark 27 on the control information record track 25, the controller 35 generates a clear signal to reset the counter 33. Then,the control information record track 25 is readout to generate the readout signal, and the prerecord mark 26 is detected by the prerecord mark detector 31 from the readout signal to generate the detection signal. Further, the detection signal is counted by the counter 33.

When the prerecord mark 26 is constructed by a material having lower reflectivity than that of the other portion, the readout signal is obtained as shown in Fig. 10A. The detection signal of the prerecord mark can be obtained as shown in Fig. 10B by comparing a level of the readout signal with a suitable detection level as shown in Fig. 10A.

The controller.35 detects what number of the information units does the currently reading prerecord mark 26 correspond, by means of the count signal supplied from the counter 33. When the detected number is identical with the number of the information unit to be recorded, the-controllex 35 supplies the mark record command signal to the laser write mark recorder 34 to generate a mark record signal consisting of patterns corresponding to the attribute of the information unit to be recorded. The laser write mark 27 is recorded on the record portion defined by the corresponding prerecord mark 26 of the optical card 21 by the laser beam modulated with the mark record signal.

Next, an operation of detecting the laser write mark 27 will be explained. Also in this case, prior to a reading of the control information record track 25, the controller 35 generates the clear signal to reset the counter 33. Then, the control information record track 25 is readout to generate the readout signal, and the prerecord mark 26 is detected by the prerecord mark detector 31 from the readout signal to generate the detection signal. Further, the detection signal of the prerecord mark is counted by the counter 33. In addition, the laser write mark 27 is detected by the laser write mark detector 32 to generate the detection signal of the laser write mark, and the detection signal of the laser write mark is supplied to the controller 35.

The controller 35 detects what number of the information units does the currently reading prerecord mark 36 correspond, by means of the count signal supplied from the counter 33. Then, the attribute of the information unit is detected from the detection signal of the laser write mark corresponding to the counted value.

Fig. 11 is a schematic view showing still another embodiment of the optical card according to the present invention. In this embodiment, a record layer 42 having tracks for recording data and extended in a longitudinal direction of an optical card 41 is arranged on a substrate of the optical card 41. The record layer 42 v - 15 comprises an ID portion 43 in which data representing track addresses are previously recorded, and data record regions 44A, 44B and 44C for recording data. An operation of recording information data to the data record regions 44A, 44B and 44C is performed by exposing an inner layer having low reflectivity by irradiating a laser beam modulated with the information data. An operation of reading the information data is effected by detecting the difference in reflectivity of the recorded data. Moreover, in the ID portion 43, the track addresses are recorded by means of patterns each having different reflectivity and formed previously by the printing method.

In this embodiment., a predeterminedtrack among a plurality of tracks of the optical card 41 is used for a control information record track for recording the control information such as the latest track etc. For example, the fi.rst track is used for a control information record track 45A of the data record region 44A, and the 301st track counted from the first track is used for a control information record track 45B of the data record region 44B. In addition, the 501st track is used for a control information record track 45C of the data record regi on 44C, and the other tracks are used for the data record track. That is to say, the control information of the data record region 44A existing from the second track to the 300th track is recorded on the first track (control information record track 45A), the control information of the data record region 44B existing from the 302nd track to the 500th track is recorded on the 301st track (control information record track 45B), and the control information of the data record region 44C existing from the 502nd track to the last track is recorded on the 501st track (control information record track 45C).

Figs. 12A and 12B are schematic views showing another embodiment of a method for recording the control information, respectively. In this embodiment, every time the data are recorded on the data record track, a mark 46 having a predetermined length Z is recorded continuously. That is to say, when the data are recorded on the first track of the data record tracks (second track of the optical card 41), the ID portion 43 is read out to confirm the control information record track 45A, and the mark 46 having a predetermined length Z and representing the end of recording on the first track is recorded on the control information record track 45A as shown in Fig. 12A. When the data are recorded on the next data record track, the ID portion 43 is read out and the mark 46 having a predetermined length 1 is recorded continuously with respect to the previous mark 46 as shown in Fig. 12B. After that, the same operation 1 G - of recording the mark 46 having a predetermined length ú continuously on the control information record track 45A is repeated every time the data are recorded on the data record track.

05- Here, if it is assumed that L is a length of area which can record the data in respective tracks, the control information record track 45A has an area of length L which can record the data. Therefore, respective control information record tracks can record the marks-46 of L/1 pieces. By measuring the whole length of marks 46 recorded on the control information record track 45A, it is possible tp-know how many data record tracks already recorded are there in the data record region 44A. Moreover, if the data are to be recorded on successive data record tracks, it is possible to know the latest track address of the recorded data. The length of the mark 46 can be measured by moving the optical card 41 and a pickup head relatively in a track direction, actuating a counter by a constant clock from a recording start position of the mark 46, and stopping the relative movement at a recording end position of the mark 46. Further, if it is necessary to manage the data record tracks more than L/1 pieces, it is sufficient to set previously a few tracks as the control information record track 45A.

