JPH0683226B2 - Information transfer control method - Google Patents

Description

DETAILED DESCRIPTION [Table of Contents] Outline Industrial field of application Conventional techniques and problems to be solved by the invention Means for solving problems Problems Working Example Effect of the invention [Outline] A plurality of devices Group, and an information transfer control method by a polling method between a control device for controlling the device group, even if there is a device in a power-off state among a plurality of device groups For the purpose of avoiding the situation that the processing for the device has been waiting for a long time, means for monitoring the time until the status response from each device in response to the status inspection command (polling command) from the control device, Means for monitoring the response to the input / output command from the control device, and means for storing, for each device, that the polling command issued to the device last timed out are provided. , For devices that show an excess (timeout) to the above response monitoring,
When the control device detects that there is an input / output request from the host device to the device, it issues the polling command before issuing the input / output command, and detects a timeout again. Is configured to suppress the issuance of the input / output command.

[Industrial application field]

The present invention relates to an information transfer system between a plurality of device groups and a control device for controlling the device groups, and in particular, the device status is a status check command (polling command) from the control device.
The present invention relates to an information transfer control method in a communication mode in which a response from a device is provided, that is, a communication mode having no function of interrupting each device to a control device.

With the recent diversification of data processing by computer systems and the increase in processing volume, the number of input / output devices connected to the computer system is increasing, and all the input / output devices are powered on. I'm getting less and less.

When data is transferred between the plurality of input / output device groups and a control device for controlling the input / output device groups by the polling method, a power supply is provided in the plurality of input / output device groups. If there are mixed input / output devices that have not been turned on, a timeout will occur if an input / output command is issued to the input / output devices that have not been turned on from the host information processing device, for example. During that time, the control device cannot perform processing for other input / output devices, and there is an adverse effect that the response of other operating input / output devices deteriorates due to the device that is not originally malfunctioning. There is a need for an information transfer control method that does not deteriorate the responsiveness of a device in operation even if the device exists.

[Problems to be solved by conventional technology and invention]

FIG. 4 is a diagram showing a configuration example of a polling type information processing system.

In the figure, 1 is an information processing device, 2 is a control device, and 31
~ 3n are input / output devices.

As the input / output device, for example, a display device,
Alternatively, there is a printer device.

The control device 2 and each of the input / output devices 31 to 3n are connected to each other by a coaxial cable, and communication between the control device 1 and the input / output devices 31 to 3n is performed from the control device 1. The input / output devices 31 to 3n respond to the command of.

For example, when the attention key is pressed on the display device, no interrupt is generated from the display device to the control device 2, and the event is held in the display device.

Then, when the display device receives the polling command from the control device 2, the display device reports "holding attention" in the status information notified as the response.

FIG. 5 is an operation time chart in the polling type information processing system.

(A) of the figure shows that the control device 2 sequentially issues a polling command to the input / output devices (hereinafter sometimes simply referred to as devices) 31 to 3n in order to inspect their states. It is the figure which has shown. Here, “Idle” indicates a “vacant” time during which the control device 2 is not performing the polling process.

In the figure, 41 indicates the time from the transmission of the polling command to the device 31 to the status response from the device 31 to the command.

During this time, the control device 2 is dedicated to the processing relating to the device 31.

Similarly, 42 is a controller 2 for polling device 32.
4n is the time when the control device 2 is used for polling the device 3n.

As described above, the control device 2 sequentially performs the polling operation such as the polling of the first device 31, the polling of the second device 32, and so on. After the polling operation of the nth device,
The polling of the first device 31 is performed again.

Normally, polling commands are short-time (1 to 2 ms)
Then, the control device 2 waits for a response for a maximum of several ms. If no response is reported from the input / output device even after the waiting time has elapsed, the control device 2
Then, the command timeout is recognized, and the polling for the next I / O device is started.

FIG. 9B shows a time chart when a write command is issued from the control device 2 to the input / output devices 31 to 3n.

While the above polling operation is activated by a timer mechanism (not shown) inside the control device 2, normally, the write operation and the read operation are performed in response to a request from the information processing device 1 shown in FIG. As a result, it is transmitted from the control device 2 to the lower input / output devices 31 to 3n.

In some cases, like the screen data copy from the display device to the printer device, the write operation and the read operation from the control device 2 are performed without a request from the information processing device 1.

In the figure (b), while the control device 2 repeats the boring operation, a factor of the write operation occurs and the device 32
It shows how to send a write command to.

In the figure, reference numeral 52 designates a device that has transmitted a write command to the device 32, and has undergone a write command process on the device 32 side (display of screen data, fetching process to a buffer inside the device, etc.).
The time from 32 to the status response to the control device 2 is shown.

