Editing Error detection and correction (section)

=== {{Anchor|LINUX-EDAC|BLUESMOKE}}Error-correcting memory ===
{{Main|ECC memory}}

[[Dynamic random-access memory]] (DRAM) may provide stronger protection against [[soft error]]s by relying on error-correcting codes. Such error-correcting memory, known as ''ECC'' or ''EDAC-protected'' memory, is particularly desirable for mission-critical applications, such as scientific computing, financial, medical, etc. as well as extraterrestrial applications due to the increased [[cosmic ray|radiation]] in space.

Error-correcting memory controllers traditionally use [[Hamming code]]s, although some use [[triple modular redundancy]]. [[Error correction code#Interleaving|Interleaving]] allows distributing the effect of a single cosmic ray potentially upsetting multiple physically neighboring bits across multiple words by associating neighboring bits to different words. As long as a [[single-event upset]] (SEU) does not exceed the error threshold (e.g., a single error) in any particular word between accesses, it can be corrected (e.g., by a single-bit error-correcting code), and the illusion of an error-free memory system may be maintained.<ref>{{cite web
 |title       = Using StrongArm SA-1110 in the On-Board Computer of Nanosatellite
 |publisher   = Tsinghua Space Center, [[Tsinghua University]], Beijing
 |access-date  = 2009-02-16
 |url         = http://www.apmcsta.org/File/doc/Conferences/6th%20meeting/Chen%20Zhenyu.doc
|archive-url = https://web.archive.org/web/20111002152735/http://www.apmcsta.org/File/doc/Conferences/6th%20meeting/Chen%20Zhenyu.doc
|url-status  = dead
|archive-date = 2011-10-02
}}<!-- I wish I had a better reference --></ref>

In addition to hardware providing features required for ECC memory to operate, [[operating system]]s usually contain related reporting facilities that are used to provide notifications when soft errors are transparently recovered. One example is the [[Linux kernel]]'s ''EDAC'' subsystem (previously known as ''Bluesmoke''), which collects the data from error-checking-enabled components inside a computer system; besides collecting and reporting back the events related to ECC memory, it also supports other checksumming errors, including those detected on the [[PCI bus]].<ref>{{cite magazine
 | url = http://www.admin-magazine.com/Articles/Monitoring-Memory-Errors
 | title = Error Detection and Correction
 | access-date = 2014-08-12
 | author = Jeff Layton | magazine = [[Linux Magazine]]
}}</ref><ref>{{cite web
 | url = http://bluesmoke.sourceforge.net/
 | title = EDAC Project
 | access-date = 2014-08-12
 | website = bluesmoke.sourceforge.net
}}</ref><ref>{{cite web
 |url         = https://www.kernel.org/doc/Documentation/edac.txt
 |title       = Documentation/edac.txt
 |work        = Linux kernel documentation
 |date        = 2014-06-16
 |access-date  = 2014-08-12
 |publisher   = [[kernel.org]]
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20090905174616/http://www.kernel.org/doc/Documentation/edac.txt
 |archive-date = 2009-09-05
}}</ref> A few systems{{specify|date=December 2021}} also support [[memory scrubbing]] to catch and correct errors early before they become unrecoverable.