You may be looking for the computer on Platform One, see: Control (Computer)
Control was a long-lived being who was a member of Light's survey of ancient Earth. When Light became dormant after the survey's conclusion, Control was locked away in the ship (by the mission's surveyor, Josiah Samuel Smith who had seized power during Light's dormancy), which now resided in the cellar of Gabriel Chase in Perivale. Due to her isolation, she became confused and childish over the years, wanting to attain her freedom and aspiring to become a proper lady. When freed, she began to evolve, and would set off to travel the universe together with Redvers Fenn-Cooper and Nimrod, her job as Control replaced by Josiah. (DW: Ghost Light)