The Commodore 64 was a personal computer manufactured by the Commodore corporation beginning in September of 1982. During its heyday, the Commodore 64 was an extremely impressive and powerful machine, and is still the best-selling computer model of all time. However, obviously, by 2005 it would have become just a wee bit dated.
According to TOS mythology, TOS TrekMUSE is run off of MacGyver's Commodore 64. This explains such diverse phenomena as the MUSE lagging horribly whenever a battleship leaves dock, the thing going down every few months and then staying there for an extended period of time, and TOS's seemingly archaic code structure, simply because the ol' Commodore would explode if it had to deal with something more modern. A common response to a lag spike is to yell on public about how MacGyver must have KaZaA open on the ol' Commodore 64.