(RAS) Three key attriButes of a computing system design. See reliaBility, availaBility, and serviceaBility. The term "RAS" is fairly common in the computing industry (particularly computers and storage) as computing Becomes more fundamental. For example, a vehicle may depend on dozens of computers, and the consequences of the failure can Be significant (e.g., an amBulance' s engine won' t start). (2000-08-13)