JPH07104821B2 - Data transfer control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] Regarding data transfer control of a system in which a channel device and an input / output control device are connected by a serial interface, a notification from the channel device to the input / output device when a data error occurs, For the purpose of smooth and speedy retry processing when the completion report from the I / O controller causes a time lag, the channel device should not have data that is invalid for the I / O controller. When the data transfer completion report is received after the notification, the data transfer completion report is held for a certain period of time, and means for notifying again that the data is invalid is provided, and the input / output control device is provided. , When a notification that the data is invalid is received within a certain time after the completion of the data transfer to the channel device, the data transfer to the channel device is notified. It is configured by providing means for making a retry request.

The present invention relates to a serial interface in which a channel device and an input / output control device transfer data from the channel device to the input / output control device, and a data transfer from the input / output control device to the channel device. The present invention relates to control of data transfer in a system connected by a serial interface and a pair of serial interfaces, and particularly, detection of an error occurring when data is transferred from the input / output control device to the channel device. The present invention relates to a control method capable of promptly performing control related to the retry of the data transfer without depending on the OS.

[Prior Art] In a so-called parallel data transfer system in which a channel device and an input / output control device are connected by a bus for data transfer and a tag line for control, a control signal on the tag line is Since the data on the bus is controlled by the exchange, the I / O control device side can know whether the data sent to the channel device has been correctly transferred or not relatively early, and the data can be transferred correctly. If it was detected that it was not, it was possible to request the channel device to retry the data transfer. On the other hand, conventionally,
In a system in which the channel device and the I / O controller are connected by a serial interface, there is no means on the channel device side to notify the I / O controller even if this is detected. Therefore, the data transfer reported by the channel device The end result is the OS
First found out that the data was inconvenient and based on this, the OS instructed the I / O device to retry, so the processing when a data error occurred during transfer was very slow. There was a problem of becoming. Therefore, as a method to solve such problems,
The channel device is provided with means for monitoring the legitimacy of data, and when invalid data is detected by the means, this is notified to the input / output control device, and the input / output control device performs data transfer based on this. A technique has been proposed in which the reliability of data transfer can be improved by requesting the channel controller to issue a retry command.

FIG. 3 is a diagram provided to explain the retry of data transfer in the case of such a conventional serial interface, in which 51 is a channel device, 52 is an input / output control device, and 53-
55 is an input / output device, 56 is a data check unit, 57 is a command analysis unit, 58 is a status information generation unit, 59 is a serial interface optical cable for transferring data from the channel device to the input / output control device, and 60 is from the input / output control device. Fig. 3 represents a serial interface optical cable that transfers data to a channel device.

In the figure, when data is transferred from the input / output control device 2 to the channel device 1 and the data check unit 56 detects invalid data, the channel null device 51 reads the input / output control device 52. If the data is invalid, a data invalid command (DER) is issued.

Upon receipt of this, the input / output control unit 52 analyzes the command by the command analysis unit 57, and when it knows that it is a data illegal command, it immediately stops the data transfer, and the status information generation unit 58.
The end status information is generated and reported to the channel device 51, and a retry request is made in the end status information.

Upon receiving this retry request, the channel device 51 instructs the I / O controller 52 to retry the data transfer. All of these operations are performed between the channel device and the input / output control device, and are performed quickly without depending on the OS of the host computer.

[Problems to be Solved by the Invention] Although the conventional serial data transfer system as described above can perform very efficient control in normal operation, when the channel device issues a data illegal command, If it happens that the data transfer operation of the input / output control device is about to end, it is assumed that the data transfer has been normally performed before the input / output control device receives the illegal data command. May be done.

In this way, if the data illegal command from the channel device side and the end status report from the I / O controller side have passed each other, the retry is naturally made in the end status report from the I / O controller. Will not be fulfilled.

In such a case, the channel device has to rely on the control program (OS) of the host computer for the process related to the retry of the data, which causes a burden on the OS and slows down the process. There was a problem.

According to the present invention, even when the data illegal command issued by the channel device and the end status report of the input / output control device pass each other as described above, the hardware detects this early and retries. It is possible to provide a control method that does not impose a burden on the OS of the host computer.

[Means for Solving the Problems] According to the present invention, the above-mentioned object is achieved by the means described in the claims. That is, the present invention is
The channel device and the input / output control device are configured to send and receive control information and data using a pair of serial interfaces, and means for monitoring the validity of the data sent from the input / output control device to the channel device. , When the data is detected to be invalid by the means, the means for notifying the input / output control device of this is provided, while the channel device is notified when the input / output control device receives the notification. In a data transfer control system provided with means for requesting a retry of data transfer, after the channel device is notified to the input / output control device that the data is invalid, the data transfer is completed from the input / output control device. When the report is received, the data transfer completion report is held for a certain period of time and the I / O controller is again notified that the data is invalid. In addition to providing the means, when the input / output control device receives a notification from the channel device that the data is invalid within a certain time after the completion of the data transfer report to the channel device, the data is sent to the channel device. This is a data transfer control system provided with means for making a transfer retry request.

