JPH0573704U - Magnetic tape unit - Google Patents

Abstract

(57) [Summary] [Object] To provide a magnetic tape device capable of improving the reliability of data written on a magnetic tape. [Structure] In the case of a read command and a write command, the magnetic tape T runs in the forward direction to up-count the block counter 3 of the magnetic tape T, and the magnetic tape T runs in the reverse direction. The T block counter 3 is down-counted. In the case of a rewind instruction and an unload instruction, the magnetic tape T is run in the reverse direction to read the write data, and whether or not there is an error is checked by, for example, a parity check. Also,
When the magnetic tape T runs in the reverse direction and the start position BOT is determined, it is determined whether the value of the block counter is "0",
If it is not "0", the number of write blocks is not normal and a warning is issued.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic tape device that reads write data on a magnetic tape and checks whether the data is correctly written.

[0002]

[Prior Art]

 Generally, data written on a magnetic tape is not always reliable, so in a conventional magnetic tape device, the magnetic tape is run to write the data, and the written data is read and written correctly. For example, it is configured to check whether or not it is a parity check.

[0003]

[Problems to be solved by the device]

 However, the method of checking whether the write data is read correctly and whether it is correctly written by, for example, a parity check or the like has a problem that the reliability of the data is poor at present. There are few users of systems that use magnetic tape devices.

Therefore, an object of the present invention is to provide a magnetic tape device capable of improving the reliability of data written on a magnetic tape.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention counts the current block position of the magnetic tape, reads the write data of the magnetic tape at the time of rewinding after the writing is finished, detects an error, and detects the error. The error is detected by comparing with the count value of the block position when is rewound to the starting position. That is, according to the present invention, in a magnetic tape device that checks data written in blocks on a magnetic tape, the magnetic tape is run in the forward direction of the read direction and the write direction, and in the reverse direction of the rewind direction. Magnetic tape driving means for causing the magnetic tape to move, a counting means for counting the current block position of the magnetic tape running by the magnetic tape driving means, and a write data of the magnetic tape is read at the time of rewinding after the completion of writing to detect an error. At the same time, there is provided a magnetic tape device characterized by having an error detecting means for detecting an error by comparing the block positions of the counting means when the magnetic tape is rewound to its starting position. It

[0006]

[Action]

 Since the present invention has the above-mentioned configuration, the write data of the magnetic tape is read and an error is detected at the time of rewinding after the writing is finished, and the current block position of the magnetic tape is counted to make the magnetic tape start position. When it is rewound, the number of write blocks is checked by comparing with this count value. Therefore, since the write data and the number of write blocks are checked, the reliability of the data written on the magnetic tape can be improved.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram showing an embodiment of a magnetic tape device according to the present invention, FIG. 2 is an explanatory diagram showing a value of a block counter when writing from a block in the middle of a magnetic tape, and FIG. 6 is a flowchart for explaining the operation of the magnetic tape device.

In FIG. 1, the magnetic tape T runs in the forward direction (the right direction in the drawing) of the reading direction and the writing direction by the motor M, and runs in the reverse direction (the left direction in the drawing) of the rewinding direction. Data is written to the magnetic tape T block by block via the magnetic head H, and the written data is read. The writing means 1 drives the magnetic tape T in the forward direction by driving the motor M, and at the same time, writes the data to the magnetic tape T via the magnetic head H for each block. At the time of reading, the motor M is driven to move the magnetic tape T in the forward direction, and data is read from the magnetic tape T for each block via the magnetic head H.

The block counter 3 counts up the current block position of the magnetic tape T when the magnetic tape T is running in the forward direction under the control of the writing unit 1 or the reading unit 2. Therefore, when writing (or reading) from the magnetic tape start position BOT (Beginning Of Tape) as shown in FIG. 1, the value from the tape start position BOT is up-counted by the block counter 3, and As shown in FIG. 2, the current block position is also counted by the block counter 3 when writing is started from a block in the middle.

