Tertiary storage

From Wikipedia, the free encyclopedia

Tertiary storage, or tertiary memory, is a computer storage system consisting of one or more storage drives and an automatic media library, for example a tape library or optical disc jukebox. Tertiary storage is used for archival of rarely accessed information, since it is much slower than secondary storage (e.g. 5-60 seconds vs. 1-10 milliseconds). However, unlike off-line storage, a computer can access tertiary storage without human action.

When a computer needs to read information from the tertiary storage, it will first consult a catalog database to determine which tape or disc contains the information. Next, the computer will request a robotic arm to fetch the medium and place it in a drive. When the computer has finished reading the information, the robotic arm will replace the medium to the library.