JPH0480468B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for recognizing a block in which specific pattern data of a specified length is written.

It is generally possible to store large amounts of data,
Moreover, magnetic tape devices, which are easy to handle, are being used as external storage devices for information processing systems that are rapidly developing in recent years, and are currently being further improved as external storage devices that can store data at higher density and at a lower cost. has been added.

Normally, multiple tracks are created in parallel on the medium of a magnetic tape device, and these tracks are divided into multiple blocks, each of which contains user data and specific pattern data (file delimiter signal). (tape marks, etc.) are written on it.

Generally, when writing the above data, immediately after writing to the motor with the write head, the read head reads the data to check whether there are any errors in the written data. A checking method is adopted, and sometimes specific pattern data is considered to be good if a certain length of specific pattern data is read continuously.

On the other hand, as the use of information processing systems becomes more sophisticated and complex, there is a strong demand for more efficient data processing methods. There has been a demand for practical use of devices that take measures such as reducing the number of times.

[Conventional technology]

A conventional block recognition method will be explained with a focus on a magnetic tape control device.

FIG. 3A is a block diagram showing a conventional magnetic tape control device, and FIG. 3B shows the situation on a recording medium.

Next, the conventional recognition operation of a block for recording specific pattern data will be explained by dividing it into "writing operation" and "reading operation".

"A During write operation" (1): Microprocessor (hereinafter referred to as MPU)
3 sets the write block length L in the write distance control counter 8. Further, an initial value ΔL is set in the pattern detection counter 7.

(2): Next, the MPU 3 instructs the magnetic tape device 2 to run the tape 2c, and instructs the write distance control counter 8 to start counting up.

When the write distance control counter 8 counts up by the previously set block length L,
Instruct MPU3 to that effect, and as a result, MPU3
terminates the write operation.

(3): Operations during the above period will be as follows. That is,
The MPU 3 outputs a signal instructing the write circuit/block pattern generation circuit 4 to generate a write signal for specific pattern data, and the write head 2a of the magnetic tape device 2 writes the magnetic tape 2c.
Write specific pattern data to.

At the same time, the read head 2b immediately reads the written specific pattern data and outputs a read signal to a pattern detection circuit 5 and an interblock gap (hereinafter referred to as IBG) detection circuit 6.

(4): The MPU 3 confirms the start of reading specific pattern data from the data from the pattern detection circuit 5 and IBG detection circuit 6.

For example, IBG is detected when there is no confirmation of data signals on all tracks for a certain period of time,
While the specific pattern following the IBG is confirmed and the specific pattern data is detected, the reference counter 9 gives a subtraction instruction to the pattern detection counter 7 at regular intervals to cause the pattern detection counter 7 to count.

Note that the output line of the reference counter 9 becomes "1" at regular intervals, and in response to this, the MPU 3 gives a subtraction instruction to the pattern detection counter 7. Also MPU
When 3 recognizes "1", the output line becomes "0".

(5): Once the value of pattern detection counter 7 is “0”
When this happens, the MPU 3 determines that the writing has been performed normally. If the pattern detection circuit 5
When a specific pattern becomes unrecognizable due to
The MPU 3 resets the initial value of ΔL in the pattern detection counter 7.

The MPU 3 completes the write operation according to the instruction from the write distance control counter 8, and the IBG
The process continues until the detection circuit 6 detects IBG.

That is, if the value of the pattern detection counter 7 is "0", the MPU 3 determines that writing of the specific pattern data has been completed normally, and if it is not "0", it determines that the writing of the specific pattern data has failed. .

"B During reading operation" (1): The MPU 3 sets the initial value ΔL to the pattern detection counter 7 in advance, and connects the pattern detection circuit 5 and IBG.
Specific pattern data is detected from the read signal via the detection circuit 6, and while the specific pattern data is being detected, a subtraction instruction is given to the pattern detection counter 7 at regular intervals to cause the pattern detection counter 7 to count.

Once the value of pattern detection counter 7 is “0”
When this happens, the MPU 3 recognizes that a specific pattern block has been detected, and from then on the pattern detection counter 7
No subtraction instructions are given. Before the value of the pattern detection counter 7 becomes “0”, the pattern detection circuit 5
When a specific pattern becomes unrecognizable due to
The MPU 3 resets the initial value of ΔL in the pattern detection counter 7.

