JP2805703B2 - Data recording method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a data recording method for recording data sent from a computer or the like using a rotary head type digital audio tape recorder (DAT). [Summary of the Invention] The present invention relates to a data recording method for recording data from a computer or the like in accordance with the DAT format by using a DAT, wherein two data constituting one frame in the DAT format are provided. The main data is recorded in the main area of the inclined track, and the sub data including the serial number of the frame is recorded in the sub area. At this time, the main data recorded in the main area of each of the two inclined tracks forming one frame are recorded. By recording data for detecting an error of the track as a part of the sub-data in the sub-area of the same inclined track as that of the sub-data, an error such as a drop-in error occurs in one of the main area and the sub-area of each track. Is to be able to detect it easily even if it occurs. 2. Description of the Related Art In a computer, in order to protect (back up) data written on a hard disk or the like, such data is transferred to a data streamer (data recorder) once a day and recorded. Have been done. As a conventional data recorder, a normal analog audio tape recorder has often been used. However, in such an analog tape recorder, the consumption of the magnetic tape becomes extremely large, and since the data rate at the time of recording is low, it takes much time to transfer and record. However, there is a problem that the dispensing cannot be easily performed. Therefore, it has been considered to use a digital audio tape recorder, a so-called DAT, based on a helical scan method using a rotating head, which has been commercialized in recent years, as a data recorder. When a DAT is used as a data recorder, data from a host computer is converted into a DAT format and recorded. In the DAT format, two inclined tracks formed when two heads having different azimuths make one rotation are defined as one frame, and 16-bit PCM audio data is interleaved and recorded in units of one frame. , Auxiliary sub-data is recorded. In that case,
As will be described later, each track has a main area where PCM data is recorded and a sub area where sub data is recorded. In addition, in DAT, when recording another signal on a recorded tape, generally, without using an erase head,
By recording a new signal by so-called double writing, the previous signal is erased. Therefore, for example, if the head momentarily leaves the tape or double writing is not performed normally due to head clogging, etc., the previous signal remains unerased, which is a cause of data error called so-called drop-in. Becomes As a countermeasure, in the DAT format, an error detection code is added to each of the main area and the sub area of each track to be recorded, and if a part of the track remains unerased, it is detected as an error. I have to. [Problems to be Solved by the Invention] As described above, in the DAT format, an error detection code is added to the main area and the sub area of one track so that drop-in can be detected in each area. I have. However, even if such an error detection code is added, for example, when the entire main area or the entire sub-area is left unerased, if the error detection code in that area is normal, , The drop-in cannot be detected. If the signal to be recorded is an audio signal, it is possible to eliminate the remaining part of the signal due to the correlation before and after, but when using DAT as a data recorder, it is generally not possible to use the correlation of data. Can not. When used as a data recorder, it is required to record and reproduce data more accurately than when an audio signal is handled. [Means for Solving the Problems] According to the present invention, two inclined tracks are formed on a tape-shaped recording medium by one rotation of a rotary head. A data recording method for recording data having a predetermined data format and a continuous frame number for each frame, wherein a first area in which main data is recorded and sub data including the frame number are recorded. A second area to be recorded is formed on each inclined track, and at this time, an error of main data recorded in the first area of the two area tracks constituting one frame is detected. Data is recorded as a part of the sub data in the second area of the same inclined track. [Operation] Based on the data for detecting the error and the continuity of the frame number, it is possible to detect an error such as drop-in in at least one of the main area and the sub-area. [Embodiment] FIG. 1 shows a configuration when a DAT is used as a data recorder, where 1 is a DAT, 2 is an interface bus,
3 is a host computer, and 4 and 5 are inner buses. DAT1 is a recording / reproducing unit 6, a recording amplifier 7, a reproducing amplifier 8, a signal processing circuit 9, a RAM 10, a data controller 11,
Interface board 12, system controller 13,
It is mainly composed of a servo and motor drive circuit 14 and the like. The system controller 13, the signal processing circuit 9, and the data controller 11 are connected to an absolute frame number AFN described later.
O, check data, a mode instruction, a logical frame number LFNO, a determination result based on the check data, and a predetermined signal such as a data transfer instruction are transmitted and received. The recording / reproducing unit 6 is provided with a rotating head drum (not shown), and the magnetic tape is wound around a range of about 90 degrees around the drum and transferred by a capstan. This drum has different azimuth angles A,
B2 heads are provided, and two inclined tracks are recorded and reproduced on the tape by one rotation of the drum. Digital data supplied from the host computer 3 via the buses 5, 2, and 4 is transmitted to an interface board.
