JPH05166301A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To easily recorded data which has an error when recording tracks are formed at an angle and input data is recorded by executing read-after-write in a magnetic recording and reproducing device such as the external memory of a computer. CONSTITUTION:Varied data number VDNO is set so that value is successively varied with a minimum unit to record recording data in a magnetic tape and reproduced data is processed by using the varied data number VDNO as a standard. Further, status information identifying the recording data of one group recording a pointer indicating a changed postscript start position and/or to be recorded is added, and the input data is recorded.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial Application Conventional Technology (FIGS. 14 and 15) Problem to be Solved by the Invention (FIGS. 14 and 15) Means for Solving the Problem (FIGS. 9 and 12) Action (FIGS. 9 and 12) ) Example (1) Overall configuration (FIGS. 1 to 7) (2) Read-after-write process (FIGS. 8 and 10) (3) Change-addition process (FIGS. 11 to 13) (4) Example Effects (5) Other Examples Effects of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, and can be applied to, for example, an external storage device of a computer.

[0003]

2. Description of the Related Art Conventionally, in this type of magnetic recording / reproducing apparatus, recording tracks are sequentially formed on a magnetic tape at an angle.
A so-called ID-1 format data recorder has been proposed which is capable of recording and reproducing desired data at high density (ANSI x3.175-1990 19mm Type ID-1 Recorded
Instrumentation).

That is, as shown in FIG. 14, in this type of data recorder, the magnetic tape 1 is wound around a rotary drum which rotates at a predetermined speed, and the magnetic tape 1 is run at a predetermined speed to cause the rotary drum to rotate. Recording tracks TR (TR)
1, TR2, TR3, TR4, TR1, TR2, ...)
And the desired data is recorded in the recording track TR1. Furthermore, at this time, the data recorder
Recording tracks TA, CTL, and TC extending in the longitudinal direction are formed on the upper and lower ends of the magnetic tape 1, and the recording tracks CT are formed.
The track set ID of the recording track TR is recorded in L.

Here, the track set ID is absolute position information starting from the beginning of the magnetic tape 1 and is sandwiched between predetermined sync signals and recorded in the recording track TR in four track cycles. There is. Further, the recording tracks TA and TC are adapted to record user management data and the like, whereby the recording tracks TA and C are recorded.
By reproducing TL and TC, it is possible to easily search the data recorded at high density in the recording track TR.

Further, in the data recorder, when data is recorded on the recording track TR, the data is recorded with a parity code for error detection and correction, which is a so-called product code, and the desired data is recorded. It is designed so that recording and reproduction can be surely performed. That is, FIG.
As shown in, the data recorder has a predetermined unit (= 36,108
[BITE]) takes in the data DATA, divides the data DATA into 306 blocks, and adds a Reed-Solomon error detection and correction code (that is, C2 code) to each block. ..

After the block is further divided into first and second fields FIELD0 and FIELD1, the Reed-Solomon error detection and correction code (that is, the C1 code) is orthogonal to the C2 code for each field FIELD0 and FIELD1. Is added). As a result, in the data recorder, the bit error rate can be improved by error-correcting the reproduced data using the C1 and C2 codes during reproduction.

Further, in the data recorder, when the data DATA to which the C1 and C2 codes are added in this way is recorded on the magnetic tape 1, interleave processing is performed for each recording track TR, and even if a dropout or the like occurs due to this. The data DATA can be surely reproduced. That is, in the data recorder, the arrows a1, a2, ..., An-1, an, an + 1, a
Data D to be input in the order shown by n + 2, ... ax-1, ax
Arrows b1, b2, ..., bn-1, bn to ATA
As shown in, the order of input is changed and the data DA
TA is recorded, and thereby the data DATA is interleaved.

Further, at this time, in the data recorder, the sync signal SYNC and the sync block data ID are added for each predetermined unit (hereinafter referred to as sync block), and the preamble and the postamble data are added as a whole to make the data DATA concerned. To record. As a result, during reproduction, in the magnetic recording device, the sync signal SYNC, the sync block data ID, and the data DAT are based on the track sync data included in the preamble.
A is reproduced, and deinterleave processing can be performed based on the sync signal SYNC and the sync block data ID.

By further performing deinterleave processing, even if dropout occurs, C1 and C1
It is designed to effectively avoid the concentration of errors exceeding the error correction capability of the two codes in one place.

[0011]

By the way, in the data recorder of the ID-1 format for recording and reproducing desired data as described above, about 10 ^-10 which is practically sufficient as a data recording / reproducing device mainly for measurement. The bit error rate is guaranteed. If this bit error rate can be improved to about 10 ^-15 , it is considered that extremely important data can be stored by applying it to a magnetic tape device of a computer system used in, for example, banks. Therefore, the usability of this type of data recorder can be improved correspondingly and the application field can be expanded.

