JP2838911B2 - Electronic disk subsystem - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic disk subsystem, and more particularly, to an electronic disk subsystem provided with three electronic disk devices. The present invention relates to an electronic disk subsystem that collates read data and determines and outputs correct data even if there is an error in one electronic disk device.

[0002]

2. Description of the Related Art A conventional electronic disk subsystem has two electronic disk devices, and the same data is stored in the two electronic disk devices. When reading data, the data read from the two electronic disk devices is read. The data was output after checking that there was no error in the data.

[0003]

In the above-described conventional electronic disk subsystem, when data read from two electronic disk devices is compared with each other and a mismatch is detected in the data, which data is correct. However, there is a drawback that it is difficult to determine whether or not this is the case.

An object of the present invention is to provide an electronic disk subsystem which can identify an electronic disk device whose data has been destroyed and which can use data of an electronic disk device whose data has been confirmed to be correct. To provide.

[0005]

An electronic disk subsystem according to the present invention comprises a first electronic disk device, a second electronic disk device, a third electronic disk device, and the first, second, and third electronic disk devices. An electronic disk subsystem comprising an electronic disk control device and an electronic disk control device connected via a communication line.
And (A) a storage unit for storing data from the electronic disk control device,
(B) a storage unit control circuit for controlling data transfer from the electronic disk control device to the storage unit, and data transfer from the storage unit to the electronic disk control device; (C) received from the electronic disk control device A comparison circuit that compares data with data received from the storage unit; and (D) an electronic disk interface control circuit that controls transmission and reception of data to and from the electronic disk control device; (E) a first mechanical storage unit for bringing the second electronic disk device into an offline state, and (F) a second mechanical storage unit for bringing the third electronic disk device into an offline state. Wherein the second electronic disk device comprises: (G) a third mechanical storage unit for bringing the first electronic disk device into an offline state;
(H) a fourth mechanical storage unit for setting the third electronic disk device to an offline state, wherein the third electronic disk device sets (I) the second electronic disk device to an offline state. And (J) a sixth mechanical storage unit for bringing the first electronic disk device into an off-line state.

[0006]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the electronic disk subsystem of the present invention.

In FIG. 1, an electronic disk control device 1
Are connected to the electronic disk devices 3a, 3b and 3c via the communication line 2.

The electronic disk device 3a includes a storage unit 7a for storing data and the like, a storage unit control circuit 6a for controlling data transfer to and from the storage unit 7a, data received from the communication line 2 and data received from the storage unit 7a. 5a, an electronic disk interface control circuit 4a for controlling transmission and reception of data via the communication line 2, and a latch relay (first relay) for setting the electronic disk device 3b to an offline state.
Mechanical storage unit) 8, a latch relay (second mechanical storage unit) for bringing the electronic disk device 3c into an offline state
9.

The electronic disk device 3b includes a storage unit 7b for storing data and the like, a storage unit control circuit 6b for controlling data transfer with the storage unit 7b, data received from the communication line 2 and data received from the storage unit 7b. 5b, an electronic disk interface control circuit 4b for controlling data transmission / reception via the communication line 2, and a latch relay (third relay) for setting the electronic disk device 3a to an offline state.
And a latch relay (fourth mechanical storage unit) 11 for bringing the electronic disk device 3c into an off-line state.

The electronic disk device 3c includes a storage unit 7c for storing data and the like, a storage unit control circuit 6c for controlling data transfer with the storage unit 7c, data received from the communication line 2, and data received from the storage unit 7c. 5c, an electronic disk interface control circuit 4c for controlling transmission and reception of data via the communication line 2, and a latch relay (the fifth relay) for setting the electronic disk device 3b to an offline state.
And a latch relay (sixth mechanical storage unit) 13 for bringing the electronic disk device 3a into an off-line state.

Next, the operation will be described.

When writing data from the electronic disk control device 1 to the first, second and electronic disk devices, the electronic disk device 3a first controls the data from the communication line 2 by the electronic disk interface control circuit 4a. Is sent to the storage unit control circuit 6a, and data is written to the storage unit 7a under the control of the storage unit control circuit 6a. At the same time, data is written to the storage unit 7b of the electronic disk device 3b and the storage unit 7c of the electronic disk device 3c in the same procedure.

