JPH0778964B2 - Data recording method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording method by a sequential access type data recording / reproducing apparatus having a spiral track such as an optical disc or a magnetic tape as a recording medium.

2. Description of the Related Art In the case of a sequential access type data recording / reproducing apparatus which reads out target recording data according to a recording order, recording of data on a magnetic tape used as a recording medium thereof is generally performed as shown in FIG. To be done.

That is, FIG. 4 (1) is a schematic diagram showing an array of data recorded on the magnetic tape T by the data recording / reproducing apparatus. Each data file F (i-1), F (i), F
(I + 1) represents a collection of related data,
Between the recording area of each data file and the recording area of the next data file, there is provided a recording area of a file mark M indicating a delimiter of these data files.

Each data file is composed of a plurality of data blocks with a block of data (hereinafter referred to as a data block) to which error detection / correction parity is added as a constituent element. For example, in the case of data file F (i), 6
It is composed of data blocks Di0, Di1, Di2, Di3, Di4, Di5, and is recorded on the magnetic tape T in this order.

In addition, from the data files recorded in this way, an arbitrary data file, for example, data file F
(I) is a data file F with a smaller data amount than this
When rewriting to (I), the recording data on the magnetic tape T is arranged as shown in the schematic view of FIG. 4 (2).

That is, in the data file F (i) before rewriting, the data blocks Di0 to Di3 are new data files F.
(I) is rewritten into the four data blocks DI0 to DI3 that make up the remaining 2 of the data file F (I) before rewriting.
The data blocks Di4 and Di5 for the individual pieces are left as they are as the old data.

On the other hand, when the data file F (I) rewritten as shown in FIG. 4 (2) is read by the above-mentioned data recording / reproducing apparatus, the position and data of the data file are used as a recording area for searching each data file. By referring to the directory at the beginning of the magnetic tape T on which the number of blocks and the like are recorded, the data blocks Di4, Di
5 is controlled not to read.

Problems to be Solved by the Invention However, as described above, when the data file before rewriting is rewritten to a data file having a smaller data amount than this, if the old data that is not rewritten is left as it is, the data in the directory is rewritten at the time of reproduction. When the error rate when reading is high and the data cannot be corrected due to error correction, and the data becomes defective, or when the data cannot be read due to a flaw in the directory, etc. Data block DI to be read by device
There is a problem that it becomes impossible to control the identification of 0 to DI3 and the data blocks Di4 and Di5 which cannot be read, and the data file F (I) rewritten by reading unnecessary data cannot be controlled after all.

Further, when the above-mentioned recording method is used, in order to search for the target data file, it is necessary to distinguish the data block that should be read from the data block that should not be read, so the data in the directory is required, In the case where the recording medium is a magnetic tape or the like for reading the data, it also takes a long time to search the data file.

Therefore, an object of the present invention is to provide a data recording method capable of enabling accurate reading of recorded data without depending on the data in the directory.

Means for Solving the Problems The present invention is used in a sequential access type data recording / reproducing apparatus for reading target recording data in accordance with a recording order, and a recording medium is provided with a data file between a plurality of data files and another data file. In the data recording method, in which a data mark is recorded via a file mark that distinguishes from each other, and each data file records data over a plurality of data blocks, the data recorded in the data block of any data file When rewriting to a new data file with a small amount of data, of the data blocks of the data file before rewriting, the remaining data blocks that cannot be rewritten to the data of the new data file are rewritten to an unrecorded area with no data, and The number of data blocks that make up a large data file A data recording method characterized by comprising to match the number of data blocks of the previous data block.

Operation According to the present invention, when a data file before rewriting is rewritten to a data file having a smaller data amount,
Since the data block, which is the recording area of the old data that remains without being rewritten, is rewritten to the unrecorded area without data, the data that can be read and the data that should not be read at the time of reading the rewritten data file are identified. Such control is unnecessary, there is no need to rely on the directory for its identification, and data can be read accurately and quickly.

Embodiment FIG. 1 is a block diagram showing a schematic configuration of a data recording / reproducing apparatus in which the data recording method of the present invention is implemented.
The writing / reading circuit 1 is a circuit including a rotating drum 2, amplifiers 3, 4, etc., and recording media are recording heads W1, W2 and reproducing heads R1, R2 arranged on the peripheral surface of the rotating drum 2. The magnetic tape T is sequentially scanned, and the recording heads W1 and W2
Data is sequentially recorded on the magnetic tape T by scanning
It has a function of reading recorded data on the magnetic tape T by scanning the reproducing heads R1 and R2. The signal processing circuit 5 has a function of converting data input from the outside into a signal suitable for recording and giving the signal to the writing / reading circuit 1, and the data read from the magnetic tape T by the writing / reading circuit 1 before recording. It is a circuit having a function of converting into a signal and outputting.
The control circuit 6 is a circuit for controlling the operation timing and the like of the write / read circuit 1 and the signal processing circuit 5.

FIG. 2 is a schematic diagram showing an arrangement of data recorded on the magnetic tape T as a recording medium by the data recording method according to the embodiment of the present invention. Of these, FIG. 2 (1) shows the arrangement of the data recorded first on the magnetic tape T on which no data is recorded, and FIG. 2 (2) shows the magnetic tape T.
Shows an array of data when an arbitrary recorded data file F (i) is rewritten to another data file F (I) having a smaller data amount.