In this case, the bit error rate is improved by reproducing the data immediately after recording while recording and executing a so-called read-after-write process for error detection, and re-recording the input data when an error occurs. A method can be considered. However, when data is recorded by sequentially forming recording tracks diagonally on the magnetic tape in this way,
If the magnetic tape is rewound to the position where the error is found and the data is recorded again, there is a problem that it takes much time to record the data.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a magnetic recording / reproducing apparatus capable of easily re-recording data in which an error has occurred even when performing read-after-write. is there.

[0014]

In order to solve such a problem, according to the present invention, recording tracks TR1, TR2, TR3, ... Are sequentially formed on a magnetic tape, and recording tracks TR1, TR2, TR3 ,. The desired input data DO are sequentially recorded in the recording tracks TR1, T2, ...
In the magnetic recording / reproducing apparatus 10 for reproducing the recording data D12 recorded in R2, TR3, ..., At the time of recording, the minimum unit for recording the input data DO on the magnetic tape, the valid data number VDNO which sequentially changes in value is generated. Then, the valid data number VDNO together with the input data DO is recorded in the recording tracks TR1, TR2, TR3, ... At the time of reproduction, the record data D12 which is sequentially reproduced is stored in the memory circuit with reference to the valid data number VDNO. And then output.

Further, in the second invention, recording tracks TR1, TR2, TR3, and
...... is formed and recording tracks TR1, TR2, TR3,
In the magnetic recording / reproducing apparatus 10 for sequentially recording desired input data DO in ... During recording, while sequentially recording the input data DO, the recorded input data DO is reproduced to detect an error, and the error is detected. And the following recording track TR
In the case where the input data DO is recorded again from a portion where an error is detected instead of the input data DO following 1, TR2, TR3, ... And the input data DO is recorded on the magnetic tape on which the input data DO has already been recorded, The input data DO is recorded with a pointer OWSF indicating a recording start position and / or status information VDNO identifying a group of input data to be recorded.

[0016]

In the minimum unit for recording the input data DO, the valid data number VDNO whose value sequentially changes is recorded together with the input data DO, and the recorded data D12 which is sequentially reproduced at the time of reproduction is based on the valid data number VDNO. If the data is stored in the memory circuit and then output, then correct data can be reproduced easily and surely even in the case of a write retry. Further, a pointer OWSF indicating the recording start position
And / or if the input data DO is recorded with status information VDNO for identifying a group of input data to be recorded,
Even if the write retry and the postscript change are combined,
It is possible to reliably reproduce correct data.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings.

(1) Overall Configuration (1-1) Configuration of Computer System In FIG. 1, reference numeral 10 generally indicates a schematic configuration of a computer system to which the present invention is applied, and write data sent from a host computer 11 together with a write request. W
R is supplied as recording data REC through the data recorder control device 12 to the data recorder 13 of ID-1 format, and the write data WR is written in the recording track on the magnetic tape.

In response to a read request input from the host computer 11, the magnetic tape of the data recorder 13 is reproduced, and the reproduced data PB obtained as a result is read out by the read data R through the data recorder controller 12.
It is input to the host computer 11 as D.

The data recorder control device 12 comprises a host interface control section 14 and a format control section 15, and the host interface control section 14
Controls the channel interface with the host computer 11, and the format control unit 15 controls the memory 1
6 is used to format the data to be transferred to and from the data recorder 13. In addition, the host interface control unit 14
The control information between the control unit 15 and the format control unit 15 is exchanged with reference to the control tower 17.

Thus, in the computer system 10, since the data recorder control device 12 is provided, the host computer 11 side has the same interface as the conventional magnetic tape device, and the data recorder 13 is connected to the external storage device of the host computer 11. It is designed to be used as

(1-2) Recording Area on Magnetic Tape Here, in the computer system 10, as shown in FIG.
As shown in FIG. 5, the magnetic tape 1 loaded in the data recorder 13 has a recording area AREC in the central portion of the tape where the degree of damage to the tape itself is relatively small in the longitudinal direction.
The bit error rate can be improved.

That is, as shown in FIG. 2A, the logical tip LBOT is located at a position, for example, 10 [m] behind the physical tip PBOT of the magnetic tape 1, and the magnetic tape 1 is physically For example, the position 15 [m] before the end PEOT is the logical end LEOT, and the logical end LB
The area from the OT to the logical end LEOT is the recording area ARE.
Used as C.

