Positioning controller

A positioning controller can position a head at a starting position of an unrecorded region on a disk in a shorter time than a conventional positioning controller, information being recorded on the disk by means of the sequentially inner-to-outer recording method or the sequentially outer-to-inner recording method. The positioning controller judges whether or not information is recorded at a predetermined position on the disk, and then executes the binary search method in a recording direction from the predetermined position of the disk when judged the information is recorded at the predetermined position or in a direction opposite to the recording direction from the predetermined position when it is judged that the information is not at the predetermined position. Therefore the direction in which searching by the binary search method is executed is determined by the above judgement. The term "the sequentially inner-to-outer recording method" means a method for recording information sequentially from the most inner track to the most outer track on the disk. And the term "the sequentially outer-to-inner recording method" means a method for recording information sequentially from the most outer track to the most inner track on the disk. The present invention is particularly applicable to write-once optical disk storages.

What is claimed is:

1. A positioning controller which is used for a disk storage device including a disk on which addresses are prerecorded in a recordable region by means of sequential addressing, disk driving means for driving of the disk, a head for recording information on the disk and reproducing information therefrom, and actuating means for moving the head to a position corresponding to a predetermined address on the basis of address information indicating the predetermined address, the information being recorded sequentially on the disk, said positioning controller comprising:

first control means for controlling an operation of the disk driving means and/or a recording and/or reproducing operation of the head;

second control means, connected to the actuating means, for supplying the address information to the actuating means;

first judging means, connected to said first control means and second control means, for judging whether or not the information is recorded on an arbitrary position on the disk;

position searching means, connected to said first judging means, after the information is reproduced by the head at a predetermined position by said first control means and said second control means, for executing a first binary search for addresses from the predetermined position in a forward direction in which the information is recorded if said first judging means judges the information is recorded at the predetermined position, for executing a second binary search for addresses from the predetermined position in a backward direction opposite to the forward direction if said first judging means judges the information is not recorded at the predetermined position, for continuing one of the first binary search and the second binary search in the forward direction if said first judging means judges the information is recorded at a searched position which has been searched by one of the first binary search and the second binary search, and for continuing one of the first binary search and the second binary search in the backward direction if said first judging means judges the information is not recorded at a searched position which has been searched by one of the first binary search and the second binary search, in order to search a target address before second information is recorded on the disk, which target address approximately corresponds to the last recorded position of first information recorded just before the second information; and

memory means, connected to said position searching means, for memorizing the target address searched by said position searching means as the address information, the target address being one of a last recorded address corresponding to the last recorded position of the first information and a recording start position next to the last recorded address in the forward direction, and said second control means being connected to said memory means for supplying the address information memorized by said memory means to the actuating means so that the head is positioned at the recording start position corresponding to the recording start address.

2. A positioning controller according to claim 1, wherein the predetermined position is at an almost central position of the disk corresponding to an address having a number which is half the total number of addresses.

3. A positioning controller according to claim 1, wherein said position searching means further comprises:

first searching means for searching a first address located in the vicinity of the target address by executing a binary search a predetermined number of times according to a judgment of said first judging means; and

second searching means, connected to said first judging means and the first searching means, for searching sequentially from the first address in the forward direction if said first judging means judges the information is recorded at the first address, and for searching sequentially from the first address in the backward direction if said first judging means judges the information is not recorded at the first address, in order to search the target address.

4. A positioning controller according to claim 3, wherein the second searching means detects the target address to be one of the last recorded address and the recording start address by means of the level of a reproduced signal of the information, the second searching means detecting the recording start address because of the low level of the reproduced signal thereat if the information is recorded at the first address, the second searching means detecting the last recorded address because of the high level of the reproduced signal thereat if the information is not recorded at the first address, and said memory means memorizing the target address and correlating the target address with the level of the reproduced signal.

5. A positioning controller according to claim 4, wherein said second control means further comprises second judging means for judging whether the target address memorized by said memory means is the last recording address or the recording start address on the basis of the level of the reproduced signal, and the second control means supplies the address information to the moving means according to a judging result of the second judging means.

6. A positioning controller according to claim 1, wherein said position searching means further comprises:

third searching means for searching sequentially a predetermined number of addresses initially in the forward direction, the information being reproduced by the head at the predetermined position only when the third searching means can not search the target address.

7. A positioning controller according to claim 6, wherein the predetermined position is a position corresponding to a fifth address which is centered between a third address and a fourth address, the third address being located farthest in the forward direction among the predetermined number of addresses, and the fourth address being located farthest in the forward direction among all addresses on the disk.

8. A positioning controller according to claim 3, wherein said position searching means further comprises:

third searching means for searching sequentially a predetermined number of addresses initially in the forward direction, the information being reproduced by the head at the predetermined position only when the third searching means can not search the target address.

9. A positioning controller according to claim 1, wherein said positioning controller further comprises:

third judging means for judging whether or not the disk storage device has a predetermined status, said positioning searching means beginning to search the target address only when the third judging means judges the disk storage device has a predetermined status.

10. A positioning controller according to claim 7, wherein the status is a recording mode.

11. A positioning controller according to claim 7, wherein the disk storage device includes said first control means, said second control means, said first judging means, said position searching means and memory means.

12. A positioning controller according to claim 1, wherein said first control means, said second control means, said first judging means and position searching means are located in a microcomputer connected to the disk storage device, and said memory means is located in a random access memory which is connected to the microcomputer.

13. A positioning controller according to claim 1, wherein the disk is a write-once optical disk, the head is an optical head, and the disk storage is a write-once optical disk storage.