Data recording method and data recording/reproducing device, recording medium

The present invention provides a data recording method a data recording and/or reproducing apparatus for recording data transmitted from a computer to a magnetic tape. In case a recording head fails to write data (data ID=582) of fragment ID=5 to a track (track 7), then, the data is rewritten to the first fragment (ID=0) of a next track (track 8). Thus, the data can be rewritten not on the track basis but on the fragment basis, which can reduce loss of tape capacity significantly.

TECHNICAL FIELD

The present invention relates to a data recording method for recording data transmitted from a computer to a magnetic tape, etc., a data recording and/or reproducing apparatus, and a recording medium.

BACKGROUND ART

Conventionally, there is known the Digital Audio Tape (DAT) as a system for recording and reproducing digital data, in particular digital data of music, to and from a magnetic tape. Also, there is used the Digital Data Storage (DDS) as a system for recording and reproducing digital data of large capacity (several G bytes˜scores of G Bytes) stored in a computer to and from a magnetic tape based on the DAT.

In the DDS, inclined tracks are recorded to a magnetic tape using a tape streamer of the helical scanning type having rotary heads. In each of the tracks, there are recorded 96 data blocks called fragments. In each of the fragments, a fragment ID to discriminate the respective fragments from others is recorded other than recording data.

In a recording and/or reproducing apparatus of the DDS, read after write (RAW) processing is performed to monitor whether or not fragments are normally recorded. In case a fragment is not normally recorded, rewrite processing is performed to rewrite a track including the fragment entirely to another position.

In the rewrite processing, even though there is raised only one fragment which is not normally recorded, a track including the fragment is rewritten entirely to another track. Also, since several tracks during a period from the time when a fragment which is not normally recorded is detected and until the time when the rewrite processing is performed are caused to be dummy, there is raised a problem that loss of tape capacity is enlarged.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention has an object to overcome the above-mentioned drawbacks of the prior art by providing a data recording method, a data recording and/or reproducing apparatus, and a recording medium which can reduce loss of tape capacity to the utmost.

The above object can be attained by providing a data recording method for recording tracks each composed of a plurality of data blocks each containing recording data to a tape-shaped recording medium, wherein

each of the data blocks has recorded therein a first identifier to identify the block in the track, and

each of the data blocks has recorded therein a second identifier to identify the recording data recorded in the data block.

Also, the above object can be attained by providing a data recording and/or reproducing apparatus for recording tracks each composed of a plurality of data blocks each containing recording data to a tape-shaped recording medium, including:

means for recording a first identifier to identify the block in the track to each of the data blocks, and

means for recording a second identifier to identify the recording data recorded in the data block to each of the data blocks.

Also, the above object can be attained by providing a recording medium of a tape shape which is to have recorded thereto tracks each composed of a plurality of data blocks each containing recording data, wherein

each of the data blocks has

a first area in which a first identifier to identify the block in the track is recorded, and

a second area in which a second identifier to identify the recording data recorded in the data block.

Thus, according to the present invention, each of the data blocks has recorded therein the second identifier to identify the recording data recorded in the data block. So, data can be rewritten on the data block basis, which can reduce loss of tape capacity significantly as compared with the conventional manner.

These objects and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will further be described below concerning the best modes with reference to the accompanying drawings.

FIG. 1shows a block diagram of a tape streamer drive1employing the DDS recording system according to the present invention. The tape streamer drive1uses a tape cassette in which a magnetic tape of 8 mm in width is housed, and records and reproduces data to the magnetic tape in the helical scanning manner.

As shownFIG. 1, a rotary drum13has two recording heads15a,15band two reproducing heads16a,16barranged thereon. The rotary drum13has a magnetic tape14wound around the side thereof which is drawn from a tape cassette, and is caused to rotate by a drum motor12. Also, the magnetic tape14is caused to run by a capstan motor and a pinch roller (not shown). The drum motor12is controlled by a mechanical controller10which performs drum servo processing, tracking servo processing, etc. The mechanical controller10is bidirectionally connected to a system controller6which controls the tape streamer drive1wholly.

Recording data to be recorded to the magnetic tape14is modulated by a modulation/demodulation circuit9, and modulated data is supplied to the recording heads15a,15bvia an RF amplifier11. Then, the recording heads15a,15bwrite thus supplied data to the magnetic tape14forming inclination against the longitudinal direction of the magnetic tape14. The recording heads15a,15bhave azimuth angles different from each other. Thus, two tracks recorded by the recording heads15a,15bwith inclination are of azimuth angles different from each other.

An SCSI interface4is used to send and receive data. In recording data to the magnetic tape14, a host computer3sends data with its one record formed by 32 kilo bytes to a data compression/expansion circuit5via the SCSI interface4.

The data compression/expansion circuit5performs compression and expansion of data using LZ codes. Using the LZ codes, repetition of input strings are detected to compress data. For example, specific codes are allocated to strings which are processed in the past, and are stored in a lexicon. Then, input strings are contrasted with the lexicon, and input strings which correspond to the lexicon are replaced with the lexicon codes, while the specific codes are allocated to input strings which do not correspond to the lexicon to be registered in the lexicon. Thus, data is compressed by registering input strings in a lexicon and replacing strings with lexicon codes.

