Data core
A data core was a part of computer systems.
The Data Core was the data core which served as the hard drive for the Lux Foundation Library. (TV: Forest of the Dead)
While investigating a distress call at Lodestar Station 479 on Hurala, the Tenth Doctor was trapped in the data core room. He used a spoon to tap out an SOS, which was finally detected five days later when the Wayfarer landed on Hurala for refuelling. (PROSE: Prisoner of the Daleks)
The Eleventh Doctor extracted the data core from the grating section of a New Dalek Paradigm Supreme Dalek to download all of the Daleks' information about the Silence. (TV: The Wedding of River Song)
In the Warrior's universe, the Master introduced his and the Warrior's personality prints into Xoanon's data core, causing confusion. (AUDIO: Who Am I?)