JPS6314305A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To increase the recording capacity by erasing an error block without rewinding when an error block length (l) is smaller than or equal to a head interval L and applying re-write so as to reduce the non-recorded part of a magnetic tape. CONSTITUTION:The head interval L of 1st and 2nd read heads 13, 14 is decided as a criterion as to whether a magnetic tape 7 is to be rewound or not depending onto which degree an error block length (l) shares to the total length of the block of a written data. An error detection circuit 4 detects an error and an error block length comparison circuit 5 compares the error block length (l) with the head interval L. When the error block length (l) is larger than the head interval L, the tape is rewound and erasure/rewrite is applied and when the error block length (l) is smaller than or equal to the head interval L, the tape is not rewound and the erasure/rewrite is applied. Thus, the waste of operating time is reduced and the magnetic tape is used efficiently to increase the recording capacity.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic tape device, and in particular records write data in blocks, and when a write error occurs in this block, erases the error block and erases the error block. The present invention relates to a magnetic tape device that rewrites blocks.

[Conventional technology]

Conventionally, this type of magnetic tape device includes an erasing head, a writing bed, and a reading head in sequence in the running direction of the magnetic tape, and when a write error in a predetermined block is detected during a write operation in this block, As shown in Figures 5 and 6, a process called backspace erase write involves rewinding the magnetic tape a certain distance, erasing a certain distance including the block where the error occurred, and then rewriting this block. It was configured to perform retry operations.

Therefore, the unrecorded portion becomes longer, and when the magnetic tape is rewound,
The positioning operation from erasing the error block to rewriting takes time, resulting in a large loss of magnetic tape and operating time.

[Problem that the invention seeks to solve]

The conventional magnetic tape device described above is configured to eliminate error blocks through a restrying operation called backspace erase write when an error is detected.
There is a lot of wasted operating time, and since the erase operation to remove error points unconditionally erases a fixed length, the ratio of unrecorded parts to the total length of the magnetic tape increases, resulting in a lot of wasted magnetic tape and a reduction in recording capacity. It has the disadvantage that it does.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic tape device that can reduce wasted operating time and increase recording capacity by efficiently using magnetic tape.

[Means for solving problems]

The magnetic tape device of the present invention includes a first erase head that erases data written on the magnetic tape in response to a first erase signal, a write head that writes written data on the magnetic tape, and a write head that writes written data on the magnetic tape. The first step is to read the stored data respectively.
and a second read head and a second erase head for erasing data written on the magnetic tape by a second erase signal, which are sequentially arranged at predetermined intervals along the running direction of the magnetic tape. outputting the first erase signal to the head unit during a write operation and when inputting an erase instruction signal;
a write control unit that outputs a write instruction signal whose output is stopped in response to an error signal;
or a write block control circuit that re-outputs the temporarily stored write data in response to a second rewrite instruction signal, and a corresponding output from the write block control circuit that outputs the read data of the first read head. an error detection circuit that detects an error in the read data by comparing it with the data and outputs the error signal; and an error block that generates the error signal when the error signal is input from the successive data of the second read head. determine whether the leading data of the block has passed through the second reading head, and compare the head spacing between the first and second reading heads with the error block length l from the leading data of this block to the error data; and an error block length comparison circuit that outputs a repositioning instruction signal when the error block length l is greater than the head spacing, and outputs the first rewrite instruction signal and the second erase signal when the error block length l is equal to or smaller than the head spacing. and controlling the rewinding and running of the magnetic tape by the repositioning instruction signal, and determining the erase position and rewrite position of the error block on this magnetic tape, and the erase instruction signal and the second rewrite instruction signal. and a repositioning circuit that outputs the error block length! When is larger than the head spacing, the magnetic tape is rewound to erase and rewrite the error block, and when it is equal to or smaller than the head spacing, the error block is erased and rewritten without rewinding the magnetic tape. have.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

The magnetic head unit 1 includes a first erasing head 11 that erases data written on the magnetic tape in response to a first erasing signal V):1, and a write head 12 that writes write data WD on the magnetic tape. , first and second read heads 13 and 14 for respectively reading data written on the magnetic tape, and a second erasing head 13 for erasing data written on the magnetic tape by a second erasing signal ■8□. Heads 15 are sequentially arranged at predetermined intervals along the running direction of the magnetic tape.

The write control unit 2 outputs a first erase signal VEI during a write operation and when an erase instruction signal ES is input, and also outputs a write instruction signal WS that stops outputting when an error signal Er is input. , and further outputs the write data WD in block units sequentially.

The write block control circuit 3 sequentially outputs and temporarily stores the write data WD from the write control unit 2 in response to a write instruction signal WS, and outputs the write data WD from the write control unit 2 in response to a first or second rewrite instruction signal RW, , R.
W2 re-outputs this temporarily stored write data.

The error detection circuit 4 compares the read data RD of the first read head 13 with the corresponding write data WD from the write block control circuit 3, detects an error in the read data RD, and outputs an error signal E. Output.

