JP3757443B2 - Recording apparatus and recording method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is, for example, data streamer called data recording equipment, etc. suitable recording device for application in, it relates to a recording how.
[0002]
[Prior art]
In a helical scan recording system widely used in a data recording system using a magnetic tape as a recording medium, a magnetic tape is wound around a rotary head, and head scanning is performed obliquely with respect to the tape traveling direction, as shown in FIG. Thus, the track TK is formed on the magnetic tape T in an oblique direction.
[0003]
Among such data recording systems, there is one known as a so-called non-tracking system.
In the non-tracking method, as shown by Pa and Pb in FIG. 16 at the time of reproduction, a higher density scan is performed than at the time of recording, so that all data on the track TK can be read without accurately tracing the track. Further, the read data is rearranged by using addresses recorded together with the data so that an accurate reproduction data stream can be reconstructed.
[0004]
FIG. 17 shows the configuration of the track TK on the magnetic tape in the non-tracking method.
As shown in FIG. 17A, one track is composed of 108 blocks. One block is 288 bits.
The central 92 blocks of the track are used as a main data area, and an inner double recording area of 9 blocks and an outer double recording area of 7 blocks are formed on both sides thereof.
[0005]
In the inner double recording area, data having the same content as the blocks in the main data area 92 blocks away from the position in the outer direction is recorded, and in the outer double recording area, 92 blocks away from the position in the inner direction. Data having the same content as the block in the main data area is recorded.
Specifically, data having the same content as the first 7 blocks hatched in the data area DA1 in FIG. 17A is also recorded in the outer double recording area, and hatched in the data area DA2. Data having the same contents as the last nine blocks are also recorded in the inner double recording area.
[0006]
The inner double recording area and the outer double recording area are provided in order to improve the signal reading reliability at the start and end of the track in the relative relationship between the track and the head. In other words, even if the head hit position shifts due to the swing of the tape, the data as the blocks recorded in the main data area are compensated for each other, and the unreadable block (data Content) does not occur. For example, even if the start start position (scanning start position) of the track and the head is shifted and the first few blocks in the data area DA1 cannot be read, the data can be read from the outer double recording area.
[0007]
As for the main data area of 92 blocks, the central two blocks are sub-code (AUX), each block on both sides is IBG (Inter-block Gap), and each block on both sides is control code (CTL) area It is said. Further, 40 blocks of data areas DA1 and DA2 are formed on both sides thereof.
[0008]
The signal format within one block is as shown in FIG.
First, the first 11 bits are used as a sync pattern, and then the address ADRS is recorded with 13 bits. This address ADRS is composed of a 6-bit track address and a 7-bit block address.
Since the track address and the block address are recorded in each block in this way, the data stream can be reconstructed in an appropriate block order during reproduction.
[0009]
In the case of the non-tracking method, the reproducing head does not necessarily trace accurately on the track TK, so that all blocks can be read for each track by performing high-density scanning as shown in FIG. However, in this case, the reading order of each block is random. The read block data is temporarily stored in the RAM. At this time, a write address is generated on the RAM using a track address and a block address, and each block data is written. Therefore, at the stage where all the blocks are read for a certain track, all the data of that track are arranged on the RAM. Therefore, if the block data is read in order from the RAM, an appropriate data stream is reconstructed.
[0010]
Following the address ADRS, four words of P and Q parity (P _OD , Q _OD , P _EV , Q _EV ) are recorded with 12 bits each.
Following the parity word, 16-word data (DT _{1 to} DT ₁₆ ) is recorded with 12 bits each.
Following 16 words of data (DT _{1 to} DT ₁₆ ), two CRC (Cyclic Redundancy Check code) words are recorded with 12 bits each. In addition, an overwrite protect code (hereinafter referred to as OWP code) is recorded in the CRC word.
[0011]
In the non-tracking method, the recording area is allowed to be shifted, so that old data may remain unerased near both ends of the track. Further, due to dropout at the time of recording or clogging of the head, an unerased portion that has not been erased at the time of overwriting may occur. At the time of reproduction, such unerased data is erroneously recognized as correct data because the CRC becomes safe. Therefore, an OWP code is recorded as a code that is updated every break of the recording operation.
[0012]
At the time of reproduction, an OWP code is extracted from each block read for a track to be reproduced and scanned, and a reference OWP code is set by majority vote.
When an unerased portion is generated in a certain part in one track, the OWP code extracted from the unerased block is different from the OWP code extracted from the overwritten block.
However, when one track is played back, even if there are unerased parts, most of the correctly overwritten blocks can be read. Therefore, by taking a majority decision as the OWP code, the OWP code on the majority side is correctly overwritten. It can be discriminated from the OWP code set when it is set.
Then, the OWP code is set as the reference OWP code, and in the reproduction for the series of recordings, the data of the block having a different OWP code can be determined to be unerased data, and can be invalidated. It is possible to prevent the output of output data.
[0013]
The OWP code is recorded after arranging the same two words and taking a 24-bit CRC and exclusive-OR. Therefore, at the time of reproduction, the OWP code can be restored by taking exclusive logic with the CRC generated from the reproduction data.
[0014]
[Problems to be solved by the invention]
By the way, when recording data such as a computer program on a magnetic tape, it is necessary to avoid missing data or recording wrong data during recording. For this reason, the data recorded at the time of recording, called check after write, is checked immediately after recording.