Then, at the time of rewinding after the writing is completed, the reading means 2 drives the magnetic tape T in the reverse direction by driving the motor M, and at the same time, the data is read in blocks by the magnetic tape T via the magnetic head H. The block counter 3 counts down when the magnetic tape T is running in the reverse direction.

The error detecting unit 4 checks the data read by the reading unit 2 at the time of rewinding after the end of writing, for example, by using a parity or the like, and the magnetic tape T rewinds to the tape start position BOT. If the count value of the block counter 3 is not 0, an error is detected. When the error detecting means 4 detects an error, the alarm means 5 gives an alarm to the user by a display or a buzzer. The writing means 1, the reading means 2, the block counter 3, and the error detecting means 4 shown in FIG. 1 can be configured by software of a microprocessor, and the count value of the block counter 3 is a microprocessor. Will be stored in the work area.

Next, the operation of the above embodiment will be described with reference to FIG. First, in step S1, it is determined whether it is a read command, a write command, a rewind command, or an unload command. In the case of a read command and a write command, the processes shown in steps S2 to S4 are executed to rewind. In the case of an instruction and an unload instruction, the processing shown in steps S5 to S11 is executed.

In the case of the read command and the write command, the block counter 3 of the magnetic tape T is up-counted when the magnetic tape T is traveling in the forward direction (steps S2 and S3), and the process returns to step S1. When the magnetic tape T is running in the reverse direction, the block counter 3 of the magnetic tape T is down-counted (steps S2 and S4) and the process returns to step S1. Therefore, the block position of the magnetic tape T where the magnetic head H is currently located is detected and stored.

On the other hand, in the case of the rewind instruction and the unload instruction, it is judged whether or not it is the start position BOT of the magnetic tape T (step S5), and if it is not the start position BOT, the magnetic tape T is reversed in step S6. Direction is run to read the write data. That is, high-speed rewinding processing is not performed in this step S6. Then, in step S7, it is checked whether or not the data read from the reverse direction has an error by, for example, a parity check, and if there is no error, the block counter 3 is down-counted in step S8, Return to S5. On the other hand, if an error is detected in step S7, the process branches to step S10, and the warning means 5 gives a warning.

When the start position BOT of the magnetic tape T is determined in step S5, it is determined in step S9 whether or not the value of the block counter 3 is "0". If it is not "0", the number of write blocks is determined. Since it is not normal, the process proceeds to step S10 to issue a warning, and the process proceeds to step S11. If the value of the block counter is "0" in step S9, the number of write blocks is normal, so the process directly proceeds to step S11 to perform the rewinding process or the unloading process.

Therefore, according to the above-described embodiment, the magnetic tape T is run in the reverse direction at the time of rewinding to read the write data to check the error, and when the magnetic tape T runs to the start position BOT, the write block is read. Since it is checked whether the number is normal or not, the reliability of the write data on the magnetic tape T can be improved.

[0017]

[Effect of the device]

 As described above, according to the present invention, when rewinding after the end of writing, the write data of the magnetic tape is read to detect an error, and the current block position of the magnetic tape is counted to detect the magnetic tape. When it is rewound to the start position, the count value is compared with this count value to check the number of write blocks, so that the reliability of the data written on the magnetic tape can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic tape device according to the present invention.

FIG. 2 is an explanatory diagram showing a value of a block counter when writing from a block in the middle of a magnetic tape.

FIG. 3 is a flowchart for explaining the operation of the magnetic tape device of FIG.

[Explanation of symbols]

 3 block counter 4 error detection means H magnetic head M motor T magnetic tape

Claims (1)

[Scope of utility model registration request] 1. A magnetic tape device for checking data written in blocks on a magnetic tape, for moving the magnetic tape in a forward direction of a reading direction and a writing direction and in a reverse direction of a rewinding direction. Magnetic tape driving means, counting means for counting the current block position of the magnetic tape running by the magnetic tape driving means, reading the write data of the magnetic tape at the time of rewinding after the end of writing to detect an error, and A magnetic tape device comprising: an error detecting unit that detects an error by comparing the block position of the counting unit when the tape is rewound to the starting position.