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's Supreme to get all its information about the Silence. (TV: The Wedding of River Song)