Write Once Read Many (WORM)

Write Once Read Many (WORM) describes storage that permanently fixes content at the moment of writing, after which it can be read freely but never modified or deleted before its retention period expires. Originally associated with optical media like CD-R and DVD-R, WORM is now commonly implemented in software as logical or compliance locks on hard disk, flash, and cloud object storage.

In recordkeeping, WORM matters because it enforces the integrity and immutability that authentic records require. By guaranteeing that a record cannot be silently changed, WORM supports trustworthiness, defensible disposition, and protection against tampering or premature destruction—qualities essential when records face litigation holds or regulatory audit.

For example, an agency might store final, signed determinations on WORM storage so that the captured version is provably the version of record. This differs from ordinary read/write storage, where files can be edited in place. As modern electronic records standards evolved—reflected in NARA’s 2022 shift away from DoD 5015.2 endorsement toward the Universal ERM Requirements—immutability and verifiable retention remain core expectations regardless of the underlying technology.