rareobsolete

rareobsolete is a descriptive label used in archival, library, and cultural heritage contexts to denote items that are both rare and obsolete. It emphasizes that an object or data format is scarce in availability and at risk of becoming inaccessible due to technological change or discontinuation of support.

Etymology and usage: The term is a portmanteau of rare and obsolete. It emerged in professional discourse in the early 21st century and is not a formal standard; rather, it appears in catalog notes, preservation plans, and metadata as a warning signal for heightened preservation action.

Applications and examples: Rareobsolete can apply to physical media such as magnetic tapes, floppy disks, or early digital storage, as well as to software and file formats that require old hardware or legacy software to read. In digital collections, items with rareobsolete may include proprietary document formats, obsolete codecs, or software environments that are no longer produced.

Preservation implications: Labeling items as rareobsolete helps archivists assign priority for digitization, migration, or emulation. It prompts risk assessments for data loss due to hardware degradation, bit rot, media deterioration, or software obsolescence and supports planning for access strategies or community-driven restoration efforts.

Related concepts: digital preservation, data migration, and emulation.