可靠性、可用性和可維護性

可靠性、可用性和可维护性（）是電腦硬體上的術語，最初來自IBM公司為其大型主機所做的宣傳廣告，強調大型主機系統的堅韌強固。如今這個概念已廣為人知，並被簡稱為RAS。

定義

可靠性（Reliability）是指定時間 t 內，產生正確輸出的機率。
可用性（Availability）是指系統的運作時間，工作時間比總時間，一般用百分比表示，例如99.999%（5個9）。
可维护性（Serviceability）是指若系統發生故障，是否可以快速檢查和維修。

參見
高可用性
RAMS

参考文献

 Itanium Reliability, Availability and Serviceability (RAS) Features  Overview of RAS features in general and specific features of the Itanium processor.
 POWER7 System RAS Key Aspects of Power Systems Reliability, Availability, and Serviceability. Daniel Henderson, Jim Mitchell, and George Ahrens. February 10, 2012  Overview of RAS features in Power processors.
 Intel Corp. Reliability, Availability, and Serviceability for the Always-on Enterprise (appendix B) and Intel Xeon Processor E7 Family: supporting next generation RAS servers. White paper. Overview of RAS features in Xeon processors.
 zEnterprise 196 System Overview. IBM Corp. (Chapter 10)  Overview of RAS features of IBM z196 processor and zEnterprise 196 server.
 Maximizing Application Reliability and Availability with the SPARC M5-32 Server RAS features of Oracle’s SPARC M5-32 server
Category:容错计算机系统
Category:系统工程