n. (abbr. persistent URL or PURL)perla unique web resource identifier used to facilitate the redirection of a Hypertext Transfer Protocol (HTTP) search query to its permanent network locationStone 2000PURL is implemented as an HTTP redirection service. It derives its “persistence” from the promise of the service provider that there will always be an HTTP server at the given domain name capable of resolving all of the PURLs for which it is responsible . . . PURLs are resolved using the existing HTTP protocol so every HTTP client and Web user agent is already capable of resolving PURLs.Zepheira 2007The PURL service has been hosted by OCLC for 12 years and provides persistent, stable World Wide Web (WWW) addresses for the international library and education community, government, business, and non-profit organizations, and private citizens. PURLs are Web addresses or Uniform Resource Locators (URLs) that act as permanent identifiers in the face of a dynamic and changing Web infrastructure. ¶ Instead of resolving directly to Web resources, PURLs provide a level of indirection that allows the underlying Web addresses of resources to change over time without negatively affecting systems that depend on them. This capability provides continuity of references to network resources that may migrate from machine to machine for business, social or technical reasons. PURLs grew out of the long involvement of OCLC’s Office of Research with the Internet Engineering Task Force (IETF) Uniform Resource Identifier working groups.Paradigm 2008A PURL is essentially a URL; the difference is that it does not take the user directly to the location specified by the URL, but to an intermediate PURL Resolution Service. The resolution service associates the PURL with the relevant URL and returns that URL to the user, who can then access the server direct and retrieve the resource.DeRidder, Presnell, and Walker 2012, 147Should the digital content itself be moved to a separate system, we need not modify the EAD finding aid, but simply update the database that provides redirection for the persistent URLs.Duff and Haskell 2015, 49NARA invited participants to contribute their “mashups” to win one of the twenty prizes; the archives reminded participants to include the original captions and persistent URLs for the archival photographs.IDF 2015A PURL is a Persistent Uniform Resource Locator. Functionally, a PURL is a URL. However, instead of pointing directly to the location of an Internet resource, a PURL points to an intermediate resolution service. The PURL resolution service associates the PURL with the actual URL and returns that URL to the client as a standard HTTP redirect. The OCLC PURL Service has been strongly influenced by the active participation of OCLC’s Office of Research in the Internet Engineering Task Force Uniform Resource Identifier working groups. PURLs are an approach to fixing the problem of unstable URLs.OCLC 2016PURLs (Persistent Uniform Resource Locators) are Web addresses that act as permanent identifiers in the face of a dynamic and changing Web infrastructure. Instead of resolving directly to Web resources, PURLs provide a level of indirection that allows the underlying Web addresses of resources to change over time without negatively affecting systems that depend on them. This capability provides continuity of references to network resources that may migrate from machine to machine for business, social or technical reasons.
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Developed in 1995 by the work of OCLC’s Office of Research with the Internet Engineering Task Force (IETF) Uniform Resource Identifier working groups, PURLs represent an approach to address the problem of “link rot,” where hypertext links fail to direct searches to the proper Web resource due to site reorganization, page removal, or URL change. A PURL is a permanent uniform resource locator used in conjunction with an intermediate resolution service, which associates the PURL to the current URL, and thus redirects the HTTP search to the appropriate Web resource.