For example, the heads A ₁ and B ₁ are provided as heads disposed on the rotating drum, and the heads A ₂ and B ₂ are provided at positions facing the heads A ₁ and B ₁ . Then, data is recorded as tracks by the heads A ₁ and B ₁ , and the data of the tracks recorded by the heads A ₂ and B ₂ is reproduced to check whether the data is correctly recorded.
The heads A ₂ and B ₂ trace the recorded tracks with a track difference of several tracks on the magnetic tape with respect to the heads A ₁ and B ₁ .
[0015]
Here, when recording is performed with the heads A ₁ and B ₁ , the track address (ADA-V) is a repetitive value of 0 to 31 and is incremented for each rotation of the drum, and the address ADRS of each block in FIG. Recorded in.
For example, when there is a data file recorded in the past on the tape T as shown in FIG. 18A, for each track constituting the data file, “0” to “31” as shown in FIG. 18B. Track address (ADA-V) is repeatedly recorded. As described above, the track address (ADA-V) is also used as the RAM address for temporarily storing data during recording and reproduction. That is, when the RAM has a capacity of 32 tracks, the track address (ADA-V) is used. -V) is set to a value from 0 to 31.
[0016]
For example, it is assumed that recording of a new data file is started from the position indicated as recording start in FIG. 18A following the data file recorded in the past.
In this case, if the track address (ADA-V) of the last track when the recording of the data file recorded in the past is “16”, the track address (ADA-V) is used for recording a new data file. The value of starts from “17”. For each track, the track address (ADA-V) is updated as “18” “19”... “31” “0” “1”.
[0017]
Here, when the recording by the heads A ₁ and B ₁ is started, the heads A ₂ and B ₂ that perform tracing with a track difference of several tracks are initially traced to the track of the past data file. Become. Therefore, the data traced by the heads A ₂ and B ₂ at this time is data having no correlation with the data of the tracks recorded by the heads A ₁ and B _{1 in the} current recording operation, and the head A ₂ , B ₂ are unnecessary for the data check.
[0018]
Actually, however, it cannot be determined from the reproduced data where the track by the current recording starts, so the data check process using the data read by the heads A ₂ and B ₂ is actually recorded as the current data file. Must be running before reaching the first track on which is started.
In addition, the data check process using data from tracks recorded in the past has a problem of wasteful power consumption and, in some cases, an inappropriate check operation is executed.
[0019]
Further, when a series of data files are recorded on the tape T as described above, an OWP code is added. For example, for a track that becomes a file X as shown in FIG. 19A, an OWP code is assigned to each block. Recorded as _X. For the track that is the file Y, the OWP code is recorded as OWP _{Y in} each block.
[0020]
For example, when the file X is reproduced, the reference OWP code is set to OWP _X and compared with the OWP code for each block to be read, and the case where it matches the reference OWP code is regarded as valid data. At this time, even if the reproduction scan is performed in the direction indicated by the broken line P in the drawing and the block of the file Y is read, the block is OWP _Y and is different from the reference OWP code (= OWP _X ). Not valid data.
Thereafter, when proceeding to the reproduction of the file Y, a larger number of OWP codes that become OWP _Y are read, so that the reference OWP code is changed to OWP _Y, and the block of the file Y becomes valid data.
[0021]
Here, it is assumed that the data file Z is overwritten at the tape position where the file X was recorded as shown in FIG. It is assumed that the OWP code in this case is OWP _Z.
However, it is assumed that some unerased parts have occurred for some reason such as clogging of the head, and the data of the past file X is partially left as shown by the hatched part REC-ER in FIG. .
[0022]
When this is reproduced, the data read from the tape T by the reproducing head includes the unerased data D _X constituting the file X in the middle of the data D _Z constituting the file Z as shown in FIG. Will be. The OWP code of the block that becomes the data D _X is OWP _{X as shown} in FIG.
[0023]
When reproducing the file Z, is first set to the reference OWP code OWP _Z, to be compared with the data D _Z become block OWP code (OWP _Z), as shown in FIG. 19 (f), the data by the matching D _Z is an effective reproduction output.
However, when proceeding to the reproduction of the remaining unerased portion (REC-ER), a large number of OWP _X are read, so that the reference OWP code is changed to OWP _X as shown in FIG. After the change of the reference OWP code, the unerased data D _X that is read out is processed as valid data. After reproduction of the unerased portion, many OWP _Z are read again, so that the reference OWP code is set to OWP _Z again, and the read data D _Z is set as an effective reproduction output.
As a result of the above operation, as shown in FIG. 19 (f), unnecessary data is made valid during the period ED _{1 in} the figure and read out during the period ED _{2 in} the figure. Legitimate data may be lost, which has been a serious problem of reducing reliability.
[0024]
[Means for Solving the Problems]
In view of these problems, an object of the present invention is to reduce power consumption by unnecessary processing and to improve reliability as a data recording / reproducing apparatus.
[0025]
Therefore, data recording is performed by forming one track with each block having a predetermined amount of data on the magnetic recording medium, and the track number for each track and the block number for each block are recorded together. When recording is started, recording is started after setting the track number to a predetermined fixed value, and reading of data is started. After the start of data reading, it is monitored that the track number of the read data becomes a predetermined fixed value, and the read data is used based on the fact that the track number becomes a predetermined fixed value. The operation for determining the suitability of the recording operation is started.
