JPS6226054B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a data transfer system, and more particularly to a high-speed and highly reliable data transfer system between a channel control device and an input/output control device.

[Prior art]

Data transfer between conventional channel controllers and input/output controllers is accomplished using bus signals called BUSOUT and BUSIN and tag signals called TAGOUT and TAGIN. Here, the bus signal is a group of signal lines necessary to transfer n bytes (n>1) of data, and the tag signal is
This is a signal line that indicates the validity of data on the bus line and serves as a response signal for data transmission and reception.

FIG. 1 is a diagram showing the flow of data in a conventional data transfer system and the flow of TAGIN and TAGOUT signals, and FIG. 2 is a time chart showing the relationship between conventional tag signals and bus signals.

In Figure 1, CH is a channel control device,
IOC is an input/output controller. Also, Figure 2a is for read data transfer, and Figure 2b is for write data transfer.
Each case of data transfer is shown. In the case of the read data transfer shown in FIG. 2a, the data indicated by the TAGIN signal .
, data D1, data D2, data D3, etc. are output on BUSIN and transferred from the input/output control device IOC to the channel control device CH. When the channel control device CH recognizes the TAGIN signal transferred from these input/output control devices IOC, it inputs the data on BUSIN to CBIB (channel bus in buffer) 2 and
TAGOUT generation circuit 3 outputs TAGOUT signals (1) (2) (3)... in response to each TAGIN signal,
Reports receipt of data to the input/output controller IOC. In this case, there is no data on BUSOUT and it is in an unused state NU.

In the case of write data transfer in Figure 2b, the input/output controller IOC
The TAGIN generation circuit 8 outputs the TAGIN signal... In this case, there is no data on BUSIN and it is in an unused state NU. When the channel control device CH recognizes the TAGIN signal transferred from the input/output control device IOC, it writes write data D.
1, D2, D3... are input to CBOB (channel bus out buffer) 1, TAGOUT generation circuit 3 outputs TAGOUT signals (1)(2)(3)...,
Data D1, D2, D3... indicated by TAGOUT signal
... is output from CBOB1 to BUSOUT and transferred to the input/output controller IOC.

In the above transfer method, the TAGIN signal and
There are two ways to respond to the TAGOUT signal. One is used for relatively low-speed data transfer, and is used to transfer data D1 from the input/output controller IOC.
In response to the TAGIN signal, the channel controller CH
Responds with TAGOUT signal (1) and input/output controller IOC
This is an interlock system in which the TAGIN signal and the TAGOUT signal are interlocked, in which the TAGOUT signal that is the response to the data D1 is checked and the TAGIN signal for the data D2 is output. Data D2...
TAGOUT signal which is a response signal from channel control device CH to output TAGIN signal...
This is a so-called non-interlock method that performs (1), (2)... without checking, and is used for relatively high-speed data transfer.

In the above transfer method, the reliability of transferred data is improved by interlocking the TAGIN signal and TAGOUT signal to ensure data transmission and reception, and by performing a parity check on the bus signal. However, as data transfer speeds increase, this is achieved by sacrificing the interlock method, which has the disadvantage that the reliability of transferred data will decline as data transfer speeds increase in the future. There is.

[Purpose of the invention]

An object of the present invention is to provide a high-speed and highly reliable data transfer method by checking whether transferred data has been correctly received without increasing the time required for data transfer. .

[Summary of the invention]

The data transfer method of the present invention is a data transfer method that transfers unidirectional data using two data buses and TAGIN and TAGOUT control signal lines. - An encoding circuit that generates a byte and a decoding circuit that checks data using the check byte are provided, and the received data is transferred back to the transmitting side via the unused bus of the two data buses mentioned above. This feature allows the transmission side to check the transferred data.

[Embodiments of the invention]

FIG. 3 is a block diagram of a data transfer system showing an embodiment of the present invention.

The present invention focuses on the fact that data reliability can be significantly improved by comparing the data transferred from the transmitting side and the data received at the receiving side. However, in order to compare the transferred data with the received data, the receiving side needs to send the data back to the sending side. Therefore, among the two data buses BUSIN and BUSOUT, during read data transfer in Figure 2a,
BUSOUT becomes an unused NU, and BUSIN becomes an unused NU during the write data transfer in Figure 2b. In other words, the bus signal actually used for data transfer is only one of BUSOUT or BUSIN, and the other Note that one of the two is not used. That is, in the present invention, by using the unused bus, the received data is returned, and the transmitted data is compared with the returned data on the transmitting side, thereby improving the reliability of the data. Since data is returned using another unused bus during normal data transfer, parallel operation of transfer and return is possible, eliminating the need for the time required for return and increasing the data transfer speed. has no effect on the

As shown in FIG. 3, the difference in the transfer system of the present invention from the conventional one is that new encoding circuits 4 and 9 and decoding circuits 5 and 10 are newly added to both the channel control device CH and the input/output control device IOC, respectively. In addition to providing a control signal line (RETURN TAG) on the transmission path.
and increased data transfer buses within both control units CH and IOC. In the figure, double lines are data buses, and one solid line is a control line.