[Operation] According to the above means, when the channel device notifies the input / output control device that the data is not valid, the input / output device normally performs the data transfer before receiving the notification. Even when the status report as a thing is made (when the passing occurs), the data transfer can be surely retried.

That is, when the channel device notifies the I / O control device that the data is invalid, but when the I / O control device issues a data transfer completion report, the report is held. Then, the input / output control device is notified again that the data is invalid.

On the other hand, the I / O device sends a data transfer retry request to the channel device after receiving a data transfer completion report from the channel device within a certain period of time. Do.

In the control described above, there is no difference in the interface between the channel device and the input / output control device.
Retry of data transfer can be reliably performed.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention.
1 is a channel device, 2 is an input / output control device, 3 to 5 are input / output devices, 6 is a data check unit, 7 is a state information analysis unit,
8 is a control unit of the channel device, 9 is a serial interface optical cable for transferring data from the channel device to the input / output control device, 10 is a serial interface optical cable for transferring data from the input / output control device to the channel device, 11 is a command analysis unit, Reference numeral 12 represents a state information generation unit, 13 represents a control unit of the input / output control device, and 14 represents a timer.

In the figure, when data is transferred from the input / output control device 2 to the channel device 1 and the data check unit 6 detects invalid data, the control unit 8 of the channel device 1 causes the input / output control device 2 to operate. If the read data is invalid, the data invalid command (DER) is sent.

Upon receipt of this, the input / output control unit 2 analyzes the command by the command analysis unit 7 and when it knows that it is a data illegal command, it immediately stops the data transfer and the state information generation unit 12
The end status information is generated and reported to the channel device 1, and a retry request is made therein.

When the channel device 1 receives this retry request, it instructs the input / output control device 2 to retry the data transfer.

As a result, the data is transferred again.

If the channel device issues an invalid data command because the data sent from the I / O device 2 is invalid, a passing request will occur and a retry request will be issued with the end status information from the I / O device side. If not,
The control unit 8 holds the end state information and issues the data invalid command again to the input / output control device 2.

On the other hand, when the control unit 13 of the input / output control device 2 reports the completion of data transfer to the channel device 1 by the end state information, it sets the timer 14 and waits, and again within a predetermined time. When a data illegal command is sent from the channel device 1, the state information generation unit 2 generates end state information including a data transfer retry request and reports it to the channel device 1. When the channel device 1 receives this request for trial, it instructs the input / output control device 2 to retry data transfer.

FIG. 2 shows an example of the operation of this embodiment as a time chart. In the figure, (a) shows a normal case,
(B) shows a case where an illegal command from the channel device side of the end state information from the input / output control device side has passed.

[Effects of the Invention] As described above, according to the present invention, when the channel device receives data from the input / output control device, when an error is detected, an invalid data command is automatically issued and the input / output control device is issued. Since a retry request is issued to the host computer and the retry is performed based on this request, efficient data transfer can be performed without burdening the OS of the host computer.

Then, especially when the data illegal command is issued from the channel device, the input / output device accidentally reports that the data transfer is normally completed before the data illegal command is received, Even when the information passes each other, there is an advantage that data transfer can be automatically retried between the channel device and the input / output device without imposing any burden on the OS of the host computer.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a time chart showing an example of the operation of the embodiment of the present invention, and FIG. 3 is an explanation of data transfer retry by a conventional serial interface. FIG. 1 ... Channel device, 2 ... Input / output control device, 3-5 ...
... I / O device, 6 ... Data check unit, 7 ... Status information analysis unit, 8 ... Channel device control unit, 9 ... Serial interface optical cable for transferring data from the channel device to the I / O control device, 10 ... … Serial interface optical cable that transfers data from I / O controller to channel device, 11 …… Command analysis unit, 12 …… State information generation unit,
13 …… Control unit of input / output control device, 14 …… Timer

Claims (1)

[Claims] 1. A structure in which a channel device and an input / output control device transmit and receive control information and data using a pair of serial interfaces, and the validity of data sent from the input / output control device to the channel device. And a means for notifying the input / output control device of the fact that the data detects that the data is invalid, while the input / output control device receives the notification. In a data transfer control system provided with means for requesting a retry of data transfer to a channel device, after notifying the channel device that the data is invalid, the input / output control When the data transfer completion report is received from the device, the data transfer completion report is held for a certain period of time and the data is invalid again to the input / output control device. In addition to providing a means for notifying that, when the I / O control device receives a notification from the channel device that the data is invalid within a certain time after reporting the completion of data transfer to the channel device, A data transfer control method characterized in that means for requesting a retry of data transfer to the device is provided.