You may be looking for the computer on Platform One, see: Control (Computer)
Control was a being from anther world that arrived on Earth via Light's ship. She stayed aboard but eventually emerged into the house Gabriel Chase under which Light's ship exsisted. She was confused and became childish. All she wanted was to be a proper lady. She evoled into this position and in her job as Control was replaced by Josiah Samuel Smith. HSe was hapy about this and set of to travel the universe along with Redvers Fenn-Cooper and Nimrod. (DW: Ghost Light)