JPS6136259B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a retry control method, and more particularly to a retry control method for errors occurring in an information processing apparatus due to changes in its environmental conditions.

When some kind of error is detected in the logical operation of a known information processing device, it may be necessary to redo the operation to perform the correct logical operation depending on the nature of the malfunction.
So-called error control, which halts the execution of instructions, is well known. Furthermore, in order to detect errors in the logic circuit, it is necessary to add extra logic other than that required for the logic function to provide redundancy. Generally, parity bits are added to coded information to detect errors using an odd-even check, or Hamming codes are added to coded information to detect and correct errors. There is.

Errors in logical behavior include solid errors and intermittent errors.
It is known that the latter is far more common. There are numerous causes for this non-reproducible error, including uncertain logic operations on asynchronous signals, extraneous noise, and defects in component reliability. For malfunctions caused by these, if the same processing operation is repeated again, it will be executed correctly and will not cause any trouble. For this reason, it is common practice to retry in case of malfunction. There are two ways to retry: processing cycle retry or instruction retry. In either case, if retry is to be controlled, the following functions are required. That is, the first step is to hold retry control information, that is, to hold an indication of whether retry is possible or not, an indication of a retry starting point, saved data, etc. The second step is to count the number of retries, that is, count the number of retries, and abort the retry operation if a correct result cannot be obtained even after reaching a certain number of retries. The third is an interrupt after a retry.

In conventional information processing devices, the maximum number of retries to be repeated is usually calculated and fixed based on the rating, reliability, etc. of the device. In other words, the upper limit of the number of retries is determined at the stage of designing the information processing device.

On the other hand, causes of errors in information processing devices are often caused by environmental conditions such as temperature and humidity, in addition to the aforementioned uncertain logic operations, external noise, and reliability of parts. 2. Description of the Related Art Ratings of not only information processing devices but also electronic devices in general are determined in consideration of various environmental conditions in order for the device to operate properly. In other words, the probability that an information processing device will make an error increases as the surrounding environment conditions deviate from the specifications.

Generally, retries are performed up to a fixed upper limit of the number of retries, and if the operation is still not performed normally, the processing operation is stopped as a retry failure. Therefore, even if an error occurs due to deterioration of the environmental conditions in the information processing apparatus as described above, the processing operation will be retried a predetermined number of times and the processing operation will be stopped. Stopping the processing operation requires a considerable amount of time for subsequent maintenance work, so it is better to avoid it as much as possible.

Conventionally, as a solution to this problem, a control method has been proposed that retries a predetermined number of times after detecting an error, and if it is still not normal, changes the operating conditions such as power supply voltage and frequency, and retries the predetermined number of times. There is.
However, with current technology, it is not possible to clearly determine whether errors occur due to worsening environmental conditions or because logical operations operate unreliably under normal circumstances. It is not very desirable to change the operating conditions.

Another solution is to increase the number of retries when environmental conditions deteriorate, hoping that the retries will restore normal operation as much as possible, and then halting the equipment's processing operations to avoid the worst-case scenario. Technology can also be proposed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a retry control method that can avoid as much as possible the situation where the processing operation of the apparatus is stopped because it is assumed that the error will not be recovered even after retrying a predetermined number of times.

Another object of the present invention is to automatically set the number of retries in response to changes in at least one physical variable that determines the environmental conditions under which an information processing device can operate, thereby preventing processing operations from being stopped inadvertently. It is an object of the present invention to provide a retry control method that can lower the probability and improve the operating rate of the information processing device as a whole.

Still another object of the present invention is to provide a retry control method capable of relieving errors in processing operations caused particularly by temperature fluctuations within an information processing apparatus.

