The Recorder

 was the main computer inside Rassilon's Foundry, used by Rassilon to record his scientific projects.

While dealing with the aftermath of the explosion of anti-time, the TARDIS created a series of holographic projections, taken partly from reality and partly from the memories of the Eighth Doctor, Charley Pollard and the TARDIS itself. In one such projection, the TARDIS was recreated as part of a meeting in Rassilon's Foundry between Rassilon and the Committee of Three during the Time of Chaos, with various roles being played by the Doctor's companions. The projection of the Recorder was created using the voice of the Sixth Doctor's companion Frobisher. (AUDIO: Zagreus)