The error block length comparison circuit 5 compares the error signal E and the second
When the read data RD2 of successive heads is input and the error signal E is input, check whether the first data of the error block that generated the error signal E, - has passed through the second read head 14. The head spacing between the read heads 13 and 14 shown in FIG. When is larger than the head spacing, a repositioning instruction signal RP is output, and when it is equal to or smaller, a first rewrite instruction signal RW and a second erase signal VE2 are output.

The repositioning circuit 6 controls the rewinding and running of the magnetic tape using the repositioning instruction signal RP, determines the erasing position of the error block and outputs the erasing instruction signal ES, determines the rewriting position, and performs the second rewriting. Outputs write instruction signal RW2.

Then, the data written by the write head 12 is transferred to the first
and immediately read out by a second read head 13.14;
When an error is detected, the error block length l is compared with the head spacing, and if f>L, rewind is performed to erase a certain distance including the error block, and then rewritten, l
When ≦L, erase the error block without rewinding,
It is configured to be rewritten.

FIG. 2 is a schematic diagram showing the arrangement of each head of the magnetic head section 1 of this embodiment. First and second read heads 13.
The head spacing of No. 14 is determined based on the error block length l relative to the total length of the write data block.
It is established as a standard for whether to rewind or not to rewind.

FIG. 3 is a flowchart showing the operation of this embodiment.

Step S3 is an error detection step by the error detection circuit 4. When an error is detected, the process moves to step S4, where the error block length comparison circuit 5 compares the error block length l and the head spacing. and,
If the error block length l is larger than the head spacing, steps S6 and S7. Rewinding, erasing, and rewriting are performed in S8, and if the error block length l is smaller than or equal to the head spacing, step S5. Erasing and rewriting are performed without rewinding in S6.

4 and 5 are schematic diagrams showing the movement of the magnetic tape 7 and the state of data written on the magnetic tape 7 according to this embodiment, and FIGS. 4(a) and 5(a) are FIG. 4(b) shows the state of data written on the magnetic tape 7 when an error is detected.

FIG. 5(b) shows the movement of the magnetic tape 7, and FIG. 4(C) shows the movement of the magnetic tape 7.
), FIG. 5(c) shows the state of data written on the magnetic tape 7 after rewriting.

As shown in FIG. 4(C), immediately after erasing the error block B1 (because it is rewritten to the barley, the written block BI
The interval between O and the rewritten block B3 can be minimized.

On the other hand, in FIG. 5(C), as in the conventional case, rewriting is performed after erasing a certain distance including error block B1, so the interval between written block BIO and rewritten block B3 becomes wider. .

〔Effect of the invention〕

As explained above, the present invention reduces the unrecorded portion of the magnetic tape by erasing and rewriting the error block without rewinding when the error block length a is smaller than but equal to the head spacing. Since the recording capacity can be increased and unnecessary operating time can be reduced, there is an effect that the throughput can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a schematic diagram showing the arrangement of each head of the magnetic head section of the embodiment shown in FIG. 1, and FIG. FIGS. 4 and 5 are flowcharts showing the operation of the embodiment shown, and FIGS. FIG. 6 is a flowchart showing the operation of an example of a conventional magnetic tape device. 1... Magnetic head section, 2... Write control section, 3...
Write block control circuit, 4... error detection circuit, 5.
・Error block length comparison circuit, 6... Repositioning circuit, 7... Magnetic tape, 11... Erase head,
12...Writing head, 13.14...Reading head,
15... Erasing head. Figure 2

Claims (1)

[Claims] A first erase head that erases data written on the magnetic tape by a first erase signal, a write head that writes written data on the magnetic tape, and a write head that reads data written on the magnetic tape, respectively. first and second read heads and a second read head;
a second erasing head for erasing data written on the magnetic tape in response to an erasing signal; a write control section that outputs the first erase signal when the erase instruction signal is input and outputs a write instruction signal that stops outputting when an error signal is input; a write block control circuit that sequentially outputs and temporarily stores the temporarily stored write data, and re-outputs the temporarily stored write data in response to a first or second rewrite instruction signal; an error detection circuit that compares the read data with corresponding output data from the write block control circuit, detects an error in the read data, and outputs the error signal; and the error signal is inputted from the read data of the second read head. When the error signal is generated, it is determined whether the leading data of the error block that has generated the error signal has passed through the second read head, and the first read head is read.
Then, the head interval L of the second read head is compared with the error block length l from the head data of this block to the error data, and the error block length l is compared with the head interval L.
an error block length comparison circuit that outputs a repositioning instruction signal when the error block length is greater than the error block length, and outputs the first rewrite instruction signal and the second erase signal when the error block length is equal to or smaller than the error block length comparison circuit; a repositioning circuit that controls rewinding and running, determines the erase position and rewrite position of the error block of the magnetic tape, and outputs the erase instruction signal and the second rewrite instruction signal; When the block length l is larger than the head spacing L, the magnetic tape is rewound to erase and rewrite the error block, and when it is equal to or smaller than the head spacing L, the error block is erased and rewritten without rewinding the magnetic tape. A magnetic tape device characterized by: