18c2ecf20Sopenharmony_ci# SPDX-License-Identifier: GPL-2.0-only 28c2ecf20Sopenharmony_cimenuconfig RAS 38c2ecf20Sopenharmony_ci bool "Reliability, Availability and Serviceability (RAS) features" 48c2ecf20Sopenharmony_ci help 58c2ecf20Sopenharmony_ci Reliability, availability and serviceability (RAS) is a computer 68c2ecf20Sopenharmony_ci hardware engineering term. Computers designed with higher levels 78c2ecf20Sopenharmony_ci of RAS have a multitude of features that protect data integrity 88c2ecf20Sopenharmony_ci and help them stay available for long periods of time without 98c2ecf20Sopenharmony_ci failure. 108c2ecf20Sopenharmony_ci 118c2ecf20Sopenharmony_ci Reliability can be defined as the probability that the system will 128c2ecf20Sopenharmony_ci produce correct outputs up to some given time. Reliability is 138c2ecf20Sopenharmony_ci enhanced by features that help to avoid, detect and repair hardware 148c2ecf20Sopenharmony_ci faults. 158c2ecf20Sopenharmony_ci 168c2ecf20Sopenharmony_ci Availability is the probability a system is operational at a given 178c2ecf20Sopenharmony_ci time, i.e. the amount of time a device is actually operating as the 188c2ecf20Sopenharmony_ci percentage of total time it should be operating. 198c2ecf20Sopenharmony_ci 208c2ecf20Sopenharmony_ci Serviceability or maintainability is the simplicity and speed with 218c2ecf20Sopenharmony_ci which a system can be repaired or maintained; if the time to repair 228c2ecf20Sopenharmony_ci a failed system increases, then availability will decrease. 238c2ecf20Sopenharmony_ci 248c2ecf20Sopenharmony_ci Note that Reliability and Availability are distinct concepts: 258c2ecf20Sopenharmony_ci Reliability is a measure of the ability of a system to function 268c2ecf20Sopenharmony_ci correctly, including avoiding data corruption, whereas Availability 278c2ecf20Sopenharmony_ci measures how often it is available for use, even though it may not 288c2ecf20Sopenharmony_ci be functioning correctly. For example, a server may run forever and 298c2ecf20Sopenharmony_ci so have ideal availability, but may be unreliable, with frequent 308c2ecf20Sopenharmony_ci data corruption. 318c2ecf20Sopenharmony_ci 328c2ecf20Sopenharmony_ciif RAS 338c2ecf20Sopenharmony_ci 348c2ecf20Sopenharmony_cisource "arch/x86/ras/Kconfig" 358c2ecf20Sopenharmony_ci 368c2ecf20Sopenharmony_ciendif 37