JPS5858727B2 - Data recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data recording system on a magnetic tape, and particularly to a data recording system that provides an effective correction function on multi-byte tracks.

When information is recorded on magnetic tape, it is recorded on tracks running along the length of the tape.

In the early days of magnetic tape use, there were various numbers of tracks, but the tape width was reduced to % inches, and now nine tracks are common.

In the case of 9 tracks, 1 check bit is added to the 8-bit code, and 9 bits are simultaneously recorded and reproduced in the width direction of the magnetic tape in one row.

The recording density of information on magnetic tape is currently 50ORPI,
1600 RPI and 6250 RPI devices are widely used.

For example, the writing format of the 1600RPI recording method is the first
As shown in the figure, there is a recording density indicator IDBST near the BOT marker at the beginning of the tape, and a data block DTABLK is placed after the initial gap ING.

Data block DTABLK is preamble PRA,
Data DTA and postamble PSA are recorded in this order, and an ink block gap IBG is provided between each data block DTABLK.

The spacing between the tracks Tr provided in parallel is 1.4 mm, and the error in track spacing is ±0.08 mm.

The 800RPI NRZI method appends a CRC byte after the data to detect errors and correct single track errors, and the 1600RPI PE
The method detects and corrects the error track in a single read operation if there is a single trunk error;
50RPI GCR (Group Coded Rec
In the 7-byte data unit, 1 byte of ECC (Error Correcting
Code) is added to correct errors that occur simultaneously across two tracks.

In this way, while high-density recording and reproduction on tracks and highly reliable recording and reproduction are performed, read/write
By narrowing the head core width, the track pitch density (T
Research is also being conducted to increase PI).

However, since there is a structural limit to narrowing the core width, a method has also been proposed in which recording and reproduction are performed while shifting the core width by a fraction of the core width of the head.

In this way, it is possible to record 2 bytes (18 racks) or 4 bytes (36 trunks) in parallel on a % inch wide magnetic tape.

In addition, as shown in Fig. 2a, two rows of head cores each having 2 bytes (18 tracks) are provided, and the positions of the write head WH and read head RH are reversed by an inch. , as shown in Figure 2, a half arrangement structure is used for forward FWD recording and reproduction, and a reverse BWD
A system has been proposed in which the entire head is shifted and the other half of the head is used for reproduction.

By the way, when recording and reproducing 1 byte (9 tracks) in parallel on a tape with a width of 1.5 inches, the values of the encoded bits are distributed to each track in the order shown in FIG.

Therefore, as mentioned above, when increasing the track density (TPI) on a tape with a width of % inch and recording and reproducing, for example, 3 bytes (27 tracks) in parallel, the standard of the tape is Starting from end 1, the first byte B1. Each bit of the second byte B2 and third byte B3 is arranged.

However, in this case, the trunk density (TPI) is three times that of the conventional one (Figure 3), and each data byte is only % wider than the conventional one, so it is difficult to deal with dust and dirt on the tape. It will be affected over time.

In the 6250RPI GCR method, as mentioned above, errors that occur simultaneously in two tracks can be corrected, but
As mentioned above, if an error occurs in 3 to 4 tracks due to a slight flaw or dust, the error cannot be corrected and the reliability decreases.

The purpose of the present invention is to solve these problems by minimizing the effects of dust and dirt on the tape when recording data on a multi-byte track magnetic tape.
An object of the present invention is to provide a data recording method that improves the effectiveness of an error correction function.

In the present invention, data is recorded in parallel on a magnetic tape having multi-byte tracks, and a data group is formed for each byte in the serial direction and an error correction code is added to the data recording method. This is accomplished by allocating the coded bits of a byte of data to adjacent tracks and distributing each byte of data across the width of the magnetic tape.

An embodiment of the present invention will be described below with reference to FIG.

FIG. 5 shows a case where 3-byte data is recorded and reproduced in parallel on a % inch magnetic tape, and tracks 1 to 27 are arranged in order from reference end 1.

As shown in FIG. 3, in a tape having 1-byte tracks, the first track has a bit with a value of 22, the second track has a bit with a value of 2°, and the third track has a value of 24. Bits, parity bits, etc. are recorded on the fourth track, but in Fig. 5, bits with the same value are recorded together instead of being recorded one byte at a time. Record in order.

That is, the first, second, and third tracks all have 22
A bit having a value of 2° is recorded in the fourth, fifth, and sixth tracks, a bit having a value of 24 is recorded in the seventh, eighth, and ninth tracks, and so on.

B1. B2. By repeatedly allocating bits of different bytes in the order of B3, the total width of the tape is varied for each byte.

Now, there is dust on the magnetic tape, and the 12th to 15th
If a track is affected and an error occurs across these four tracks, the 12th to 15th tracks are not the same bytes, so the first and second pies) B1. l in B2
The error occurs only in the track, and the third byte B3 causes an error in two tracks, which can be corrected in any byte (in the case of 6250RPI GCR system).

In addition, Bl, B2. The order is not limited to B3, but B2. B
1. It is also possible to change the arrangement order of bytes like B3.

Furthermore, the order of bits within one byte from the tape reference end is arranged according to the frequency of use of alphabets, special codes, etc., and the frequency of occurrence of the corresponding bits.

Although the embodiment in FIG. 5 shows an example in which the same bits of different data bytes are recorded in adjacent tracks, the bits do not necessarily have to be the same.

As explained above, according to the present invention, when simultaneously recording on a multi-byte track using a recording method having an error correction function, each byte data is distributed and recorded over the entire width of the tape. Even if dropouts occur due to dust or dirt on the top, the effect of this is small and the error correction ability can be improved.

[Brief explanation of drawings]

Figure 1 is a recording format diagram for a magnetic tape using the 1600RPI recording system. Figures 2a and b are perspective views and explanatory diagrams of recording operations showing an example of a multi-track head. Figure 3 is for a conventional 1-byte track. Magnetic tape bit arrangement diagram,
Fig. 4 is a bit arrangement diagram of a magnetic tape for multi-byte tracks recorded by the method shown in Fig. 3, and Fig. 5 is a bit arrangement diagram of a magnetic tape for multi-byte tracks showing an embodiment of the present invention. It is. DTABLK: Take block, Tr: Track, IBG: Inter block gap, B1 to 3: Bytes 1 to 3, RH: Read head, WH write head, FWD: Forward direction, BWD: Reverse direction, PRA: Preampule, PSA: Postampule, 1: Tape reference end.

Claims (1)

[Claims] 1. A data recording method in which data is recorded in parallel on a magnetic tape having multi-byte tracks, a data group is formed for each byte in a serial direction, and an error correction code is added to the data group. A data recording method characterized by allocating bits of byte data to adjacent tracks and distributing each byte data in the width direction of a magnetic tape.