The object of the present invention is achieved by the configuration described below. Information processing devices targeted by the present invention include not only known arithmetic processing devices and main storage devices, but also
It includes various processing devices such as information storage devices such as magnetic disk devices and input/output devices. The present invention sets the number of retries in accordance with physical variables that change the frequency of error occurrence in an information processing device that is subject to retry control. When an error is detected by the error detection means, the retry operation is performed up to the set number of times at most. The physical variables are variables and temporal variables that are caused by environmental conditions for proper operation of the information processing device. In general, information processing equipment has a rating determined for proper operation. Ratings based on environmental conditions include temperature, humidity, etc. That is, as these factors approach and exceed their rated limit values, the frequency of error occurrence increases. Furthermore, it can be said that the frequency of errors occurring is high immediately after the information processing device is powered on, and the frequency decreases as time passes. Therefore, if the number of retries is set to increase or decrease according to changes in physical variables as described above, and retries are performed up to the set number of times at most, errors will not be recovered inadvertently. It is possible to avoid a situation in which the processing operation of the apparatus is stopped due to the assumption that the

The present invention can set the number of retries in accordance with changes in physical variables caused by various environmental conditions in the information processing device. For example, when setting the number of retries according to temperature changes, the temperature detection means installed at the location most susceptible to temperature effects within the information processing device and the temperature detected by the temperature detection means may be used. Correspondingly, there is provided a temperature/retry number conversion means for deriving the number of retries, and a retry counter for setting the number of retries derived from the conversion means. If an error is detected by the error detection means, a retry operation is performed, and this operation is repeated up to the number of retries set in the retry counter at most. Since the number of retries is set according to temperature changes, for example, even if the temperature changes to near the rated limit, if the number of retries is increased accordingly, errors can be recovered by this retry. The probability of doing so increases.

In the description of the embodiment using a magnetic disk device as an example, which will be described later, the number of retries is set according to temperature changes, and it is expected that the most significant effect of the present invention will be obtained. There is no problem when detecting not only temperature but also various physical variables as digital quantities, but when detecting as analog quantities, known analog/digital conversion is required.

In addition, when setting the number of retries with the passage of time, a time counter that starts timing operation when the power is turned on, and a time/number of retries conversion means are provided, and the retries derived from the conversion means are provided. The number of attempts is set in the retry counter. The subsequent configuration and operation are the same as described above. Generally, the frequency of error occurrence decreases with the passage of time, and it is necessary to set a time/retry count to that effect in the conversion means. Preferably, the number of retries does not need to be changed after a certain period of time has elapsed.

The present invention can set the number of retries according to changes in various physical variables as well as temperature and time.

According to another configuration of the present invention, a plurality of detection means for detecting physical variables, a plurality of conversion means for converting each detected variable into a corresponding number of retries, and a means for selecting the maximum number of retries, and a retry counter for setting the maximum number of retries.
Here, the plurality of detection means may be a plurality of temperature detection means installed in the same device for the same kind of physical variables, or may be a plurality of temperature detection means installed in the same device, or may be a plurality of temperature detection means installed in the same device. It may be a means for detecting multiple types of physical variables such as humidity and vibration. Therefore, it is possible to set the number of retries for the worst fluctuations in physical variables due to one or more factors determining environmental conditions, and prevent the processing operation from being stopped inadvertently. , it is possible to improve the operating rate of the information processing device as a whole.

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram when the present invention is applied to a floppy disk device. Floppy disk devices are sensitive to temperature changes and are often prone to errors due to temperature changes, especially when performing magnetic writing/reading. Therefore, it is preferable to apply the present invention to a floppy disk device.

The construction of floppy disk devices is known. The floppy disk device is generally composed of a disk controller 1, a disk drive section 2, and a floppy disk 3. The disk control section 1 is connected to a known main memory 4 and to a retry setting circuit 5 according to the present invention. Disk drive unit 2
A temperature detector 6 is provided. The detailed configuration of the retry setting circuit 5 and the temperature detector 6 will be described later.

The disk control section 1 sends a disk control signal 8 to the disk drive section 2, and writes and reads data to and from the floppy disk 3 via the data bus 9. Furthermore, a memory control signal 7 is sent to the main memory 4, and data is written and read via a data bus 9.

The configurations of the disk controller 1, retry setting circuit 5, temperature detector 6, and related configurations will be explained with reference to FIG. The disk drive unit 2 maintains its original optimum operating temperature when performing various processing operations such as addressing, reading/writing, and function specification on the floppy disk 3. As the difference from the ambient temperature increases, the probability that an error will occur in the above operation increases.

