Machina was a computer on Aoris which the fanatics Lostar and Tyrus worshipped. It knew of Romana II, the Fourth Doctor and K9 Mark II, and spoke of prophecies and foresight concerning the Doctor and friends. The computer itself had no capacity for complex processing. It was actually controlled by K9. (AUDIO: The Paradox Planet)
Machina was created as a way of protecting the TARDIS in Era 14 on the Doctor's orders. (AUDIO: Legacy of Death)