Dynamic information storage or retrieval – Control of storage or retrieval operation by a control...
Reexamination Certificate
2002-11-27
2004-08-03
Edun, Muhammad (Department: 2655)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
C369S047110, C369S053450, C369S059100
Reexamination Certificate
active
06771574
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a technique for reading disk management information in a disk device.
2. Description of the Related Art
In read-only disks, such as CDs or ROMs, or recording medium, such as optical disks, mainly intended for recording audiovisual information, there is no area for, defect management made available in advance, and the processing method against any defect in the medium is determined on the system side as required. Unlike them, optical disks, such as DVD-RAMs, for which emphasis is placed on securing reliability at or above a certain level by standardizing the defect processing method, and erasable type disks, such as magnetic disks, are checked for defects sector by sector or on some other prescribed basis at the time of manufacture and supplied to the market in a state in which the addresses of sectors or other units containing the detected defects are recorded in a prescribed area. How to record management information on these defects is determined in a protocol governing the pertinent type of disk. An erasable disk conforming to the ISO/IEC 10089.13549 protocol, for instance, has defect management information consisting of defective sectors and substitute sectors therefor in two areas each at the inner and outer ends of the user area in the disk. Namely the disk holds altogether four sets of the same management information on the inner and outer circumferences. These areas are known as defect management areas (DMAs). In the following description, the defect management information mentioned above will be referred to as first management information. The aforementioned erasable disk conforming to the ISO/IEC 10089.13549 protocol also has two sets of file management information known as the universal disk format (UDF) at the inner and outer ends of the user area. In the following description, the aforementioned UDF will be referred to as second management information. In a conventional optical disk device for recording or reproducing information onto or out of this disk, when turning on power supply to the device and when inserting the disk, all the second management information recorded in the two areas at the inner and outer ends of the user area is read in after reading in all the first management information recorded in the two areas at the inner and outer ends. The reason why the same sets of information are recorded into a plurality of areas apart from each other is that in this way the reliability of the records themselves can be increased and the reproducibility of the management information can be enhanced against impediments (including fingerprints, dust and flaws) that may arise after the information is recorded.
When all the first management information and the second management information are read by the method described above into the erasable disk provided with medium management information areas on its inner and outer circumferences, the optical head should make at least one round trip between the inner and outer circumferences of the disk, resulting in a long time taken before the recording or reproduction of information can be started. This problem is especially conspicuous with optical disk devices in which the head travels more slowly than the magnetic head. Examples of related art are found in, for instance, in the Japanese Patent Applications Laid-open Nos. 11-25575 and 10-269709. The Japanese Patent Application Laid-open No. 11-25575 discloses a technique by which, when the device finds the medium to be erasable after power supply is turned on or the medium is inserted, it reads out DMA information on the inner circumference, then records and reproduces a pattern in a drive test zone on the inner circumference to adjust recording power, moves the pickup to another drive test zone on the outer circumference to adjust recording power similarly, and processes start-up by reading out DMA information on the outer circumference. The Japanese Patent Application Laid-open No. 10-269709 describes a technique by which, in a magnetic disk device using an inerasable magnetic disk, information on the assignment of substitutes for defective portions and information on associations between defective portions and substitutes are stored into an erasable non-volatile memory to reduce the time taken to access data and to eliminate the exhaustion of the backup battery. When an instruction is received from a superior device to read in or write in a range containing defective portions, the data and management information of the aforementioned sectors are read out of written into the non-volatile memory.
On the other hand a mobile video camera or the like, which is often required to record a contingent event in a hurry, keenly needs a reduction in the length of time taken to start up. This necessitates a further cutback on the processing time of management information and the like. To meet this requirement, a conventional disk device reads first management information (medium management information) on an optical disk when the optical disk is inserted, stores the information into a D-RAM or the like, and holds the first management information in the D-RAM or the like as long as the main power is on before the optical disk is ejected. In this manner, even if the disk revolution is stopped in the power saving mode when no demand for recording or reproduction comes for a long period of time, recording or reproduction, when it is resumed, can be done using the held first management information without having to read the first management information on the disk. However, once the main power is turned off, the management information stored in the D-RAM or the like is lost.
However, by the above-described technique of storing the first management information (medium management information) into a D-RAM or the like, the first management information can be held only while the main power is on, and once the main power is turned off, the previously held first management information is lost. Therefore, if the main power is once turned off and again turned onto perform recording or reproduction, even if the disk is neither inserted nor ejected, it is necessary to take time and read the prescribed management from the outset. On the other hand, the technique disclosed in the Japanese Patent Application Laid-open No. 10-269709 takes no account of disk insertion or ejection, and accordingly cannot be applied to a disk device for which the disk is replaced. Moreover, as the technique disclosed in this application performs erasion using a non-volatile memory which permits erasion only a relatively small number of times, the memory may become unusable soon.
Or if a battery-drivable CMOS memory or the like is used instead of a non-volatile memory to store information on the replacement of defect-containing sectors in a disk and data to be stored there, a capacity of about 10 MB is likely to be required, and this would necessitate a large-capacity battery for driving the memory, making it difficult to reduce the size and cost of the device. The technique described in the cited patent application also involves an unsolved problem that, when processing is to be resumed after the replacement of the disk or temporary suspension, the time take to acquire and process management information should be reduced to shorten the start-up time.
According to the prior art, for instance, if a disk is already in the device when the main power is turned on but there is not management information or the like regarding the disk, it will be necessary to take out of the management information necessary for recording or reproduction by reading the prescribed full course of reading management information. However, if there is already management information or the like regarding the disk already acquired by the disk device and the acquired information is reliable, that acquired information can be used. If the acquired information is unreliable, management information and the like on the disk should be read and confirmed at least
Fujimoto Masahiro
Minabe Kouji
Nishijima Hideo
Uemura Kazunori
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