For this reason, the thermistor 2 of the temperature detector 6
Reference numeral 1 is installed at a location of the disk drive section 2 that is most susceptible to temperature effects, for example, near the magnetic head and various sensors. What is the temperature rating for this disk device?
If the temperature is 10 to 50°C and the optimum operating temperature is 30°C, the greater the difference between the optimum temperature of 30°C and the actually detected temperature, the higher the frequency of error occurrence. Therefore, the temperature detector 6 in this embodiment includes a reference temperature setting circuit 22 that sets the optimum temperature, and a temperature sensor that detects the difference between the actual temperature detected by the thermistor 21 and the optimum temperature from the setting circuit 22. It has a difference detection circuit 23. The temperature detection signal 11 output from the temperature detector 6 is sent to the converter 24 of the retry setting circuit 5. In this example, the temperature detection signal 11 can be strictly speaking a temperature difference detection signal. Although not shown in the figure, if the physical variables to be detected other than temperature are analog quantities, the detection signal 1
It goes without saying that a known analog/digital converter must be provided before the signal 1 is input to the converter 24.

In this embodiment, the converter 24 has a conversion table for temperature difference/retry count conversion, and the conversion table is configured with a rewritable memory.
The relationship between temperature difference/number of retries stored in this conversion table is shown in FIG. 4, for example. That is, the number of retries is set to increase as the temperature difference increases. For example, if the temperature difference is 13° C., the number of retries “16” is outputted from the converter 24 to the AND gate 25 as the number of retries signal 34. An initial start signal 35 is further inputted to the AND gate 25 from the disk control section 1, and the retry count signal 34 is set in the retry counter 26 using this signal as a timing. The initial start signal 35 also enters the execution counter 27 and resets its contents. Execution counter 27 receives judgment request signal 1
Every time 0 arrives from the disk control unit 1, it is incremented by 1. The determination request signal 10 is issued every time a retry operation is repeated, and the execution counter 27 counts the number of retries that are actually performed.

Comparator 28 compares the contents of retry counter 26 and execution counter 27 . The output of the comparator 28 is input to an AND gate 32 via an AND gate 30 and an inverter 31. These AND gates 30 and 32 also have the judgment request signal 1
A signal obtained by delaying 0 in a delay circuit 29 is inputted. If the contents of both counters match in the comparator 28, an abnormal end signal 38 is transmitted to the disk controller 1, and if they do not match, a retry signal 37 is transmitted to the disk controller 1, respectively.

In the disk control section 1, the retry signal 37 is input to the OR gate 43 together with the above-mentioned initial start signal 35, and the operation instruction control circuit 41 is activated. The operation instruction control circuit 41 issues an operation instruction signal 47 to the disk drive unit 2 in order to control writing or reading of data to or from the floppy disk 3, for example. The error detector 42 is activated by the operation result signal 48 sent from the disk drive unit 2 and detects errors in data read from the floppy disk 3. The error detection method is based on a known validity check method, CRC (cyclic redundancy check) check method, or the like. Error signal 49 which is the output of error detector 42
is applied to an AND gate 46 via an AND gate 44 and an inverter 45. Further, these AND gates 44 and 46 are provided with the operation result signal 48.
is input. When an error is detected in the error detector 42, an error signal 49 is output, an AND gate 44 is opened by the operation result signal 48, and a determination request signal 10 is issued. When the determination request signal 10 is issued, the value of the execution counter 27 is incremented by "1" and the above-described processing is performed. On the other hand, if no error is detected, the AND gate 46 is opened by the operation result signal 48 via the inverter 45;
A normal completion signal 50 is issued. When this signal 50 is output, the process moves to the next processing operation.

In such a configuration, when the temperature detector 6 detects a temperature difference of, for example, 13°C, the converter 24 outputs the number of retries "16" according to the temperature, and the initial start signal 35 outputs a retry count of "16". retry counter 2
It is set to 6.