In this figure, transmission of a write command to the device 32
Although the polling operation is performed after 4n, the write operation and the read operation do not have to be performed only at the break of the polling operation. For example, the polling operation 41 to the device 31 and the polling operation to the device 32 are performed. Between 42 and
The above write operation and read operation can be performed.

The write command and the read command require much longer time (tens to hundreds of ms) than the polling command. Then, while the write command or the read command is being executed (from the transmission of the command until the status response from the device 32 is reported), the control device 2 waits for other devices until the operation of the device 32 is completed. The command cannot be issued.

Here, consider a case where an input / output device is in a power-off state. In this case, in response to the command from the controller 2,
The I / O device cannot respond and the command from the control device 2 to the I / O device times out.

As described above, the situation in which the input / output device does not respond to the command from the control device 2 is not limited to the failure of the input / output device itself, and the power of the device is not turned on. It can happen even when it is not abnormal.

From when the command is sent to the device in the power-off state until it is recognized that the command has timed out,
The control device 2 cannot perform processing for other input / output devices.

Therefore, when there is an input / output device in a power-off state, there is an adverse effect that the responsiveness of the operating input / output device deteriorates.

The output operation from the information processing device 1 to the input / output devices 31 to 3n may be caused by the input operation from the input / output devices 31 to 3n or may be caused by the occurrence of a specific event in the information processing device 1. .

In the latter case, an output request is issued to the input / output device in the power-off state.

In this case, in the conventional method, when an output request is issued from the information processing device 1, the control device 2 controls the input / output devices 31 to 3n.
, Immediately issued a write command.

FIG. 6C is a time chart showing the operation when the output request from the information processing device 1 is issued in a state in which the input / output device is powered off and a state in which the input / output device is powered on. It is a chart.

In the figure, 60 indicates a normal polling operation when the input / output device is in a power-on state, that is, when it can respond to a command from the control device 2, and 61 indicates a polling operation when the device is in a power-off state. However, there is a feature that the polling cycle is longer than the normal polling operation 60 described above. As described above, normally, the control device 2 stores the number of the input / output device that has timed out for the issued command, and performs control such that the polling cycle for the input / output device is lengthened. There is.

Reference numeral 62 indicates a write operation when the power of the input / output device is on, and reference numeral 63 indicates a write operation when the power of the input / output device is off.

If the input / output device is in the power-off state, the write command will time out. As aforementioned,
Write commands and read commands require much longer than polling commands, and usually require several hundred ms (see 62 in this figure). Therefore, the timeout monitoring time for write commands and read commands is set to several seconds (see 63 in this figure).

Therefore, when the write command is issued to the device in the power-off state, the control device 2 is occupied for that device for several seconds, and the processing for the device in the other operating state is not executed. As described above, there is a problem that the responsiveness to the operating input / output device deteriorates.

In view of the above-mentioned conventional drawbacks, the present invention includes an apparatus in a power-off state in an information processing system that uses a polling method to control information transfer between a plurality of apparatuses and a control apparatus that controls the apparatuses. Even in such a case, it is an object of the present invention to provide an information transfer control method that avoids a situation in which a process for another operating device has to wait for a long time.

[Means for solving problems]

FIG. 1 is a time chart showing the principle of the information transfer control system of the present invention.

In the present invention, one of a plurality of device groups is selected, and a state inspection command (polling command) sent from the control device to the device in order to inspect the state of the device; Is selected, the control device issues an input / output command for operating the device, and notifies the control device of a response to these commands from the device. A state inspection time excess detecting means for inspecting that there is no response from the device within a fixed time in response to the state inspection command, and detecting a response from the device within a fixed time in response to the input / output command An information transfer control method comprising: input / output time excess inspection means, and means for storing, for each device, that the command issued to the device lastly exceeds the monitoring time, Indicates that the monitoring time has been exceeded In the case 61,
When the control device detects that there is an input / output request to the device, prior to issuing the input / output command,
When the state inspection command is issued and the response to the state inspection command again indicates that the time is exceeded, the issue of the subsequently issued input / output command is suppressed.

[Action]

That is, according to the present invention, as shown in the time chart of FIG. 1, the control device is a device in a non-responsive state, that is,
Since the device which has detected the timeout 61 by the previous command is stored, when the output request to the device is recognized, the polling command 71 is issued prior to the issuance of the write command.

When the response from the device to the added polling command times out (indicated by 71 in the figure), the issuance of the write command is suppressed and the information processing device is notified of the abnormal end. .

The I / O device in the non-responsive state responds to the polling command issuance 'prior to the issuance of the write command.
When the normal response is returned (indicated by 70 in the figure), the write command 62 is subsequently issued.