The data is input to the DAT 12 and further subjected to predetermined signal processing in the data controller 11, the RAM 10, the signal processing circuit 9 and the like in accordance with an instruction from the system controller 13, thereby performing the above-described conversion into the DAT format. The formatted signal is supplied to the recording / reproducing unit 6 through the recording amplifier 7 and is recorded on the magnetic tape by the heads A and B. The signals recorded on the magnetic tape are reproduced by the heads A and B, and the reproduced signals are supplied to a signal processing circuit 9 through a reproduction amplifier 8, where the digital data obtained by inverse conversion is taken out by a data controller 11, an interface It is supplied to the host computer 3 through the board 12 and the buses 4, 2, and 5. In the above apparatus, the format of the DAT recorded on the magnetic tape is as shown in FIG. In FIG. 2, two inclined tracks T _A and T _B are formed on the tape 15 from below as shown by the arrow a in FIG. The two tracks T _A, 1 frame is composed of T _B. One track T _A (or T _B ) is composed of 196 blocks, and one block is composed of 288 bits. Of these, 34 blocks at both ends become a sub area, and 128 blocks at the center become a main area. The sub-area is further divided into several sections.
That is, from the lower end of the track, a margin portion, a preamble portion for PLL of a subcode, a first subcode portion, a postamble portion, a gap portion of a block portion, a tracking (ATF) signal portion, a gap portion between blocks, Data PLL
Preamble portion, inter-block gap portion, ATF signal portion, inter-block cap portion, sub-code PLL preamble portion, second sub-code portion, post-amble portion,
A margin portion is provided. Of these, the first and second subcode sections are each composed of eight blocks, and the other parts are each composed of a predetermined number of blocks. still,
The length scale in the figure is not accurate. The main area consists of 128 data blocks, one block is as shown in FIG. 3, the synchronization signals from the beginning of the block, W ₁ parts, such as PCM-ID, block address, parity in each 8-bit The main data is arranged in the next 256-bit period. When handling an audio signal, the main data is 16-bit PCM data for each of the L channel and the R channel. These 16-bit main data consist of two tracks T _A , T
_It is interleaved in the main area of _B (one frame) and arranged with parity. In this case, approximately 5760 bytes of data are recorded in the main area of one frame. When used as a data recorder, the data sent from the host computer 3 is converted into 16-bit data and treated in the same manner as the PCM data, and these data are formatted as shown in FIG. Recorded in the main area of the frame. That is, in FIG. 4, the above-mentioned 5760 bytes are formed into words (0 to 1439) of 4 bytes (32 bits), and each of these words has 16 bits (2 bytes) in accordance with the audio signal. It is divided into an L channel and an R channel. And in this format,
First, a synchronization part is provided in three words (12 bytes), the first one byte of this synchronization part is all "0", the following ten bytes are all "1", and the last one byte is all "0". "
To be. Next, an 8-word (32-byte) header section is provided. The first four bits of the L-channel of the word 3 in the header 3 and the 4 bits on the MSB side are used as a format ID indicating the format of the data decoder, and the last 4 bits are undecided. The remaining three bytes of this word 3 are used as a logical frame number (LFNO) area, which will be described later. The LFNO consisting of these 8 bits makes it possible to convert the binary values indicating the serial numbers 1 to 23 of the frame into, for example, 23 frames as one unit. Provided. Then, a data portion of a total of 5728 bytes is provided in the subsequent words 7 to 1438, and a data signal from the host computer 3 is sequentially provided by 4 bytes in each word. Further, the word 1439 is used as an error detection code (EDC) part, and an error detection code (EDC) is generated for each of the data signals in the header part and the data part described above for a data string in which each data bit is viewed in a vertical direction. Provided. Here, in the DAT format, the data of the L channel and the data of the R channel are alternately distributed to two tracks by 2 bytes and recorded. For example, tracks are formed on both sides of the drawing. The heads A and B are shown as azimuths (±).