In this recording area AREC, FIG.
As shown in (B), a region between the logical leading end LBOT and a position behind by 10 [m] is used as the directory information track region DITA.

Also, this directory information track area D
After ITA, a non-recording area NRA of a predetermined length is sandwiched,
An area between the logical end LEOT and the end near NEOT at a position 15 m before, for example, is used as a user recording track area UDA, and the end near NEOT is further used.
The area between the logical end point LEOT and the logical end point LEOT is used as the volume end information area VEOVA.

(1-3) Format of recording track Here, in this computer system 10, the ID
The user data area of 36,108 [BYTE] for one recording track defined by -1 format is formatted as shown in FIG. 3, and the formatted data is interleaved in units of 4 tracks. It is designed to improve the bit error rate. Note that FIG. 3 (A) conceptually shows the type and length of information included in one track,
Further, FIG. 3B is a specific example of the C3 error correction block before the ID-1 formatting is performed.

That is, in the computer system 10,
As shown in FIG. 3A, the write data WR from the host computer 11 is composed of four tracks, for example, one block per recording track TR is 32,768 [BY].
[TE] recording data DATA is recorded.

At this time, regarding 1 recording track TR, 3
With respect to the recording data DATA that is less than 2,768 [BYTE], the first supplementary data PD1 is added to make the entire recording data 32,768 [BYTE]. In addition, 320 [BYTE] subcode data SCD is prepared to store the auxiliary information of the one recording track TR.

In addition to this, the data recorder control unit 12
3B for every 94 [BYTE] of the subcode data SCD, the recording data DATA or the first supplementary data PD1.
As shown in FIG. 5, a Reed-Solomon error detection and correction code (hereinafter referred to as C1, C2 in the ID-1 format) of 8 [BYTE] using a predetermined generator polynomial.
C3 code C3) is added according to the code), whereby error correction can be performed more strongly,
The bit error rate can be further improved.

Further, as shown in FIG.
With respect to the sub-code data SCD, the recording data DATA, the first supplementary data PD1 and the C3 code C3 which have been formatted in units of recording tracks, the data for four recording tracks TR1, TR2, TR3 and TR4 are tracked by a predetermined method. Interleaved over time,
This makes it possible to further improve the bit error rate.

As described above, the four recording tracks TR1 and T
204 [BY] is added to the beginning of the data for one recording track interleaved for R2, TR3, and TR4.
TE] second supplementary data PD2 is added, whereby the data amount for one recording track TR is ID-1 as a whole.
It is designed to be 36,108 [BYTE] specified by the format.

Since the second supplemental data PD2 is formatted at the head, the supplemental data PD2 is recorded at the plunging portion of the magnetic head where the magnetic tape 1 itself is highly damaged and the tracking is unstable in the recording track. It can be assigned, and this allows the recorded data DATA
The bit error rate can be further improved.

(1-4) Layout of recording track Here, in the case of the computer system 10, the auxiliary information of the recording track 1 stored in the subcode data SCD is the track type information indicating the type of the corresponding recording track TR. The TRID, the block number BLNO to which the recording track TR belongs, the file number FLNO to which the recording track TR belongs, the number of write retries RTCT for the recording track TR, the byte number BYCT of the data contained in the recording track, etc.

The track type information TRID includes a volume information table VIT and a file information table FI.
T, update information table UIT, dummy data track information DMY, user data track information UDT, tape mark track information TM, or recording end information EOR type information is recorded.

In practice, as shown in FIG. 5, first, the track type information TRID of the recording track TR formed in the directory information track area DITA of the magnetic tape 1.
As the volume information table VIT, the file information table FIT, the update information table UIT, or the dummy data track information DMY is used.

This directory information track area DIT
A directory information table DIT for managing files on the magnetic tape 1 as a whole is recorded in A. First, a rising area RUA of 1.5 [m] from the logical leading end LBOT of the magnetic tape 1 is recorded, and then a volume information table VI.
The recording track of T is recorded with 4 tracks of track set.

In the recording data DATA of the volume information table VIT, the head and end position information of the data block recorded in the user recording track area UDA with the entire magnetic tape 1 as one volume, the length information and recording of the file information table FIT are recorded. Sometimes the block number of the data block that executed the write retry is recorded.

Following the volume information table VIT
The file information table FIT is recorded in 256 recording tracks. Recorded data D of this file information table FIT
In the ATA, the head position information and block length of the file are recorded for each file recorded in the user recording track area UDA.

Further, following the file information table FIT, dummy data track information DMY with a predetermined number of tracks.
Is recorded, and the update information table U is recorded with the following four recording tracks.
Record IT. In the record data DATA of the update information table UIT, information indicating the presence / absence of update is recorded.