FIG. 3 is a flow chart showing the procedure of the data recording method of this embodiment. The data recording method of this embodiment will be described below with reference to FIG.

First, in the data recording operation of FIG.
Following the start of n1, in step n2, a data file is first recorded on the unrecorded magnetic tape T as shown in FIG. That is, the data processed by the signal processing circuit 5 is sequentially written on the magnetic tape T by the recording heads W1 and W2 of the rotary drum 2 in the writing / reading circuit 1. At this time, each data file F (i-1), F (i), F (i is recorded on the magnetic tape T as shown in FIG.
+1) represents a collection of related data.

Each data file is composed of a plurality of data blocks, with the data block to which error detection / correction parity is added as a constituent element. As is clear from FIG. 2 (1), the number of data blocks forming each data file is the same, and is 6 in this embodiment. For example, the data file F (i) is composed of six data blocks Di0, Di1, Di2, Di3, Di4, Di5, and is recorded on the magnetic tape 1 in these orders.

Following the recording of one data file, the next step n3
Then, a file mark M that distinguishes the data file from the data file to be recorded next is recorded. Whether or not all the data files have been recorded is confirmed by the judgment of step n4, and when it is judged that the recording has not been completed, the operations of steps n2 and n3 are repeated, whereby each data file is recorded on the magnetic tape T. F (i-1), F
(I), F (1 + 1), ... Are recorded sequentially. If it is determined in step n4 that all the data files have been recorded, the process moves to step n5 and the data recording operation ends.

Next, in the data rewriting operation of FIG. 3 (2), in steps n7, n8, and n9, of the recorded data on the magnetic tape 1, for example, the data file F (i), which is an arbitrary data file, is As shown in FIG. 2B, re-recording is performed by rewriting to another data file F (I) whose data amount is smaller than that of the data file F (i) by 2 data blocks. At this time, the new data file F (I) to be rewritten is composed of four data blocks DI0 to DI3.

First, in step n7, the data file F to be rewritten
The search (i) is performed, and in step n8, four data blocks DiO to Di3 of the data blocks Di0 to Di5 forming the old data file F (i) are changed to the new data file F.
It is rewritten to the blocks DI0 to DI3 constituting (I). That is, also in this case, the data to be written is processed by the signal processing circuit 5 and the recording head W of the writing / reading circuit 1 is processed.
It is sequentially written on the magnetic tape T by 1, W2.

In the next step n9, the data blocks Di4 and Di5 remaining in the old data file F (i) without being rewritten are rewritten into the unrecorded area NR having no data. Unrecorded area
The NR is formed by recording a flag indicating an unrecorded area in the area, or by additionally writing an insignificant signal in the data area.
As a result, the old data does not remain in the new data file F (I). After this, the data recording process is completed in step n11.

On the other hand, when the rewritten data file F (I) as shown in FIG. 1 (2) is read by the above-mentioned data recording / reproducing apparatus, unnecessary data blocks Di4, Di5 of the old data file F (i) are read. Has been erased and its recorded area has been rewritten to the unrecorded area NR, control for distinguishing new data from old data is unnecessary, and it is not necessary to refer to the directory. That is, the data can be read without depending on the directory.

EFFECTS OF THE INVENTION As described above, according to the data recording method of the present invention, when a data file before being rewritten is rewritten to a data file having a smaller data amount than that, a data block of old data that remains without being rewritten Is rewritten to an unrecorded area that does not contain data, so control such as distinguishing between data that can be read and data that should not be read at the time of reading the rewritten data file becomes unnecessary. Data can be read accurately and quickly without the need to rely on a directory.

Further, according to the present invention, even when rewriting to a data file having a small amount of data, it is necessary to rewrite to a data file having the next largest amount of data by maintaining the number of data blocks in the data file before rewriting. When
It is possible to rewrite without interrupting another adjacent data file.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a data recording / reproducing apparatus in which the data recording method of the present invention is implemented, and FIG. 2 is recorded on a magnetic tape by the data recording method according to one embodiment of the present invention. FIG. 3 is a schematic diagram showing the arrangement of data, FIG. 3 is a flow chart showing the procedure of the data recording method,
The figure is a schematic diagram showing an array of data recorded on a magnetic tape by a conventional data recording method. T: Magnetic tape, F (i-1), F (i), F (i +
1), F (I) ... Data file, Di0 to Di5, DI10 to DI3
…… Data block, M …… File mark, NR …… Unrecorded area

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hidenori Minoda 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Yoshihiro Okamoto 22-22, Nagaike-cho, Abeno-ku, Osaka, Osaka Incorporated (72) Inventor Takeshi Tanaka 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Incorporated (56) Reference JP-A-51-43908 (JP, A)

Claims (1)

[Claims] 1. A file mark used in a sequential access type data recording / reproducing apparatus for reading out target recording data according to a recording order, and a file mark for distinguishing a data file from other data files on a recording medium. In a data recording method in which data is recorded by interposing and data is recorded over a plurality of data blocks in each data file, the data recorded in the data block of an arbitrary data file can be newly recorded with a smaller data amount than this. When rewriting to a data file, of the data blocks of the data file before rewriting, the remaining data blocks that cannot be rewritten to the data of the new data file are rewritten to an unrecorded area with no data to form a new data file. The data block number before rewriting the data block number A data recording method characterized in that the number of data blocks is the same.