Performance of microkernel vs monolithic kernel. As is always the answer (or at least the preface) to performance-related questions: know your problem domain, run comparative benchmarks, and remember what premature optimization is.
A summary of the difference between contactors, motor starters, relays and circuit breakers. Switches, circuit breakers, and contactors are used to control what parts of an electrical system are energized or de-energized. Fuses are used to protect the electrical system when something goes wrong, and can isolate the faulted parts from the normal parts.
Circuit breakers are rated for a certain maximum current and will trip if that current is exceeded. This is to prevent electrical discharge and a possible fire from short circuits or faulty wiring. Because breakers are re-useable, the modern electrical panel is an improvement over the fuse boxes in older homes.