Following this update information table UIT, from the beginning of the directory information track area DITA
The dummy data track information DMY is recorded in the recording track TR up to 2.5 [m], and the remaining 2.5 [m] of the directory information track area DITA is secured as the spare area MGA.

Next, the user data track information UDT, the tape as the track type information TRID of the recording track TR formed in the user recording track area UDA sandwiching the non-recording area NRA following the directory information track area DITA of the magnetic tape 1. Mark Track Information TM
Alternatively, the recording end information EOR is used.

As the recording track TR of the user recording track area UDA, the user data track information for a plurality of blocks forming one file by sandwiching it between the recording tracks TR of the tape mark track information TM whose unit is four tracks is used. The recording track TR of the UDT is recorded, and the recording track TR of the recording end information EOR is recorded following the end of the user data track information UDT.

The recording data DATA of the tape mark track information TM and the recording end information EOR contains 32,768
The first supplementary data PD1 for [BYTE] is recorded, and the data corresponding to the write data WA input from the host computer 11 is recorded in the recording data DATA of the recording track TR of the user recording track area UDA.

Thus, the computer system 10
, A directory information track area DITA is provided at the beginning of the magnetic tape 1, and a user recording track area U
By managing the contents of the DA on a file-by-file basis, the data recorded in the data recorder 13 as viewed from the host computer 11 can be accessed in the same manner as an external recording device.

(1-5) Structure of Recording Format Unit of Format Control Unit Here, the format control unit 15 of the data recorder control unit 12 in the computer system 10 together with the memory 16 has the recording format shown in FIGS. 6 and 7. It comprises a section 20 and a reproduction format section 40.

That is, in the recording format controller 20, the host interface controller 14 stores the data of every 32 bits as the write data D0 of the 4-channel 8-bit parallel (that is, the first in first out). Consists of (FIF
O)) is input to the circuit 21 to synchronize the write data D0 with the internal clock CK, which is written as the input data D1 in the buffer memory 22 and CR.
It is sent to the C error detection circuit 23.

Although the write data D0 is processed every 4 channels in the recording format control unit 20, the description of the recording format control unit 20 will explain the data for one channel.

The CRC error detection circuit 23 receives the input data D
The error detection using CRC (cyclic redundancy code) is performed for 1 and the detection result CRCK is input to the system control circuit 24 having a computer configuration including a CPU.

When the system control circuit 24 detects an error in the input data D1 based on the detection result CRCK of the CRC error detection circuit 23, the system control circuit 24 returns this to the host interface control unit 14 as an error detection signal ER. As a result, for example, the host interface control unit 14
Executes the resend process for the write data D0 having an error.

The buffer memory 22 buffers the input data D1 by one recording track TR as described above with reference to FIG. 3, and outputs the recording data DATA obtained as a result.
Corresponding to the first buffer data D2 is sent to the first multiplexer 25.

In addition to the first buffer data D2, the first multiplexer 25 has the first supplementary data PD1 and the dummy data generation circuit 27 for the tape mark track information TM sent from the tape mark generation circuit 26, respectively. Dummy data track information DMY sent from
Dummy data for recording, the first supplementary data PD for the record data DATA sent from the supplementary data generation circuit 28.
1 is input.

As a result, the first multiplexer 25 responds to the control signal CNT input from the system control circuit 24 to record data DATA of the first buffer data D2.
To the second multiplexer 29 by adding the first supplemental data PD1 to the second buffer data D3.

In the second multiplexer 29, in addition to the second buffer data D3, the sub-code generating circuit 31 generates the contents of the directory information table DIT and the directory information table 30 sent from the directory information table memory 30. Subcode data SDC is input.

Actually directory information table memory 3
0 stores the directory information table DIT described above with reference to FIG. 5, and the subcode generation circuit 31 determines the start and end position information of the data block and the file information table F according to the contents of the directory information table DIT.
The IT length information and the block number of the data block for which the write retry is executed at the time of recording are generated.

As a result, the second multiplexer 25 converts the sub-code data S3 into the second buffer data D3 according to the control signal CNT inputted from the system control circuit 24.
The format described above with reference to FIG. 3 is formed by adding DC, and this format is sent to the C3 code generation circuit 32 as the third buffer data D4.

The C3 code generation circuit 32 generates the C3 code C3 of 8 [BYTE] and adds it to the third buffer data D4 as described above with reference to FIG. 3, and the resulting recording track data D5 is supplied to the interleave circuit 33. Send out.

The interleave circuit 33 executes the interleave processing for four tracks shown in FIG. 4 by sequentially fetching the recording track data D5 for four tracks into the interleave memory and outputting them in a predetermined order. The second recording track data D6 is sent to the third multiplexer 34.

