Realtime data recording method

Details Realtime data recording method Realtime data recording method

1999-02-25

2003-10-14

Tran, Thai (Department: 2615)

Motion video signal processing for recording or reproducing

Local trick play processing

With randomly accessible medium

C386S349000

Reexamination Certificate

active

06633724

ABSTRACT:

FIELD
The present invention relates to a realtime data recording method and apparatus, and more particularly, to a realtime data recording method and apparatus having an arrangement allowing file data which was recorded without corresponding updated management data (e.g., due to an apparatus fault), to be accessed and management data related thereto to be updated, and is especially useful for a camcorder recording system using an optical disk, a magneto-optical disk or the like.
BACKGROUND
Recently, with popularization of computers, an optical disk, a magnetic disk, a magneto-optical disk and the like have become popular and miniaturized, and further, with development of image-signal digital processing techniques, “compression-encoding” processing can now be performed with respect to image data without serious degradation of image quality. One example implementation of use of such image processing techniques is a camcorder having one of the above-mentioned mass-storage arrangements. In the magnetic disk, the optical disk, the magneto-optical disk and the like, data such as the aforementioned image data can be stored thereon, and such data may be managed as files. Although practice of the present invention is not limited thereto, the following discussions will focus on examples using a magneto-optical disk to record image (e.g., video) data. However, it should be remembered that such focus is made only for the sake of brevity/conciseness of this disclosure.
For file management, files may be arranged according to a logical structure having a management data and a file data part, with a predetermined number of bytes constituting a sector and a predetermined number of sectors corresponding to the logical structure. A command of recording, reproduction or deletion of a file may be inputted and conducted with respect to the magneto-optical disk. When the command of recording, reproduction or deletion is inputted, data is recorded, reproduced or deleted with respect to a file area of the disk.
With regard to problems to be solved by the invention, in a disadvantageous file management arrangement, when data is to be recorded as a file, file data is recorded in a data recording area, and then management data is recorded in corresponding management (e.g., directory and file name/size) area on the disk. More particularly, attention is directed to the recording operation flowchart
500
of
FIG. 5
, wherein after a start block
502
, flow moves to a block
504
where a predetermined amount of sectors of file data are recorded onto a recording medium. At a block
506
, it is determined whether recording of file data onto the recording medium has been finished, and if not, flow moves through loop
508
and again to block
504
to conduct additional recording of file data. Once it is determined within block
506
that recording of file data has been finished, flow moves to a block
510
wherein a bitmap of recorded sectors on the recording medium is updated, then to a block
512
wherein file management data on the recording medium is updated, and finally, flow is ended at an end block
514
. The bitmap may have bits in one-to-one correspondence to available sectors on the recording medium, and may have a first logical value (e.g., a logical “1”) written within bitmap bits where data has been written into a corresponding recording medium sector, or a second logical value (e.g., a logical “0”) written within bits where data has not been written into a corresponding sector.
In the above recording method, for example, if a disturbance (e.g., a fault of power loss, a mechanical shock due to droppage, vibration) occurs in the apparatus before the blocks
510
or
512
are performed, file management data on the recording medium will not be updated to match the file data which has been newly written, and accordingly, the recording medium's file management information and file data will be mismatched, and a data and/or system error may occur if the faulted recording medium is attempted to be read/reproduced. Such problem is especially likely to occur in image recording apparatuses, where the above “compression encoding” processing may be performed, for example, for long term processing/recording for a video image on a tape capable of holding a video of about 80 minutes long. That is, since file data with respect to the video image is recorded for substantially long bursts of time (e.g., 5-10 minutes) with a camcorder before the management data is updated, if a disturbance occurs (e.g., power loss, mechanical shock, vibration, etc), a substantial amount of recorded file data may be lost, i.e., lost because of non-updated/mismatched management data.
As further limitations which may contribute to the fault potential, physical and processing limitations of the recording apparatus and/or the compression/recording processes may prevent the management data from being updated more frequently. More particularly, the file data area and the management data area on the recording medium may be physically separated from one another, such that a substantial amount of time may be required to move a recording head from one area to the other, preform recordation, and then move back again. In direct opposition, image data compression and recording may be an extremely time/processing intensive operation requiring substantially uninterrupted use of the recording head for recording at the file data area, i.e., time/processing requirements may be so intensive that there may be insufficient time to move the recording head from the file data area to the management data area, perform management data updating, and then move the recording head back to the file data area, without suffering substantial image data loss.
As a result of all of the foregoing, the above-described problem that data being recorded upon occurrence of fault cannot be read is highlighted.
Art of possible interest with respect to the present invention includes Japanese Patent Application Laid-Open No. 9-167447. Such technique provides an arrangement which allows determination of the existence/absence of a recording abnormality. However, with such technique, content of data management information cannot be read, and further, recorded data recorded before the abnormality cannot be recovered as a readable file.
SUMMARY
Accordingly, a first embodiment of the present invention is directed to a data recording method for realtime recording a file onto a recording medium, including the steps of: before recording of the file, first generating management data pertaining to a realtime recording of the file to be recorded, and non-volatilely storing the management data; next, recording file data for the file on the recording medium; then, updating the management data to reflect an actual status of recording the file data, and non-volatilely storing the updated management data.
Another embodiment is directed to a realtime data recording method for recording data in a realtime manner on a random-accessible data recording medium, including: before recording of file data, generating initial management data for the file data to be recorded, then recording the initial management data on the data recording medium, and starting recording of the file data on the data recording medium; during the recording of the file data on the data recording medium, at least intermittently generating realtime management data corresponding substantially to a realtime the file data recorded on the data recording medium, and recording the realtime management data in a non-volatile recording medium different from the data recording medium; and upon restarting a use of the data recording medium after occurrence of a fault, reading the initial management data and detecting the fault, and using the realtime management data from the non-volatile recording medium to generate updated management data, and recording the undated management data onto the data recording medium.


REFERENCES:
patent: 5241672 (1993-08-01), Slomcenski et al.
patent: 5787445 (1998-07-01), Daberko
patent: 5799212 (1998-08

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