(2): Next, the MPU 3 performs the operation of (1) on the IBG detection circuit 6.
When a certain length IBG is detected, the reading of the specific pattern block is terminated, and if the count value of the pattern detection counter 7 is "0", the read data is determined to be a specific pattern block, and if it is not "0", the reading of the specific pattern block is terminated. Otherwise, it will not be recognized as a specific pattern block.

[Problem that the invention seeks to solve]

When writing or reading the specific pattern data as described above, writing or reading of the specific pattern data may be intermittently due to some defect in the block (block length L, where L>>ΔL) that records the specific pattern data, for example, When ΔL1, ΔL2, and ΔL3 are read intermittently due to defective locations b and b' shown in Figure 3B (however, ΔL≦ΔL1+ΔL2+ΔL3
), it is not determined to be specific pattern data,
For example, in the case of reading a recording density indicator written at the beginning of a tape, subsequent data blocks cannot be read.

Also, in the case of tape mark blocks, there was a problem in that files were skipped.

[Means for solving problems]

The present invention aims to realize a new block recognition method that solves the above problems. a first means for detecting that a certain length of pattern data has been continuously obtained; and a first means for detecting that a certain length of the specific pattern data has been obtained by summing the lengths of the specific pattern detected intermittently; and a second means for
This problem is solved by the block recognition method according to the present invention, which recognizes the block of the specific pattern data by the first means and the second means.

[Effect]

That is, as detection circuits for specific pattern data (hereinafter referred to as block patterns) for recognizing specific blocks, a circuit for detecting continuous length block patterns and a circuit for detecting intermittent length block patterns are provided. The condition for recognizing normal writing when writing a block pattern is that the continuous length detection data and the intermittent length detection data (total detection length) exceed a reference value.

In addition, as a normal reading recognition condition when reading a block pattern, either the continuous length detection data or the intermittent length detection data (total detection length) must exceed the standard value, and these setting conditions will improve the block recognition ability. We aimed to improve this.

〔Example〕

The gist of the present invention will be specifically explained below with reference to embodiments shown in FIGS. 1 and 2.

FIG. 1 is a block diagram showing an embodiment of the magnetic tape control device according to the present invention, and FIG. 2 is an operational flowchart of the magnetic tape control device according to the present invention, where A indicates the time of writing and B indicates the time of reading. Each is shown below. The same symbols indicate the same objects or contents throughout the figures.

Next, this example will be focused on the operation of MPU3,
The explanation will be divided into "writing operation" and "reading operation".

"A During write operation" (1): First, the MPU 3 sets the write distance control counter 8 to an initial value L, the block pattern continuous detection counter 12 to an initial value L1, and the block pattern intermittent detection counter 13 to an initial value L2. ,
At the same time, it is confirmed that the continuous block pattern length detection flag and the intermittent block pattern length detection flag of both counters 12 and 13 are "0" (flags indicating that no block pattern has been detected).

(2): Next, the MPU 3 causes the write circuit/block pattern generation circuit 4 to generate block pattern data, and outputs a signal instructing writing to a specific track on the magnetic tape 2c of the magnetic tape device 2.

The block pattern signal written by the write head 2a is immediately read out by the read head 2b, and the read signal is output to the block pattern detection calculation circuit 10 and the IBG detection calculation circuit 11.

It is assumed that the IBG detection calculation circuit 11 outputs a signal "1" when the read signals of all tracks become "0".

The block pattern detection arithmetic circuit 10 is connected via a predetermined block pattern detection notification line a or
The IBG detection calculation circuit 11 notifies the MPU 3 of each detection signal through the IBG detection notification line.

Note that the block pattern detection calculation circuit 10 has detection notification lines a to 1 for each of various block patterns.
n is provided.

(3): The MPU 3 checks the write status of the block pattern data instructed to the write circuit/block pattern generation circuit 4 by checking the block pattern detection notification line a.
Monitor through.

(4): Next, the MPU 3 sets the block pattern detection notification line a to the signal “1” (“1” in this embodiment).
The reference counter 9 outputs the continuous block pattern detection counter 12 and the intermittent block pattern detection counter 1 at regular intervals while outputting
Subtract 3.

