1*4882a593Smuzhiyun# SPDX-License-Identifier: GPL-2.0-only 2*4882a593Smuzhiyunmenuconfig RAS 3*4882a593Smuzhiyun bool "Reliability, Availability and Serviceability (RAS) features" 4*4882a593Smuzhiyun help 5*4882a593Smuzhiyun Reliability, availability and serviceability (RAS) is a computer 6*4882a593Smuzhiyun hardware engineering term. Computers designed with higher levels 7*4882a593Smuzhiyun of RAS have a multitude of features that protect data integrity 8*4882a593Smuzhiyun and help them stay available for long periods of time without 9*4882a593Smuzhiyun failure. 10*4882a593Smuzhiyun 11*4882a593Smuzhiyun Reliability can be defined as the probability that the system will 12*4882a593Smuzhiyun produce correct outputs up to some given time. Reliability is 13*4882a593Smuzhiyun enhanced by features that help to avoid, detect and repair hardware 14*4882a593Smuzhiyun faults. 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun Availability is the probability a system is operational at a given 17*4882a593Smuzhiyun time, i.e. the amount of time a device is actually operating as the 18*4882a593Smuzhiyun percentage of total time it should be operating. 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun Serviceability or maintainability is the simplicity and speed with 21*4882a593Smuzhiyun which a system can be repaired or maintained; if the time to repair 22*4882a593Smuzhiyun a failed system increases, then availability will decrease. 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun Note that Reliability and Availability are distinct concepts: 25*4882a593Smuzhiyun Reliability is a measure of the ability of a system to function 26*4882a593Smuzhiyun correctly, including avoiding data corruption, whereas Availability 27*4882a593Smuzhiyun measures how often it is available for use, even though it may not 28*4882a593Smuzhiyun be functioning correctly. For example, a server may run forever and 29*4882a593Smuzhiyun so have ideal availability, but may be unreliable, with frequent 30*4882a593Smuzhiyun data corruption. 31*4882a593Smuzhiyun 32*4882a593Smuzhiyunif RAS 33*4882a593Smuzhiyun 34*4882a593Smuzhiyunsource "arch/x86/ras/Kconfig" 35*4882a593Smuzhiyun 36*4882a593Smuzhiyunendif 37