JPS60182565A - Error processing system - Google Patents

Abstract

PURPOSE:To start correctly the error processing at an error generated point despite the replacement of a magnetic tape device, by writing an abnormality block to a magnetic tape in case a writing action is retried out. CONSTITUTION:Both the write data and the write start data are supplied to a writing circuit 13 from terminals A and B after undergoing the processing through a mudulation circuit 10 via an AND gate 12 which is opened by the set output of an FF11. Then the block information containing the preample, data, postample, etc. is written to a magnetic tape 4 via a write head 14. While a signal which is reset in the middle part of data is supplied to an FF11 after a retry-out. Then the data between the preample and the postample of the corresponding block to be written to the tape 4 is turned into an abnormality block which is set at ''0'' at the middle part. Even in case the tape 4 is reproduced by said abnormality block through another magnetic tape device, the error processing can be started correctly at the error generating point.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention records data sent from a host device in sequential blocks on a magnetic recording medium, and sequentially reads the blocks recorded on the magnetic recording medium. The present invention relates to a magnetic recording/return device for reproducing data, and particularly to an error processing method that can reliably perform error recovery when an error is detected while recording data on a magnetic recording medium.

(b) Prior Art and Problems In a magnetic recording and reproducing device, particularly a magnetic tape device, which sequentially records and reproduces data, data is recorded in blocks in predetermined units. Then, when forming blocks, they are put together into a predetermined formant. FIG. 1 shows an example of a block formant in the phase modulation recording system. 1 is a preamble and a burst for the purpose of synchronization. 2 is data, and 3 is a postamble, which is a burst for the purpose of synchronization during backward reading. When data is recorded in blocks using such a formant, if an error is detected, the magnetic tape device usually erases the block and rewrites the block to recover from the error. This rewriting operation is repeated up to a predetermined number of times until writing is completed without error. FIG. 2 is a diagram illustrating error recovery processing. 4 is a magnetic tape. 5
In this case, the block was written normally. When an error is detected in block 6, block 6 is erased and rewritten in block 7, as shown by the dotted line. If an error is detected here as well, block 7 is erased and block 8 is rewritten. If an error is detected here as well, block 8 is erased and block 9 is rewritten.

If an error is detected here as well, and the predetermined number of times has been reached, this block 9 is left without being erased in order to notify the point where the error has occurred. If an error is detected even after performing the rewriting operation a predetermined number of times in this way, and a retryout occurs, the magnetic tape is rewound and transferred to another magnetic tape device in order to write to another magnetic tape device this time. transferred to a tape device. - Errors that occur when writing data are usually caused by damage to the magnetic tape or adhesion of dust, etc. If an error occurs even after rewriting the specified number of times, there may be a problem with the magnetic tape device. It's for a reason.

In this case, the magnetic tape device to which the magnetic tape has been transferred reads blocks on the magnetic tape up to the position of the block where the error occurred, and then retries are started again.

In this method, if the error in the first magnetic tape device is minor, the magnetic tape device to which this magnetic tape is transferred will normally read block 9, which is left behind to indicate the point where the error occurred. , the point of error occurrence may not be detected correctly. This is because there is a difference in the level of error checking during writing and error checking during reading from the viewpoint of reliability, and the error checking during writing is strict, and the appearance of errors differs depending on the device. Therefore, there is a drawback that error processing cannot be started at the correct error occurrence point.

(c) Object of the Invention In view of the above-mentioned drawbacks, an object of the present invention is to provide a method for detecting an error in which the magnetic head can be positioned so that error processing can be started correctly at the point where the error occurs in the process of performing error recovery by changing the magnetic tape device. The purpose is to provide a processing method.

(d) Structure of the Invention The structure of the present invention is a magnetic recording system in which data sent from a host device is sequentially divided into blocks and recorded on a magnetic recording medium, and the blocks recorded on the magnetic recording medium are sequentially read to reproduce the data. The playback device is provided with a writing means for writing an abnormal block to the magnetic recording medium, and when an error is detected during writing of the block and the writing does not end normally even after rewriting a specified number of times, the writing means is provided to write the abnormal block to the block. The abnormal block is written by means.

(e) Embodiments of the Invention The present invention provides a method for reliably detecting the point of error occurrence in other magnetic tape devices when a write operation is retryed in the first magnetic tape device in which an error occurs.
Blocks that would cause an error in any device are intentionally recorded. For this reason, a block whose format is not normal is written, for example, a block whose rear part is missing from around the center of data 2 in FIG. 1 is written.

FIG. 3 is a block diagram of a circuit showing one embodiment of the present invention.
FIG. 4 is a diagram illustrating the operation of FIG. 3. Write data enters the modulation circuit 10 from terminal A, and the fourth
As shown in FIG. B, a write start signal enters the modulation circuit 10. Therefore, the modulation circuit 10 starts operating and sends the preamble section, data section, postamble section, and write output to the AND circuit I2. The flip-flop 11 is normally set, and the output 15 of the flip-flop 11 is "1".
Therefore, the output of the modulation circuit 10 enters the write circuit 13 via the AND circuit 12. The write circuit 13 supplies a write current to the write head 14 to record blocks on the magnetic tape 4 using the former 7+- shown in FIG. When writing an error block after retry-out, a signal is input from terminal C to reset the flip-flop 11 in the middle of the data as shown in FIG. 4, and the flip-flop 11 is reset. Therefore, since the output 15 of the flip-flop 11 becomes 0'' from the middle of data recording, the AND circuit 12 blocks the output of the modulation circuit 10.

Therefore, the write current of the write circuit 13 is also stopped, and missing blocks are recorded on the magnetic tape 4 from the middle of the data to the postamble as shown in FIG. 4. Blocks formed in this manner are highly error-prone blocks that will cause errors in any device.

([) As described in detail, the present invention can reliably detect the point of error occurrence and carry out the error recovery process for the magnetic tape after replacing the magnetic tape device.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a block formant in the phase modulation recording method, FIG. 2 is a diagram explaining error recovery processing, FIG. 3 is a block diagram of a circuit showing an embodiment of the present invention, and FIG. The figure is a diagram explaining the operation of FIG. 3.

Claims (1)

[Claims] In a magnetic recording and reproducing device that sequentially records data sent from a host device in blocks on a magnetic recording medium, and that sequentially reads the blocks recorded on the magnetic recording medium and reproduces the data, an abnormality occurs in the magnetic recording medium. A writing means for writing a block is provided, and if an error is detected during writing of the block and the writing does not end normally even after rewriting a specified number of times, the writing means writes an abnormal block to the block. error handling method.