In addition to the second recording track data D6, the third multiplexer 34 outputs the second supplementary data PD1 sent from the second supplementary data generating circuit 35 and the sync code generating circuit 36. Sync code data is input.

As a result, the third multiplexer 34 adds the second supplementary data PD2 and the synchronization code data to the second recording track data D6 according to the control signal CNT input from the system control circuit 24, and as a result, The obtained third recording track data D7 is sent to the parallel-serial conversion circuit 37.

The parallel / serial conversion circuit 37 converts the third recording track data D7 consisting of 4 channels of 8 bits parallel into 32 bits of serial recording data S0, and this is output to the data recorder 13 as recording data REC through the output circuit 38. Is entered.

In this way, in the recording format control section 20 of the format control section 15, the write data D0 input from the host interface control section 14 is input.
3 to 5, the format processing described above is executed to generate the recording data REC, and the recording data REC is recorded on the magnetic tape 1 based on the ID-1 format as shown in FIGS.

(1-6) Structure of the reproduction format section of the format control section In the reproduction format section 40 shown in FIG.
Serial reproduction data P reproduced by the data recorder 13
B is input to the serial / parallel conversion circuit 41 and is converted into the first reproduction data D10 of 8 channels parallel of 4 channels for every 32 bits, and this is input to the deinterleave circuit 42.

The deinterleave circuit 42, like the interleave circuit 33 of the recording format unit 20, sequentially takes in the first reproduction data D10 and outputs it in a predetermined order, so that the deinterleave circuit corresponding to the interleave processing of the interleave circuit 33 is performed. The processing is executed, and the second reproduction data D11 obtained as a result is input to the C3 error correction circuit 43.

The C3 error correction circuit 43 is a C3 code C added by the C3 code generation circuit 32 of the recording format unit 20.
3 is used to perform error correction processing on the second reproduction data D11, and the third reproduction data D1 obtained as a result is obtained.
2 is sent out.

Of the third reproduction data D12, the user recording data track UDT is actually used as shown in FIG.
To the buffer memory 44, and those corresponding to the directory information table DIT are input to the subcode memory 45 and the directory information table memory 46.

In the buffer memory 44, the first supplementary data PD1 included in the third reproduction data D12 is deleted,
This is input to the memory circuit 47 as the fourth reproduction data D13 and synchronized with the external clock, and this is sent to the host interface control unit 14 as the read data D14 output from the reproduction format control unit 40.

When the directory information table DIT input to the directory information table memory 46 has been updated, the system control circuit 24, together with the data recorder control signal CDIR, outputs the directory information table DI.
The update information UDD of T is sent to the data recorder 13 to update the contents of the directory information table DIT on the magnetic tape 1.

Further, the system control circuit 24 outputs the output data D
Together with the control signal CHI, a response to the data reproduction request input from the host interface control unit 14 is sent.
It is sent to the host interface control unit 14 as C.

In this manner, the reproduction format control section 20 of the format control section 15 executes the reverse format processing of the format processing described above with reference to FIGS. 3 to 5 on the reproduction data PB reproduced by the data recorder 13. , Read data D14 is generated and sent to the host interface controller 14.

(2) Read-after-write processing (2-1) Valid data number In the data recorder control device 12, when the write data WR is recorded, the valid data number VDNO is sequentially updated, and the write data WR is written together. Record.

Here, as shown in FIG. 8, in the valid data number VDNO, the minimum unit that can be recorded by the data recorder 13 (that is, in the case of this embodiment, the write data WR is interleaved in units of four recording tracks). By recording, it becomes write data management data whose value sequentially increases in units of 4 recording tracks synchronized with the track set ID of the data recorder 13.
It is adapted to be assigned to one of the subcode data SCD. Therefore, the valid data number VDNO
In this case, the data is generated by the subcode generating circuit 31 and is sequentially recorded in the recording track together with the write data WR.

On the other hand, the reproduction format controller 40
In the buffer memory 44, the third reproduction data D
When 12 is stored, the valid data number VDNO
The address data is sequentially created on the basis of, and the reproduction data D12 is processed based on the valid data number VDNO.

If no error occurs, the write data D0 can be sequentially recorded on the magnetic tape in file units (FIG. 8 (A)). At this time, the valid data number VDNO is sequentially recorded along with the recording of the write data D0. Is increased (FIG. 8 (B)).

Further, in the sub-code generating circuit 31, when an error is detected by the read-after-write, or when the write data is overwritten for recording or additional recording, the valid data number VDNO is switched, so that The write data can be surely reproduced.

