Information recording/reproducing method

Abstract: An information recording/reproducing method in which a recording area is divided into a plurality of zones in the radial direction of a disk so that the lengths of recording pits may become the same in the entire recording area of the disk and the recording/reproduction of information is effected with the number of revolutions of the disk changed in each zone from the inner peripheral zone toward the outer peripheral zone includes the step of effecting the recording or reproduction of the information without changing the number of revolutions if the amount of information to be recorded or reproduced is equal to or smaller than a predetermined amount when seeking is effected from a zone in which a recording/reproducing head is on standby to a different zone to effect the recording or reproduction.

Description: This invention relates to an information recording or reproducing method of effecting the recording and/or reproduction of information on a disk-like recording medium, and particularly to an information recording/reproducing method in which the recording area of a recording medium is divided into a plurality of zones in the radial direction of the recording medium and the recording/reproduction of information is effected with the rotational speed of the disk made different in each zone, whereby the spatial record lengths of recording pits are made constant over the entire recording area. Information recording/reproducing methods of recording/reproducing information on a disk-like recording medium (hereinafter referred to as the disk) include a magnetic recording/reproducing method directed to a floppy disk and an optical information recording/reproducing method directed to a CD or a magneto-optical disk. The diameter of disks used in these methods is prescribed as 5.25 or 3 inches, and the recent technical task is how densely information can be recorded on disks of such a diameter. Various information recording/reproducing methods have heretofore been devised to solve such a task and above all, attention has been paid to a method called MCAV (modified constant angular velocity) or ZCAV (zone constant angular velocity). According to this method, the recording area on the disk is divided into a plurality of zones in the radial direction of the disk, and the recording/reproducing frequency of each zone is made higher from the inner peripheral zone toward the outer peripheral zone, thereby making the recording density on the inner and outer peripheries of the recording area constant. According to this method, as compared with the conventional method of effecting recording/reproduction with the rotational speed and the recording/reproducing frequency kept constant, there is obtained an about 50% increase in capacity. Another method to which attention has been paid is a method called MCLV (modified constant linear velocity) or ZCLV (zone constant linear velocity) in which the recording area on the disk is divided into a plurality of zones in the radial direction of the disk and the rotational speed of the disk in the respective zones is made lower from the inner peripheral zone toward the outer peripheral zone, thereby making the recording density on the inner and outer peripheries of the recording area constant. Again by this method, as compared with the conventional CAV method, there is obtained an about 50% increase in capacity. In the former method, however, the linear velocity of the disk is increased toward the outer periphery of the disk and this leads to a problem that the transfer speed of reproduced data is varied by the reproducing position of the disk, and the usability as an information recording/reproducing apparatus has been bad. Also, a reproducing signal processing system must satisfy the transfer speed of the outermost peripheral data, and such a signal processing system has become an excessive quality and wasteful in the inner peripheral portion of the disk. Also, in the latter method, the transfer speed of reproduced data is constant in the inner and outer peripheries of the disk, but when the access of a recording/reproducing head is done beyond the zone, a long time is taken until the rotational speed of a spindle motor for rotating the disk becomes equal to the rotational speed of the corresponding zone, and this has led to a problem that the access time becomes long. The present invention has been made in view of the above-noted problems and has as a concern the provision of an information recording or reproducing method in which recording density is made constant on the inner and outer peripheral portions of a disk to thereby increase the recording density, to keep the transfer speed of reproduced data constant in the inner and outer peripheral portions, and additionally to have a long start access time. PCT Patent Specification No. W088/01786 discloses an information bearing disk which has a plurality of equally spaced data storing tracks grouped in a plurality of annular zones encircling the center of the disk. The ratio of the radius of the innermost track of any given zone to the radius of the innermost track of the adjacent inner zone is a constant, k, calculated from formula (I), where R 0 is the outer radius of the outermost zone of the disk, R i is the inner radius of the innermost zone of the disk, and N is the number of disk zones. In order to overcome the problem of changing spindle speed within a brief interval during read operations, it is