JPH01155570A - Data recorder - Google Patents

Abstract

PURPOSE:To easily attain a signal processing by setting a unit consisting of optional and plural frames and recording frame numbers which continue within the unit and a signal showing that it is the last frame of the unit. CONSTITUTION:Data are recorded into two inclined tracks TA and TB constituting one frame being the format of a rotary head type digital audio taper recorder, and the unit consisting of optional and plural frames is set, whereby the continuous frame numbers within the unit and the signal showing that it is the final frame of the unit are recorded. Thus, the length of the unit can freely be changed, and the signal processing is easily attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data recorder that uses a rotating head type digital audio recorder (DAT) to record and reproduce data sent from a computer or the like.

[Summary of the invention]

The present invention is a data recorder that uses DAT to record and reproduce data from a computer, etc. in accordance with the DAT format, and the data is recorded on two inclined tracks constituting one frame in the DAT format. At the same time, by setting a unit consisting of any number of frames and recording consecutive frame numbers within that unit and a signal indicating that it is the last frame of that unit, the above unit can be recorded. The length of the signal can be changed freely to facilitate signal processing.

[Conventional technology]

In order to protect (back up) data written on a hard disk or the like in a computer, such data is transferred to a data streamer (data recorder) and recorded once a day, for example.

As conventional data recorders, ordinary analog audio tape recorders have often been used. However, in such an analog tape recorder, the amount of magnetic tape consumed is extremely large, and the data rate during recording is low, so it takes an extremely long time to transfer and record, and furthermore, it is difficult to locate the beginning of the desired recording section. There were problems such as that it was not possible to do it easily.

Therefore, it has been considered to use a helical scan type digital audio tape recorder using a rotating head, so-called DAT, which has been commercialized in recent years, as a data recorder. When using a DAT as a data recorder, data from a host computer is converted into the DAT format and recorded. In the DAT format, one frame is two inclined tracks formed when two heads with different azimuths rotate once, and 16-bit PCM audio data is incremented and recorded in one frame. At the same time, auxiliary sub-data is recorded.

In that case, as will be described later, each track is formed with a main area where PCM data is recorded and a subarea where sub data is recorded.

In addition, in DAT, when recording a new signal on an already recorded tape, an erasing head is generally not used.
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 if double writing is not performed properly due to head clog, the previous signal remains unerased, and this is the cause of data errors called drop-ins. becomes.

As a countermeasure for this, in the DAT format, an error detection code is added to the main area and subarea of each track to be recorded, so that if an unerased part of the track occurs, it will be detected as an error. I have to.

[Problem that the invention seeks to solve]

When recording data from a computer with a data recorder, it becomes easier to perform signal processing if it is possible to know some kind of break for each predetermined amount of data.

The present invention has been made in view of the above requirements.

[Means for solving the problem] In the present invention, a unit consisting of any plurality of frames is set, and consecutive frame numbers within the unit and a signal indicating that it is the last frame of the unit are set. I try to record it.

[Effect]

The length of the above unit can be freely selected, and signal processing can be easily performed.

〔Example〕

FIG. 1 shows the 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 4.5 is an inner bus. DATl is mainly composed of a recording/reproducing section 6, a recording amplifier 7, a reproducing amplifier 8, a signal processing circuit 9, a RAM 10, a data controller 11, an interface port 12, a system controller 13, a servo and motor drive circuit 14, and the like.

The system controller 13, signal processing circuit 9, and data controller 13 are connected to the absolute frame number A, which will be described later.
It is configured to send and receive predetermined signals such as FNO, check data, mode instructions, logical frame number LFNO, judgment results based on check data, and data transfer instructions.

The recording/reproducing section 6 is provided with a rotating head drum (not shown), and the magnetic tape is wound around the drum in an area of about 90 degrees and is transported by a capstan. This drum has A with different azimuth angles.
, B are provided, and two inclined tracks are recorded and reproduced on the tape by one rotation of the drum.