Therefore, as described above, by generating EDC for a data string in which each data bit is viewed in the vertical direction, EDC can be generated for two tracks forming one frame. Therefore, according to this format, it is possible to determine whether the main area remains unerased by performing the EDC operation. That is, in the above-mentioned format, if one track remains unerased, every other data for generating the EDC will be different, and the EDC calculation will not be performed correctly. Therefore, by detecting this value, it is possible to determine the remaining erase. Next, the logical frame number LFNO
It will be described with reference to the drawings. As described above, LFNO is obtained by assigning serial numbers 1 to 23 to each frame, for example, with 23 frames as one unit. That is, the frame numbers 1 to 23, 1 to 23... Are repeated every 23 frames. In FIG. 5, the entire LFNO is composed of 8 bits.
B is the last frame ID (LASTF-ID) indicating that it is the last frame of the unit, that is, if the unit is 23 frames, it is the 23rd frame. The next one bit of the MSB is set as an ECC frame ID (ECCF-ID) indicating that the frame is an ECC frame for error correction.
The bits represent 1 to 23 LFNOs. Therefore, LF
NO is variously selected from the range of 1 to 64, so that the above unit is 23
You can choose any length other than the frame. In that case, it can be known from the LASTF-ID that the frame is the last frame of the unit. ECCF-
The ID may be multiplexed not only in one frame but also in a plurality of frames. By using such units with LFNO,
The boundaries of the data at predetermined intervals become clear, and signal processing becomes easy. Also, by changing the maximum value of LFNO and selecting an appropriate unit length, signal processing can be performed more easily. Next, the data configuration of the first and second subcode portions in the subarea will be described. The first and second sub-code sections are each composed of eight sub-code blocks, each of which can record 2048-bit data. FIG. 6 shows the structure of a sub-code block. After an 8-bit synchronization signal, W ₁ , W ₂ , and parity are arranged, 256-bit sub-code data including parity is arranged. This subcode data is composed of four packs, and one pack is composed of 8 × 8 bits (8 symbols). The contents of W ₁ and W ₂ are different between the block with the block address of EVEN and the block with the ODD, and pack numbers (1 to 7) are assigned to the EVEN block and the ODD block as shown in the figure. . Also in the eighth pack is provided with a C ₁ code for error detection. W ₁ of the EVEN block are each 4-bit control code (CTL-ID), consists all zero code, W ₂ is "1" in the upper one bit, consists format ID, 4 block address bits of 3 bits. W ₁ of the ODD block is
4-bit program number code (PNO-2, PNO
NO-3) consists, W ₂ is "1" in the upper one bit, three bits of the program number code (PNO-1), is made from the block address of 4 bits. Each of the packs 1 to 7 is divided into 8 words of 8 bits. Each word includes, for example, a code indicating a lead-in area of a recording start portion on a tape, a code indicating a lead-out area of a recording end portion, Various types of codes such as codes indicating recording date and time, absolute frame numbers, logical frame numbers, and so on are provided together with the parity. FIG. 7 shows the configuration of pack 3 as an example of the seven packs. This pack 3 consists of eight 8-bit words PC1-8
Consists of The upper 4 bits of PC1 are provided with a pack number (here, “0011” indicating pack 3), and the lower 4 bits are provided with a format ID. PC2 is an undecided part. The upper four bits of PC3 are provided with an area ID indicating the lead-in area or lead-out area. The absolute frame number (AFNO) is represented by a total of 20 bits including the lower 4 bits of PC3 and PC4 and PC5. This AFNO is a serial number assigned to all frames recorded on one tape. Next, a total of 16 for PC6 and PC7
The check data CD according to the present invention is provided by bits, and the PC8 is provided with parity for PC1 to PC7. The 16-bit check data CD has an exclusive OR of all the data present in the main area provided on one track of the pack 3 is provided (T _A or T _B) (data from the computer) Things. Alternatively, an error detection signal such as a CRC for all data existing in the main area may be used as the check data CD. This check data can also be provided in undetermined portions of the other packs PC1 and PC2 to PC7 and overwritten to increase reliability. In this case, the first track and the second subcode section of 8 blocks are provided for each track, and there are 7 packs of 2 blocks. Therefore, a maximum of 56 pieces of the same check data CD are recorded on one track. be able to. Such check data CD is used as follows. At the time of reproduction, the check data CD read from one track is compared with the exclusive OR of the data read from the main area of that track. As a result, if they do not match, it is determined that either the entire main area has been erased or the entire sub-area has been erased (the previous check data CD has also been erased). can do. If the two match, it can be determined whether both the entire main area and the entire sub-area are correct or both are incorrect. In order to know which of the main area and the sub area is correct or incorrect, it can be determined by the following method using LFNO and AFNO. FIG. 8 shows the order of the judgment, and the steps S1 to S4
9 is determined based on the determination by the user, and the contents of the determination in FIG. 10 can be known based on the determination criterion. In Figure 8, first, in step S1 (hereinafter referred to main data) main area data C _1, examine whether or not the correction by C ₂ reference numerals. If the correction could not be made, it is determined that there is a dropout in the main data of the track, and a message to that effect is sent as C in FIG. Next step when correction is possible
In S2, the continuity of LFNO in the main area is checked. If there is no continuity, it is determined as B in FIG. 10 and it is determined that there is a drop-in on the track, and a message to that effect is sent. When the LFNO has continuity, the check of the main area is finished, and then the sub area is checked in step S3. For pack data of the sub-area, C ₁ code correction, pack parity, checks the reproducibility of the pack data by multiple match or the like. If this check fails, it is assumed that (5) in FIG.