proposed to maintain the angular velocity of the disk constant and thereby let the read data rate vary as data is read from one zone to the next. In accordance with one aspect of the present invention there is provided a method of recording information as set out in claim 1. In accordance with a second aspect of the present invention there is provided a method for reproducing information as set out in claim 12. In order that the present invention may be more readily understood, embodiments thereof will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a block diagram showing an embodiment of information recording/reproducing apparatus for carrying out the information recording/reproducing method of the present invention. Figure 2 is a flow chart showing the operation of a first embodiment of the present invention. Figure 3 is a flow chart showing the operation of a second embodiment of the present invention. Figure 4 is a flow chart showing the operation of a third embodiment of the present invention. Figure 5 is a flow chart showing the operation of a fourth embodiment of the present invention. Figure 6 is a time chart illustrating a predetermined amount of information in the present invention. Figure 7 is a schematic view illustrating the first embodiment of the present invention. Figure 8 is a schematic view illustrating the first embodiment of the present invention. Figure 9 is a schematic view illustrating the second embodiment of the present invention. Figure 10 is a schematic view illustrating the third embodiment of the present invention. Figure 11 is a schematic view illustrating the fourth embodiment of the present invention. Figure 12 is a schematic view illustrating the fifth embodiment of the present invention. Figure 13 is a chart illustrating an information recording/reproducing system in a sixth embodiment of the present invention. Figure 14 is a flow chart illustrating a seventh embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will hereinafter be described with reference to the drawings. Figure 1 is a block diagram showing an embodiment of an information recording/reproducing apparatus for carrying out the information recording/reproducing method of the present invention. In Figure 1, the reference numeral 1 designates a disk-like information recording medium having concentric or spiral tracks formed in a recording area provided on the surface thereof. The reference numeral 2 denotes a spindle motor for rotating the disk 1, the reference numeral 3 designates a rotational speed changing switch for selectively changing the speed of the spindle motor 2, the reference numeral 4 denotes a signal processing speed changing switch for selectively changing the processing speed of a signal processing circuit, the reference numeral 5 designates signal processing frequency setting means for setting the signal processing speed, i.e., the signal processing frequency, of the signal processing circuit selected by the signal processing speed changing switch 4, the reference numeral 6 denotes a rotation frequency setting circuit for determining the rotational speed selected by the switch 3, the reference numeral 7 designates a signal processing circuit for processing a recording/reproducing signal sent to or obtained from a recording/reproducing head, and the reference numeral 8 denotes a CPU for controlling the switch 3 and the signal processing speed changing switch 4. The CPU 8 executes access of the disk on behalf of an outside host computer (the access herein referred to is the access of the recording/reproducing head and will hereinafter be simply referred to as the access), the control of the rotational speed changing switch 3 and the signal processing speed changing switch 4 on the basis of the access and a command for recording or reproduction, and judgment based on a flow chart which will hereinafter be described. The reference numeral 9 designates a memory connected to the CPU 8, and the reference numeral 10 denotes the recording/reproducing head. On the basis of the above-described construction, description will now be made of the operation in each embodiment of the present invention. In the present invention, as shown in Table 1, the tracks in the recording area of the recording medium are divided in advance into zones logically in the unit of plural tracks in the radial direction of the recording medium, and in each zone, the recording/reproducing operation is effected with a predetermined number of recording revolutions. Also, the rotational speed of the recording medium for a recording/reproducing operation differs from zone to zone, and becomes higher toward the inner periphery of the recording medium. At this time, the recording/reproducing frequency (specifically, the frequency of a clock signal which takes the modulation timing of recorded data and the demodulation timing of reproduced data) is the same among the zones. Thus, the lengths of recording pits are the same (constant in recording density) in the entire recording area of the disk. The present invention is based on the so-called MCLV recording/reproducing system. A first embodiment of the present invention will hereinafter be described with reference to a flow chart shown in Figure 2. When an instruction for access and recording/reproducing comes from the outside host computer to the CPU 8, the CPU 8 judges whether the instruction is for access to the inner peripheral zone of the disk or not (the same zone or the outer peripheral zone). If the