Black Boxes The term "black box" is most commonly associated with the flight data recording devices installed in commercial aircraft. But the term has a long history from computing, referring to programs or loadable libraries which serve a specific purpose. "Black box" is an apt metaphor because they are closed systems – a black box takes input, processes it, and returns output or an error. For example, a black box for addition would take the input "2 2" and return "4". Many old applications are integrated into graphical systems in this way – the code which makes up the actual black box is not known and inaccessible and cannot be changed.            In User-Centered Technology Robert R. Johnson points out that the "black box" mentality is still a powerful influence in computer interface design. Systems are made to function in a very limited number of ways, their use is prescribed by designers, and access or modification of the contents of the "box" itself is seldom possible. The rhetorical focus of computer use situations is the system: the way it functions and is documented, not the user's wants or needs. Even "user friendly" systems such as the Mac OS function in this manner, though they offer the user limited freedom (selection from a range of options) as well as better documentation and logical organization (Johnson 25, 28).            Manovich's decision to embed the notion of transcoding and make the connection of culture and computing quite strong reminds us that neither computer system design nor the language of new media must follow the system-centered trend of the "black box."