Figs. 13A and 13B are schematic views showing still another embodiment of a method for recording the control information, respectively. In this embodiment, every time the data are recorded on the data record track, a pit 47 is recorded on the control information record track 45A by an interval of V. That is to say, when the data are recorded on the first track of the data record tracks, the ID portion 43 is read out to confirm the control information record track 45A, and the pit 47 representing the end of recording on the first track is recorded on the control information record track 45A as shown in Fig. 13A. When the data are recorded on the next data record track, the ID portion 43 is read out and the pit 47 is recorded by an interval V with respect to the previously recorded pit 47 as shown in Fig. 13B. After that, the same operation of recording the pit 47 with the interval ú1 on the control information record track 45A is repeated every time the data are recorded on the data record track.

In this case, if it is assumed that L is a length of area which can record the data in respective tracks as is the same as the embodiment shown in Figs. 12A and 12B, respective control information record tracks can record the pits 47 of L/V pieces. Therefore, by measuring the number of pits 47 recorded on the control f r It information record track 45A, it is possible to know how many data record tracks already recorded are there in the data record region 44A. Moreover, if the data are to be recorded on successive data record tracks, it is possible to know the latest track address of the recorded data.

Hereinafter, functions of the optical card shown in Fig. 11 will be explained, in..the case that the optical card is used for the prepaid card managing three kinds of purposes. In this case, the data record region 44A from the second track to the 300th track is used for the data record tracks of the first purpose, the data record region 44B from the 302nd track to the 500th track is used for the data record tracks of the second purpose, and the data record region 44C from the 502nd track to the last track is used for the data r.ecord,track for the third purpose. In the first purpose, the control information record track 45A is read out to detect the latest-address in the data record region 44A from the second track to the 300th track, and the data record track corresponding to the latest address thus detected is read out to know, for example, the balance if the first purpose is the card for shopping. When the balance is to be renewed, the balance data to be renewed is recorded on the data record track next to the data record track corresponding to the latest address, and - 20 the mark representing the end of recording the balance data to be renewed is recorded on the control information record track 45A as the control information of the latest address. In the same manner, the control information of the latest addresses for the second and third purposes can be known from the control information record tracks 44B and 44C (301st track and 501st track) for the second and third purposes respectively. In this manner, the prepaid card managing three kinds of purposes can be realized by one optical card.

Fig. 14 is a schematic view showing still another embodiment of the optical card according to the present invention in which the control information record track is divided by a sector. In this embodiment, a predetermined track, for example, the first track among a plurality of tracks of an optical card 51 is used for the control information record track. The control information record track is divided by three sectors with the aid of a sector mark 56. The control informa- tion of a data record region 54A is recorded on a control information record sector 55A, the control information of a data record region 54B is recorded on a control information record sector 55B, and the control information of a data record region 54C is recorded on sector 55C. As is the same above, the control a control information record as the embodiments mentioned Y1 Q 0 information for respective data record regions can be obtained from respective control information record sectors.

Fig. 15 is a schematic view showing still another embodiment of the optical card in which the record format is different from each data record regions. Hereinafter, an example in which medical examination data and s hopping-data are recorded on one optical card will be explained. The medical examination data -comprises examination date, stature, weight, eyesight, blood pressure, biochemistry examination, and comment as shown in Fig. 16A, and thus one examination data needs 512 bytes. Moreover, the shopping data comprises purchase date, price,' balance and name of purchase as shown in Fig. 16B, and thus one shopping data needs 64 bytes. In this case, if the examination data and the shopping data are recorded by the same data format, a unit of data needs 512 bytes for both purposes. Therefore, a data recording efficiency becomes bad because the shopping data needs one eighth of the data unit. In this case, if the examination data is recorded by a data format of unit data of 512 bytes and the shopping data is recorded by another data format of unit data of 64 bytes. it is possible to make the data recording effici ency good.

In Fig. 15, an optical card 61 comprises a data record region 64A having the data format of 1 sector/track and a data record region 64B having the data format of 8 sector/track formed by a sector mark 66. The control information of a data record region 64A is recorded on a control information record track 65A, and the control information of a data record region 64B is recorded on a control information record track 65B. In this embodiment, the controlling operation of the data record region 64A having the data format of 1 sector/track is the same as that of the embodiment mentioned above. A controlling operation of the data record region 64B having the data format of 8 sector/track will be explained. The controlling operation of the data record region 64B is performed in such a manner that a mark representing the end of recording of a sector isrecorded on the control information record track 65B. In this embodiment, one track has eight sectors. Therefore, if eight marks are recorded on the control information record track 65B, all the sectors in the first track are already recorded. Further, if fifty marks are recorded on the control information record track 65B, all the sectors in the first... sixth tracks and the first and second sectors in the seventh track are already recorded. It should be noted that the mark of this embodiment can utilize the mark 46 shown in Fig. 12A or the pit 47 shown in i r M Fig. 13A. In this manner, when one track has a plurality of sectors, it is possible to manage the data having different format easily by recording the mark having a constant length or the pit with a constant interval every sectors.

