JPH01155569A - Recording method for data - Google Patents

Abstract

PURPOSE:To prevent the transfer rate of data from dropping by recording frame numbers which continue within a unit consisting of plural frames and a signal showing the final frame of the unit, and recording new data through an amble part after a prescribed interval is left from the subsequent signal at the time of append. CONSTITUTION:Data of a prescribed quantity are recorded in one frame, and the unit consisting of optional and plural frames is set and the frame numbers which continue within the unit and the signal showing that it is the final frame LASTF-ID of the unit are recorded. For adding data, the signal is detected and the amble part in prescribed frame numbers is generated after through the prescribed number of the frames, and new data is recorded. Thus, data can be added without deteriorating the transfer rate of data at the time of recording.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention uses a rotating head type digital audio tape recorder (DAT) to record and reproduce data sent from a computer, etc. This relates to the recording method.

[Summary of the invention]

The present invention is a data recording method suitable for use in a data recorder, etc., which uses DAT to record and reproduce data from a combination device, etc. in accordance with the DAT format. At the same time, set a unit consisting of any number of frames, record consecutive frame numbers within that unit and a signal indicating that it is the last frame of that unit, and add data. When performing this, the above signal is detected, and based on this detection, after a predetermined number of frames have passed, an amble portion of a predetermined number of frames is formed, and then new data is recorded.
This allows additional data to be written without lowering the data transfer rate during recording.

[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, with such analog tape recorders, 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 could not be done 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 such a data recorder, new data may be appended to the middle of data recorded on a magnetic tape. When appending such data, the method shown in Figure 7, for example, can be considered in order to protect data near the boundary (append point) between previously recorded data and newly recorded data. .

In FIG. 7A, data (1) (
2) --------- are recorded via the amble section, respectively. The amble portion is formed of dummy data such as all zeros, for example. This tape 1
When recording new data after data (1), the next amble part of data (1) is detected, and based on this detection, new data is recorded from this amble part as shown in the figure. (1), (2) ---------, --- are recorded through the amble section, respectively. According to this method, data (1
) and data ■ around the append point without damaging the data.

[Problem that the invention seeks to solve]

In the data append method shown in FIG. 7 described above, an amble section is formed every time data is recorded, so the data transfer rate decreases by the time it takes to write the amble section, and the recording capacity of the tape 12 ( utilization rate) will also decline.

[Means for solving problems]

In the present invention, a unit consisting of a plurality of arbitrary frames is set, and consecutive frame numbers within the unit and a signal indicating that it is the last frame of the unit are recorded, and when appending, the above-mentioned signal is recorded. After a predetermined interval, new data is recorded via the amble section.

[Effect]

Data can be additionally written without lowering the data transfer rate and recording capacity during recording.

〔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. DATI mainly includes a recording and 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, the signal processing circuit 9, and the data controller 13 use the absolute frame number A, which will be described later.
FNO% mode instruction, logical frame number LFN
It is configured to send and receive predetermined signals such as O 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 trunks TA, T are formed from the bottom side of the tape 15 as indicated by arrows a in the figure by one revolution of the heads A and B. These two tracks T a and T B constitute one frame. One track TA (or T.

) consists of 196 blocks, one block is 288
Consists of 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 between the blocks. part, a data PLL preamble part, an inter-block gap part,
ATF signal section, interblock cap section, subcode P
A preamble section for LL, a second subcode section, a postamble section, and a margin section are provided. Of these, the first and second subcode sections each consist of eight blocks, and the other sections each consist 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, as shown in Figure 3, has a synchronization signal, W of PCM-ID, program address, and parity, respectively, from the beginning of the block. Arranged in 8 bits, next 2
Main data is arranged in a period of 56 bits. 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 incremented in the main area of two tracks Ta and Ti (one 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 byte of this synchronization part is all "0", the following 10 bytes are all "1", and the last one is
The bite is all 10''.

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 azimuth (±) of the head ASB is 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.

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.---m=-.- will be 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.
If it is composed of 3 frames, the last frame ID (LASTF-I) indicating that it is the 23rd frame.
D).

In addition, the next 1 bit of MSH is an ECC frame ID (ECCF-) indicating that it is an ECC frame for error correction.
IO'), and the next 6 bits represent LFNO of 1 to 23. 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 LAS
From the TF-ID, it can be known that the frame is the last frame of the unit. Also, ECCF-I
D may be overwritten 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. Additionally, data can be added using the LASTF-ID, which will be described later.

Next, the first and second subcode portions in the subarea each consist of eight subcode blocks,
2048 bits of data can be recorded on each. These subcode blocks are divided into 8 words of 8 bits each, and each word contains, for example, a code indicating the lead-in area at the beginning of recording on the tape, and a code indicating the lead-out area at the end of recording. Various types of codes are provided along with parity, such as a code indicating 8 o'clock recording, an absolute frame number, etc.

Note that an LFNO may be provided in this subcode block.

Next, a data additional writing method according to the present invention will be explained with reference to FIG.

In FIG. 6A, the tape 12 has data (11 (
2)(3)(41--・--・-... are recorded for each unit. In this case, there is no amble part between each unit, and each unit is adjacent. Also, here, 1 unit is composed of 23 frames, and the LASTF-ID described above is recorded in the 23rd frame of each unit.

Next, when new data is to be additionally written from data (3) on this tape 12, as shown in FIG. 6B, the LASTF-ID of data (2) is first detected. After this detection 1
After recording several frames of the amble part in the main area within ~10 frames, new data ■■-・−−−−−−
--- are recorded adjacently for each unit.

At this time, the LASTF-ID is also recorded for each unit.

When playing back the tape 12 shown in FIG. 6B on which data has been added in this way, data (1), (2), and (3) are read out, but the amble part is played back in the middle of data (3). Therefore, it can be seen that this data (3) can be discarded. And the data read after the amble part■■
---------- is taken in as valid data.

According to the above, the first data (1), (2), (3),
(4) When recording --------1, there is no need to record the amble part, so the data transfer rate during recording does not decrease, and the recording capacity of the tape 12 also decreases. There is no. Even when additional recording is performed, only part of the previous data (3) and an amble of several frames are formed at the beginning of the first new data, which reduces the transfer rate and tape recording capacity. Data near the abend point can also be protected.

〔Effect of the invention〕

According to the present invention, the delimitation of the predetermined amount of data is made clear by the unit, and the length of the unit is changed by arbitrarily selecting the LFNO from, for example, 1 to 64 and changing the size of the predetermined amount. By doing so, signal processing can be easily performed. Furthermore, the last frame of the unit can be known from the LASTF-ID, and data can be additionally written without reducing the data transfer rate or the recording capacity of the recording medium.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a D
Figure 3 shows the data structure of the main data block, Figure 4 shows the data structure of the main area of one frame, Figure 5 shows the data structure of the logical frame number, and Figure 6 shows the data structure of the AT format. FIG. 7 is a tape recording pattern diagram showing a conventional data additional recording method. In addition, in the symbols used in the drawings, ---Host computer 13-
・−1−−−−−−−−System controller L
P N 0---------・--Logical frame number LASTF-ID...Last frame ID.

Claims (1)

[Claims] A predetermined amount of data is defined as one frame, and data having a predetermined data format is recorded for each frame, and a unit consisting of any plurality of frames is set,
The consecutive frame numbers within the unit and the signal indicating that it is the last frame of the unit are recorded, and when writing additional data, the signal indicating that it is the last frame of the unit is first detected. After a predetermined number of frames have elapsed based on this detection, an amble portion is formed in the predetermined number of frames, and then new data is recorded.