[0026]
That is, when the recorded data is read out immediately after recording and so-called check after write is performed, if the top track at the start of recording can be determined, the data read before reaching the top track is data that does not need to be checked. It is possible to control so as not to execute the check processing. In this case, if the track address ADA-V is set to a certain fixed value at the start of recording, the head track (block included in the head track) related to the recording operation can be determined.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a recording / reproducing apparatus according to an embodiment of the present invention will be described. This recording / reproducing apparatus is a data streamer for recording / reproducing computer data or the like using a magnetic tape as a recording medium. FIG. 1 shows a configuration as a data streamer, and FIG. 2 shows a configuration of an external device (such as a host computer) connected to the data streamer.
[0030]
First, the configuration of the data streamer 10 will be described with reference to FIG.
In FIG. 1, an interface 12 is connected to an external device such as a computer. The interface 12 supplies data supplied from an external device to the data processing circuit 13.
The data processing circuit 13 is connected to a data processing memory 14 and performs processing for converting data supplied from the outside into data for recording, and processing for converting reproduced data into data for output. In addition, a process of dividing data supplied from the outside into predetermined blocks and adding block number data and an error correction code for each block is performed. These data processing circuits 13 are performed under the control of a central control unit (CPU) 21 which is a microcomputer for controlling the operation of each part of the streamer.
[0031]
Then, the recording data processed for recording by the data processing circuit 13 is subjected to modulation processing for recording by the modulation circuit 15 to be a recording signal, and this recording signal is supplied to the RF amplifiers 16 and 17. In this case, the RF amplifier 16 and the RF amplifier 17 are alternately supplied for each track of recording data (the data for one track is composed of a plurality of blocks).
The RF amplifier 16 is connected to magnetic heads A1 and A2 in a rotary head drum (not shown) via a rotary transformer 18, and the recording RF signal amplified by the RF amplifier 16 is supplied to the magnetic head A1. Record on magnetic tape.
The RF amplifier 17 is connected to the magnetic heads B1 and B2 in the rotary head drum via the rotary transformer 18, and the recording RF signal amplified by the RF amplifier 17 is supplied to the magnetic head B1 to be magnetic tape. To record.
[0032]
The reproduction signals of the magnetic heads A1 and A2 are supplied to the RF amplifier via the rotary transformer 18, and the reproduction signal RF signal amplified by the RF amplifier 16 is detected by the detection circuit 19, and the reproduction data and The clock component is detected and supplied to the data processing circuit 13.
[0033]
Similarly, the reproduction signals of the magnetic heads B1 and B2 are supplied to the RF amplifier 17 via the rotary transformer 18, and the reproduction RF signal amplified by the RF amplifier 17 is detected by the detection circuit 20 and reproduced data is obtained. And its clock component are detected and supplied to the data processing circuit 13.
[0034]
The data processing circuit 13 performs a synthesis process for restoring the reproduced data to one track at a time using the data memory 14, and uses the error correction code added to the reproduced data to perform error detection and error correction processing. I do.
When the data of each track becomes complete data by the above processing, the data is supplied to the interface 12 together with the clock, and the reproduction data is transmitted to the connected external device side.
[0035]
In the case of this example, at the time of recording using the magnetic head A1 and the magnetic head B1, signals recorded using the magnetic head A2 and the magnetic head B2 are reproduced immediately after recording. In this case, the reproduction data supplied to the data processing circuit 13 performs error detection for each block using a correction code included in the reproduction data. Then, the presence / absence data of the detected error is added to the address data for each block and supplied from the interface 12 to the external device.
[0036]
Further, a RAM 22 in which a control program and the like are recorded is connected to the central controller 21 of this example. Based on the command from the central controller 21, the rotary head drum motor 24 is driven to rotate at a predetermined speed under the control of the drum motor drive circuit 23. In this case, the rotation state of the rotary head drum is detected by a frequency generator (FG) 25.
Further, the control motor 27 for winding the magnetic tape mounted on the recording / reproducing apparatus around the drum is driven under the control of the control motor driving circuit 26 based on a command from the central controller 21. Further, the sensor 28 detects the winding state of the magnetic tape.
[0037]
The arrangement of the magnetic head of the rotary head drum of this example is shown in FIG. As shown in FIG. 3, a magnetic head A1 and a magnetic head B1 are arranged on the rotary head drum 11 in the vicinity of a predetermined location. In this case, the azimuth angle of the magnetic head A1 and the magnetic head B1 is changed from one to the other, and the mounting height of the magnetic heads A1 and B1 is changed by one track.
The magnetic heads A1 and B1 are recording / reproducing heads.
[0038]
Two read-only magnetic heads A2 and B2 are arranged close to each other at a position 180 degrees away from the magnetic heads A1 and B1. For these two magnetic heads A2 and B2, the azimuth angle is changed to one and the other. That is, the magnetic heads A1 and A2 have one azimuth angle, and the magnetic heads B1 and B2 have the other azimuth angle. The mounting height of the magnetic head A2 and the magnetic head B2 is changed by one track.
[0039]
The mounting height of the other set of magnetic heads A2 and B2 with respect to one set of magnetic heads A1 and B1 is shifted by several tracks (here 6 tracks).
A magnetic tape T is wound around the rotary head drum 1 at an angle range of about 100 °.