instruction is for access to the inner peripheral zone, the CPU 8 then judges whether the amount of information to be recorded/reproduced exceeds a predetermined amount. Here, the predetermined amount is the amount of information to be recorded or reproduced when the total of the time during which the speed of the spindle motor is varied to a speed corresponding to the zone to be sought and the time required for recording or reproducing at the varied speed coincides with the total of the average access time and the time required for recording or reproducing at the speed for the previous zone, and is prescribed by the following equation (1): B = R T (T R -T A ){R 1 /(R 2 -R 1 )} where T A is the average access time, T R is the time required for increasing the rotational speed, B is the amount of information to be recorded/reproduced (the number of bytes), R T is a recording/reproducing transfer rate corresponding to a predetermined zone, R 1 is the present rotational speed and R 2 is a rotational speed corresponding to the zone to be sought. In an example shown in Figure 6, from the above equation (1), the predetermined amount is 420 K byte. When 420 K byte is exceeded, it will shorten the whole processing time to increase the speed to a speed corresponding to the zone to be sought and effect recording/reproduction. For the reason set forth above, if the amount of information to be recorded/reproduced is equal to or greater than the predetermined amount, the switch 3 is controlled to increase the rotational speed of the spindle motor 2 to the speed corresponding to the zone to be sought and at the same time, access is executed and recording/reproduction is effected. Thereafter, there is brought about the state where the spindle motor waits for an instruction at that speed If the amount of information is smaller than the predetermined amount, access is effected without changing the rotational speed of the spindle motor 2 and the switch 4 is controlled to change the recording/reproducing frequency of the signal processing circuit 7 so that even if in the zone to be sought, recording/reproduction is effected at that rotational speed the length of recording pit in that zone may be the same as the length of recording pit in the other zones, and recording/reproduction is effected. Thereafter, there is brought about the state in which the spindle motor waits for an instruction at that speed. When access is to be effected in the same zone and recording/reproduction is to be effected, the speed of the spindle motor 2 and the recording/reproducing frequency of the signal processing circuit are not changed. Also, when access is to be effected in the outer peripheral zone and recording/reproduction is to be effected, the switch 3 is controlled to change the speed of the spindle motor 2 to the speed for the corresponding zone, and the recording/reproducing frequency of the signal processing circuit is not changed. Figure 7 is a schematic view showing the operation when the amount of information is smaller than the predetermined amount, and although when the spindle motor is rotating at 2400 rpm in a zone A, there has come an instruction to access to the inner peripheral zone B and effect recording/reproduction, the speed should originally become 3000 rpm in the zone B because the amount of information is smaller than the predetermined amount, but yet recording/reproduction is effected at 2400 rpm. Figure 8 is a schematic view showing the operation when the amount of information is equal to or greater than the predetermined amount, and simultaneously with access, the speed of the spindle motor is increased to 3000 rpm which is the rotational speed for the zone B, and recording/reproduction is effected. According to the present invention, even if the recording/reproduction of a small amount of information frequently takes place from a zone corresponding to the speed at the starting point of time to the inner peripheral zone, the speed is not changed each time and therefore, the access time can be shortened and thus, the recording/reproducing process time can be shortened. A second embodiment of the present invention will now be described with reference to the flow chart of Figure 3 and the schematic view of Figure 9. The speed of the spindle motor 2 at the starting point of time will be described with respect to a case where the spindle motor is rotating at a speed of 2400 rpm corresponding to the zone A in Table 1. The operation of the present embodiment follows the operation of the aforedescribed first embodiment. An instruction for access and recording/reproducing comes from the outside host computer to the CPU 8 and which zone should be sought is stored in the memory 9. The recording/reproducing head is in the zone A at first and has sought the zone B more inner than the zone A, but the amount of information to be recorded/reproduced is smaller than the predetermined amount (the amount of information defined by the aforementioned equation (1)) and therefore, recording/reproduction is executed still at 2400 rpm. Thereafter, which zone has been accessed is stored in the memory 9 each time access is effected, so that the history of the zones which have been accessed ten times in the past can be known. In the case of Figures 3 and 9, an instruction for accessing and recording/reproducing finally comes from the state of B.B.B.B.B.A.B.B.B.A. (present → past), and by an instruction for seeking to the zone B, there is brought about the state of