JPS63195876A - Magnetic tape controller - Google Patents

Abstract

PURPOSE:To prevent misrecognition of a data block by providing a data register for storing data including block numbers. CONSTITUTION:After writing a data block, if an error arises in an operation after reading its block, the backward read is executed, and the readout data at that time are stored in the data register 10. A block number part BNO is taken out of the data stored in the data register 10 to be sent to a microprocessor 9 to confirm whether a block skip has accurately been performed or not.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic tape control device, and particularly to a magnetic tape control device suitable for accurately positioning a data block on a magnetic head and accurately performing error recovery during data writing. This invention relates to a magnetic tape control device.

[Conventional technology]

Conventionally, when data is recorded on a magnetic tape, recovery when a write error occurs is performed by backing up the magnetic tape by skipping one data block in the reverse direction, as described in Japanese Unexamined Patent Publication No. 52-45314. - This was done by issuing a space command, then issuing an erase command, and then issuing the same write command again.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, when a backspace command is executed, it is blocked without checking the data content, so there is no consideration given to ensuring blocking in the presence of noise, and the magnetic head The problem with positioning is that data blocks may stop, leak, or be lost due to defects.

The present invention was made in view of the problems of the prior art described above, and it is an object of the present invention to provide a magnetic tape control device in which a magnetic head is correctly positioned and data blocks are not discontinued, leaked, or lost. .

[Means for solving problems]

The magnetic tape control device of the present invention transmits and receives data between a host device and a magnetic tape device, and is particularly provided with a data register for storing data including block numbers for confirming block positions read from the magnetic tape. It is characterized by things.

[Effect]

In the present invention, in order to confirm the block position of the magnetic tape, a data register is provided to store read data from the magnetic tape including a block number, and the block number is confirmed to recognize the correct block position. .

Since the block number is recorded in the data, the block number cannot be obtained by determining whether or not there is data (whether or not there is a part without data (IBG) after the data block) as in the past. do not have.

Therefore, the block number cannot be known unless the data is read and the contents of the data are obtained. Here, the data buffer is filled with write data from the host device, so
The read data cannot be loaded into the data buffer.

Therefore, in the present invention, a data register is prepared in advance for such an error recovery operation. As a result, a write error occurs, and the read data during reverse reading can be taken into the data register. Since the block number can be read from the captured data and it can be confirmed that the block has been correctly skipped, erroneous recognition of data blocks can be prevented.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. Write data is output from the upper position 1 and stored in the data buffer 5 via the upper unit connection section 4 in the magnetic tape control device 2. When this data buffer 5 is divided and used by a plurality of magnetic tape devices 3, data for the number of magnetic tape devices 3 is stored until the data is filled. When the buffer 5 is filled, the data is sent to the magnetic tape device 3 via the writing section 6 and the device connection section 8 and written in accordance with instructions from the microprocessor 9.

When reading data from the magnetic tape device 3, the data is stored in the data buffer 5 via the device connection section 8 and the reading section 7 according to instructions from the microprocessor 9.

Once a certain amount of read data has been stored, the data is transferred to the host device connection section 4 according to instructions from the microprocessor 9.
is sent to the host device 1 via.

Next, an error recovery operation when an error occurs during writing will be explained. Now, after writing a certain data block, if an error occurs in the read-after-write operation of that block, reverse reading of the magnetic tape is executed, and the read data at that time is stored in the data register 10. As shown in FIG. 2, the data block DB recorded on the magnetic tape 1 is composed of a data section and a block number section BNo, and the block number section BN'O is also stored in the data register 10 as a matter of course. Therefore, it is possible to extract the block number part BNO from the data stored in the data register IO and send it to the microprocessor 9 to check whether block skipping has been performed accurately. Moreover, since read data is not written to the data buffer 5, data for rewriting can be stored as is.

The size (number of bytes) of the data register 10 may be the expected maximum value of the data block DB, or may be the required amount of data such as the block number part BNO.

As is clear from the above description, according to this embodiment, the block number in the data block can be obtained when performing reverse reading when a write error occurs, and the accuracy of blocking can be confirmed.

In the above embodiment, the case of reverse reading during read-after-write was explained, but the present invention is not limited to this, and after returning the magnetic tape sufficiently, forward reading is performed. It can be applied to reading, and can also be applied to confirming the position of a block when it becomes unknown.

Further, as shown in FIG. 2, a cartridge-type magnetic tape is known as a magnetic tape in which a block number BNO is provided in the data block DB, but the present invention is not limited to this. , block number BO
It is applicable to magnetic tapes with N written on them.

〔Effect of the invention〕

According to the present invention, even when the data buffer in the magnetic disk control device is filled with data for writing, it is possible to buffer read data, confirm block numbers, and recognize block positions. It becomes possible to rewrite from the position. As a result, data block failures such as leaving unnecessary blocks or erasing necessary blocks can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the structure of data blocks recorded on a magnetic tape. 1... Host device, 2... Magnetic tape control device, 3.
...Magnetic tape device, 4...Upper device connection section, 5...
・Data buffer, 6...Writing section, 7...Reading section, 8...Device connection section, 9...Microprocessor, 10...Data register, 11...Magnetic tape, DB...・Data block, D...Data, BN
O...Block number.

Claims (1)

[Claims] 1. A magnetic tape control device that controls data transmission and reception between a host device and a magnetic tape device is characterized by being provided with a data register that stores data read from the magnetic tape and including a block number for confirming the block position. Magnetic tape controller.