Editing ARC (file format) (section)

{{Short description|Type of data compression and archival format}}
{{for|the Internet Archive's ARC_IA format|Web ARChive}}
{{Missing information|the file format specifications and its byte signature|date=February 2019}}{{Infobox file format
| name = ARC
| icon = 
| screenshot = 
| caption = 
| extension = .arc, .ark
| mime = application/octet-stream
| type code = 
| uniform type = public.archive.arc
| magic = 
| owner = [[System Enhancement Associates]]
| genre = [[Data compression]]
| container for = 
| contained by = 
| extended from = 
| extended to = 
| standard = 
}}
'''ARC''' is a [[Lossless compression|lossless]] [[data compression]] and [[file archiver|archival]] [[file format|format]] by [[System Enhancement Associates]] (SEA). The file format and the program were both called ARC. The format is known as the subject of controversy in the 1980s, part of important debates over what would later be known as [[open format]]s.

ARC was extremely popular during the early days of the dial-up [[Bulletin board system|BBS]]. ARC was convenient as it combined the functions of the [[SQ (program)|SQ program]] to compress files and the LU program to create [[LBR (file format)|.LBR archives]] of multiple files. The format was later replaced by the [[Zip (file format)|ZIP]] format, which offered better [[data compression ratio|compression ratio]]s and the ability to retain directory structures through the compression/decompression process.

The '''.arc''' [[filename extension]] is often used for several unrelated file archive-like file types. For example, the [[Internet Archive]] used [[Heritrix#Arc_files|its own ARC format]] to store multiple web resources into a single file.<ref>{{Cite web|url=http://crawler.archive.org/articles/developer_manual/arcs.html |title=13. Internet Archive ARC files |access-date=2012-07-17}}</ref><ref>{{Cite web|url=https://archive.org/web/researcher/ArcFileFormat.php |title=Internet Archive: ARC File Format Reference |access-date=2012-07-17}}</ref> The [[FreeArc]] archiver also uses a .arc extension, but uses a completely different file format. Nintendo uses an unrelated "ARC" format for resources, such as audio, or text, in GameCube and Wii games. Several unofficial extractors exist for this type of ARC file.{{Which|date=May 2023}}{{Citation needed|date=March 2019}}

.arc can also be related to another type of file with the same ending. .arc is an ancrypted type of compression only useable through specific websites.