JPS605026B2 - input/output control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an input/output control system, particularly an input/output control device, with a data buffer to perform data transfer, and, for example, with respect to a write operation to an input/output device.
When the data has been transferred from the channel side to the data buffer, the channel end and device end are reported and connected to the channel without waiting for the data to be transferred from the data buffer to the input/output device. Improved the difficulty of the input/output control system that was designed to solve the problem, and issued the device end after waiting for the data to be transferred to the input/output device for the last command regarding command chained processing. The present invention relates to an input/output control system that can effectively report errors during data transfer to input/output devices.

In a relatively slow I/O control system, the data transfer capacity between the channel and the I/O control device is
The data transfer capacity between the input/output controller and the input/output device is small. For this reason, a data buffer is provided in the input/output control device to absorb the difference. On the other hand, the end status of a data transfer command has traditionally been defined as channel end and device end. For example, when writing to an input/output device, data is received from the channel side into the data buffer. It becomes the channel end at the stage,
The device ends when the data has been transferred from the data buffer to the input/output device. but,
As will be described later with reference to Figures 2A and B, if multiple input/output control devices are subordinate to a channel, the connection between one input/output control device and the channel should be released early. In order to enable the channel to control other input/output control devices, the channel end and device end are are to be reported.

In such an input/output control system, if an error occurs while actually transferring data to an input/output device, the device end is already reported as described above. It is extremely difficult to determine whether an error has occurred related to the command date.

The present invention aims to solve the above points,
For example, a process corresponding to a so-called disconnect command chain sequence such as a seek command related to disk control is performed regarding data transfer,
The purpose is to solve the above-mentioned difficulties.

Therefore, the input/output control system of the present invention includes a channel, a plurality of input/output control devices subordinated to the channel, and one or more input/output devices subordinated to each input/output control device, and In an input/output control system in which at least one input/output control device has a data buffer, a channel interface for said channel, and a buffer interface for said input/output device and is controlled by a stored program control unit, a data transfer command is provided. Reports the termination status of the data transfer based on the command chain, the corresponding channel end and the corresponding device end, and reports the end status of the data transfer based on the command chain. The last command of the transfer corresponds to reporting channel end upon receipt of data into said data buffer and reporting device end upon completion of transferring data to said input/output device; The stored program control unit is characterized in that the stored program control unit controls data transfer. This will be explained below with reference to the drawings. FIG. 1 is a system according to an embodiment of the present invention, FIGS. 2A, B, and C are explanatory diagrams explaining the prerequisite problems of the present invention and aspects of control according to the present invention, and FIG. 3 is an input/output used in the present invention. 1 shows an example configuration of a control device. In Figure 1, 1 is the channel, 2 - 0
, 2-1, . . . are input/output control devices, 3-0, respectively.
0, 3-01, . . . represent input/output devices, respectively. In a conventional system, for example, in a data write operation to the input/output device 3100',
When channel 1 captures controller 210 and transfers data to a data buffer within input/output controller 210,
The input/output controller 2-0 reports the channel end and buffer end to the channel, thereby causing the channel 1 to disconnect from the input/output controller 2-0 and transmit to other input/output controllers. While the input/output controller 210 is configured to transfer the contents of the data buffer to the input/output device 310.

This is because there is generally a difference in the data transfer ability between the channel and the input/output control device 2-i, and the data transfer ability between the input/output control device 2-i and the input/output device 3-ij. Related.

In other words, when data is transferred using a command chain, for example, as shown in Figure 2A, a channel end (CE) is issued when data is received from the channel, and when the data has been sent to the input/output device. This is because if a device end (OE) were issued, it would take a long time to transfer data through the command chain.
For this purpose, as shown in Figure 2B, the channel end (CE) and device end (DE) are reported together when data is received from the channel, and the connection with the channel is released early. Therefore, it can be considered that the input/output control device slowly transfers data to the input/output device later. However, in the case of this dependent method, although the channel has the great advantage of being able to control other input/output controllers, such as 2-1, at an early stage, If an error occurs when the input/output device 310 transfers the data later, the input/output control device 210 issues an input/output interrupt at this point and reports the error. However, it is extremely difficult for the upper level device including channel 1 to determine which command the error corresponds to.