The digital data supplied from the host computer 3 via the bus 5.2.4 is transferred to the interface port 1.
2, and further undergoes predetermined signal processing in the data controller 11, RAM 10, signal processing circuit 9, etc. according to instructions from the system controller 13, thereby converting the data into the DAT format described above. This formatted signal is supplied to the recording and reproducing section 6 through the recording amplifier 7, and is recorded on the magnetic tape by the heads A and B.

Also, the signal recorded on the magnetic tape is head A.

This reproduced signal is supplied to the signal processing circuit 9 through the reproduction amplifier 8, and the digital data taken out after being inversely converted is sent to the host computer through the data controller 11, interface port 12 and bus 4.2.5. 3.

In the above-mentioned apparatus, the format of the DAT recorded on the magnetic tape is as shown in FIG.

In FIG. 2, two inclined tracks TA and Ti are formed on the tape 15 from the bottom side as indicated by arrow a in the figure by one rotation of the heads A and B. These two tracks TA and T constitute one frame. 1
A book track TA (or TB) consists of 196 blocks, and one block consists of 288 bits. Of these, 34 blocks at both ends become sub areas, and 128 blocks at the center become the main area.

The subarea is further divided into several sections. That is, from the bottom end of the track, the margin section, the preamble section for PLL of the subcode, the first subcode section, the postamble section, the gap section of the block section, the tracking (ATF) signal section, and the gap section between blocks. , preamble section for data PLL, gap section between blocks, A
TF signal section, inter-block cap section, subcode PL
A preamble section, a second subcode section, a postamble section, and a margin section for L are provided. The first of these
and the second subcode portion are each made up of eight blocks, and the other portions are each made up of a predetermined number of blocks. Note that the length scale in the figures is not exact.

The main area consists of 128 data blocks, and each block has a synchronization signal, W1 part such as PCM-ID, block address, and parity arranged in 8 bits from the beginning of the block, as shown in Figure 3. and the next 256
Main data is placed in the bit period. When handling audio signals, this main data is PCM data of 16 bits each for the L channel and the R channel. These 16-bit main data are stored in two tracks TA, T! The data are interleaved in the main area of l (1 frame) and arranged together with parity.

In this case, the main area of one frame contains approximately 5760
Bytes of data are recorded. When used as a data recorder, the data sent from the host computer 3 is converted into 16-bit data and treated as the above 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 configured into words (0 to 1439) each consisting of 4 bytes (32 bits), and each word is composed of 16 bits (2 bytes) each in accordance with the audio signal. It is divided into an L channel and an R channel. In this format, a synchronization part is first provided in 3 words (12 bytes), the first 1 hide of this synchronization part is all "0", the following 10 bytes are all "1", and the last one is
Byte is set to all "0".

Next, a portion of the 8 word (32 byte) header is provided. The MSB side 4 bits of the first half byte of the L channel of word 3 in this header part are used as a format ID indicating the format of the data decoder, and the latter 4 bits are left undefined. Also, the remaining 3 of this word 3
The byte is a logical frame number (LPNO), which will be described later.
) area, and the 8-bit LFNO provides a binary value indicating frame serial numbers 1 to 23, with 23 frames as one unit, for example.

Subsequent words 7 to 1438 are provided with a data portion of a total of 5728 bytes, and data signals from the host computer 3 are sequentially provided in each word by 4 bytes.

Furthermore, word 1439 is an error detection code (EDC) section, which is an error detection code (EDC) for each data signal of the header part and data section described above, and is applied to a data string in which each data bit is viewed in the vertical direction. ) is generated and provided.

In the DAT format, L channel data and R channel data are alternately distributed and recorded by 2 bytes each on two tracks.For example, tracks are formed on both sides of the diagram. The azimuths (±) of heads A and B are shown.

Therefore, by generating an EDC for a data string in which each data bit is viewed in the vertical direction as described above, it is possible to generate an EDC for two tracks forming one frame.