(2-2) Write Retry Here, the data recorder 13 has a recording magnetic head and a monitor magnetic head for scanning the recording track following the recording magnetic head. The recording magnetic head is used to sequentially record the recording data REC, and the monitoring magnetic head is used to reproduce the recording data immediately after recording.

In the data recorder controller 12,
A read-after-write process is executed by using the monitor function of the data recorder 13. Further, in the data recorder control device 12, when an error is detected in the read-after-write processing, the data is re-recorded from the portion in which the error has occurred (that is, write retry) so that the data can be surely recorded / reproduced. Has been done.

That is, in the recording mode, the reproduction format control section 40 sequentially takes in the reproduction data PB output from the data recorder 13, and the C3 code correction circuit 4
At 3, the error detection process is executed.

When an error is detected here, the system control circuit 24 outputs the control data to the sub-code generation circuit 31, the buffer memory 22 and the like, and the position where the error occurs (in this embodiment, the error is detected). The write data DO is re-recorded in the subsequent recording track (which is composed of the generated data block).

That is, as shown in FIG. 9, the recording format control unit 20 reads the buffer memory 22 when an error is detected in the data recorded at time t1 when the N file and the N + 1 file are continuously recorded. The address is switched, and the write data D2 is output again from the data block in which the error is detected (FIG. 9A). Thus, in the buffer memory 22, the write data D output to the multiplexer 25
A practically sufficient storage capacity is allocated so that the write data D2 can be held until the error detection result for 2 is obtained.

As a result, in the recording format control unit 20, after the error is detected, from the time t2 after the lapse of a predetermined period, the write data from the position where the error is detected is sequentially recorded in the succeeding recording track. Thus, the write retry can be performed without rewinding the magnetic tape. Therefore, the time required to record the data can be shortened by that amount and the data can be surely recorded.

By the way, when the data is retried in this way, the processing of the reproduced data becomes complicated during reproduction. Therefore, in this embodiment, the recording format control unit 20 allocates the original value and generates the valid data number VDNO when performing the write retry (FIG. 9).
(B)).

As a result, in the reproduction format control section 40, when the write address of the buffer memory 44 is generated on the basis of the valid data number VDNO, the reproduction data D12 which is write-retryed is output instead of the reproduction data D12 in which an error has occurred. Thus, it is possible to reliably process the reproduction data with a simple structure.

That is, as shown in FIG. 10, the recorded data with the valid data number VDNO (N, N + 1, N + 2, ...) Synchronized with the track set ID (1, 2, 3, ...) Is reproduced. In the case (FIG. 10 (A)), the valid data number V is sequentially stored in the buffer memory 44.
The reproduction data D12 is accumulated in units of DNO. In this state, for example, when an error is detected in the data with the valid data number VDNO of the value N + 2 and write retry is performed,
In the buffer memory 44, the values N, N + 1, N +
The reproduction data D12 with the valid data numbers VDNO of 2 and N + 3 are respectively transferred to the buffer blocks M and M +.
After accumulating in the area of 1, M + 2, M + 3, the valid data number VDNO of the same value is repeated,
Playback data is accumulated again in the areas of buffer blocks M, M + 1, M + 2, and M + 3 from the track set ID of value 5 (FIG. 10 (B)).

As a result, in the area of the buffer block M + 2, the correct reproduction data that has been write-retryed can be stored, and the correct data can be recorded and reproduced by write-retry without rewinding the magnetic tape.

Thus, in the buffer memory 44,
Similar to the buffer memory 22, a practically sufficient storage capacity is allocated so that the processing can be executed.

On the other hand, when the reproduction data D12 stored in the buffer memory 44 has a discontinuous portion in which the reproduction data D12 is not stored (for example, for the track set ID of value 7 during reproduction). When an error occurs in the reproduction data D12, etc.), the data recorder 1 is required for write retry.
After driving 3, the magnetic tape is rewound and the reproducing operation is repeated. That is, in FIG. 10, the system control circuit 24
Can be determined to be the write retry data when the trackset ID of the value 5 is obtained, and the trackset IDs of the value 5 to the value 8 can be determined to be the write retry recording data.

Therefore, in this case, the system control circuit 24
After the reproduction data D12 is fetched up to the trackset ID of value 8, the magnetic tape is rewound and the reproduction operation is repeated from the trackset ID of value 5. Thus, at the time of recording, by performing read-after-write and write retry, it is possible to reproduce correct data by repeating the reproducing operation.

In this embodiment, the recording format control unit 20 writes the write retry count data WR indicating the write retry number when the write retry is performed.
C is assigned to the sub-code SCD and recorded, so that not only the number of write retries but also wear of the magnetic tape, dirt of the magnetic head, etc. can be determined based on the write retry count data WRC. ing.