On the other hand, when the error detector 42 of the control unit 1 detects an error in the data read from the floppy disk 3, it outputs the judgment request signal 10 via the AND gate 44, and adds the value of the execution counter 27. Make “1”. If the first attempt is incorrect, the execution counter 27 is first set to "1". Thus, the content of the retry counter 26, ie, "16", and the content of the execution counter 27, ie, "1" are compared. In this case, there is a mismatch, so AND gate 3
A retry signal 37 is outputted via 0 and transferred to the operation instruction control circuit 41 in the control section 1. The operation instruction control circuit 41 provides the disk drive unit 2 with an operation instruction signal 47 for reading out the data again. The data thus read out is again subjected to error detection by the error detector 42. Thereafter, the same operations as described above are repeated. As a result of a plurality of retry operations, if the values of the execution counter 27 and the retry counter 26 match, an abnormal end signal 38
is output to notify that the retry operation failed.
Of course, if the error detector 42 no longer detects an error during the retry operation before the values of both counters 26 and 27 match, the normal end signal 50 is output and the process moves on to the next process.

In this manner, according to this embodiment, the number of retries can be set according to the change in temperature detected by the thermistor 21. In the above embodiment, the number of retries outputted from the converter 24 was explained as being set in the retry counter 26 by the initial start signal 35, but the number of retries outputted from the converter 24 was set in the retry counter 26.
As a modification, it can be set at regular intervals, or by instructions from a higher-level device such as a central processing unit or terminal control unit, or every time a temperature change that changes the number of retries occurs. Examples include things to do. For example, in the case of performing the process at regular intervals, the output of an oscillator that emits a signal at regular intervals may be applied to the AND gate 25 instead of the initial start signal 35 shown in FIG. Of course, comparator 2
Retry counter 2 during comparison operation in 8
In order to prevent the read operation from 6 and the write operation from occurring at the same time, it is necessary to add a known gate means to inhibit the write operation during read, for example.

Other modifications of the embodiment shown in FIG. 2 include the following. That is, the configuration of the conversion table for the temperature difference in the converter 24 in FIG. 2/the number of retries is made as shown in FIG. 4, but for example, the upper and lower limits of temperature that can be determined from the rating are set, The converter may be configured to change the number of retries only when the temperature detected by the temperature detector deviates from the upper and lower limits.

FIG. 3 is a block diagram for explaining a second embodiment of the present invention. In this embodiment, the number of retries is variably controlled as time passes after the device is powered on. That is, the time detection circuit 51
includes a time counter 53 that performs a counting operation upon being reset by a power-on signal 54, and an oscillator 52 that sends a pulse signal of a constant period to the time counter 53. Then, the output of the counter 53 is the second
The signal is sent to the converter 24 shown in the figure. The rest of the structure is the same as that in FIG. 2, but the structure of the conversion table in the converter 24 is different from that of the embodiment described above. In other words, since the steady state has not yet been reached immediately after the power is turned on, initial transient errors are likely to occur. Therefore, in order to eliminate these errors as much as possible through retry operations, the number of retries is increased immediately after the power is turned on, and then the number of retries is gradually decreased as time passes, and after a certain period of time, the number of retries is kept constant. Set the conversion table time/retry count. The operation of this embodiment is the same as that of the previously described embodiment, so the explanation thereof will be omitted.

In this way, according to the second embodiment, there is no need to provide a special detector unlike the above-mentioned embodiments, and it can be realized at low cost with a simple configuration such as a timer.

The present invention is capable of variably controlling the number of retries in accordance with the detected values by detecting not only temperature and humidity but also various physical variables in various environmental conditions that cause malfunctions of the device. Further examples include vibration, brightness, etc. In a known optical character reading device, characters are recognized by shining light from a light emitting source onto a form and deciphering the light reflected from the form. However, errors in character recognition may occur due to the lifespan of the light emitting source, abnormalities in the voltage applied to the light emitting source, and the like. Therefore, by detecting the amount of light from the light emitting source, the number of retries can be variably controlled in accordance with the detected value.

