Reliability, availability and serviceability

Reliability, availability and serviceability (RAS), also known as reliability, availability, and maintainability (RAM), is a computer hardware engineering term involving reliability engineering, high availability, and serviceability design. The phrase was originally used by International Business Machines (IBM) as a term to describe the robustness of their mainframe computers.^[1]^[2]

Computers designed with higher levels of RAS have many features that protect data integrity and help them stay available for long periods of time without failure^[3] This data integrity and uptime is a particular selling point for mainframes and fault-tolerant systems.

^ Siewiorek, Daniel P.; Swarz, Robert S. (1998). Reliable computer systems: design and evaluation. Taylor & Francis. p. 508. ISBN 9781568810928.. "The acronym RAS (reliability, accessibility and serviceability) came into widespread acceptance at IBM as the replacement for the subset notion of recovery management."
^ Data Processing Division, International Business Machines Corp., 1970 (1970). "Data processor, Issues 13-17". {{cite journal}}: |author= has generic name (help); Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)- "The dependability [...] experienced by other System/370 users is the result of a strategy based on RAS (Reliability-Availability-Serviceability)"
^ Siewert, Sam (Mar 2005). "Big iron lessons, Part 2: Reliability and availability: What's the difference?" (PDF).

[1] Siewiorek, Daniel P.; Swarz, Robert S. (1998). Reliable computer systems: design and evaluation. Taylor & Francis. p. 508. ISBN 9781568810928.. "The acronym RAS (reliability, accessibility and serviceability) came into widespread acceptance at IBM as the replacement for the subset notion of recovery management."

[2] Data Processing Division, International Business Machines Corp., 1970 (1970). "Data processor, Issues 13-17". {{cite journal}}: |author= has generic name (help); Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)- "The dependability [...] experienced by other System/370 users is the result of a strategy based on RAS (Reliability-Availability-Serviceability)"

[3] Siewert, Sam (Mar 2005). "Big iron lessons, Part 2: Reliability and availability: What's the difference?" (PDF).

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