(3) Processing of change and additional recording In a data recorder of this type, it is considered convenient if input data can be overwritten and recorded to change the content of the recorded data. Also, if you can record by adding input data after the recorded data,
It is considered to be convenient (hereinafter, such recording for changing and adding recording data is referred to as change-addition recording). However, when the write retry is performed as in this embodiment, the original data to be originally updated may be erroneously output.

That is, as shown in FIG. 11, write data is recorded in the order of N file, tape mark TM, and N + 1 file. At this time, an error is detected to detect N file,
The tape mark TM and the N + 1 file are written and retried (FIG. 11A). In this state, the second tape mark T
When the N + 1 file after M2 is updated, the old N + 1 file data and the updated N + 1 file data are mixed and overlapped on the magnetic tape (indicated by diagonal lines), and the write retry causes The data of both files is the same valid data number VDN
O is added to the magnetic tape, and it exists on the magnetic tape.

In this case, in the buffer memory, the updated N + 1 files are stored and then updated N times.
N + which was rewritten with +1 file data and eventually updated
One file of data is output. However, the updated N
When an error occurs during reproduction in the duplicated data B on the +1 file side, the old N + 1 file data A having no error is accumulated in the buffer memory 44, and therefore the old N + 1 file data A is erroneously output at this portion. May be caused (FIG. 11 (B)).

Similarly, when data is additionally recorded following a desired tape mark, if there is a write-rewritten area immediately before that, erroneous data may be output.

For this reason, in this embodiment, the overwrite start flag OWSF is set to identify the start position of additional change recording. That is, the recording format control unit 2
In 0, the subcode generation circuit 31 generates the overwrite start flag OWSF and records the overwrite start flag OWSF as one of the subcode data SCD in the head recording unit of the data to be additionally recorded.

Further, in the recording format control unit 20, when the change is additionally recorded, the valid data number VDNO is set.
Is added and recorded by a value of 16, so that the value of the valid data number VDNO is sharply increased by more than the recording unit required for write retry at the beginning of the change and additional recording.

As a result, as shown in FIG. 12, after the write retry, the change of N + 1 file data is added.
Further, when changing and additionally writing the N + 2 file data, the overwrite start flag OWSF rises at the beginning of the new N + 1 and N + 2 file data (see FIG. 12).
(A)), in the valid data number VDNO,
At the rising edge of the overwrite start flag OWSF, the value rapidly changes by 16 (FIG. 12B). Therefore, the start position of the additional write change can be detected based on the overwrite start flag OWSF, and when the valid data number VDNO continues, it can be determined that the data has been recorded as a group of data.

On the other hand, at the time of reproduction, in the reproduction data format section 40, the system control circuit 24 monitors the overwrite start flag OWSF and the valid data number VDNO, and when the overwrite start flag OWSF rises, the valid flag is set. Data number VD
The reproduction data D12 is processed by subtracting the value 16 from NO. As a result, as shown in FIG.
Can process the reproduction data S12 so that the valid data number VDNO is continuous in the area where the change is added, and the data where the change is added can be surely reproduced.

Further, when the overwrite start flag OWSF rises, the system control circuit 24 sets the value 16
Playback data S that has already been accumulated by tracing back to the buffer block of the overwrite start flag OWSF obtained by subtracting only
Erase 12 This makes it possible to prevent erroneous output of the original data even when the write retry is performed immediately before.

On the other hand, the system control circuit 24 detects that the overwrite start flag OWSF is not detected and the continuity of the buffer block is not maintained (that is, when the valid data number VDNO changes rapidly). , A control signal is output to the data recorder 13, the magnetic tape is rewound, and the reproducing operation is repeated.

Thus, at least the recording unit required for the write retry, the valid data number V is added at the beginning of the changed and added data.
By suddenly switching the DNO value, the valid data number VDNO value will change discontinuously in the part where the change is added, regardless of what kind of write retry or even write retry is repeated immediately before. To do. Therefore, when the overwrite start flag OWSF is not detected in the relevant portion, the continuity of the buffer block is not maintained and the reproducing operation can be surely repeated, whereby the original data is not detected even if the overwrite start flag OWSF is not detected. It is possible to prevent erroneous output of. As a result, the reproduction operation can be repeated and the correct reproduction data D12 can be accumulated and output.