Therefore, according to this format, it is possible to determine whether the main area remains unerased by performing EDC calculations. That is, in the above-described format, if one track remains unerased, the data for every other track that generates the EDC will be different, and the EDC calculation will not be performed correctly. Therefore, by detecting this value, it is possible to determine whether there is any unerased data.

Next, the above-mentioned logical frame number LFNO will be explained with reference to FIG. 5.

As described above, the LFNO is made up of, for example, 23 frames as one unit, and each frame is given a serial number from 1 to 23. That is, every 23 frames 1~23.1~
The frame numbers of 23---------- are repeated. In FIG. 5, the entire LFNO consists of 8 bits, of which the MSB is the last frame of the unit, that is, the unit is 2 bits.
In the case of 3 frames, it is set as the last frame ID (LASTF-ID) indicating that it is the 23rd frame. Also, the next 1 bit after the MSB is used as an EC for error correction.
ECC frame ID indicating that it is a C frame (E
CCF-ID) and the next 6 bits are LFN of 1 to 23.
Let it represent O. Therefore, by selecting various LFNOs in the range of 1 to 64, the unit can be selected to have any length other than 23 frames. In that case, the above L
The ASTF-ID allows it to be known that the frame is the last frame of the unit. Also ECCF
-ID may be multiplexed not only in one frame but also in multiple frames.

By using such a unit with an LFNO attached, divisions for each predetermined amount of data become clear, and signal processing becomes easier. Furthermore, by changing the maximum value of LFNO and selecting an appropriate unit length, signal processing can be performed more easily.

Next, the data structure of the first and second subcode sections in the subarea will be explained.

The first and second subcode sections each consist of eight subcode blocks, and can each record 2048 bits of data.

FIG. 6 shows the structure of a subcode block, in which 8-bit synchronization signals, 1, h, and parity are arranged, and then 256-bit subcode data including parity is arranged. This subcode data consists of four packs, one pack of which consists of 8×8 bits (8 symbols).

The content of the rivalry is different between the block whose block address is EVEN and the block whose block address is ODD, and the back numbers (1 to 7) are different from each other as shown in the figure.
It is attached across the DD block. Further, the eighth back is provided with a C+ code for error detection.

Each EVEN block 1 consists of a 4-bit control code (CTL-ID) and an all-zero code, and -2 consists of the upper 1 bit of "1", a 3-bit format ID, and a 4-bit block address. ODD
Each block Wl consists of a 4-bit program number code (PNO-2, PNO-3), and W2 consists of the upper 1 bit "1", a 3-bit program number code (PNO-1), and a 4-bit block. It consists of an address.

Backs 1 to 7 are divided into 8 words of 8 bits each, and each word includes, for example, a code indicating the lead-in area at the start of recording on the tape, a code indicating the lead-out area at the end of recording, Code indicating recording date and time, absolute frame number, logical frame number
Many types of codes such as -1, -, etc. are provided along with parity.

FIG. 7 shows the configuration of bag 3 as an example of seven packs.

This pack 3 contains 8 words PC1-8 of 8 bits each.
Consists of. The upper 4 bits of the PCI are provided with a back number (in this case, "roll" indicating back 3), and the lower 4 bits are provided with a format ID. PO2
is the undetermined part.

The upper 4 bits of PO3 are provided with an area ID indicating the lead-in area or lead-out area. The total of the lower 4 bits of PO3, PO4, and PO2 is 2.
The 0 bit represents the absolute frame number (AFNO). This AF No. is a consecutive number assigned to all frames recorded on one tape. Next, PO2
and PO2, a total of 16 bits, provides a check data CD regarding the present invention, and the PCB includes PC1 to Pc7.
Parity is set for .

The above 16-bit check data CD is included in this pack 3.
This is the exclusive OR of all data (data from the computer) existing in the main area provided on one track (TA or Ta) provided with. Alternatively, as the check data CD, an error detection signal such as a CRC for all data existing in the main area may be used.

This check data also applies to other punctures Pct, PO2-
It is also possible to increase reliability by providing the undetermined portion of No. 4 for multiple writing. In that case, each track is provided with 8 blocks of first and second subcode sections, and there are 7 backs in 2 blocks, so 1
Up to 56 pieces of the same check data CD can be recorded on a book track.