[0040]
Since the four magnetic heads are arranged in this manner, the scanning shown in FIG. 4 is performed by each magnetic head by rotating the rotary head drum 11 once. That is, when the rotary head drum 11 rotates once and the magnetic head A1 scans the track along the locus indicated by A1 in FIG. 4, the magnetic head B1 scans the adjacent track delayed by one track with respect to the tape running direction. A trajectory B1 is obtained, the trajectory A2 of the magnetic head A2 is a trajectory delayed by 6 tracks from the trajectory A1 of the magnetic head A1, and the trajectory B2 of the magnetic head B2 is a trajectory delayed by 6 tracks from the trajectory B1 of the magnetic head B1.
[0041]
In the case of this example, a system capable of reciprocating the magnetic tape is used. In other words, when the cassette with the magnetic tape attached is mounted with the surface facing up, recording and playback can be performed in one direction on the upper side of the magnetic tape, and when the cassette with the magnetic tape mounted is mounted with the back side up, the magnetic tape It is possible to record and playback in the other direction of the lower stage. In FIG. 4 and the like, only one-way recording and reproduction patterns are shown as tape patterns.
[0042]
In the case of this example, since it is a non-tracking method, tracking control for matching the scanning trajectory of the magnetic head with the recording track during reproduction is not performed.
[0043]
Next, FIG. 2 shows a configuration of an external device connected to the data streamer having such a configuration. The data streamer 10 whose configuration has been described with reference to FIG. 1 is connected to a host computer 40 via a data converter 30.
[0044]
The host computer 40 includes a central control device 41 that is a main arithmetic processing unit, a memory 42 that stores data used for arithmetic processing, and a disk unit 43 that is a large-capacity data storage unit using a hard disk or the like. The disk unit 43 is connected to each part via an interface 44 and a bus line for transmitting data.
As this bus line, a bus line for data and a bus line for transmitting address data of the transmitted data are prepared. An interface 45 for connecting to the data converter 30 is connected to each bus line.
[0045]
Data sent from the interface 45 of the host computer 40 to the data conversion device 30 is converted into data that can be received by the data streamer 10 in the data conversion device 30 and transmitted to the interface 12 in the data streamer 10.
The data sent from the interface 12 in the data streamer 10 to the data converter 30 is converted into data that can be received by the host computer 40 in the data converter 30 and transmitted to the interface 44 in the host computer 40. The
[0046]
Next, processing when data supplied from the host computer 40 is recorded on a magnetic tape using the data streamer of this example will be described.
FIG. 5 is a diagram showing the recording timing of this example. As shown in FIGS. 5C and 5D, the magnetic head A2 and the magnetic head B2 are first connected to the magnetic tape during the period in which the rotary head drum 11 first rotates. Two adjacent tracks are reproduced at timings P1 and P2 at which T is scanned. However, at the start of recording, a portion having no recording track or a portion that becomes a file recorded in the past is reproduced.
Then, as shown in FIG. 5A, recording for one track is performed at a timing R1 when the magnetic head A1 scans the magnetic tape T. At this time, another recording magnetic head B1 does not perform recording at the timing of scanning the magnetic tape T as shown in FIG.
[0047]
As shown in FIGS. 5C and 5D, during the period in which the rotary head drum 11 makes one rotation next, two adjacent tracks are scanned at timings P3 and P4 when the magnetic head A2 and the magnetic head B2 scan the magnetic tape T. Reproduce. Then, as shown in FIG. 5B, recording for one track is performed at a timing R2 when the magnetic head B1 scans the magnetic tape T. At this time, recording is not performed at the timing of scanning the magnetic tape T, as shown in FIG.
[0048]
In this way, every time the rotating head drum 11 rotates, one track is recorded. At this time, since recording is performed by alternately using the magnetic head A1 and the magnetic head B1 having different azimuth angles, one recording azimuth angle track and the other recording azimuth angle track are alternately formed.
[0049]
Since the reproduction is performed by the magnetic heads A2 and B2 different from the magnetic heads A1 and B1 during recording, the recorded signal is immediately reproduced.
In this example, as shown in FIG. 4, since the track scanned by the magnetic heads A2 and B2 is a track delayed by 6 tracks from the track scanned by the magnetic heads A1 and B1, 6-track recording proceeds after the recording is started. At this point, the recorded signal is reproduced by the magnetic heads A2 and B2, and thereafter the recording signal is reproduced with a delay of 6 tracks. A so-called check after write process is performed by this reproduction signal.
[0050]
That is, the reproduction data detected from the reproduction signal being recorded is supplied to the data processing circuit 13, and error detection is performed for each block using the correction code included in the reproduction data.
When an error is detected, the track number and block number data, which are the address data of the block in which the recording error has occurred, are transmitted from the data processing circuit 13 to the data converter 30 via the interface 12.
On the data conversion device 30 side, the address data of the location where this recording error has occurred is stored.
[0051]
When the recording of one unit of data supplied from the host computer 40 is completed at this time, the data conversion device 30 requests the host computer 40 to retransmit the data of the portion where the recording error has occurred from the host computer. Send a signal. Then, the data output from the host computer 40 in response to the request signal is transmitted to the data streamer 10 via the data converter 30 and recorded on the magnetic tape again. Also at this time, as shown in FIG. 5, the recorded signal is reproduced immediately to check whether there is a recording error, and when the recording error is detected, the recording of the same data is further repeated.
[0052]
By recording in this way, for example, as shown in FIG. 6, when one unit of data D1 is recorded at a predetermined location on the magnetic tape, a portion in which a recording error has occurred in the recorded data D1. The data D1 is recorded again as data D1 ′ or D1 ″ after the portion where the data D1 is recorded.
