JPS586515A - Method and apparatus for controlling error of magnetic tape device - Google Patents

Abstract

PURPOSE:To reduce the time required for error retrial, by detecting and storing an error during write or readout to a magnetic tape, reading and storing error information toward the reversing direction from the normal direction and comparing the information with the stored error. CONSTITUTION:A data entering a data transfer circuit 3 from an upper-order device 1 is transmitted to a write head 12 via a modulation circuit 6 and a write circuit 9 and stored on a magnetic tape. The stored data is outputted to the device 1 via a readout circuit 14, a demodulation circuit 17 and the circuit 3. If an error takes place during said operation, it is transmitted to an error detection circuit 25, which stores the error signal to an error storage circuit 46 via an AND gate 44. The circuit 25 reverses a capstan 21 via a control circuit 23. The circuit 25 receives an error generating signal and gives an output to an error analysis circuit 35 via an AND gate 45. The circuit 35 compares and analyzes the error signal stored in the circuit 46 and detects a circuit having the error for recovery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an error control method for a magnetic tape device, which improves the control when an error occurs in a magnetic tape device, and a control device therefor.

Traditionally, magnetic chi! If an error occurs during reading or writing to the device, first the magnetic chip device notifies the host device of the error occurrence. Upon receiving the error occurrence signal, the host device outputs to the magnetic tape device an instruction to write or read the block space, write or read the error block, ie, a read 2 signal. Next, Magnetic Chee received a retry signal! The device performs IJ) lie operation. The above operation is performed a plurality of times, and if an error occurs in all IJ) write operations, the host device processes it as a tryout. However, since all of the plurality of attempts to paste are repeated writing and reading operations under the same conditions, there was a problem in that the result was often a read/write/read error.

The present invention is intended to solve the above-mentioned problems, and its purpose is to provide an error control method and apparatus for performing Sheller recovery by reading back the error block again and comparing and analyzing the error contents. It is about providing.

The % mold of the present invention is that in a magnetic tape device, an error that occurs during the operation of writing upper button information on a magnetic tape medium or reading information on the magnetic tape medium is stored, and the magnetic tape medium is transferred to a normal tape. A magnetic chip device that performs Sheller recovery by reading out information that has caused an error when moving in a direction opposite to the running direction in a direction opposite to the normal information reading direction and comparing it with the stored error contents. An object of the present invention is to provide an error control method.

Hereinafter, detailed explanation will be given using examples of the present invention.

When an error occurs during convolution and readout in the magnetic chip device, it is possible to isolate the error location by reading the pattern error check in the forward word direction and the packed word direction. equipment control circuit, unit circuit margin change)
It is also possible to prevent the error by changing the Hi-Fri trial method. The present invention provides Sheller treatment using the above method.
This is a method of preventing the occurrence of errors during a serial try by separating the parts and changing the margins of the control circuit and unit circuit of the error theory PfrK magnetic tape device, or changing the try method.

FIG. 1 is a diagram showing a tenth embodiment of an error control method when reading information recorded by slipping on a magnetic tape. (,) is a diagram showing the format of 120 pieces written on a magnetic tape. First, the preamble is written, then the title.

Finally, a postamble is written. Assuming that the chip speed when the one block was written was ｽ), the frequency at the time of reproduction increases as shown in (e)k. When the magnetic tape device performs an operation to read 1f lock data, if no quadrangle is detected in the forward direction P, an error of no quadrangle detection occurs. The 0th order packed word stored in the error memory is read. At this time, if the operation is normal, a read try is sent to the host device using a packed word read, and if there is an error, for example an f-store unknown error, the margin of the pull-in frequency of the variable frequency oscillator is changed. and sends a retry request to the higher-level device.

Said! - If the margin change is not performed automatically within the magnetic chip device but is operated by an instruction from the higher-level device, a margin change request is output to the higher-level device to notify the higher-level device of a retry.

FIG. 2 is a diagram showing a second embodiment of an error control method when reading information written at a low level. (a
) When writing a signal with a modulated waveform shown by K onto a magnetic tape medium, if the recording level is low, the data is read by 7 OR words and demodulated to obtain the signal shown in (a). At this time, the multi-amplitude is smaller than the slice level at points ■ and @, that is, a drop out error occurs at points ■ and @. The error is stored in memory.

Next, a packed word read is performed. At this time, if the operation is normal, it will notify the host device that the pack word read is read 2, and if it is abnormal and it is 1 -), for example, if a trailing lag out is detected at the same point as the forward read or on another track. If the slice level is lower than that, a retry is sent to the higher-level device. If the operation of lowering the slice level is not performed automatically within the magnetic chip device but is operated based on an instruction from a higher-level device, a request to lower the slice level is output to notify a retry. Furthermore, if a dragout is detected during a forward read and the packed word is normal, it is also possible to lower the slice level.

FIG. 3 is a diagram showing an embodiment of the error control device of the present invention. The data input/output terminal 2 of the host device 1 is connected to the data transfer circuit 30 and the input/output terminal 4.