B.B.B.B.B.B.A.B.B.B. (present → past), and the frequency of access to the zone B exceeds 90%. That is, the frequency with which access and recording/reproduction are executed in the zone B exhibits a high probability, and the adoption of 3000 rpm corresponding to the zone B results in better recording/reproducing process efficiency in terms of time. Accordingly, when the CPU 8 judges that fact in accordance with the content of the memory, the speed of the spindle motor 2 is increased to 3000 rpm after the recording/reproducing process when so judged is terminated, and the next instruction is waited for. A third embodiment of the present invention will now be described with reference to the flow chart of Figure 4 and the schematic view of Figure 10. In the previous embodiment, the frequency of zone access has been calculated from the history of the past zone access, and on the basis of the result thereof, the rotational speed has been adjusted, but a simpler algorithm is shown in Figure 4. The difference of the present embodiment from the previous embodiment is that whether the same zone has been accessed ten times on end in the past and recording/reproduction is effected is judged and if the same zone has been accessed ten times on end in the past and recording/reproduction is effected, the rotational speed of the spindle motor 2 is increased to the rotational speed for that zone. The present embodiment is simpler in control than the previous embodiment. The previous embodiment will be sufficiently effective even if access is effected only for the recording/reproduction of an amount of information smaller than the predetermined amount of information. A fourth embodiment of the present invention will now be described with reference to the flow chart of Figure 5 and the schematic view of Figure 11. In the previous embodiment, when the amount of information to be recorded/reproduced is equal to or greater than the predetermined amount, the rotational speed has been increased, and recording/reproduction has been executed, whereafter there has been brought about the state in which the instruction is waited for, but when the next instruction is to access the outer peripheral zone it has been necessary that the rotational speed of the spindle motor 2 be decreased without fail to the speed for a corresponding zone. The reason for this will hereinafter be described. In the MCLV system, this premises that over the entire recording area, recording/reproduction is effected at substantially the same recording/reproducing frequency, but the recording/reproducing frequency set for that purpose is usually increased as much as possible in practice to enhance the transferring rate. As previously described, when without the speed of the spindle motor 2 being changed, access is to be effected from the zone in which the head is at present to the inner peripheral zone and recording/reproduction is to be effected, the recording/reproducing frequency must be changed, but in such case, the speed is higher for the inner peripheral side zones and thus, the recording/reproducing frequency is made lower than the recording/reproducing frequency when recording/reproduction is effected at the rotational speed for a corresponding zone. However, when the outer peripheral zone is to be accessed, an attempt to effect recording/reproduction at the number of revolutions before access without the speed of the spindle motor 2 being decreased to the speed for a corresponding zone makes it necessary to increase the recording/reproducing frequency. In such case, as previously described, the recording/reproducing frequency when recording/reproduction is effected at the rotational speed corresponding to that zone is increased as much as possible in practice, and it is possible in performance to reduce the frequency below it, but it is unreasonable in performance to increase the recording/reproducing frequency above it. Therefore, when the outer peripheral zone is accessed the rotational speed of the spindle motor 2 must be decreased without fail to the speed to the zone to be sought. The present embodiment shortens the processing time to the utmost when the outer peripheral zone is accessed for recording/reproduction. The recording area on the disk is first divided into a plurality of partitions, and then the head is moved to the outermost peripheral zone in one of the partitions to effect a continuous recording/reproducing process. The spindle motor 2 is then rotated at a rotational speed corresponding to the outermost peripheral zone in that partition (the partition referred to here is the recording area logically divided to efficiently manage the information on the recording medium, and includes a plurality of zones). According to Figure 11, the spindle motor starts at 2400 rpm, the speed corresponding to the outermost peripheral zone A in the partition consisting of zones A, B and C. Next, when there is an instruction for accessing and recording/reproducing, whether the position to be sought is the outermost peripheral zone in the partition is judged. If it is the outermost peripheral zone, the instruction is executed without the rotational speed being changed. If the position to be accessed is any other zone than the outermost peripheral zone, whether the amount of information to be recorded/reproduced next is equal to or greater than the predetermined amount (the amount of information prescribed by the aforementioned equation (1)) is judged. If the amount of information to be