Starfleet Registry was a starship database on the computers of Starfleet vessels. It listed the name, type and crew information of all vessels registred to Starfleet, including cargo drone ships. The database was used to identify the vessels from sensor data, before they came into visual range.
In 2268, when the M-5 computer was installed on the USS Enterprise, a large slow moving ship was detected with the ships sensors. M-5 used Starfleet Registry to identify it as the Woden, an old-style ore freighter converted to automation, with no crew on board. It automatically relayed this information to the bridge crew before intercepting the Woden and destroying it with photon torpedoes. (TOS: "The Ultimate Computer")