When the amount of data D1 ′, D1 ″ to be rerecorded is small, not only the data of the block in which the recording error has occurred but also the data in the vicinity thereof are recorded again, and the data D1 ′, D1 ″ are recorded. Is recorded as data of at least several tracks.
[0053]
By performing the recording process as described above, the data supplied to the data streamer 10 is reliably recorded on the magnetic tape, and the data can be reliably stored. Furthermore, in this example, since the signal reproduced after recording is only subjected to error detection using a correction code, it is possible to easily determine the presence or absence of a recording error without performing processing such as verification of recorded data and reproduced data. It can be configured so that reliable recording is possible.
[0054]
As shown in FIG. 6, the data at the location where the recording error has occurred is recorded in another location on the magnetic tape, but the data is controlled under the control of the data converter 30 or the host computer 40 during reproduction. By correspondingly controlling the reproduction locations, the data can be reproduced as a continuous unit of data.
[0055]
Next, a description will be given of processing in the case where recorded data is reproduced from the magnetic tape and supplied to the host computer 40 using the data streamer 10 of this example.
FIG. 7 is a diagram showing the reproduction timing of this example. As shown in FIGS. 7C and 7D, the magnetic head A2 and the magnetic head B2 are first connected to the magnetic tape as shown in FIGS. Two adjacent tracks are reproduced at timings P11 and P12 for scanning T.
Then, as shown in FIGS. 7A and 7B, two adjacent tracks are reproduced at timings P13 and P14 when the magnetic head A1 and the magnetic head B1 scan the magnetic tape T. The timings P13 and P14 are preceded by 6 tracks before the tracks reproduced at the timings P11 and P12.
[0056]
Similarly, during the period in which the rotary head drum 11 next rotates, the magnetic head A2 and the magnetic head B2 are adjacent at the timings P15 and P16 when the magnetic tape T is scanned, as shown in FIGS. Two tracks are reproduced, and then, as shown in FIGS. 5A and 5B, adjacent two tracks are reproduced at timings P17 and P18 when the magnetic head A1 and the magnetic head B1 scan the magnetic tape T.
[0057]
Thereafter, reproduction using all four heads A1, A2, B1, and B2 is repeated for each rotation.
[0058]
The reproduction data detected from the reproduction RF signal is written in the data memory 14 connected to the data processing circuit 13.
Here, the configuration of the data memory 14 will be described. In the memory 14 of this example, recording areas for 32 tracks of 0V to 31V are prepared as shown in FIG. 8, and from the area of the track number 0V to the area of the track number 31V. After being written in order, the data is written back to the area of track number 0V, and the storage area for 32 tracks is used cyclically. In the area for one track, areas from 0BK to 107BK are set corresponding to 108 blocks.
[0059]
For example, when the recording signal of track number 2V is reproduced by magnetic head A1 at a certain timing, the reproduction data at this time is stored in the corresponding block position in the area of track number 2V. For example, if the data is block number 3, it is stored in the area of block number 3BK with track number 2V.
At this timing, the track reproduced by the magnetic head A2 becomes a recording signal of track number 8V delayed by 6 tracks, and this reproduction data is stored in the corresponding block position in the area of track number 8V. Even when the data reproduced by the magnetic head A1 is already stored in the area of the track number 8V, the data reproduced by the magnetic head A2 is written to update the stored data.
[0060]
As described with reference to FIG. 17, a track address (track number) and a block address (block number) are recorded in each block. That is, the track address and the block address of the reproduced block are shown in FIG. Write address in the memory area.
Therefore, no matter what order the blocks are reproduced, they are taken into the data memory 14 and read out from the data memory 14 at the time when each block constituting one track is stored. It will be rearranged.
[0061]
At the time of recording, data is once written in the data memory 14 for each track. At this time, each track is assigned with a track address (ADA-V) of 0V to 31V and stored. That is, 0V to 31 are write addresses to the data memory 14 of data for each track.
The write address is incremented for each track unit of data, and the data memory 14 is used in a ring shape. The read addresses (REC-V) are sequentially read and supplied to the recording heads 1A and 1B. The track address and block address recorded in the block correspond to the addresses in the data memory 14. Will be given to.
[0062]
By performing the reproduction process as shown in FIG. 9, the data recorded on each track of the magnetic tape is reproduced at a density four times that at the time of recording, and the scanning density of the reproducing head at the time of reproduction is sufficiently high. The data recorded on the magnetic tape can be completely reproduced.
Hereinafter, this will be described with reference to an example of an actual reproduction state. For example, as shown in FIG. 9, tracks on which data is recorded on the magnetic tape T, such as tracks TA1, TB1, TA2, TB2,. ing. In this case, it is assumed that the tracks TA1, TA2,... Are recording azimuth angles that can be reproduced by the magnetic heads A1, A2, and the tracks TB1, TB2,.
[0063]
Here, a description will be given focusing on the track TA2 having a recording azimuth angle that can be reproduced by the magnetic heads A1 and A2.
First, it is assumed that the magnetic head A1 first scans on the tape with the locus (1), and then the magnetic head A1 scans on the tape with the locus (2) after one revolution of the drum. Thereafter, after one revolution, the magnetic head A1 scans on the tape as trajectories (3), (4). At this time, the trajectories (1), (2), (3), and (4) are shifted by the pitch of one track.
