Abstract
Fault tolerant computer architecture is essential to achieve high reliability in today's computing systems. This paper focuses on implementations of fault tolerance in different computing systems. The focused areas are disk arrays, routing, group communications, and fail stop processors. The paper starts by describing different types and phases of fault tolerance and also by stating redundancy- an important issue of fault tolerance. The ideas described relate to techniques used in different systems to achieve reliable and fault free operations. Thus, the main goal of the paper is to present what is currently known about a fault tolerant computing system and its recent advancements and to provide an impetus for research in new fault tolerant architectures.