19b45ef44SBorislav Petkovmenuconfig RAS 29b45ef44SBorislav Petkov bool "Reliability, Availability and Serviceability (RAS) features" 39b45ef44SBorislav Petkov help 49b45ef44SBorislav Petkov Reliability, availability and serviceability (RAS) is a computer 59b45ef44SBorislav Petkov hardware engineering term. Computers designed with higher levels 69b45ef44SBorislav Petkov of RAS have a multitude of features that protect data integrity 79b45ef44SBorislav Petkov and help them stay available for long periods of time without 89b45ef44SBorislav Petkov failure. 99b45ef44SBorislav Petkov 109b45ef44SBorislav Petkov Reliability can be defined as the probability that the system will 119b45ef44SBorislav Petkov produce correct outputs up to some given time. Reliability is 129b45ef44SBorislav Petkov enhanced by features that help to avoid, detect and repair hardware 139b45ef44SBorislav Petkov faults. 149b45ef44SBorislav Petkov 159b45ef44SBorislav Petkov Availability is the probability a system is operational at a given 169b45ef44SBorislav Petkov time, i.e. the amount of time a device is actually operating as the 179b45ef44SBorislav Petkov percentage of total time it should be operating. 189b45ef44SBorislav Petkov 199b45ef44SBorislav Petkov Serviceability or maintainability is the simplicity and speed with 209b45ef44SBorislav Petkov which a system can be repaired or maintained; if the time to repair 219b45ef44SBorislav Petkov a failed system increases, then availability will decrease. 229b45ef44SBorislav Petkov 239b45ef44SBorislav Petkov Note that Reliability and Availability are distinct concepts: 249b45ef44SBorislav Petkov Reliability is a measure of the ability of a system to function 259b45ef44SBorislav Petkov correctly, including avoiding data corruption, whereas Availability 269b45ef44SBorislav Petkov measures how often it is available for use, even though it may not 279b45ef44SBorislav Petkov be functioning correctly. For example, a server may run forever and 289b45ef44SBorislav Petkov so have ideal availability, but may be unreliable, with frequent 299b45ef44SBorislav Petkov data corruption. 309b45ef44SBorislav Petkov 319b45ef44SBorislav Petkovif RAS 326c36dfe9SBorislav Petkov 33*8636a1f9SMasahiro Yamadasource "arch/x86/ras/Kconfig" 346c36dfe9SBorislav Petkov 359b45ef44SBorislav Petkovendif 36