[0064]
First, after the magnetic head A1 scans the tape on the locus (1) and then the drum rotates six times, the magnetic head A2 scans on the locus (1) 'which is substantially the same as the locus (1). It is assumed that the magnetic head A2 scans along the locus (2) on the tape after the rotation. Thereafter, after one revolution, the magnetic head A2 scans on the tape as trajectories (3), (4),...
It is assumed that the trajectories of (1) to (4) and (1) 'to (4)' are slightly inclined with respect to the track as shown in FIG.
[0065]
By performing such scanning, the RF signals shown in FIGS. 10 (a), (b), (c), and (d) are reproduced by scanning each locus (1), (2), (3), and (4). Is done.
That is, as shown in FIG. 10A, the signal of the track TA2 is reproduced a little at the beginning of the scanning of the locus (1), and the signal of the track TA1 is reproduced in the remaining portion. Further, as shown in FIG. 10B, the signal of the first track TA2 in the scanning of the locus (2) is reproduced, and the signal of the track TA1 is reproduced a little in the second half. Further, as shown in FIG. 10C, the signal of the track TA3 is reproduced a little at the beginning of the scanning of the locus (3), and the signal of the track TA2 is reproduced in the remaining portion. Further, as shown in FIG. 10 (d), the signal of the track TA3 is reproduced at the beginning of the scanning of the locus (4), and the track TA2 signal is reproduced slightly in the latter half.
[0066]
Actually, as described with reference to FIG. 17, the data constituting one track is divided into 108 blocks. However, for simplification of explanation, it is assumed that 1 track = 24 blocks and the data reproduction state is changed. explain.
Then, the block number of the data of the track TA2 detected by the scanning of the locus (1) becomes the block number “1” to the block number “5” as shown in FIG. As shown in FIG. 10 (f), the block number of the data of the track TA2 to be detected is the block number “4” to the block number “13”, and the block of the data of the track TA2 detected by the scanning of the locus (3). The numbers are the block numbers “12” to “19” as shown in FIG. 10G, and the block number of the data of the track TA2 detected by the scanning of the locus (4) is shown in FIG. As shown, the block number is “21” to the block number “24”.
[0067]
Here, it is assumed that the data of the block number “7” is lost due to the occurrence of a reproduction error as shown in FIG. Further, as can be seen from FIGS. 10G and 10H, it is assumed that the data of the block number “20” has not been reproduced in any scanning.
[0068]
The storage state of the data of each block in the storage area of the track TA2 of the data memory 14 connected to the data processing circuit 13 is as shown in FIG. 10 (i) as data reproduced first by scanning the locus (1). The data of block number “1” to block number “5” is stored.
Hereinafter, as the scanning progresses, the data of the reproduced block number is written, so that the data of each block number is arranged in order as shown in FIGS. 10 (j), (k), and (l). At the time when the scanning of the locus (1) to the locus (4) is completed, the data of the block number “7” and the data of the block number “20” are missing as shown in FIG.
[0069]
Here, in the present example, the magnetic head A2 again scans the locus (1) ', (2)', (3) ', and (4)' as shown in FIG. The data of block No. 7 and the data of block No. 20 are reproduced by scanning “, (2)”, (3), and (4) ”, and as shown in FIG. The data of the block will be finally obtained.
[0070]
In the above example, the setting of the track address (= write address to the data memory 14) ADA-V at the time of recording will be described.
As described above, at the time of recording, the write address ADA-V is incremented with respect to the data memory 14 in a cycle of one track unit (one drum rotation), and the track data is written into the data memory 14. Then, the track data is sequentially read by the read address REC-V, supplied to the heads A1 and B1, and recorded on the magnetic tape.
Here, in this example, the control shown in FIG. 13 is executed for the write address ADA-V and the check after write operation described above during recording.
[0071]
When data is supplied from the host computer 40 side to the data streamer 10 and a recording operation is started (F101), first, the write address ADA-V is forcibly set to 0 V (F102). For example, even if the write address ADA-V is nV as shown in FIG. 11 (a), the pointer is set at the position of the write address ADA-V = 0V as shown in FIG. 11 (b). The Then, the recording process is started (F103). That is, data in units of tracks is sequentially stored in the data memory 14 from this 0 V area, and is further read by the read address REC-V, supplied to the heads A1 and B1, and recorded on the magnetic tape. become.
[0072]
Here, at the time of recording, the track data is reproduced from the magnetic tape by the heads A2 and B2, and the check after write process is executed as described above. In this embodiment, the recording is performed in the reproduced block data. The process of confirming the track address ADA-V being performed is performed (F104).
Then, the process waits until the block having the track address ADA-V = 0V is reproduced, and when the data of the block having the ADA-V = 0V is reproduced, the check after write process is started (F105). .
[0073]
The above processing will be described with reference to FIG.
For the first track at the start of recording, the track address ADA-V is set to 0 V, so that when the current recording is started from the recording start position in FIG. The track address ADA-V shown in this block is as shown in FIG. That is, the track address ADA-V = 0V is set for the first track for the current recording, and the track address ADA-V is set to 1V, 2V, 3V,... 31V, 0V, 1V,. It will be done.
[0074]
Here, at the time when the recording by the heads A1 and B1 is started, the tracks of the past data file are initially traced for the heads A2 and B2 that perform tracing with a track difference of 6 tracks. In this case, since it is not the trace of the track recorded by the heads A1 and B1 in the current recording operation, the data read by the heads A2 and B2 becomes unnecessary for the data check.