The output 5 of the data transfer circuit 3 enters the input cuff of a modulation circuit 60, and the output 8 of said modulation circuit 6 enters the input cuff 10 of the write circuit 9.
Enter C. The output 11 of the write circuit 9 is connected to the write circuit 12. Readhead 13 is connected to input 15 of readout circuit 14 . The output 16 of the readout circuit 14 goes into the demodulation circuit 170 input 18 and the demodulation circuit 170 output 19 goes into the data transfer circuit 30 input 20. A drive circuit 22 that drives the cab stan 21 is connected to a control circuit 23. The output 27 of the error detection circuit 25 is input to the input 24 of the control circuit 23 . Error outputs of the modulation circuit 6, write circuit 9, demodulation circuit 17, read circuit 14, control circuit 23, and drive circuit 22, respectively.
33 is connected to the error input 34 of the output 2-detection circuit 25. The correction output 36 of the error analysis circuit 35 is variable Wlj
A circuit 6, write circuit 9, demodulation circuit 19, read circuit 1
4, are connected to correction input terminals 37, 38, 39, 40, 41, and 42 of the control circuit 23 and the drive circuit 22, respectively. The detection output 43 of the error detection circuit 25 enters one input of the AND/DART 44 and 45. and f-) 44
The output of is sent to the error storage circuit 46 as ANDP-) 45
The outputs of each enter the error analysis circuit 35. The output 47 of the error storage circuit 46 is the input 48 of the error analysis circuit 350.
to go into. Output 49 of the error analysis circuit 35 is connected to the host device 1 of the company. Data entering the data transfer circuit 3 from the host device 1 is transmitted to the write head via the modulation circuit 6 and the write circuit 9, where it is recorded on the magnetic tape medium.

The recorded data is read out by a four-way readout circuit 14 and a demodulation circuit 17.
, enters the host device via the data transfer circuit 3. If an error occurs in the above operation, KFi, the circuit that detects the error notifies the error detection circuit 25 of the occurrence of step 2-.

When the error occurrence signal enters the error detection circuit 25, the error detection circuit 25 outputs the error signal via the AND gate 44 to the storage circuit 46 for storage. It should be noted that when outputting to the memory circuit 46, it is done at the time of forward read, or at the same time, the error detection circuit 25 outputs its output 27 to the control circuit 23. Outputs a signal that instructs the button to turn on or off. When the control circuit 23 receives a signal instructing the rebooting, the control circuit 23Fi drives the capstan 21 in the reverse direction via the drive circuit 22. At this time, the error block is read again. The circuit that detects an error during the operation notifies the error detection circuit 25 of the occurrence of the error. Step 2 - When the detection circuit 25 receives the error occurrence signal,
This time, the error occurrence signal is outputted to the error analysis circuit 35 via ANDf-) 45. Furthermore, andr
-) 44 is turned on at the first error, that is, an error at the forward word), and r -) 45 is turned on at the second knee 2, that is, the error at the time of the pack word. The error analysis circuit 35 compares and analyzes the forward word error signal stored in the error storage circuit 46 with the packed word error signal, and detects a circuit that has generated a sheller based on the comparison result. Outputs a correction signal to the circuit system where the error occurred. Alternatively, depending on the content of the analysis, a retry method report signal is output to the host device, and the IJ) method from the host device is changed, thereby preventing the error from occurring again in the retry operation. Note that the error analysis circuit only performs comparative analysis of error signals, and outputs the results of the comparative analysis to a higher-level device, and can also output a correction signal to the circuit system in which the error occurred. be.

Furthermore, the present invention can be used for all errors that can be detected and corrected.

As described above, according to one aspect of the present invention, recurrence of the error can be prevented by performing an error retry in response to an error during writing or reading. As a result, the time required for error retrying can be shortened, and furthermore, it is possible to minimize the need for correction of the entire j and f due to beam tryouts.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing an embodiment of the method of the present invention, and Figure 3 is a diagram showing an embodiment of the method of the present invention.
The figure is a block diagram of an embodiment of the device of the invention. 25...Error detection circuit, 35...Error analysis circuit, 46...Error storage circuit.

Claims (2)

[Claims] (1) In a magnetic chip device, an error that occurs during an operation of writing information onto a magnetic chip medium or reading information from the magnetic chip medium is stored, and the magnetic chip medium is moved in the opposite direction to the normal tape running direction. The magnetic chip is characterized in that Sheller recovery is performed by reading the information in which an error occurred when moving the information in the direction opposite to the normal information reading direction and comparing it with the stored error contents. Equipment error control method. (2) Magnetic Chee! In the apparatus, information is written on a magnetic chip medium or the magnetic chip is written on the magnetic chip medium. means for detecting an error occurring during an operation of reading information on a medium, means for storing the contents of the error, and moving the magnetic tape medium to its original position when the error is detected. means for reading the information in the reverse direction; means for comparing the error content of the information obtained by the reading means in the reverse direction with the error content stored in the storage means; 9. An error control device for a magnetic chip device, characterized in that it has means for performing error recovery based on the results.