Dynamic magnetic information storage or retrieval – General processing of a digital signal – Data verification
Reexamination Certificate
1996-01-24
2001-04-24
Sniezek, Andrew L. (Department: 2651)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Data verification
C360S072200, C360S073060, C360S074400, C360S128000, C386S349000, C386S349000
Reexamination Certificate
active
06222693
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic tape recording/reproducing apparatus for recording and reproducing digital data supplied from for example an external computer.
2. Description of the Related Art
A magnetic tape recording/reproducing apparatus that is used as an external storage unit for a computer is known. In this case, a drive unit that loads a digital cassette tape is connected to a host computer through an interface. As an example of the data recorder, a helical scan type recorder that records digital data on a cassette tape with a rotating head is known.
Such a data recorder is connected to for example a SCSI (Small Computer Interface System) standard interface. Since the host computer recognizes the interface unit as a data recorder, it has a function for generating a file format on a tape and sending/receiving data to/from the tape (this function is referred to as formatter). The interface unit has a buffer memory that temporarily stores data transmitted between the host computer and the data recorder.
When an uncorrected error that cannot be corrected by signal processes such as a data recording process and a signal reproducing process takes place, with data temporarily stored in a buffer memory, write retry/read retry operations can be performed for the magnetic tape. For example, when data is read from the buffer memory and recorded on the tape for every buffer unit, the write retry operation is performed at an area (including a non-record area) followed by an invalid area in which data has not been recorded. When data is reproduced, the read retry operation is performed from an area in which data has not been reproduced.
As described above, the write retry operation and the read retry operation for data are certainly effective if a magnetic tape is partially damaged. However, in the case that dregs adhere on the tape or that magnetic particles of the magnetic tape adhere on a recording head or a reproduction head (this situation is referred to as head clogging), even if the different heads are used, since the tape with dregs is used, the write retry operation and the read retry operation for data cannot be performed. Alternatively, even if the different tape is used or the record area on the tape is changed, since the heads with dregs are used, the write retry operation and the read retry operation for the data cannot be performed.
OBJECT AND SUMMARY OF THE INVENTION
The present invention is made from the above-described point of view. An object of the present invention is to provide a magnetic tape recording/reproducing apparatus for performing a retry operation so as to record/reproduce data to/from a magnetic tape even if data cannot be recorded or reproduced due to head clogging or the like.
The present invention is a recording apparatus for a magnetic tape, comprising a recording means having a magnetic head for recording input digital data on the magnetic tape at a normal speed, a reproducing means for reproducing data recorded by the recording means, a driving means for driving the magnetic tape, a detecting means for detecting an error in data reproduced by the reproducing means and outputting an error detection signal representing the detected result, and a control means for controlling the driving means and the recording means corresponding to the error detection signal so that the input digital data corresponding to the detected error is re-recorded on the magnetic tape after the magnetic tape is moved to a re-recording start position corresponding to a tape position at which the error is detected at a speed higher than the normal speed so as to remove dregs from the magnetic head and the magnetic head.
When data with an uncorrected error is detected by a system controller
31
, the system controller
31
sends a control signal to a motor drive circuit
49
. With the control signal, a motor
50
is driven and thereby a magnetic tape
91
is moved from a first position to a second position. Thereafter, the magnetic tape
91
is moved to the first position once again. At the first position, a write retry operation or a read retry operation is performed.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.
REFERENCES:
patent: 3731289 (1973-05-01), Batgert et al.
patent: 5043828 (1991-08-01), Sasho
patent: 5253126 (1993-10-01), Richmond
patent: 5349713 (1994-09-01), Stimpfl
patent: 5525902 (1996-06-01), Nakajima et al.
Aoki Shinji
Morita Shinya
Suzuki Kumiko
Chang Dexter T.
Frommer William S.
Frommer Lawrence & Haug LLP.
Sniezek Andrew L.
Sony Corporation
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