Editing Error detection and correction (section)

=== Data storage ===
Error detection and correction codes are often used to improve the reliability of data storage media.<ref>{{Cite book|last1=Kurtas|first1=Erozan M.|url=https://books.google.com/books?id=Vx_NBQAAQBAJ&q=Error+detection+and+correction+codes+are+often+used+to+improve+the+reliability+of+data+storage+media&pg=PR5|title=Advanced Error Control Techniques for Data Storage Systems|last2=Vasic|first2=Bane|date=2018-10-03|publisher=CRC Press|isbn=978-1-4200-3649-7|language=en}}{{Dead link|date=March 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>  A parity track capable of detecting single-bit errors was present on the first [[magnetic tape data storage]] in 1951. The [[optimal rectangular code]] used in [[group coded recording]] tapes not only detects but also corrects single-bit errors. Some [[file format]]s, particularly [[archive formats]], include a checksum (most often [[CRC32]]) to detect corruption and truncation and can employ redundancy or [[parity file]]s to recover portions of corrupted data. [[Cross-interleaved Reed–Solomon coding|Reed-Solomon codes]] are used in [[compact disc]]s to correct errors caused by scratches.

Modern hard drives use Reed–Solomon codes to detect and correct minor errors in sector reads, and to recover corrupted data from failing sectors and store that data in the spare sectors.<ref>{{cite web |archive-url=https://web.archive.org/web/20080202143103/http://www.myharddrivedied.com/presentations_whitepaper.html |archive-date=2008-02-02 |url=http://www.myharddrivedied.com/presentations_whitepaper.html |title=My Hard Drive Died |author=Scott A. Moulton}}</ref> [[RAID]] systems use a variety of error correction techniques to recover data when a hard drive completely fails.  Filesystems such as [[ZFS]] or [[Btrfs]], as well as some [[RAID]] implementations, support [[data scrubbing]] and resilvering, which allows bad blocks to be detected and (hopefully) recovered before they are used.<ref>{{Cite book|last1=Qiao|first1=Zhi|last2=Fu|first2=Song|last3=Chen|first3=Hsing-Bung|last4=Settlemyer|first4=Bradley|title=2019 IEEE International Conference on Cluster Computing (CLUSTER) |chapter=Building Reliable High-Performance Storage Systems: An Empirical and Analytical Study |date=2019|pages=1–10|doi=10.1109/CLUSTER.2019.8891006|isbn=978-1-7281-4734-5|s2cid=207951690}}</ref> The recovered data may be re-written to exactly the same physical location, to spare blocks elsewhere on the same piece of hardware, or the data may be rewritten onto replacement hardware.