By controlling in this way, the time when the control device is occupied by the output request to the device in the power-off state is much shorter than the time-out time of the write command (that is, the polling command time-out monitoring time). can do.

Therefore, in the present invention, in response to the output request to the device in the non-responsive state, by issuing the polling command which requires a much shorter time-out monitoring time than the write command, the power-off state Even if there is a device, there is an effect that it is possible to avoid waiting for a long time for processing for a device that is in operation.

〔Example〕

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

The above-mentioned FIG. 1 is a time chart showing the principle of the information transfer control system of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 9 is a flow chart of output processing, which is steps 91 and 9 in FIG.
2,93 are the means necessary to carry out the present invention. The same reference numerals denote the same objects throughout the drawings.

The information transfer control method of the present invention will be described below with reference to FIGS.

First, the timer processing unit 20 in the control device 2
It is activated by a timer mechanism (not shown) inside and activates the polling processing unit 22.

The activated polling processing unit 22 determines a device to execute the polling operation next, generates a polling command, passes the command to the command executing unit 25, and then enters a waiting state.

The information passed from the polling processing unit 22 to the command execution unit 25 includes the device number of the transmission destination and the timeout monitoring time value of the command in addition to the command to be transmitted.

The command execution unit 25 that has received the polling command transmits the polling command to the designated devices 31 to 3n and waits for the reception of the status response from the destination devices 31 to 3n.

Then, when there is a status response from the device within the timeout monitoring time instructed by the polling processing unit 22, the command executing unit 25 notifies the polling processing unit 22 of the status information received from the device.

The polling processing unit 22 that has received the status information indicates that the device is in a state in which it can respond normally.
23, further, in the received status information,
Check whether there is a processing request from the device side.

In this inspection, if there is a request from the device side, the input / output processing unit 21 is activated. The input / output processing unit 21 that has received the processing request from the device, according to the content of the processing request,
Attention notification to the higher-level information processing apparatus 1 and input / output processing for the request source apparatus or another apparatus are performed.

In response to the execution of the polling command from the polling processing unit 22, if the response from the device is not obtained within the time-out monitoring time, the command execution unit 25 regards it as a command time-out to the polling processing unit 22 which is the request source. Notice.

Polling processing unit notified of the command timeout
The unit 22 stores in the unit state storage unit 23 that the unit requires operator intervention.

Next, in the information processing device 1 or the control device 2, a device
The operation when an input / output request for 31 to 3n is generated will be described.

The input / output request is recognized by the input / output processing unit 21 of the control device 2, and the protocol unit 24 is activated.

The protocol unit 24 inspects the device status in the device status storage unit 23 for the device instructed to perform the input / output operation. Then, when it is recognized that the device has normally returned a response, the protocol unit 24 converts the requested input / output request into a write command or a read command,
After handing over the command to the command execution unit 25, it enters a waiting state.

The information passed from the protocol unit 24 to the command execution unit 25 includes the device number of the transmission destination and the timeout monitoring time value of the command in addition to the command to be transmitted.

The command execution unit 25 sends a command to the designated devices 31 to 3n, and sends a status response from the devices 31 to 3n.
Alternatively, it waits for the reception of the data response.

Then, if there is a response from the device within the time-out monitoring time, the command execution unit 25 sends the status information or data received from the device to the protocol unit 24.
To notify.

In this case, the protocol unit 24 stores in the device state storage unit 23 that the device is in a state in which it can respond normally.

When the processing requested by the input / output processing unit 21 is completed, the protocol unit 24 notifies the input / output processing unit 21 of the processing result.

When the response is not obtained from the device within the timeout monitoring time instructed by the command execution request from the protocol unit 24, the command execution unit 25 notifies the requesting protocol unit 24 as a command timeout.

Protocol part 24 notified of the command timeout
Stores in the device state memory 23 that the device requires operator intervention.

Next, a method of processing an input / output request when the device is in a power-off state will be described with reference to FIG.

The protocol unit 24 activated by the input / output processing unit 21 checks the device status in the device status storage unit 23 for the device instructed to perform the input / output operation.

Then, when it is recognized that the device requires the intervention of the operator, the protocol unit 24 performs the polling operation prior to the issuance of the write command or the read command based on the requested input / output request. That is, the protocol unit 24 creates a polling command, passes the command to the command execution unit 25, and then enters a waiting state.

At this time, the information passed from the protocol unit 24 to the command execution unit 25 includes the device number of the transmission destination and the timeout monitoring time value of the polling operation in addition to the polling command.

Upon receiving the polling command, the command execution unit 25 sends the polling command to the designated device and waits for a status response from the device. And
When there is a status response from the device within the timeout monitoring time, the command executing unit 25 notifies the protocol unit 24 of the status information received from the device.

