Eddie is the shipboard computer on the Heart of Gold. He is programmed with an overly
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Eddie in the Hitchhiker's Guide to the Galaxy TV series

cheerful personality, one who is pleasant in an unpleasant way, even when the ship is in imminent danger. He is equipped with a GPP, or Genuine Person Personality (see Sirius Cybernetics Corporation). It is described as being "brash and cheery as if it was selling detergent". Later in the series he is shown to get sarcastic and dry when aggravated or overtaxed.

He is capable of carrying on conversations with the crew and records everything he says on a ticker tape.

Eddie has a backup personality as well, which doesn't do much toward making the computer less irritating. This alternative personality has its own voice and concerns; a motherly personality who cajoles, berates, and acts protectively to encourage cooperation and safety among the ship's occupants. Whatever personality he takes on, however, he is thoroughly loathed by Ford, Trillian, Arthur, and Zaphod.

Eddie controls and permeates the whole of the Heart of Gold. He can manipulate navigation, defence, weapons, shielding, the Improbability Drive, escape pods, airlocks, and various other systems. He is capable of talking with other computers aboard the ship such as doors and Nutri-Matic food systems.

He has a massive computer memory but it is capable of being filled by exceptionally large requests (such as, for example, why someone would like tea). The semi-official Eoin Colfer novel And Another Thing... has Eddie replaced by Zaphod's detached second head, thereafter referred to as Left Brain. He is shown to be more competent and causes fewer accidents than Eddie (having been Zaphod's smarter head), but can still be overtaxed and frozen.