In recording data to the magnetic tape14, data from the host computer3is sent to the data compression/expansion circuit5via the SCSI interface4. Then, the data compression/expansion circuit5compresses thus supplied data, and sends compressed data to a buffer controller7. Then, the buffer controller7stores the compressed data in a buffer memory8temporarily. Data is recorded for each group. One group is made up of data of tracks of a predetermined number. Data corresponding to one block which is sent from the buffer memory8is supplied to the modulation/demodulation circuit9. Then, the modulation/demodulation circuit9modulates the recording data, and sends modulated data to the recording heads15a,15bvia the RF amplifier11. Then, the recording heads15a,15bwrite the modulated data to the inclined tracks on the magnetic tape14.

In reproducing data from the magnetic tape14, the reproducing heads16a,16bread out data recorded on the magnetic tape14, and send thus read out data to the modulation/demodulation circuit9via the RF amplifier11. Then, the modulation/demodulation circuit9demodulates the read out data, and sends demodulated data to the buffer controller7. Then, the buffer controller7stores the demodulated data in the buffer memory8temporarily. Data which is sent from the buffer memory8is supplied to the data compression/expansion circuit5. Then, the data compression/expansion circuit5expands thus supplied data to restore original data. Then, the restored original data from the data compression/expansion circuit5is sent to the host computer3via the SCSI interface4.

FIG. 2shows a format on the magnetic tape14in employing the tape streamer drive1. There are arrayed 96 blocks B numbered from 0 to 95, each containing a fragment ID as an identifier, in an inclined track Tn which is recorded by one recording head.

FIG. 3shows a format of one block of the respective blocks shown inFIG. 2. As shown in the format, the block are composed of or divided into sync patterns21, a fragment ID22as a first identifier, an area ID29, a frame number28, subcodes24, header parities25, a data ID26as a second identifier, and user data27.

The sync patterns (B1˜B8)21have recorded therein patterns for synchronously detecting the head of the fragment ID22. The subcodes24have recorded therein data to which track numbers for search are attached. The user data27have recorded therein divided user data to which serial numbers from 0 to 123 are attached. The data ID26has recorded therein identifiers for identifying data recorded in the block to which a serial number beginning from 0 is attached. That is, for example, in case the fragment ID of the second track is 0 (first block), the data ID of the first block is 96. Also, in case the fragment ID of the seventh track is 5 (sixth block), the data ID of the sixth block is 582.

Next, the method for recording the data blocks shown inFIG. 2andFIG. 3will be explained.

As shown inFIG. 1, data from the host computer3is sent to the buffer memory8via the SCSI interface4and the data compression/expansion circuit5to be temporarily stored therein. Then, thus stored data is sent to the recording heads15a,15bvia the modulation/demodulation circuit9and the RF amplifier11under the control of the system controller6and the buffer controller7. Then, the recording heads15a,15bwrite thus supplied data to the magnetic tape14. At this time, the reproducing heads16a,16b,which rotate together with the recording heads15a,15b,read out the recorded data, and store thus read out data in the buffer memory8for performing parity check. The parity check may be performed, for example, every one track. Then, as shown inFIG. 4, in case the recording head15afails to write data of fragment ID=5 (data ID=582) to the seventh track (track7), the failure is detected by the parity check. Then, the data is rewritten to the first fragment (ID=0) of the next eighth track (track8). Thus, only the fragment of data ID=582 is rewritten, and rewriting of all the track is not necessary.

Next, the method for reproducing thus recorded data will be explained. For example, in case a direction of reproduction from fragment0to fragment10of the track7shown inFIG. 4is sent from the host computer3, among data of the track7and a track8which is read out by the reproducing heads16a,16band stored in the buffer memory8, data recorded in from fragment0to fragment4of the track7, data recorded in fragment0of the track8, and data recorded in from fragment6to fragment10of the track7is sent to the host computer3via the data compression/expansion circuit5and the SCSI interface4under the control of the system controller6and the buffer controller7.

FIG. 5shows rewriting of all the track in the conventional manner. As shown, even though only one fragment ID=5 of the track7is not normally recorded, the entire track T7has to be recorded to a track12, which is the fifth track from the track7. Furthermore, since four tracks during a period from the time when the fragment which is not normally recorded is detected and until the time when the rewrite processing is performed are caused to be dummy, loss of tape capacity is enlarged.

On the other hand, in the embodiment according to the present intention, in case one fragment ID=5 of the track7is not normally recorded, data ID 582 is rewritten to the first fragment ID=0 of the eighth track T8, as shown inFIG. 6, which can significantly reduce loss of tape capacity.

INDUSTRIAL APPLICABILITY

As in the above, according to the present invention, data can be rewritten not on the track basis but on the fragment basis, which can reduce loss of tape capacity significantly.