This is because channel 1 has already received the device end report. In the case of the present invention, as shown in FIG.
and device end (DE), and for the last command, the channel end (CE) upon data receipt.
The end of the device is reported when the data transfer to the input/output device is completed.

This kind of control corresponds to the so-called disconnect command chain sequence, which has traditionally been used for disk control commands that involve mechanical operations on input/output devices, such as seek commands. .

In the present invention, it can be considered that such a sequence is applied to data transfer. For cheek-like control, channel end (CE)
From when DE is reported until the next device end (DE) arrives, channel 1 is, so to speak, "empty" and can control other input/output control devices. In this case, if an error occurs while transferring data to the input/output device, you can correctly and easily correct the error by raising the unit check together with the device end (DE). It becomes possible to make a report. FIG. 3 shows the configuration of an embodiment of the input/output control device used in the present invention.

The reference numeral 2 in the figure corresponds to that in FIG. 1, 4 is a stored program control unit, 5 is a channel interface sequence control unit, 6 is a data transfer control unit, 7 is a data buffer control unit, 9 represents a data buffer, 9 represents a data transfer control section, and 10 represents a device interface control section. Furthermore, the stored program control unit 4 clearly represents its control mode using a flowchart. The channel interface sequence control section 5 receives control from the control unit 4 and controls data transfer with the channel 1 shown in FIG.
Data transfer control units 6 and 9 similarly control data transfer from/to data buffer 6, respectively. The device interface control section 10 controls data transfer between the input/output devices 3100, 3101, . . . shown in FIG.
In the input/output control device of the present invention, as shown in the control unit 4 shown in FIG. 3, data transfer is performed as follows.

That is, [1' When a command corresponding to a write operation to an input/output device is received, the corresponding status is reported.

■ Then, the channel interface sequence control section 5, data transfer control section 6, and data buffer control section 7 receive the data into the data buffer 8,
Reports channel end (CE).

If there is a '31 command chain and the buffer is empty, data transfer is instructed from data buffer 8 to input/output device 3100, and route A
Reports the device end (DE) through.

{41 In response to the data transfer instruction, the data buffer control unit 7, data transfer control unit 9, and device interface control unit 10 control the input/output devices 3-00.
Data transfer is performed for.

{5} On the other hand, channel 1 issues the following command based on the device end (DE) corresponding to the above process 3''.

'6) Process a series of chained commands and, in case of the last command, similarly
However, since there is no command chain, it instructs data transfer to the input/output device via route B.

{7} If the data transfer to the input/output control system is successfully completed, report the device end (DE) via route C.

Shelf Then, the series of processing ends.

side If an error occurs in data transfer to the input/output device, the device end (D
Report the unit check along with E).

'10 Needless to say, when a unit check is reported, channel 1 examines the contents of the subchannel memory corresponding to I/O controller 210 and takes appropriate action.

As described above, according to the present invention, when a command chain does not exist regarding data transfer, a so-called disconnect command chain sequence processing mode is used to perform data transfer between input and output devices. In addition, if a command chain exists, the channel end and device end are immediately reported so that chained commands can be received.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the system of the present invention, Fig. 2 A, B, C
3 is an explanatory diagram for explaining the prerequisite problems of the present invention and aspects of control according to the present invention, and FIG. 3 shows the configuration of an embodiment of an input/output control device used in the present invention. In the figure, 1 is a channel, 2i is an input/output control device, 3i is
i is an input/output device, 4 is a stored program control unit, 5 is a channel interface sequence control unit, 6 and 9 are data transfer control units, 7 is a data buffer control unit, 8 is a data buffer, and 10 is a Represents a device interface control unit. 1 figure, 2 figures, 3 figures

Claims (1)

[Claims] 1 A channel, a plurality of input/output control devices subordinated to the channel, and one or more input/output devices subordinated to the input/output control device, the at least one input/output control device having a data buffer and A channel interface for the above channel and a device interface for the above input/output device are provided.
In an input/output control system controlled by a program control unit, the end status of a data transfer command is determined at the end of the channel and subsequently by the device in response to the beginning and intermediate commands of the data transfer based on the command chain.・Reports the end of the channel, and reports the end of the channel when data is received in the data buffer in response to the last command of the data transfer based on the command chain, and transfers the data to the input/output device. An input/output control system characterized in that the stored program control unit controls data transfer so as to report a device end when the data transfer is completed.