[0075]
Therefore, the track address ADA-V recorded in the block data reproduced from the heads A1 and B1 is confirmed, and the process waits until this becomes 0V. The block where the track address ADA-V = 0V is data of the first track related to the current recording operation. Therefore, by starting the check after write process when the data of the block where ADA-V = 0V is reproduced, the unnecessary check process up to that point can be eliminated, and thus the useless check process is eliminated. It is possible to eliminate power consumption in processing and to prevent an inappropriate check operation from being executed.
[0076]
In this example, the first track address related to the recording operation is set to 0V. However, this may not be 0V, and a predetermined value from 0 to 31 may be set.
In any case, depending on the capacity of the data memory 14, when the number of tracks that can be recorded is from track 0 to track n, the fixed value to be set is selected and set in advance from 0 to n. It only has to be.
[0077]
Next, processing at the time of reproduction in this example, particularly processing related to the valid data discrimination operation by the OWP code will be described.
As shown in FIG. 19, when a series of data files are recorded on the magnetic tape T, an OWP code is added. For example, for a track that becomes a file X as shown in FIG. Recorded as _X. For the track that is the file Y, the OWP code is recorded as OWP _{Y in} each block.
Here, it is assumed that the data file Z in which the OWP code is set to OWP _Z is overwritten with respect to the tape position in FIG. 14A, and at this time, a part of the unerased portion is generated due to a head clogging or the like. Suppose that the data of the past file X is partially left as shown by the hatched portion REC-ER in FIG.
[0078]
When such a file Z is reproduced, the data to be read out includes unerased data D _X constituting the file X in the middle of the data D _Z constituting the file Z as shown in FIG. It will be. Further, as the OWP code to be read out, OWP _X is left in the unerased portion as shown in FIG.
For this reason, as described with reference to FIG. 19, in the conventional reproduction of the file Z, the data of the unerased file X is regarded as valid data and the normal data of the file Z is lost. .
[0079]
Therefore, in this example, the processing of FIG. 15 is performed during reproduction.
When the reproduction operation is started by the reproduction operation command, data is reproduced for a predetermined period as step F201, and the OWP code recorded in each block is read as identification data. Then, the value that is the majority of the values of the fetched OWP code is set as the reference identification data ID1 (F202).
Thus, for example, if the reproduction operation is for the file Z in FIG. 14B, the reference identification data ID1 = OWP _Z is set.
[0080]
After the reference identification data ID1 is set, the identification data reproduced together with the data from each block is compared with the reference identification data ID1 in step F203 for each block or each track.
If the value of the identification data to be reproduced matches the reference identification data ID1, the data reproduced from the block is determined as valid data and reproduced and output (F205).
[0081]
However, when the majority of the values of the identification data to be reproduced do not match the reference identification data ID1, in step F204, the majority of the mismatched values are used as the temporary reference identification. Set as data ID2.
The reason that the majority of the values of the identification data to be reproduced does not coincide with the reference identification data ID1 is that the reproduction has shifted from the file X portion to the file Y portion in FIG. Or the reproduction has reached the unerased portion indicated by the hatched portion REC-ER in the case of FIG. 14B.
[0082]
When the temporary reference identification data ID2 is set, in step F206, the identification data read by the subsequent reproduction operation is confirmed, and whether or not the majority of the identification data returns to a state in which it matches the reference identification data ID1. Is determined.
Further, in step F211, whether or not the majority of the read identification data does not return to the state where the majority of the identification data matches the reference identification data ID1, and the state where the majority of the identification data matches the temporary reference identification data ID2 is continued. Will be monitored.
[0083]
After the provisional reference identification data ID2 is set, if a state where most of the read identification data matches the temporary reference identification data ID2 continues for a predetermined period or longer, the reproduction operation is performed, for example, in the file of FIG. It can be determined that this is the case when the file is transferred from the X part to the file Y part.
That is, the data of the block from which the identification data matching the temporary reference identification data ID2 is to be output should be output as valid data.
[0084]
Therefore, the process proceeds from step F211 to F212, and the value of the temporary reference identification data ID2 is set as the new reference identification data ID1. That is, the reference identification data ID1 is updated. Then, the data of the block that has been read up to that point, that is, the data of the block whose identification data matches the temporary reference identification data ID2, is reproduced and output as valid data (F213). Then, returning to step F203, it is determined whether or not the data to be reproduced thereafter is valid data based on the comparison between the identification data and the new reference identification data ID1.
[0085]
On the other hand, if it is determined in step F206 that, after setting the temporary reference identification data ID2, it has been determined that most of the read identification data has returned to a state that matches the reference identification data ID1 again, until then, It can be determined that the section from which the reference identification data ID2 has been read is a minute defect section such as the hatched portion REC-ER in FIG.
In such a case, if the reference identification data ID1 is updated, the data of the defective portion is regarded as valid data.
[0086]
Therefore, when the process proceeds to step F207 and is determined to be a minute defect section, the tape is rewound to at least the position before the minute defect section starts, and the value of the reference identification data ID1 is fixed (inhibition of update). The playback operation is resumed in the state (F208). Then, the block data in the minute defect section where the identification data having a value different from the reference identification data ID1 is read is output as invalid data (F209, F210).
