Reliability

Reliability is an important issue in systems architecture. Components may be replicated to enhance reliability and increase availability of the system functions. Such applications as aircraft control and manufacturing process control are likely to run on systems with backup processors ready to take over if the main processor fails, often running in parallel so the transition to the backup is smooth. If errors are potentially disastrous, as in aircraft control, results may be collected from replicated processes running in parallel on separate machines and disagreements settled by a voting mechanism. Computer scientists are involved in the analysis of such replicated systems, providing theoretical approaches to estimating the reliability achieved by a given configuration and processor parameters, such as average time between failures and average time required to repair the processor. Reliability is also an issue in distributed systems. For example, one of the touted advantages of a distributed database is that data replicated on different network hosts are more available, so applications that require the data will execute more reliably.