The protocol unit 24 that has received the status information stores in the device status storage unit 23 that the device is in a state in which it can respond normally, and shifts to the input / output processing requested by the input / output processing unit 21. The subsequent processing is the same as when the device status storage unit 23 recognizes the device as a normal response device. {Refer to the time charts 61, 70, 62 in FIG. 1} Even if there is a processing request from the device in the status notified by the polling operation, in the case of the present invention, the protocol section 24 uses this information. Ignore. Then, the processing request can be processed when the normal polling operation is performed by the polling processing unit 22 next time.

If the device does not respond to the polling operation performed by the protocol unit 24, the command processing unit 25
The protocol unit 24, which is the request source, is notified of the command timeout.

Protocol part 24 notified of the command timeout
Recognizes that the relevant device still requires operator intervention, and reports an abnormality to the input / output processing unit 21 without sending a write command or a read command to the device.
(Refer to the time charts 61 and 71 in FIG. 1) FIG. 3 shows a case where an output instruction is issued from the input / output processing unit 21.
7 is a flowchart of the process of the protocol unit 24.

The device specified by the protocol unit 24 is not responding, that is, it requires the intervention of the operator.
If is displayed in, send a polling command. (Refer to steps 91 to 93) However, in the case of command timeout, abnormal termination occurs as described above (step
93, 97).

Then, as described above, the write command is transmitted in the case of normal termination. (See step 94) As described above, according to the present invention, the state of each input / output device responds to the polling command from the control device controlling the input device, that is, from each input / output device to the control device. In the information transfer control method in the communication mode that does not have the interrupt function, when the control device issues a polling command to a specific input / output device and detects a command timeout, the state is stored in the device state storage unit. When an input / output request is issued from a higher-level information processing device or the like, a polling command is transmitted to the device and if a command timeout is detected again, a write command or read command for the input / output request is sent. The call is suppressed, but if the relevant device normally returns the status information, the input / output processing that received the request is started. Is characterized in Unishi was place.

〔The invention's effect〕

As described above in detail, the information transfer control method of the present invention includes means for monitoring the time until the status response from each device in response to the status check command (polling command) from the control device, and the control device. Means for monitoring the response to the input / output command from the device, and means for storing, for each device, that the polling command issued to the device last timed out, and the storage means responds to the response monitoring. For the device indicating the excess (timeout), the above polling command is issued prior to the issuance of the I / O command, and when the timeout is detected again, the issuance of the I / O command is suppressed. This is a policy that requires a much shorter timeout monitoring time than the write command for output requests to the device that was in the non-responsive state. By pre issuing Gukomando, even when the apparatus power-off state is present, the effect of avoiding the processing for the device in operation is kept waiting for a long time.

[Brief description of drawings]

FIG. 1 is a time chart showing the principle of the information transfer control system of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a flow chart of input / output processing according to the present invention. FIG. 4 is a diagram showing a configuration example of a polling method information processing system, and FIG. 5 is an operation time chart in the polling method information processing system. In the drawings, 1 is an information processing device, 2 is a control device, 20 is a timer processing unit, 21 is an input / output processing unit, 22 is a polling processing unit, 23 is a device state storage unit, 24 is a protocol unit, and 25 is a command execution unit. , 31 to 3n are input / output devices, or devices, 41 to 4n are times when the control device 2 is occupied by the devices 31 to 3n by the polling command, 52 is time when the control device 2 is occupied by the device by the write command, 60 is the polling operation when the device is in the power-on state, 61 is the polling operation when the device is in the power-off state, 62 is the write operation when the device is in the power-on state, 63 is the device is in the power-off state A write operation in a certain case, 70 and 71 indicate a polling operation according to the present invention, and 90 to 97 indicate processing steps.

Claims (1)

[Claims] 1. A plurality of device groups (31 to 3n), a state inspection command for inspecting the states of the device groups (31 to 3n), and the device group (31 to 3n) operation following the state inspection command. An information transfer control method, comprising: a control device (2) that issues an input / output command to cause the device group (31-3n) to notify the control device (2) of a response to the state inspection command. The control device (2) detects a state inspection time excess detecting unit that detects that there is no response from the device group (31 to 3n) to the state inspection command within a certain time, and the state inspection time excess unit. Detected by the device (31 ~
3n) is stored in the storage means (23), and when the input / output request from the host device is detected, the storage means (23) causes the device group (31 to 3n) to exceed the inspection time. If it indicates that the status check command is issued () before the input / output command is issued, and if the device group (31 to 3n) exceeds the test time, An information transfer control method characterized in that the input / output command issued subsequently is suppressed ().