Such check data CD is used as follows.

The check data CD read out from one track during playback is compared with the exclusive OR of the data read out from the main area of that track. As a result, if the two do not match, it means that either the entire main area was left unerased or the entire sub area was left unerased (the previous check data CD was also left unerased). can be determined. Further, when the above two match, it can be determined that either the entire main area and the entire sub area are correct or both are incorrect. To find out whether the main area or subarea is correct or incorrect, use LFNO and A.
The determination can be made by the method described below using FNO.

FIG. 8 shows the order of determination, and each step 31 to S
4, the determination criterion shown in FIG. 9 is obtained, and based on this determination criterion, the content of the determination shown in FIG. 10 can be known.

In FIG. 8, first, in step S1, data in the main area (hereinafter referred to as main data) is set to C8, C.
2 Check whether the correction using the code was successful or not. If the correction could not be made, it is determined as C in Figure 10 that there was a dropout in the main data of that track, and
Send a message to that effect. When the correction is successful, the continuity of LFNO in the main area is checked in the next step s2.

If there is no continuity, it is determined as B in FIG. 10 that there is a drop-in on that track, and a message to that effect is sent. When there is continuity in LPNO,
After checking the main area, proceed to step S3.
Chesso the subarea. The reproducibility of the pack data is checked using C3 code correction, pack parity, multiple matching, etc. for the data in the pack of the subarea. If this check fails, check (5) in Figure 10.
), it is determined that there is a drop-in in the subarea data (subdata) and that the main data is correct. When the reproducibility check is completed, check the continuity of AFNO and check data C in step S4.
D is checked on the main data, and based on the results of each check, the judgment criteria shown in FIG. 9 are obtained, and the details of the judgment shown in FIG. 10 are obtained based on these judgment criteria.

The content of each determination is as follows: A-(1)・----------------The main data is correct.

A-(2)--111--There was a drop-in for both main data and sub data.

A - (3) -------------- There was a drop-in in the main data. AFNO continued from corner to corner.

A-(4)... There was a drop-in in the sub data. In this case, let AF NO run automatically and make sure the main data is correct.

A-(5)...-------There was a dropout in the sub data. In this case, AFNO is allowed to run by itself and the main data is correct.

Note that a flag is set when a drop-in is detected by the check data CD, and based on this flag, error correction can be performed using an error correction code ECC. Further, in order to prevent misreading of the check data CD and the data in the main area, detection using the check data CD may be performed multiple times.

[Effects of the Invention] According to the present invention, the division of the predetermined amount of data is made clear by the above unit, and the thickness of the predetermined amount can be changed by arbitrarily selecting LFNO from, for example, 1 to 64. By changing the length of the unit, signal processing can be easily performed. Also, the last frame of the unit can be known from the LASTF-ID.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an embodiment of the present invention.
A diagram showing the AT format. Figure 3 is a data configuration diagram of the main data block. Figure 4 is a data configuration diagram of the main area of one frame. Figure 5 is a data configuration diagram of logical frame numbers. Figure 6 is a data configuration diagram of the main area of one frame. Figure 7 is a data configuration diagram of a sub-code block pack, Figure 8 is a flowchart showing the error determination method, Figure 9 is a diagram showing error determination criteria, and Figure 10 is the content of determination. FIG. In addition, in the symbols used in the drawings, T AT m '--m----- Track 1--
−−−−−−−−−−−−D A T3−−−−−−
−−−−−−−−−Host computer 13・−−−
−−・−−1−−・−・System controller LPNO
・--111--This is a logical frame number.

Claims (1)

[Claims] Two inclined tracks are formed on the recording medium by one rotation of the rotary head, these two inclined tracks are regarded as one frame, and data having a predetermined data format is recorded in each frame. and a data recorder that sets a unit consisting of any plurality of frames and records consecutive frame numbers within the unit and a signal indicating that it is the last frame of the unit. .