Editing SCSI (section)

{{short description|Set of computer and peripheral connection standards}}
{{Redirect|Scuzzy|the historic sternwheeler known by that name|Skuzzy (sternwheeler)}}
{{Use mdy dates|date=November 2011}}
{{Infobox connector
| name = SCSI<br />Small Computer System Interface
| type = [[Bus (computing)|Bus]]
| logo = [[File:Scsi logo.svg|class=skin-invert|100px]]
| caption = Single-ended parallel SCSI icon
| designer = Team led by Larry Boucher at [[Shugart Associates]]
| design_date  = {{start date and age|1981|9}}<ref name="draft" />
| production_date = Since 1983
| superseded_by = 
| standardization_date = [[ANSI]] X3.131-1986, June 1986
}}

'''Small Computer System Interface''' ('''SCSI''', {{IPAc-en|ˈ|s|k|ʌ|z|i}} {{respell|SKUZ|ee}})<ref>{{cite book|title=The Book of SCSI|last=Field|page=1}}</ref> is a set of standards for physically connecting and transferring data between computers and [[peripheral devices]], best known for its use with storage devices such as [[hard disk drive]]s. SCSI was introduced in the 1980s and has seen widespread use on servers and high-end workstations, with new SCSI standards being published as recently as [[Serial Attached SCSI|SAS-4]] in 2017.

The SCSI standards define [[SCSI command|commands]], protocols, electrical, optical and logical [[Interface (computing)|interfaces]]. The SCSI standard defines command sets for specific peripheral device types; the presence of "unknown" as one of these types means that in theory it can be used as an interface to almost any device, but the standard is highly pragmatic and addressed toward commercial requirements. The initial [[Parallel SCSI]] was most commonly used for [[hard disk drive]]s and [[tape drive]]s, but it can connect a wide range of other devices, including scanners and [[optical disc drive]]s, although not all controllers can handle all devices.

The ancestral SCSI standard, X3.131-1986, generally referred to as SCSI-1, was published by the X3T9 technical committee of the [[American National Standards Institute]] (ANSI) in 1986. SCSI-2 was published in August 1990 as X3.T9.2/86-109, with further revisions in 1994 and subsequent adoption of a multitude of interfaces. Further refinements have resulted in improvements in performance and support for ever-increasing data storage capacity.<ref>{{cite web|url=https://global.ihs.com/doc_detail.cfm?document_name=ANSI%20INCITS%20131&item_s_key=00009673&item_key_date=911231 |title=ANSI INCITS 131 94th Edition, 2004 |publisher=global.ihs.com |access-date=2017-04-25}}</ref>