FIG. 5 is a block diagram for explaining still another embodiment of the present invention. In this embodiment, a plurality of detectors are provided in the same device, and the number of retries is variably controlled based on the detection values from these detectors. In the figure, a temperature detector 55, a light amount detector 5
6. The humidity detectors 57 are installed at locations within the same device that are easily affected by temperature, light intensity, humidity, etc.
Of course, if there are many locations within the same device that are easily affected by temperature, or if only the influence of temperature can be considered, an appropriate number of the above-mentioned detectors may be installed. Detected values from these detectors 55, 56, 57 are sent to converters 58, 59, 60, respectively.
Note that for the detected analog quantity, it is necessary to convert it from analog to digital before sending it to the converter. Converter 58, 59, 6
0 is provided with a conversion table for converting each detected value into the number of retries. Transducer 58 converts temperature/
The converter 59 converts the number of retries, and the converter 59 converts the amount of light/
The converter 60 converts the number of retries and converts the humidity/
The number of retries is converted respectively. converter 58,5
The retry counts output from 9 and 60 are set in corresponding registers 61, 62, and 63, respectively. The maximum value detection circuit 64 detects the maximum value among the contents of the registers 61, 62, and 63. This detection circuit 64 can be easily constructed using a known logical combinational circuit. The maximum number of retries detected by the detection circuit 64 is set in the register 65. The number of retries set in register 65 is read out as signal 34 by initial start signal 35, and is set in retry counter 26 in FIG. 2 via AND gate 25. Note that the other configurations and operations are the same as those shown in FIG. 2, so explanations will be omitted.

According to such an embodiment, it is possible to set the number of retries according to the worst environmental condition within the same device, and it is possible to improve the operating rate of the device as a whole.

Although several embodiments of the present invention have been described above, it will be obvious that the present invention can be implemented with various modifications without departing from the spirit of the present invention. For example, in the second embodiment described above, it has been stated that the time measurement operation is started in response to a power-on signal. However, information processing equipment installed in a designated location is generally prone to malfunctions in the early stages of operation, so the number of retries is set to a large number for a designated number of months or several days after the equipment starts operating. It is easy to configure the conversion means so that it gradually decreases after a period of time has elapsed. This can be easily achieved using a timer included in the information processing device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a specific example of the present invention implemented in a floppy disk device, and FIG. 2 is a block diagram for explaining the setting of the number of retries and the retry operation in the floppy disk device.
FIG. 3 is a block diagram for explaining an embodiment in which the number of retries is set according to the passage of time, FIG. 4 is a diagram showing details of the converter in FIG. 2, and FIG. FIG. Explanation of symbols: 1... Disk control unit, 2... Disk drive unit, 3... Floppy disk, 5... Retry setting circuit, 6... Temperature detector, 26... Retry counter, 42... Error detector.

Claims (1)

[Scope of Claims] 1. In an information processing device that, when an error is detected, determines the number of retries based on physical variables that change the frequency of occurrence of the error and performs a retry, physical quantity/retry number converting means for setting the number of retries corresponding to the physical quantity detected by the detecting means, and setting the number of retries derived from the converting means. 1. A retry control method comprising a retry counter, and when an error is detected in the information processing device, retrying is performed at most up to the number of times set in the retry counter. 2. The physical quantity/retry number conversion means sets upper and lower limits of physical variables that can be determined based on the rating of the information processing device, and the physical variables detected by the detection means correspond to the upper and lower limits of the physical variables. 2. The retry control method according to claim 1, wherein the retry control method is configured to increase the number of retries only when the number of retries is outside an upper limit or a lower limit. 3. The physical variables are temperatures that fluctuate under environmental conditions that cause errors in the information processing device, and the detection means includes a temperature detector and a temperature sensor that detects the temperature under which the information processing device operates most appropriately. 2. The retry system according to claim 2, further comprising means for determining a difference between the temperature detected by the temperature detector, and the converting means having a conversion table of temperature difference/number of retries. Trial control method. 4. The retry control method according to claim 3, wherein the conversion table is set such that the number of retries increases as the temperature difference increases. 5. The physical variables are temporal variables that cause errors in the information processing device, the detection means has a time counter that counts the temporal variables, and the conversion means has a time counter that counts the time variables. 3. The retry control system according to claim 2, further comprising a time/retry count conversion table corresponding to the value. 6. The time counter starts counting operation at the same time as the information processing device is powered on, and the conversion table increases the number of retries immediately after the power is turned on, and then gradually decreases the number of retries as time passes, 6. The retry control method according to claim 5, wherein the number of retries is set to be constant thereafter.