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										 |  |  | # SPDX-License-Identifier: GPL-2.0-only | 
					
						
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										 |  |  | menuconfig RAS | 
					
						
							|  |  |  | 	bool "Reliability, Availability and Serviceability (RAS) features" | 
					
						
							|  |  |  | 	help | 
					
						
							|  |  |  | 	  Reliability, availability and serviceability (RAS) is a computer | 
					
						
							|  |  |  | 	  hardware engineering term. Computers designed with higher levels | 
					
						
							|  |  |  | 	  of RAS have a multitude of features that protect data integrity | 
					
						
							|  |  |  | 	  and help them stay available for long periods of time without | 
					
						
							|  |  |  | 	  failure. | 
					
						
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							|  |  |  | 	  Reliability can be defined as the probability that the system will | 
					
						
							|  |  |  | 	  produce correct outputs up to some given time. Reliability is | 
					
						
							|  |  |  | 	  enhanced by features that help to avoid, detect and repair hardware | 
					
						
							|  |  |  | 	  faults. | 
					
						
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							|  |  |  | 	  Availability is the probability a system is operational at a given | 
					
						
							|  |  |  | 	  time, i.e. the amount of time a device is actually operating as the | 
					
						
							|  |  |  | 	  percentage of total time it should be operating. | 
					
						
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							|  |  |  | 	  Serviceability or maintainability is the simplicity and speed with | 
					
						
							|  |  |  | 	  which a system can be repaired or maintained; if the time to repair | 
					
						
							|  |  |  | 	  a failed system increases, then availability will decrease. | 
					
						
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							|  |  |  | 	  Note that Reliability and Availability are distinct concepts: | 
					
						
							|  |  |  | 	  Reliability is a measure of the ability of a system to function | 
					
						
							|  |  |  | 	  correctly, including avoiding data corruption, whereas Availability | 
					
						
							|  |  |  | 	  measures how often it is available for use, even though it may not | 
					
						
							|  |  |  | 	  be functioning correctly. For example, a server may run forever and | 
					
						
							|  |  |  | 	  so have ideal availability, but may be unreliable, with frequent | 
					
						
							|  |  |  | 	  data corruption. | 
					
						
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							|  |  |  | if RAS | 
					
						
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										 |  |  | source "arch/x86/ras/Kconfig" | 
					
						
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										 |  |  | endif |