Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the record
Reexamination Certificate
2001-12-18
2004-09-07
Hudspeth, David (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the record
C360S053000
Reexamination Certificate
active
06788487
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic tape apparatus, and in particular, a magnetic tape apparatus and a recording method for adequately controlling accesses to a magnetic tape so as to prevent a particular position thereof from being intensively accessed.
2. Description of the Prior Art
In a conventional magnetic tape apparatus, logical beginning of tape (BOT) that is the start position of record data is used as physical beginning of tape.
Various types of information about record data are recorded from the beginning. When the taps is loaded to the apparatus, the information is read. When the tape is to be unloaded from the apparatus, the tape is rewound beforehand. In the case of a DAT (Digital Audio Tape) apparatus, various types of information are written to a beginning portion of a data area as a vendor group. In most backup software programs, header information such as a tape name and date of creation managed by the software program is written to a beginning block. When a tape is loaded or a backup software program is started, the vendor group or the header information is read.
In addition, there are several types of magnetic tapes that are for example cartridge type and open reel type. In addition, one type of cartridge magnetic tapes has a memory that stores system information.
As was described above, in the conventional magnetic tape apparatus, since the number of times a particular position such as the beginning portion of the magnetic tape has been accessed is much larger than the number of times the other portion has been accessed. Thus, the tape is not effectively used. Since the particular portion is quickly worn out, the life of the tape shortens.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to solve the problem of the prior art and to provide a magnetic tape apparatus and a recording method for sequentially moving a logical BOT (not limited to a physical BOT) so as to averagely and effectively use the entire magnetic tape.
According to a first aspect of the present invention, there is provided a magnetic tape apparatus for accessing a magnetic tape, the apparatus comprising: means for assigning a logical beginning of tape position on the magnetic tape and updating the logical beginning of tape position, the logical beginning of tape position being different from a physical beginning of tape position of the magnetic tape; and means for recording system information to the logical beginning of tape position.
In the magnetic tape apparatus, a logical end of tape position may be the same as a physical end of tape position on the magnetic tape.
The magnetic tape apparatus may further comprise: means for assigning a logical end of tape position on the magnetic tape and updating the logical end of tape position.
In the magnetic tape apparatus, the logical end of tape position may be adjacent to the logical beginning of tape position.
The magnetic tape apparatus may further comprise: means for measuring an error rate of data read from the magnetic tape and the number of times the magnetic tape has been accessed, wherein when the error rate exceeds a predetermined value and/or the number of times the magnetic tape has been accessed exceeds a predetermined value, the logical beginning of tape position may be updated.
In the magnetic tape apparatus, an updated logical beginning of tape position may be apart from the last logical beginning of tape in a predetermined direction by a predetermined distance.
In the magnetic tape apparatus, the magnetic tape may be contained in a cartridge which has a memory, and the apparatus may further comprise: means for writing/reading information on the logical beginning of tape position to/from the memory.
In the magnetic tape apparatus, a first group at the logical beginning of tape may be a vendor group, and the apparatus may further comprise: means for reading information on the logical beginning of tape position from the memory and reading information in the vendor group on the basis of the information on the logical beginning of tape position when the cartridge is loaded to the magnetic tape apparatus.
In the magnetic tape apparatus, the magnetic tape apparatus may use helical scan method.
According to a second aspect of the present invention, there is provided a magnetic tape cartridge having a cartridge, a magnetic tape, and a memory, wherein a logical beginning of tape is recorded to the magnetic tape, and wherein information on the logical beginning of tape position is written to the memory.
In the magnetic tape cartridge, data may be written on the magnetic tape by helical scan method.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of the best mode embodiment thereof, as illustrated in the accompanying drawings.
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Hudspeth David
NEC Corporation
Slavitt Mitchell
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