recorded/reproduced is smaller than the predetermined amount, the instruction is also executed without the rotational speed being changed. If the amount of information to be recorded/reproduced is equal to or greater than the predetermined amount, the rotational speed is increased to a speed corresponding to the zone to be accessed and the instruction is executed. Thereafter, the rotational speed of the spindle motor 2 is restored to 2400 rpm, this corresponding to the outermost peripheral zone in the partition, and an instruction is waited for in the zone wherein recording/reproduction has been effected. In the present embodiment, after the process in a zone or a series of processes are terminated, the rotational speed of the spindle motor is restored to the speed corresponding to the outermost peripheral zone in the partition and therefore, even if the next instruction is to access a zone in the outer peripheral direction, it is unnecessary to change the rate of revolution and simply by changing the recording/reproducing frequency (but only in the partition), the instruction can be executed. Thereby, when access is effected to a zone in the outer peripheral direction the processing time can also be shortened to the utmost. Also, in the present embodiment, design may be made such that after the execution of an instruction, return is made to a predetermined position (which is set arbitrarily) in the outermost peripheral zone in the partition and an instruction is waited for. In such case, however, said predetermined amount may be the amount of information to be recorded or reproduced when the total of the time during which the speed of revolution is changed to the speed corresponding to the zone to be accessed, the time required for recording or reproducing at the changed rotational speed and the time during which the rotational speed is decreased to the rate corresponding to the outermost peripheral zone in the partition coincides with the total of the time required for access (a time double the average access time) and the time required for recording or reproducing at the speed for the previous zone. It is prescribed by the following equation (2): B = 2R T (T R -T A ){R 1 /(R 2 -R 1 )} where T A is the average access time, T R is the time required for increasing the rotational speed, B is the amount of information to be recorded/reproduced (byte number), R T is the recording/reproducing transferring rate corresponding to a given zone, R 1 is the present rotational speed and R 2 is the rotational speed corresponding to the zone to be sought. In the present embodiment, when an amount of information equal to or greater than the predetermined amount is to be continuously recorded/reproduced, the rotational speed of the disk need not be changed to the rate speed corresponding to the outermost peripheral zone in the partition even after a recording/reproducing process is terminated. A fifth embodiment of the present invention will now be described. In a magneto-optical disk or the like, where the recording area is divided into partitions, FAT in each partition and information managing regions such as directory, directory entry and defect table exist and these are distinguished from the recording area used by the user. The frequency of access by the head to the information managing regions is high. In the present invention, as shown in Figure 12, in a partition a (a portion of zone A and zone B), the information managing region of that partition is placed in the zone B, and in a partition β (a portion of zone B, zone C and zone D), the information managing regions is placed in the zone D. By providing the information managing region in the outermost periphery in each partition like this, even if the rotational speed is not changed, it is made possible to carry out the recording/reproducing process in the information managing region by only changing the recording/reproducing frequency, and the processing time is shortened. Also, the present embodiment may be used in combination with the operation of the previous fourth embodiment. That is, when the recording/reproducing process in a zone or a series of recording/reproducing processes are terminated, the rotational speed is changed to a speed corresponding to the outermost peripheral zone in the partition wherein the head is at present and the next instruction is waited for. A sixth embodiment of the present invention will now be described with reference to Figures 12 and 13. In Figure 13, the reference numeral 11 designates a magneto-optical disk apparatus, the reference numeral 12 denotes a host computer for controlling the magneto-optical disk apparatus 11, and the reference numeral 13 designates a display such as a CRT. The interior of the magneto-optical disk apparatus is of such a construction as shown in Figure 1. The operation in the above-described construction will hereinafter be described. Usually, the system as shown in Figure 13 is used in a mode for effecting the search for information stored in a recording medium in the magneto-optical disk apparatus and a mode for effecting the recording/reproduction of information on the recording medium in the magneto-optical disk apparatus, and with this point taken into account, the present invention makes the search mode and the recording/reproducing mode selectively changeable over by the host computer 12 on the basis of the user's judgment. When the user selects the search mode, an instruction therefor goes from the host computer 12 to the