First, in the case of read data transfer, the TAGIN signal generation circuit 8 of the input/output control device IOC
The TAGIN signal is sent out, and data synchronized with it is sent from IBIB (input/output bus-in buffer) 7.
Channel controller CH transferred on BUSIN
Incorporated into CBIB (Channel Bus-in-Bass) 2.

In the present invention, this data is
At the same time, the output of CBIB2 is taken into CBOB (channel bus-out buffer) 1, and the TAGOUT signal is output as a response signal to the TAGIN signal.
The data of CBOB1 is output on BUSOUT and sent back to the input/output controller IOC. input/output control device
When the IOC outputs data from IBIB (input/output bus-in buffer) 7 to BUSIN, the data is input to encoding circuit 9, where a check byte is generated. In addition, the channel control device CH
The data returned from the IOIB (input/output bus-out buffer) 6 is input to the decoding circuit 10 at the same time. The above operations are continued until the data transfer is completed. When the transfer is completed, the check byte generated by the encoding circuit 9 is input to the decoding circuit 10, and the channel control device
Compare with the data sent back from CH and error ER
Detect.

Next, in the case of write data transfer, a request for write data is made from the input/output control unit IOC using TAGIN. In response to the request, the channel controller CH sends the data indicated by the TAGOUT signal.
Output on BUSOUT and transfer to I/O controller IOC. The input/output controller IOC imports the transferred data into IBOB6 and at the same time
The data of IBIB7 is input to BUSIN at RETURMTAG which is fetched into 7 and outputted by TAGIN generation circuit 8.
and sends it back to the channel control device CH.
Hereinafter, the checking method is the same as in the case of read data transfer, except that the device that performs the check is the channel control device CH.

FIG. 4 is a time chart showing the relationship between transferred data and returned data. In the case of read data transfer shown in Figure 4a, the input/output controller IOC
Data D1, data D2, data D3, . . . indicated by TAGIN, . . . are output on BUSIN and transferred to the channel control device CH. In response to these TAGIN signals, the channel controller CH
At the same time as outputting TAGOUT(1), (2), (3)...
It outputs return data D1, data D2, data D3, etc. on BUSOUT, and returns the data to the input/output control device IOC. Next, in the case of the write data shown in Figure 4b, TAGIN from the input/output controller IOC
In response to the signals,,..., the channel control device CH outputs the transfer data D1, D2, D3... indicated by the TAGOUT signals (1), (2), (3)... onto the BUSOUT, and Transfer to control device IOC. The input/output control device IOC transfers data D1, D2, D3...
When you receive it, RETURN TAG,,...
Return data D1, D2, D3... shown in
Output on BUSIN and send data back to channel controller CH.

Furthermore, as is clear from Fig. 4b, the light
In the case of data transfer, the TAGIN signal line is first used to request write data from the input/output controller IOC, and in parallel, the channel controller
Since a TAG signal line is required to return the transfer data from the CH, a new RETURN TAG line will be added. In the case of read data transfer, the transfer data from the input/output control device IOC is simply returned, and there is no need to send control signals from the channel control device CH in advance, so the same number of transfers as before
A TAG signal line is sufficient.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to check whether transferred data has been correctly received without increasing the time required for data transfer, thereby achieving high-speed and highly reliable data transfer. becomes possible. In the embodiment, a data transfer system between a channel control device and an input/output control device has been described as an example, but the present invention is not limited to this case, and can be applied between a computer and a terminal device, between terminal devices, etc. , is applicable to all data transfer systems that meet the same conditions.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional data transfer system, FIG. 2 is a time chart of the data transfer operation in FIG. 1, FIG. 3 is a block diagram of a data transfer system showing an embodiment of the present invention, and FIG. 4 is a time chart of the data transfer operation in FIG. 3. 1: Channel bus out buffer (CBOB), 2: Channel bus in buffer (CBIB), 3: TAGOUT generation circuit, 4, 9: Encoding circuit, 5, 10: Decoding circuit, 6: Input/output bus out - Buffer (IBOB), 7: Input/output bus-in buffer (IBIB), 8: TAGIN generation circuit.

Claims (1)

[Claims] 1. Two data buses, TAGIN, TAGOUT
In a data transfer method that performs unidirectional data transfer using the control signal line of A decoding circuit that checks the transferred data is provided, and the received data is transferred back to the transmitting side via the unused bus of the two data buses, so that the transmitted data can be checked on the transmitting side. A data transfer method characterized by: 2. Claim 1, characterized in that when a request for transfer data is first made from the receiving side to the transmitting side, a RETURN TAG signal line for data return is provided in addition to the TAGIN signal line. data transfer method.