It is determined that the sub-area data (sub-data) has a drop-in and the main data is correct. When the reproducibility check is completed, the continuity of AFNO is checked and the main data is checked using the check data CD in step S4. Based on the result of each check, a ninth check is performed.
The judgment criteria shown in the figure are obtained, and the contents of the judgment shown in FIG. 10 are obtained based on the judgment criteria. The content of each judgment is as follows: A- (1) The main data is correct. A- (2): Both main data and sub data have drop-ins. A- (3): There was a drop-in in the main data.
AFNO continued in every corner. A- (4)... There was a drop-in in the sub data. In this case, make AFNO self-propelled and the main data is correct. A- (5): There was a drop-in in the sub data. In this case, the AFNO will run on its own and the main data will be correct. When a drop-in is detected by the check data CD, a flag is set, and based on this flag, error correction using the error correction code ECC can be performed. Further, in order to prevent the reading error of the check data CD and the data of the main area, detection by the check data CD may be performed a plurality of times. [Effects of the Invention] In the present invention, two inclined tracks are formed on a tape-shaped recording medium by one rotation of a rotary head. At this time, these two inclined tracks are defined as one frame, and a predetermined A data recording method for recording data having a data format and a continuous frame number, wherein a first area in which main data is recorded and a second area in which sub-data including the frame number are recorded. Are formed on each inclined track, and at this time, data for detecting an error of the main data respectively recorded in the first area of the two inclined tracks forming one frame is transmitted to the sub-track. The data is recorded in the second area of the same inclined track as a part of the data. Therefore, when a drop-in or the like occurs in the entire first area or the second area, it can be easily detected, and the specific content of the error can be known. Can be improved when using as a data recorder.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 shows a data structure of a main data block, FIG. 4 shows a data structure of a main area of one frame, FIG. 5 shows a data structure of a logical frame number, and FIG. FIG. 7 is a data structure diagram of a pack of a subcode block, FIG. 8 is a flowchart showing an error determination method,
FIG. 9 is a diagram showing an error judgment criterion, and FIG. 10 is a diagram showing the contents of the judgment. In the reference numerals used in the drawings, T _A , T _B, track 1, DAT 3, host computer 13, system controller AFNO, absolute frame number CD, check data.

Continued on the front page (72) Inventor Hiroshi Ishibashi 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Kentaro Odaka 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Stock In-company (72) Inventor Masaki Yamada 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation Inside (72) Inventor Katsuzumi Inazawa 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (56) References JP-A-63-26865 (JP, A) JP-A-62-275356 (JP, A) JP-A-62-219266 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 20/12 102

Claims (1)

(57) [Claims] One rotation of the rotary head causes two rotations on the tape-shaped recording medium.
The two inclined tracks are formed, and the two inclined tracks are defined as one frame.
A data recording method for recording data having a predetermined data format and a continuous frame number for each frame, comprising: a first area in which main data is recorded; Is formed on each inclined track, and at this time, an error of main data recorded on the first area of each of the two inclined tracks constituting one frame is detected. A data recording method for recording the data as a part of the sub data in the second area of the same inclined track as the sub data.