When data is read from the electronic disk device 3a to the electronic disk controller 1, the electronic disk device 3a first reads data from the storage unit 7a under the control of the storage unit control circuit 6a, and reads the data from the electronic disk interface control circuit 4a. Is sent to the electronic disk control device 1. In the electronic disk device 3b, the data transmitted from the electronic disk device 3a to the communication line 2 is
It is received through the electronic disk interface control circuit 4b. Then, under the control of the storage unit control circuit 6b, the data read from the storage unit 7b is compared by the comparison circuit 5b. This comparison result is reported to the electronic disk control device 1 via the communication line 2.

The electronic disk device 3c also stores data received from the communication line 2 in the same manner as the electronic disk device 3b.
The data read from the storage unit 7c is compared with the comparison circuit 5c, and the result is reported to the electronic disk control device 1.

Therefore, during reading, the electronic disk device 3
b, when a report indicating that the comparison result does not match is sent to the electronic disk control device 1, the electronic disk control device 1 sets the electronic disk device 3b to an offline state, the latch relay 8 of the electronic disk device 3a, and the electronic disk control device. The latch relay 12 of the device 3c is set. The electronic disk interface control circuit 4b of the electronic disk device 3b includes:
When the latch relays 8 and 12 for setting the electronic disk device 3b to an offline state through the triple writing disk interfaces 24 and 28 are set, the electronic disk device 3b
Is offline, and data transfer with the electronic disk control device 1 is performed only by the electronic disk device 3a and the electronic disk device 3c.

Similarly, when a report of a mismatch is received from the electronic disk device 3c alone, the electronic disk device 3c is set to the offline state by setting the latch relays 9 and 11 for setting the electronic disk device 3c to the offline state. The data transfer with the electronic disk control device 1 is performed only by the electronic disk device 3a and the electronic disk device 3b.

Further, when receiving a report that the comparison result is inconsistent from both the electronic disk device 3b and the electronic disk device 3c, the electronic disk control device 1
By setting the latch relays 10 and 13 for setting a to the off-line state, the electronic disk device 3a is set to the off-line state, and data transfer with the electronic disk control device 1 is performed only by the electronic disk device 3b and the electronic disk device 3c. When the latch relay 10 that sets the electronic disk device 3a to the offline state is set, the electronic disk device 3b sends data from the storage unit 7b to the electronic disk control device 1 via the communication line 2 at the time of reading.

By doing so, even if data is destroyed in any of the three electronic disk devices, it is possible to determine which electronic disk device it is, and to send incorrect data to the electronic disk controller. The data transfer with the electronic disk control device 1 can be performed between the remaining two electronic disk devices and the electronic disk control device 1 without sending.

[0020]

As described above, the electronic disk subsystem of the present invention uses three electronic disk devices, so that the data of one of the electronic disk devices is destroyed and the other two electronic disk devices are destroyed. Even if the comparison result with the electronic disk unit does not match, it is possible to identify the electronic disk unit whose data has been destroyed, and use the data of the other two electronic disk units that have been confirmed to be correct. It has the effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an electronic disk subsystem of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic disk control device 2 Communication line 3a-3c Electronic disk device 4a-4c Electronic disk interface control circuit 5a-5c Comparison circuit 6a-6c Storage part control circuit 7a-7c Storage part 8-13 Latch relay 24-29 Triple writing interface

Claims (1)

(57) [Claims] 1. A first electronic disk device, a second electronic disk device, a third electronic disk device, and connected to the first, second, and third electronic disk devices via a communication line. An electronic disk subsystem configured with an electronic disk control device,
And (A) a storage unit for storing data from the electronic disk control device,
(B) a storage unit control circuit for controlling data transfer from the electronic disk control device to the storage unit, and data transfer from the storage unit to the electronic disk control device; (C) received from the electronic disk control device A comparison circuit that compares data with data received from the storage unit; and (D) an electronic disk interface control circuit that controls transmission and reception of data to and from the electronic disk control device; (E) a first mechanical storage unit for bringing the second electronic disk device into an offline state, and (F) a second mechanical storage unit for bringing the third electronic disk device into an offline state. Wherein the second electronic disk device comprises: (G) a third mechanical storage unit for bringing the first electronic disk device into an offline state;
(H) a fourth mechanical storage unit for setting the third electronic disk device to an offline state, wherein the third electronic disk device sets (I) the second electronic disk device to an offline state. An electronic disk subsystem, comprising: a fifth mechanical storage unit for performing the operation; and (J) a sixth mechanical storage unit for bringing the first electronic disk device into an offline state.