For some circuits, there can be substantial redundancy. This includes memory, disks and networks. Sometimes that redundancy is in hardware, sometimes software and sometimes a mix.
For other hardware, there is almost the of redundancy. In those parts of the system, you depend on multiple components all working correctly with no chance of detecting errors at the circuit level. This means that if you have 10 components with expected life of 6-20 years (with a mean of 10) you can expect an actual life of about 6, not the mean life at all. The weakest link and all that.
Reading this, I am wondering what failures in the transistor (field effect transistor) can be tolerated by the circuit?
I forgot all the analog and digital circuitry classes in college. I don't recall there is any redundancy in the circuit design.
Is redundancy built in the circuit design therefore the chip?