During this period, when the block pattern intermittent detection counter 13 becomes "0", the block pattern continuous length detection flag is set to "1", and when the block pattern intermittent detection counter 13 becomes "1", the block pattern continuous length detection flag is set to "0". .

Next, when the block pattern detection notification line a becomes a signal "0", the block pattern continuous detection counter 12 is reset to the initial value L1. Furthermore,
When the write distance control counter 8 reaches the initial value L, the MPU 3 instructs the write circuit/block pattern generation circuit 4 to stop the write operation.

Note that the subtraction operation between the block pattern continuous detection counter 12 and the block pattern intermittent detection counter 13 is performed when the IBG is detected by the IBG detection calculation circuit 11, and the IBG is sent to the MPU 3 through the IBG detection notification line.
Stop when notified.

(5): In the MPU 3, when the writing distance control counter 8 reaches the initial value L and writing of block pattern data is completed, the pattern detection flags of the block pattern continuous detection counter 12 and the block pattern intermittent detection counter 13 are set. “1”
If so, it is recognized that writing has ended normally, and if either flag is "0", it is recognized that writing has ended abnormally.

(6): The reference counter 9 outputs a signal “1” at regular intervals.
is output to MPU3, and MPU3 outputs reference counter 9.
When referenced, it becomes "0", and after a certain period of time, it becomes "1", and the output is held until the next time the MPU 3 refers to it.

"B During reading operation" (1): First, the MPU 3 sets the initial value L1 to the continuous block pattern detection counter 12 and the initial value L2 to the intermittent block pattern detection counter 13, and simultaneously detects the block pattern of both counters 12 and 13. Confirm that the flag is "0" (a flag indicating that no block pattern has been detected).

(2): The read signal read by the read head 2b is connected to the block pattern detection calculation circuit 10.
When the block pattern detection is output to the IBG detection calculation circuit 11 and the block pattern detection is notified to the MPU 3 via the block pattern notification lines a to n, the MPU 3 performs the block pattern continuous detection counter 12 and the block pattern The detection counter 13 is decremented. The following operations are also similar to those in "A write operation".

(3): The recognition standard for whether or not the MPU3 has read normally is that it is determined to be normal when either the flag of the continuous block pattern detection counter 12 or the flag of the intermittent block pattern detection counter 13 is "1". be done.

As described above, in this embodiment, the write operation is more strictly restricted so that the next process cannot proceed unless the conditions of both detection counters 12 and 13 match, and high quality of data is ensured. On the other hand, during a reading operation, even if the read signal is only detected intermittently due to scratches or dust on the tape, if a specific pattern of a certain length is detected intermittently, it is assumed that a specific pattern block has been detected, and subsequent processing is performed. The aim was to improve block recognition ability.

〔Effect of the invention〕

According to the present invention as described above, repetition of recognition operations due to erroneous recognition etc. is eliminated, block recognition operations are shortened, and recognition ability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the magnetic tape control device according to the present invention, and FIG. 2 is an operational flowchart of the magnetic tape control device according to the present invention, in which A is for writing, B is for reading, Third
FIG. 3A shows a block diagram of a conventional magnetic tape control device, and FIG. 3B shows the situation on a recording medium. In the figure, 1 is a magnetic tape control device, 2 is a magnetic tape device, 2a is a write head, 2b is a read head, 2c is a magnetic tape, 3 is an MPU, 4 is a write circuit/block pattern generation circuit, 5 is a pattern detection circuit, and 6 is an IBG detection circuit, 7 is a pattern detection counter, 8 is a writing distance control counter, 9 is a reference counter, 10 is a block pattern detection calculation circuit, 11 is an IBG detection calculation circuit, 12 is a block pattern continuous detection counter, 13 is a block pattern detection circuit. The pattern intermittent detection counters are shown respectively.

Claims (1)

[Claims] In a data recording device that provides a plurality of tracks in parallel on a recording medium and writes data in block units and in parallel on the plurality of tracks, when recognizing a block in which specific pattern data has been written for a specified length, A first means for detecting that a certain length of specific pattern data has been continuously obtained; and a first means for detecting that a certain length of the specific pattern data has been obtained by summing the lengths of the intermittent detection of the specific pattern. 1. A block recognition method, comprising: a second means for detecting, and a block of said specific pattern data is recognized by said first means and said second means.