Reading up books: Reference for design of fault tolerant systems: Learn how to design systems that are highly reliable, highly available, and easily maintainable

In a narrow sense, a fault tolerant system is one that is capable of error-free operation as seen from the terminals of the system, even though some internal components may have failed. Thus, the use of backup computers on a space mission allows the safe return of the crew to Earth, even though the primary computer may have failed. The vehicle is said to be tolerant of faults in the primary computer system. This design technique, known as the standby spare technique, is a familiar example of the use of redundant components in the design of fault tolerant systems. There are a great many critical applications where human life depends on the proper operation of electronic equipment. Medical equipment, automatic landing systems on commercial aircraft, and nuclear reactor controllers are just a few of these life-critical systems. Such applications require extremely highly reliable designs.