Dynamic magnetic information storage or retrieval – General processing of a digital signal – Data verification
Reexamination Certificate
1995-01-20
2001-01-30
Hindi, Nabil (Department: 2753)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Data verification
C360S048000, C714S723000
Reexamination Certificate
active
06181498
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a recording and reproducing apparatus, an information signal recording and reproducing system and a method of managing invalid area information for use with a recording and reproducing system using a so-called data recorder as a storage apparatus in which data supplied from a host computer is digitally recorded on a recording medium and data digitally recorded on the recording medium is reproduced in response to a request from the host computer.
Digital data recorders (referred to hereinafter as “data recorders”) have hitherto been known to digitally record information to be recorded, i.e., file data, such as document data, program data, image data and audio data used on a computer, on a magnetic tape so as to form helical tracks.
The simplest system employing the data recorder is arranged as follows. A host computer and an SCSI (small computer systems interface) formatter are connected via an SCSI interface, and the SCSI formatter and a data recorder are connected via an RS422 interface. The SCSI formatter is adapted to form a file format on a tape to exchange data on the file format.
The format used by the data recorder will be described below. A logical volume that is equivalent to one drive on a hard disk or the like, for example, is set on the tape. One volume is composed of volume information formed of position information of various data in the logical volume and directory information composed of information provided within a directory. The directory information is read out by the SCSI formatter when a tape cassette is loaded onto the data recorder and stored in a memory of the SCSI formatter. File data or the like supplied from the host computer is recorded behind the directory information.
The host computer issues a write command. Then, when file data (or a plurality of file data) is supplied to the SCSI formatter, the SCSI formatter sequentially accumulates file data supplied thereto in a buffer. When the host computer does not issue the next write command, the SCSI formatter adds data called EOD (end of data) to the last portion of data accumulated in the buffer and transfers the data stored in the buffer to the data recorder. The data recorder records data supplied thereto from the SCSI formatter on the tape so as to form slant tracks.
The EOD is information required by the SCSI formatter to recognize the status of recorded data and to control the data recorder based on such recognition when the shot computer issues the next command.
If the next command issued by the host computer is a write command, then when file data (or a plurality of file data) to be written next is stored in the buffer of the SCSI formatter, the SCSI formatter adds the EOD to the last portion of the data stored in the buffer and transfers the same to the data recorder. Simultaneously, the SCSI formatter sets the tape position of the data recorder to the position of the EOD recorded on the tape, whereby data supplied to the data recorder is sequentially recorded from the position of the EOD recorded on the tape. Accordingly, the previously-recorded EOD is erased by new data to be recorded next. Also, new EOD is added to the last portion of the new data, which as a result extends the USER area.
The SCSI formatter updates the directory information stored in the memory when data is written by the execution of write command. After the data is written, the directory information on the tape is updated by recording the directory information stored in the memory at the position where the directory information is recorded on the tape. Accordingly, when any command is supplied to the SCSI formatter from the host computer, the SCSI formatter constantly obtains accurate directory information on the tape by reading the updated directory information and can control the data recorder based on the accurate directory information.
U.S. Pat. No. 5,313,341 and Japanese laid-open patent publication No. 5-128807 describe the techniques relating to the above-mentioned recording and reproducing apparatus.
When the SCSI formatter records directory information on the tape of the tape cassette loaded onto the data recorder, if directory information cannot be updated because the supply of power to the data recorder and the SCSI formatter is stopped or because the data recorder and the SCSI formatter are failed, the tape cassette used at that time cannot be used any more.
The reason for this is that, although the directory structure on the tape is changed by the write operation, the directory information is not updated and hence information recorded on the tape cannot be accessed by the reference directory information.
When any accident occurs and the file format is troubled as described above, it is necessary to carry out a recovery operation to reconstruct a file format. In order to carry out the recovery operation, the SCSI formatter enables the data recorder to read the tape from its beginning to the end. Then, the SCSI formatter detects the directory structure on the tape by checking all resulting data. Thereafter, directory information has to be generated one more time based on the detected result. Therefore, the processing in the recovery operation becomes complex and takes plenty of time.
SUMMARY OF THE INVENTION
In view of the aforesaid aspect, it is an object of the present invention to provide a magnetic recording apparatus in which a recovery operation can be carried out in a short period of time with ease.
According to a first aspect of the present invention, there is provided a recording and reproducing apparatus for recording an information signal composed of at least data information and management information for managing the data information including at least invalid area information of a tape-shaped recording medium on the tape-shaped recording medium and reproducing the information signal from the tape-shaped recording medium. This recording and reproducing apparatus is comprised of recording and reproducing means for recording the information signal on the tape-shaped recording medium and reproducing the information signal from the tape-shaped recording medium, invalid area information memory means for temporarily memorizing the invalid area information reproduced from a predetermined position of the tape-shaped recording medium by the recording and reproducing means, invalid area detecting means for detecting an invalid area of the tape-shaped recording medium based on an information signal reproduced from the tape-shaped recording medium by the recording and reproducing means, invalid area information updating means for updating invalid area information memorized in the invalid area information memorizing means each time the invalid area is detected by the invalid area detecting means, and control means for controlling the recording and reproducing means such that the recording and reproducing means records end information including end position information representing a recording end position of the data information and the invalid area information memorized in the invalid area information memorizing means on the tape-shaped recording medium each time recording of the data information by the recording and reproducing means is interrupted and that the recording and reproducing means overwrites the management information in which at least the invalid area information is updated at the predetermined position of the tape-shaped recording medium when the tape-shaped recording medium is unloaded.
According to a second aspect of the present invention, there is provided an information signal recording and reproducing system which is comprised of a tape-shaped recording medium recording and reproducing apparatus for recording an information signal composed of data information and management information for managing the data information including at least invalid area information concerning an invalid area of the tape-shaped recording medium on the tape-shaped recording medium or reproducing the information signal from the tape-shaped recording
Kikuchi Akihiro
Miyakawa Teruyuki
Frommer William S.
Frommer Lawrence & Haug LLP.
Hindi Nabil
Kessler Gordon
Neal Regina Y.
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