CPU 8 of the magneto-optical disk apparatus 11, and in the CPU 8, the spindle motor 2 is first rotated at the rotational speed rate corresponding to the outermost peripheral zone in the partition wherein search information exists, and then, when an instruction for access and search arrives from the host computer 12, whether the position to be sought is the outermost peripheral zone in the partition is judged. If said position is the outermost peripheral. zone, the instruction is executed without the rotational speed rate being changed. If said position is any other zone than the outermost peripheral zone, whether the amount of information to be accessed next is equal to or greater than the predetermined amount (the amount of information prescribed by the aforementioned equation (1)) is judged. If it is smaller than the predetermined amount, the instruction is also executed without the rotational speed rate being changed. If said amount of information is equal to or greater thap the predetermined amount, the speed is increased to the speed corresponding to the zone to be sought and the instruction is executed. Thereafter, the rotational speed of the spindle motor 2 is restored to the speed corresponding to the outermost peripheral zone in the partition, and an instruction is waited for (see the flow chart of Figure 5). When the recording/reproducing mode is selected, an instruction therefor goes from the host computer 12 to the CPU 8 of the magneto-optical disk apparatus 11, and in the CPU 8, when an instruction for access comes from the host computer 12, whether the instruction is for access to the inner peripheral zone of the disk or not (the same zone or the outer peripheral zone) is judged. If the instruction is for access to the inner peripheral zone, whether the amount of information to be recorded/reproduced is equal to or greater than the predetermined amount (the amount of information prescribed by the aforementioned equation (1)) is judged. If the amount of information to be recorded/reproduced is equal to or greater than the predetermined amount, the switch is controlled to increase the rotational speed of the spindle motor 2 to the speed corresponding to the zone to be sought and at the same time, access is executed and recording/reproduction is effected. Thereafter, an instruction is waited for at that rotational speed rate. If the amount of information is smaller than the predetermined amount, access is executed without the rotational speed rate of the spindle motor 2 being changed and the switch 4 is controlled to change the recording/reproducing frequency of the signal processing circuit 7 so that in the zone to be accessed,the length of recording pit may become the same as that length of recording pit in the other zones even if recording/reproduction is effected at that rotational speed, and recording/reproduction is effected. Thereafter, an instruction is waited for at that speed. When seeking is effected in the same zone and recording/reproduction is effected, the rotational speed of the spindle motor 2 and the recording/reproducing frequency of the signal processing circuit are not changed. Also, when access is effected to the outer peripheral zone and recording/reproduction is effected, the switch 3 is controlled to change the rotational speed of the spindle motor 2 to the rate for the corresponding zone and the recording/reproducing frequency of the signal processing circuit is not changed (see the flow chart of Figure 5). As described above, in the search mode, the file of a small amount of reproduction is frequently accessed beyond the zone and therefore, the control system shown in the flow chart of Figure 5 is effective, and in the recording/reproducing mode, recording/reproduction is continuously effected and therefore, the control system shown in the flow chart of Figure 2 is effective. In the present invention, the selection of these modes is not judged by the CPU 8 of the magneto-optical disk apparatus 11, but the modes are changed over on the basis of the user's judgment and therefore, it becomes possible to shorten the processing time. A seventh embodiment of the present invention will now be described with reference to the flow chart of Figure 14. In the control method based on the flow chart of Figure 2, access is effected from the zone A in which the head is at present to the zone B more inner than the zone A and further, when the amount of information to be recorded/reproduced is smaller than the predetermined amount, the instruction is executed without the rotational speed rate of the spindle motor 2 being changed, and even if thereafter an instruction for recording/reproducing an amount of information equal to or greater than the predetermined amount comes into the same zone B, the instruction is executed without the speed rate of the spindle motor 2 being changed. In the present invention, however, when an instruction for effecting recording/reproduction in the same zone has come after access is effected to the inner peripheral zone and the recording/reproduction of an amount of information smaller than the predetermined amount is effected without the rotational speed rate being changed, if the amount of information to be recorded/reproduced is equal to or greater than the predetermined amount (the amount of information prescribed by the aforementioned equation (1)), the speed rate of the spindle motor 2 is increased and recording/reproduction is effected. The processing time is thus shortened.

