JPS627572B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an input/output control device for an information processing system, and particularly to an input/output device that can record the same data redundantly on different input/output devices.

In the past, it was not common to record the same information twice in two different input/output devices (for example, magnetic disk devices). Although this is partly due to the high cost, for example, in the case of magnetic disk devices, the following alternative methods are possible. Firstly, most disk packs can be replaced with magnetic disk devices at any time, so even if the device itself (hereinafter referred to as a drive) breaks down, processing can be completed in most cases by replacing the disk pack with another drive. By copying a second copy of the recorded contents of the magnetic disk device onto a magnetic tape, etc., and storing the record of the updated information on the magnetic tape, etc., you can prevent the magnetic disk from being damaged by any chance. This is because even if the contents were destroyed, the data could be reproduced, thereby making it possible to minimize the destruction of the recorded contents of the magnetic disk device and the system failure. However, if the magnetic disk device is fixed to the drive rather than the replaceable disk pack method, the first method described above cannot be used, and the second method has the disadvantage that the processing time is extremely long. be. Also, when using a conventional magnetic disk control device to record the same information redundantly on two magnetic disk devices,
Just as when writing different data to different magnetic disk drives using software, write commands must be issued to different magnetic disk drives, which doubles the software write processing to the magnetic disk drives, improving processing efficiency. There was a drawback that the value decreased significantly.

Therefore, an object of the present invention is to record the same information redundantly on two different input/output devices with a single write command without significantly reducing the processing efficiency of the software. The present invention aims to provide an input/output control device capable of dual-write recording, which makes it possible to significantly improve reliability.

According to the present invention, there is provided an input/output control device for recording data transferred from a central processing unit in two input/output devices redundantly, the data being transferred to a first input/output device.
a first write control unit for writing to the input/output device; a read control unit for reading the written data when the writing is finished; a data buffer for writing the read data; and a data buffer for writing the read data; When writing is completed, a second write control unit reads the contents of the data buffer and writes it to a second input/output device, and is controlled by the read control unit and the second write control unit, and controls the data buffer. a data buffer control unit having a function of controlling input/output of data and reporting completion of writing to the read control unit when writing of the read data to the data buffer is completed; A dual write recording system configured to send a completion report to the central processing unit as a report indicating that data writing to the first input/output device has been completed and wait for an instruction to start the next step operation. A possible input/output control device is obtained.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, mainly showing the portion that performs the data double write operation (circuits related to the data read operation from the input/output device are omitted). In FIG. 1, the input/output control device 1 includes an interface control circuit 3 that controls data transfer from the central processing unit 2, and a first interface control circuit 3 that is connected to this circuit 3 and writes data to the first input/output device 4. a read control unit 6 that reads data written to the first input/output device 4; a read control unit 6 that is connected to the read control unit and transfers the data read from the input/output device 4 to the data buffer 7; A second write control section 10 connected to the data buffer 7 and the buffer control section 8 and writing the contents of the data buffer 7 to a second input/output device 9 is included.

The write data transferred via the input/output interface 11 based on a write command from the central processing unit 2 is transferred to the first write data via the internal interface 12 under the control of the interface control circuit 3. The data is transferred to the control section 5 and written to the first input/output device 4 via the device interface 13 under the control of the write control section 5 . When data writing to the first input/output device 4 is completed, a write completion report is reported from the device to the first write control unit 5 via the device interface 13. instructs the read control unit 6 to read the write data via the internal interface 14. The read control unit 6 reads the write data from the first input/output device 4 via the device interface 15 and causes the buffer control unit 8 to write the read data to the data buffer 7 via the internal interface 16. Give instructions. The buffer control unit 8 confirms the empty state of the data buffer 7 and instructs the data buffer 7 via the internal impedance 17 to write the read data from the read control unit 6 to the data buffer 7 via the internal interface 18. When the writing of the read data to the data buffer 7 is completed, the completion of writing to the data buffer 7 is reported to the read control unit 6 via the internal interface 16. The read control unit 6 reports the completion of writing to the data buffer 7 to the first write control unit 5 via the internal interface 14. The first write control unit 5 determines that data writing to the first input/output device 4 is completed based on the completion report, and writes the data to the central processing unit 2 via the interface control unit 3. It reports the completion of the import command, and starts the operation of the next step, such as requesting the transfer of the next data according to instructions from the central processing unit 2. On the other hand, the buffer control section 8
When the read data from the first input/output device 4 is finished writing to the data buffer 7, the second write control unit 10
The internal interface 1 is configured to write the above write data of the data buffer 7 to the input/output device 9.
Give instructions via 9. The second write control unit 10 reads the write data from the data buffer 7 via the internal interface 20 based on instructions from the buffer control unit 8, and sends the write data to the second input/output device 9 via the device interface 21. Writes read data from data buffer 7. When data writing to the second input/output device 9 is completed, a write completion report is sent from the input/output device 9 to the second write control unit 1 via the device interface 21.
0, and the second write control unit 10 reports to the buffer control unit 8 via the internal interface 19 that data writing to the second input/output device has been completed. The buffer control unit 8 places the data buffer 7 in an empty state in accordance with the data write completion report. By adopting a double buffer system for the data buffer, it is possible to minimize the decrease in processing efficiency of the host device.

Therefore, according to the device shown in FIG. 1, when the input/output control device control program in the central processing unit writes the same data to two input/output devices in duplicate,
It is not necessary to issue write commands to each input/output device, and dual write processing is possible with a single write command, and the write processing of the input/output control device control program is significantly improved.

As explained above, the present invention uses a set of data buffers to record the same data redundantly in two input/output devices with a single command from the host device, so that the host device can see the same data as if it were a single device. It appears as if the data is being recorded only on the input/output device, and has the effect of achieving high reliability through dual recording while minimizing a decline in processing efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, mainly showing the portion that performs a data double write operation. Explanation of symbols: 1 is the input/output control device, 2 is the central processing unit, 3 is the interface control circuit, 4 is the first
5 is a write control section, 6 is a read control section, 7 is a data buffer, 8 is a data buffer control section, 9 is a second input/output device, and 10 is a second write control section. , 11 to 21 all indicate interfaces.

Claims (1)

[Claims] 1 An input/output control device for redundantly recording data transferred from a central processing unit to two input/output devices, the first write control device writing the data to the first input/output device a read control unit that reads the written data at the end of the write;
a data buffer for writing the read data; a second write control unit for reading the contents of the data buffer and writing the same to a second input/output device when writing to the data buffer is completed; and a read control unit; A function controlled by the second write control unit to control input/output of data to the data buffer, and to report completion of writing to the read control unit when writing of the read data to the data buffer is completed. a data buffer control unit having a data buffer control unit, and transmits the write completion report to the central processing unit as a report indicating that data writing to the first input/output device has been completed, and performs the next step operation. An input/output control device capable of dual-write recording configured to wait for activation instructions.