[0087]
Then, after passing through the minute defect section, the original data file data is read out. In this case, the majority of the identification data to be read returns to a state that matches the reference identification data ID1. At this time, the process returns from step F209 to F203 to continue the subsequent processing.
[0088]
If a negative result is obtained in step F211, that is, if the majority of the identification data is neither the reference identification data ID1 nor the temporary reference identification data ID2, a new defect section is obtained in step F214. As a result, the necessary processing is performed.
[0089]
The operation shown in FIG. 15 will be described by applying it to the reproduction of the file Z shown in FIG.
First, the reference identification data ID1 = OWP _Z is set.
At the time of reproduction of the unerased portion REC-ER, the majority value of the identification data becomes OWP _X different from the reference identification data ID1, and the defect data (REC-ER) is restored by returning to the state of identification data = OWP _{Z to} be read thereafter. ) Is detected, the reference OWP value is fixed to OWP _Z at the time of rewinding to some extent (FIG. 14 (e)). Then, the reproduction operation is executed again from the rewind position. Then, as shown in FIG. 14 (f), the reproduction data of the unerased portion REC-ER is determined as invalid data because the OWP data is OWP _X , and from the point past the unerased portion REC-ER. Since the OWP data becomes OWP _Z, it becomes valid data, and the data in the file Z is not mistakenly recognized as invalid data and is not lost.
[0090]
With this operation, even if an unerased portion is generated during recording, proper data output can be performed and reliability can be improved. Note that the data of the file Z that was not recorded in the unerased portion was confirmed to have a recording error in accordance with the check after write process at the time of recording, and the data that could not be recorded at other positions as described in FIG. Since it is recorded, all data in the file Z can be definitely read and output during reproduction.
[0091]
As examples was applied to a data streamer for recording and reproducing data for a computer, the present invention is also applicable to a recording equipment for recording other data, such as audio signals.
[0092]
【The invention's effect】
As described above, in the present invention, the track number of the first track to be recorded at the start of recording is set to a predetermined fixed value. As a result, it is possible to determine the head track for the recording operation. When so-called check after write is performed at the time of recording, the head track when recording is started by the recording head is determined from the track number, and the check process is started from that track. For this reason, useless check processing as check after-write processing can be eliminated, thereby achieving the effect of eliminating power consumption in useless processing and preventing the execution of inappropriate check operations. .
[Brief description of the drawings]
FIG. 1 is a block diagram of a data streamer according to an embodiment of this invention.
FIG. 2 is a block diagram of a system configuration according to the embodiment.
FIG. 3 is an explanatory diagram of a rotary head drum according to an embodiment.
FIG. 4 is an explanatory diagram of a trace state of the head according to the embodiment.
FIG. 5 is an explanatory diagram of recording processing timing according to the embodiment;
FIG. 6 is an explanatory diagram of a recording state according to the embodiment.
FIG. 7 is an explanatory diagram of timing of reproduction processing according to the embodiment.
FIG. 8 is an explanatory diagram of a memory area configuration according to the embodiment;
FIG. 9 is an explanatory diagram of a head trajectory during reproduction according to the embodiment;
FIG. 10 is an explanatory diagram of a data reproduction state according to the embodiment.
FIG. 11 is an explanatory diagram of a track address setting operation during recording according to the embodiment.
FIG. 12 is an explanatory diagram of a track address setting state during recording according to the embodiment.
FIG. 13 is a flowchart of processing during recording according to the embodiment.
FIG. 14 is an explanatory diagram of a reproduction retry operation in which the reference OWP code is fixed according to the embodiment.
FIG. 15 is a flowchart of processing including a playback retry operation in which the reference OWP code is fixed according to the embodiment;
FIG. 16 is an explanatory diagram of a recording / reproducing state of a non-tracking method.
FIG. 17 is an explanatory diagram of a track data format of a non-tracking method.
FIG. 18 is an explanatory diagram of a track address state in a non-tracking method.
FIG. 19 is an explanatory diagram of a data error that occurs due to the influence of an unerased portion when an OWP code is added.
[Explanation of symbols]
10 Data Streamer 11 Rotary Head Drum 12 Interface 13 Data Processing Circuit 14 Data Memory 21 Central Controller (CPU)
30 Data conversion device 40 Host computer A1, A2, B1, B2 Head

Claims (2)

Recording means for recording data by forming one track with each block having a predetermined amount of data on a magnetic recording medium and recording the track number for each track and the block number for each block. When,
Data reading means capable of reading data recorded by the recording means during a recording operation by the recording means;
A recording operation discriminating unit for discriminating whether or not the recording operation by the recording unit is properly performed from the data read by the data reading unit;
At the start of the recording operation by the recording means, the track number of the first track to be recorded is set to a predetermined fixed value to start the recording operation by the recording means, and the track number of the data obtained by the data reading means is Control means for performing control so as to start the determination operation by the recording operation determination means based on the detection that the predetermined fixed value has been reached;
A recording apparatus comprising: Data recording is performed by forming one track with each block having a predetermined amount of data on the magnetic recording medium, and recording the track number for each track and the block number for each block. As a recording method,
Start recording after setting the track number to a predetermined fixed value at the start of recording, and start reading data,
After starting to read data, monitor that the track number for the read data becomes the predetermined fixed value,
A recording method comprising: starting an operation for determining whether or not a recording operation using read data is appropriate based on a track number having reached the predetermined fixed value.

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