(4) Effects of the Embodiments According to the above configuration, the valid data number is set so that the value sequentially changes in the minimum unit for recording the record data on the magnetic tape, and the valid data number is used as the reference. By processing the reproduction data in this manner, the reproduction data can be processed easily and surely even when the write retry is performed without rewinding the magnetic tape. Furthermore, by raising the overwrite start flag at the beginning of the change addition and rapidly changing the valid data number by the value 16, even in the portion where the write retry and the change addition are combined, the overwrite start flag and the flash are changed. It is possible to easily detect the part for additional writing of the change based on the tuned data number, so that the additional data for the change can be surely reproduced as desired data.

(5) Other Embodiments In the above-mentioned embodiments, the case where the valid data number is rapidly changed by the value 16 at the beginning of the additional change has been described, but the present invention is not limited to this. It can be changed to various values according to.

Further, in the above-mentioned embodiment, a case has been described in which the value of the valid data number is drastically changed to represent a group of data that has been additionally written, but the present invention is not limited to this, and various status information is provided. Can be assigned and expressed.

Further, in the above-described embodiment, the case where the overwrite start flag, which is a pointer indicating the change additional recording start position, and the valid data number, which is status information for identifying a group of recording data to be recorded, are used at the same time will be described. However, the present invention is not limited to this, and only one of them may be used within a practically sufficient range.

Further, in the above-mentioned embodiments, the case where the present invention is applied to the D-1 format data recorder has been described, but the present invention is not limited to this, and is widely applied to a magnetic recording / reproducing apparatus for recording various data. Can be applied.

[0105]

As described above, according to the present invention, the valid data number is set so that the value sequentially changes in the minimum unit for recording the recorded data on the magnetic tape, and the valid data number is used as a reference. By processing the reproduction data, it is possible to obtain a magnetic recording / reproducing apparatus capable of easily and surely processing the reproduction data by performing write retry without rewinding the magnetic tape. Further, when a write retry and a change-addition are combined by setting a pointer to the start of the change-addition recording at the beginning of the change-addition recording and recording the input data with status information identifying the group of recorded data to be recorded. However, it is possible to obtain the magnetic recording / reproducing apparatus which can easily detect the additionally recorded portion and can surely reproduce the desired data by additionally recording the alteration.

[Brief description of drawings]

FIG. 1 is a block diagram showing a computer system according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a recording area on the magnetic tape.

FIG. 3 is a schematic diagram showing a recording format on the magnetic tape.

FIG. 4 is a schematic diagram for explaining an interleaving process between recording tracks.

FIG. 5 is a schematic diagram showing a track format on a magnetic tape.

FIG. 6 is a block diagram showing a recording format control unit.

FIG. 7 is a block diagram showing a reproduction format control section.

FIG. 8 is a schematic diagram for explaining a valid data number.

FIG. 9 is a schematic diagram for explaining write retry.

FIG. 10 is a schematic diagram for explaining a process of write-retry reproduction data in a buffer memory.

FIG. 11 is a schematic diagram used for a basic description of a change additional write operation.

FIG. 12 is a schematic diagram used for explaining a case where a write retry and a change additional recording are combined.

FIG. 13 is a schematic diagram for explaining the data on the magnetic tape.

FIG. 14 is a schematic diagram for explaining a D-1 format.

FIG. 15 is a schematic diagram for explaining the interleave processing.

[Explanation of symbols]

11 ... Host computer, 12 ... Data recorder control device, 13 ... Data recorder, 15 ... Format control unit, 22 ... Buffer memory, 24 ... System control circuit, 32 ... C3 code generation circuit, 33 ... Interleaved memory, 42 ... Deinterleaved memory,
43 ... C3 error correction circuit.

Claims (3)

[Claims] 1. A magnetic recording / reproducing apparatus for sequentially forming obliquely recording tracks on a magnetic tape, sequentially recording desired input data on the recording tracks, and reproducing the recorded data recorded on the recording tracks. When the input data is recorded on the magnetic tape, a valid data number whose value changes sequentially is generated, and the valid data number is recorded on the recording track together with the input data. A magnetic recording / reproducing apparatus characterized in that the recorded data to be reproduced is stored in a memory circuit based on the valid data number and then outputted. 2. A magnetic recording / reproducing apparatus for sequentially forming recording tracks obliquely on a magnetic tape and sequentially recording desired input data on the recording tracks, while recording the input data while recording the input data in sequence. When the input data is reproduced to detect an error and the error is detected, the input data is recorded again from the portion where the error is detected instead of the input data following the subsequent recording track, and the input data is When the input data is recorded on the already recorded magnetic tape, the input data is recorded with a pointer indicating a recording start position and / or status information for identifying a group of the input data to be recorded. Magnetic recording / reproducing device. 3. The status information is characterized in that a valid data number whose value sequentially changes in a minimum unit for recording the input data on the magnetic tape is used by switching the group of input data to be recorded. The magnetic recording device according to claim 2.