The present invention is not limited to the embodiments mentioned above, but various modifications are possible. For example, the data record region and the control information record region can be arranged on different record layers. Further, the present invention can be used not only for the opt ical card, but' also for the optical disc etc. As for the control information, use can be made of not.only the latest address., but also an exchange address. That is to say, since the optical record medium such as the optical and the optical disc has a high error rate, a strong error correcting operation is performed. In order to make the error correcting operation effective, the data are read out just after the data are recorded (Read After Write) to effect the error correcting operation, and the data are prerecorded on another data record track if the error correcting operation is impossible (data exchange operation). In this case, the exchanged address can be preferably used for the control information recorded on the control information record track.

Further, as for the control information record region, use is made of an optomagnetic record medium and a perpendicular magnetic record medium. Moreover, as for the control information, use is made of a directory of for example floppy disc such as file name, record track address, record date etc. Furthermore, the control information record region can be arranged to an opposite surface of the optical card with respect to the data record region.

As mentioned above in detail, according to an embodiment of the present inventionsince the optical record medium has the control information record region arranged separately from the data record region, it is possible to perform the data recording and reading operations in an easy and inexpensive manner even in the on-line processing.

Further, when the data record region is divided and the thus divided data record region has the control information record region respectively, the data for various purposes can be managed by one optical record medium.

v

Claims

1. An optical-record medium comprising a substrate, a first record layer arranged on said substrate and defining a data record region on which data are recorded in an optically readable manner, and a second record layer arranged on said substrate separately from said first record layer and defining a control information record region on which a control information for managing the optical record medium is recorded.

2. An optical record medium according to claim 1, wherein said optical record medium is an optical card.

3. An optical record medium according to claim 1, wherein said second record layer is formed by a rewritable record layer.

4. An optical record medium according,to claim 3, wherein said rewritable record layer is formed by a magnetic tape.

5. An optical record medium according to claim wherein said data record region and said control information record region are divided for managing various purposes, and the divided data record regions correspond to the divided control information record regions respectively.

6. An optical record medium according to claim 5, wherein said divided data record regions have different data recording formats from each other.

7. An optical record medium according to claim 1, wherein said second record layer is formed by an optical record layer of write once type.

8. An optical record medium according to claim 7, wherein said control information,record region comprises a plurality of record portions divided by prerecord marks corresponding to the number of data record tracks in said record region to be managed.

9. An optical record medium according to claim 8, wherein said prerecord mark has a different reflectivity as compared with that of the other portion.

10. An optical record medium according to claim 8, wherein a write mark representing an attribute of data recorded on the data record track is recorded on said record portion corresponding to the data record track.

11. An optical record medium according to claim 8, wherein the data are successively recorded on data record tracks in said data record region, and a write mark representing the end of recording operation on the data record track is recorded on said record portion corresponding to the data record track.

1 k p 1 1

12. An optical record medium according to claim 7, wherein the data are successively recorded on data record tracks in said data record region, and said control information record region comprises a write mark whose length corresponds to the number of the recorded data record tracks in said data record region.

13. An optical record medium according to claim 12, wherein said write mark comprises a plurality of marks each having a constant length And recorded continuously.

14. An optical record medium according to claim 7r wherein the data are successively recorded on data record control number record tracks in said data record region, and said information record region comprises pits whose corresponds to the number of the recorded data tracks in said data record region.

15. An optical record medium according to claim 14, wherein said pits are recorded by a constant interval.

16. An optical record medium as hereinbefore described with reference to Figures 1, 2, 3, 4, 5, 11, 14 and 15 of the accompanying drawings.

17. A method for recording a,control information of an optical record medium comprising data record 3 tracks on which data are recorded in an optically readable manner and at least one control information record track on which a control information is recorded, comprising the steps of reading the control information record track to detect a control information of the latest data to be managed, reading the data from the data record track corresponding to the detected control information to renew the data, recording the renewed data on a data record track, and recording a control information of the renewed data on said control information record track.

18. A method according to claim 17, wherein said control information recording step comprises a step of recording a write mark whose length corresponds to the number of the recorded data tracks on the control information record track.

19. A method according to claim 17, wherein said control information recording step comprises a step of recording pits whose number corresponds to the number of the recorded data tracks on the control information record track.

20. A method as hereinabove described with reference' to Figures 9, 12 and 13 of the accompanying drawings.

Published 19BE at The Patent Office, State House. 6671 High Holborn, London WCIR 4TP. Further copies may be obtained from The patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD Printed by Multiplex techniques IUL St Mary Cray, Kent. Con. 1/87. DaAUb Dr&IIE;11, OL MaLtry Vrdy, Uj'pLrj4gLon, isem nsto ortij t=Teci oy bmuitipiex wwLitiqutib it" o4 attLry ui-ay, -- --- - - - 1