A major problem when citing and using digital (language) resources is the stability of the links used. After some time many URLs start decaying because e.g. the resource is moved to another server or the domain name of an organisation changes – a process widely known as link rot. Using persistent identifiers (PIDs) it is possible to anticipate to such unavoidable changes. Instead of citing the direct URL, one extra level of indirection is introduced, where each resource gets an own abstract code (a handle). Upon access, the user is redirected to the URL that is associated to the handle. If the physical location of the resources changes, the only thing that needs to be done is making a change to the associated URL. As such, using persistent identifiers lead to citable references that are immune to link rot.
Persistent Identifiers in practice
The use of handles is deeply integrated into the CLARIN infrastructure. They are a requirement for B centres and form a part of the Language Resource inventory and the Virtual Collection Registry. CLARIN centres can acquire handles via the EPIC consortium, a collaboration between several major computing centres to offer stable and reliable persistent identifer services.