Task based voting for fault-tolerant fail safe computer systems
View Patent ↗A system includes a first application that writes a first plurality of tasks to a first memory buffer; a second memory buffer that receives a copy of the first plurality of tasks; a second application that writes a second plurality of tasks to a third memory buffer; and a fourth memory buffer that receives a copy of the second plurality of tasks. The system further includes a first comparison module that generates a first voting signal based on a first comparison between a first task and a second task. The system further includes a second comparison module that generates a second voting signal based on a second comparison between the first task and the second task. The system further includes a first central processing unit (CPU) that selectively determines whether to de-assert a module health signal based on the first voting signal and the second voting signal.
1. A system comprising:
a first application that, during a first clock cycle, writes a first plurality of tasks to a first memory buffer;
a second memory buffer that, during a second clock cycle, receives a copy of the first plurality of tasks;
a second application that, during the first clock cycle, writes a second plurality of tasks to a third memory buffer;
a fourth memory buffer that, during the second clock cycle, receives a copy of the second plurality of tasks;
a first comparison module that i) receives a first task from the first plurality of tasks and a second task from the second plurality of tasks and ii) selectively generates a first voting signal based on a first comparison between the first task and the second task;
a second comparison module that i) receives the first task from the first plurality of tasks and the second task from the second plurality of tasks and ii) selectively generates a second voting signal based on a second comparison between the first task and the second task: and
a first central processing unit (CPU) that selectively determines whether to de-assert a module health signal based on the first voting signal and the second voting signal.
2. The system of claim 1 wherein the first CPU determines not to de-assert the module health signal in response to receiving the first voting signal and the second voting signal.
3. The system of claim 1 wherein the first CPU determines to de-assert the module health signal in response to not receiving the first voting signal.
4. The system of claim 1 wherein the first CPU determines to de-assert the module health signal in response to not receiving the second voting signal.
5. The system of claim 1 wherein the first comparison module determines whether the first task and the second task are identical.
6. The system of claim 5 wherein the first comparison module generates the first voting signal when the first comparison module determines the first task and the second task are identical.
7. The system of claim 5 wherein the first comparison module does not generate the first voting signal when the first comparison module determines the first task and the second task are not identical.
8. The system of claim 1 wherein the second comparison module determines whether the first task is identical to the second task.
9. The system of claim 8 wherein the second comparison module generates the second voting signal when the second comparison module determines the first task and the second task are identical.
10. The system of claim 8 wherein the second comparison module does not generate the second voting signal when the second comparison module determines the first task and the second task are not identical.
11. A method comprising:
writing, during a first clock cycle, a first plurality of tasks;
copying, during a second clock cycle, the first plurality of tasks;
writing, during the first clock cycle, a second plurality of tasks;
copying, during the second clock cycle, the second plurality of tasks;
receiving a first task from the first plurality of tasks;
receiving a second task from the second plurality of tasks;
selectively generating a first voting signal based on a first comparison between the first task and the second task;
selectively generating a second voting signal based on a second comparison between the first task and the second task;
selectively determining whether de-assert a module health signal based on the first voting signal and the second voting signal.
12. The method of claim 11 further comprising determining not to de-assert the module health signal in response to receiving the first voting signal and the second voting signal.
13. The method of claim 11 further comprising determining to de-assert the module health signal in response to not receiving the first voting signal.
14. The method of claim 11 further comprising determining to de-assert the module health signal in response to not receiving the second voting signal.
15. The method of claim 11 further comprising determining whether the first task and the second task are identical based on the first comparison.
16. The method of claim 15 further comprising determining to generate the first voting signal based on a determination that the first task and the second task are identical.
17. The method of claim 15 further comprising determining to not to generate the first voting signal based on a determination that the first task and the second task are not identical.
18. The method of claim 11 further comprising determining whether the first task and the second task are identical based on the second comparison.
19. The method of claim 18 further comprising determining to generate the second voting signal based on a determination that the first task and the second task are identical.
20. The method of claim 18 further comprising determining not to generate the second voting signal based on a determination that the first task and the second task are not identical.