JPS62159379A - Disk control system - Google Patents

Abstract

PURPOSE:To increase an opportunity to recover data by counting up the execution number of times of re-reading operation when a bit of information regarding a detected data error and the bit of information regarding a data error at the last time detection coincide, and controlling so as to reset a counter. CONSTITUTION:A counter 5, when the data error is not detected in a data readout time, and when the data error, the content of which is varied by the re-reading operation is detected, is reset, and zero is outputted as a count data 14, meanwhile, when the data error, the content of which is not varied by the re-reading operation, is detected, the execution number of times for the re- reading operation are counted, and a result is outputted as the count data 14. A controller 6, when it detects a strobe signal 27, outputs a strobe signal 23, and latches a syndrome 12 generated in the data readout time at a register 3, and next, it decides whether the re-reading operation of the data should be continued or terminated, and controls a re-reading request signal 28 for the data referring a data error detection signal 21 and the count data 14.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a disk control system for a data processing device. In the disk control method to be controlled, when the information regarding the detected data error is the same as the information regarding the previously detected data error, the number of executions of the re-reading operation is counted up;
By controlling the continuation or termination of the rereading operation based on the counted result by resetting it at different times, efficiency decreases due to unnecessary rereading operations in response to unrecoverable data errors can be avoided. This makes it possible to increase the chances of data recovery from data errors that can be recovered by re-reading the data without causing problems.

[Conventional technology]

When a data error is detected in data read from a disk, the data is recovered by performing a reread operation to improve the reliability of the data. Conventionally, the number of times a reread operation is executed is counted without distinguishing between data errors due to defects on the disk medium that cannot be recovered by rereading and data errors that can be recovered by rereading. m continuation or end shi 11
1 wholesaler.

[Problem that the invention seeks to solve]

However, in such conventional disk control methods, data errors that can be recovered by rereading operations caused by factors such as noise or synchronization errors are treated as unrecoverable data errors due to rereading operations such as scratches on the disk medium. They were evaluated with the same weight.

For this reason, if the upper limit of the number of reread attempts is set small, there will be fewer opportunities for data recovery (and if the upper limit of the number of reread attempts is set large), the efficiency will be reduced due to unnecessary reread operations. It had the disadvantage of lowering the

The present invention solves these drawbacks, and provides data errors that can be recovered by rereading data without reducing efficiency due to wasteful rereading operations for data errors that cannot be recovered by rereading data. The object of the present invention is to provide a disk control method that provides a high chance of data recovery against data errors.

[Means for solving problems]

The present invention includes an error detector that detects a data error occurring in data read from a disk, and a control means that controls execution of a data re-read operation when a data error is detected by the error detector. In the disk control method, the control means includes a data holding means that holds information regarding a data error detected by the error detector, and a data holding means that holds information regarding a data error detected during data reading and information held by the data holding means. a comparison means for comparing data error information with data error information, a means for counting the number of times a data rereading operation is executed when the comparison means has a matching output, and a count value of the counting means exceeds a predetermined value. The present invention is characterized by comprising means for inhibiting the re-reading operation, and means for resetting the count value of the counting means when there is no matching output from the comparing means.

[Effect]

Information regarding the data error detected during the previous data read is held by the data holding means, and compared with information regarding the data error detected during the current data read by the comparison means. When the comparison results are the same, the counting means counts up the number of times the rereading operation is executed, and when they are different, the counting means is reset. Continuation or termination of the rereading operation is controlled based on the count value of the number of executions of the rereading operation counted by the counting means in this manner. With the above control operations, data errors that can be recovered by rereading data can be corrected without reducing efficiency due to wasteful rereading operations for data errors that cannot be recovered by rereading data. This can increase your chances of recovery.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

The figure is a block diagram of a disk control device according to an embodiment of the present invention. In the figure, input data is connected to the input of the error detector 1 from a disk not shown.

Here, the feature of the present invention is the rereading control portion surrounded by a dashed line. That is, the syndrome 12 from the error detector l is connected to the negative input of the comparator 2 and the input of the register 3.

