The role of File Set Updater shall be used by Application Entities which receive a transferred File Set and updates it by the addition or deletion of objects to the media. Typical entities using this role would include ultrasound systems adding new patient records to the media and workstations which may add an information object containing a processed or modified image.

An FSU shall offer the ability to either finalize the disc at the completion of the most recent write session (no additional information can be subsequently added to the disc) or to allow multi-session (additional information may be subsequently added to the disc) or to allow packet-writing, if supported by the media and file system specified in the profile.

The FSU role is not defined for the STD-US-xx-xx-DVD profiles (i.e. for DVD media that is not DVD-RAM).