Claims: An information recording method in which a recording area is divided into a plurality of zones (A, B, C) in the radial direction of a disk so that the lengths of recording pits become the same in the entire recording area of the disk and the recording of information is effected with a disk rotational speed which changes from one zone to another, characterised in that: if the amount of information to be recorded is equal to or smaller than a predetermined amount, or if frequency of recording relative to the zone where the recording is to be effected, exceeds a predetermined value, the recording of information is effected without changing said rotational speed. A recording method according to claim 1, wherein said rotational speed becomes greater from the outer peripheral zone toward the inner peripheral zone. A recording method according to claim 2, wherein said predetermined amount is the amount of information to be recorded when the total of the time during which the speed is changed to a speed corresponding to the zone to be accessed and the time required for recording said changed rotational speed coincides with the total of the average access time and the time required for recording at rotational speed for the previous zone. A recording method according to any one of claims 1 to 3, including the step of: effecting, when a zone in which the frequency of recording exceeds a predetermined value is accessed in a series of recording operations, the next recording is carried out at a rotational speed corresponding to that zone. A method according to any preceding claim, including the step of: effecting, when a zone in which recording is effected continues a predetermined or greater number of times, the next recording or reproduction is carried out at a rotational speed corresponding to that zone. A method according to claim 5, wherein the frequency of said continuance is directed to only recording in which the amount of information to be recorded is equal to or smaller than a predetermined amount. A method according to any preceding claim, wherein said recording area is divided into a plurality of partitions including the plurality of zones, and the management information of each partition is located in the innermost peripheral zone in said partition, and effecting recording of the information without changing the rotational speed between the zone having said managed information recorded therein and the other zones when recording in said partition is effected. A method according to claim 1 or claim 2, including the step of: dividing said recording area into a plurality of partitions including a plurality of zones, and changing, after one cycle of recording is completed when the recording of continuous information is effected in one of said partitions, the rotational speed to a speed corresponding to the outermost peripheral zone in that partition. A method according to claim 8, wherein when an amount of information equal to or greater than a predetermined amount is continuously recorded or reproduced in said partition, the rotational speed is not changed to a speed corresponding to the outermost peripheral zone in said partition even if the recording or reproduction of a bit of information in that partition is completed. A method according to claim 1 or claim 2 effecting the recording of the information without changing the rotational speed and also waiting at that speed after the termination of the recording if the amount of information to be recorded is equal to or smaller than a predetermined amount when access is effected from a zone in which the recording head is on standby to the inner peripheral zone to effect the recording, effecting the speed of the information at said rotational revolutions if the amount of information to be recorded is equal to or smaller than the predetermined amount when the next recording is effected in the same zone, and effecting the recording of the information with the rotational speed changed to the speed corresponding to that zone if said amount of information is greater than the predetermined amount. A method according to claim 1, including: a first control step including the following operations: (1) effecting the recording of the information without changing said rotational speed if the amount of information to be recorded or reproduced is equal to or smaller than a predetermined amount when access is effected from a zone in which a recording head is on standby to the inner peripheral zone to effect recording, effecting the recording of the information with the rotational speed increased to a speed corresponding to the zone to be accessed if the amount of information to be recorded is greater than the predetermined amount, and waiting for the next recording at the rotational speed during recording after the termination of a series of recording operations; (2) effecting recording without changing the previous speed when the recording operation is to be performed in the zone wherein the recording head is on standby, and waiting for the next recording at the same speed during recording after the termination of a series of recording operations; (3) effecting the recording of the information with the rotational speed decreased to a speed corresponding to the zone to be accessed when access is effected from the zone in which the recording head is on standby to the outer peripheral zone to effect recording, and waiting for the next recording at the same speed during recording after the termination of the series of operations; a second control step including the following operations: first, adopting the rotational speed for the outermost peripheral zone in the partition wherein the recording head lies now; (1) effecting the reproduction of the information using the recording head as a reproducing head without changing said rotational speed if the amount of information to be reproduced is equal to or smaller than a predetermined amount when access is effected from a zone in the partition wherein the head is on standby to a different zone to effect reproduction, effecting the reproduction of the information with the speed increased to a speed corresponding to the zone to be accessed if the amount of information to be reproduced is greater than the predetermined amount, and waiting for the next reproduction with the speed decreased to a speed corresponding to the outermost peripheral zone in the partition after the termination of a series of reproducing operations; (2) effecting the reproduction of the information without changing said rotational speed if the amount of information to be reproduced is equal to or smaller than a predetermined amount when the reproducing operation is performed in the zone wherein the reproducing head is on standby, effecting the reproduction of the information with the speed increased to a speed corresponding to the zone if the amount of information to be reproduced is greater than the predetermined amount, and waiting for the next reproduction with the rotational speed decreased to a speed corresponding to the outermost peripheral zone in the partition after the termination of a series of reproducing operations; (3) effecting the reproducing operation without changing the speed when access is effected from the zone in which the head is on standby to the outer peripheral zone to effect reproduction, and waiting for the next reproduction at a speed corresponding to the outermost peripheral zone in the partition after the termination of the series of reproducing operations; and the step of changing over said first control step and said second control step in conformity with the situation. A method of reproducing data information comprising carrying out the steps of any one of claims 1 to 10 wherein a recording step is replaced by a reproducing step.

Inventors: WATANABE YOSHIHIKO, WATANABE, YOSHIHIKO, Watanabe, Yoshihiko, c/o Canon Kabushiki Kaisha
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1992
Main classification: G11B20
IPC codes: G11B7, G11B21, G11B20, G11B19