In addition, a data error detection signal 21 is sent from the error detector 1.
is connected to the detection signal input of the controller 4.6.

The previously generated syndrome 13 from the register 3 is connected to the other input of the comparator 2. A match signal 22 from the comparator 2 indicating that the comparison results match is connected to a match signal input of the controller 4. A data read operation end signal 24 is connected to the end signal input of the controller 4 from outside the figure.

When the match signal 22 is input from the comparator 2, the count-up signal 25 is connected to the count-up input of the counter 5. When the coincidence signal 22 is not input, the counter set signal 26 is connected to the reset input of the counter 5. Count data 14 from the counter 5 and a strobe signal 27 indicating that the count data 14 is valid are connected to respective inputs of the controller 6.

When the count data is continuous, a reread request signal 28 is sent out from the controller 6 outside the figure. A latch strobe signal is also connected to the launch input of register 3, and syndrome 12 is latched.

The operation of the disk control device having such a configuration will be explained. In the figure, an error detector 1 inputs input data 11 read from a disk, generates a syndrome 12, and checks whether there is an error in this data. A data error detection signal 21 indicating whether or not a data error is detected from this data is output, and a syndrome 12 is detected.
Output. Further, the comparator 2 compares the syndrome 12 with the syndrome 13 held in the register 3 and generated during the previous data read, and outputs a match signal 22 indicating that the comparison result matches. When the controller 4 detects this data read operation end signal 24, it refers to the data error detection signal 21 and the coincidence signal 22 to determine whether the data error detected by the error detector 1 occurred during the previous data read. Error detector 1
If the data error is the same as the data error detected by , the count amplifier signal 25 is output, and if they are not the same or if no data error is detected during data reading, the reset signal 26 is output. The counter 5 performs count up and reset operations in response to a run-up signal 25 and a reset signal 26, outputs count data 14, and further outputs a strobe signal 27 to indicate to the controller 6 that the count data 14 is valid. Let me know.

In other words, the counter 5 inputs the data when reading this data.
If no error is detected, or if the error content changes due to a rereading operation, the data will be reset and zero will be output to the count data 14 when an error is detected; on the other hand, data whose error content will not be affected by the rereading operation. - When an error is detected, the number of times the reread operation is executed is counted and the result is output to the count data 14.

When the controller 6 detects the strobe signal 27, it outputs the strobe signal 23, latches the syndrome 12 generated during data reading into the register 3, and then refers to the data error detection signal 21 and count data 14 to read this data. The data rereading request signal 28 is determined by determining whether to continue or terminate the rereading operation of the data.

〔Effect of the invention〕

As described above, the present invention provides data that can be recovered by rereading data, without reducing efficiency due to wasteful rereading operations for data errors that cannot be recovered by rereading data. This has an excellent effect of increasing the chances of data recovery against errors.

[Brief explanation of drawings]

The figure is a block diagram of a disk control device according to an embodiment of the present invention. 1...Error detector, 2...Comparator, 3...Register, 4.6...Controller, 5...Counter, 11...
・Input data, 12...Syndrome, 14...Count data, 21...Data error detection signal, 22.
... Match signal, 23.27 ... Strobe signal, 24
... Read operation end signal, 25 ... Count up signal, 26 ... Reset signal, 28 ... Reread request signal.

Claims (1)

[Claims] (1) Equipped with an error detector that detects a data error occurring in data read from a disk, and a control means that controls execution of a re-read operation of the data when a data error is detected by the error detector. In the disk control method, the control means includes a data holding means that holds information regarding data errors detected by the error detector, and information regarding data errors detected during data reading, which is held by the data holding means. a comparison means for comparing the data with information regarding data errors; a means for counting the number of times the data rereading operation is executed when the comparison means has a matching output; A disk control system characterized by comprising means for inhibiting a re-reading operation, and means for resetting the count value of the counting means when there is no matching output from the comparing means.