Ubiquitous computing (ubicomp) creates an environment that is extremely responsive to the user, which does not necessarily require the user to wear the computer or interface. Computer interfaces, however, are everywhere in the physical space occupied by the user, but the user is unaware of them. A very basic use of ubiquitous computing, for example, turns on a room light when it senses a person has entered. A much more advanced version, demonstrated at Xerox Palo Alto Research Center, when a room was occupied by one person, it would sense the direction in which the person is looking, and turn lights on and off so the light was never in the occupant's eyes. When the system detected an additional person or persons in the room, it would change to diffuse lighting.
Ubiquitous computing complements virtual reality, where, rather than the ubiquitous computing paradigm that senses a human in the real environment, the alternate paradigm creates the reality. Both of these technologies will involve short-range, high-speed communications, for functions such as detecting a human in a room, or, in a virtual reality system, detecting body movement and changing the generated visual perspective to match.
Both of these disciplines need considerable interaction with cognitive science, which helps define the brain inputs and outputs.
If there is a single founder of the real discipline, and we ignore hints in science fiction, it was Mark Weiser at Xerox Palo Alto Research Center. He gave two descriptions, from different perspectives, of the goal:
Inspired by the social scientists, philosophers, and anthropologists at PARC, we have been trying to take a radical look at what computing and networking ought to be like. We believe that people live through their practices and tacit knowledge so that the most powerful things are those that are effectively invisible in use. This is a challenge that affects all of computer science. Our preliminary approach: Activate the world. Provide hundreds of wireless computing devices per person per office, of all scales (from 1" displays to wall sized). This has required new work in operating systems, user interfaces, networks, wireless, displays, and many other areas. We call our work "ubiquitous computing". This is different from PDA's, dynabooks, or information at your fingertips. It is invisible, everywhere computing that does not live on a personal device of any sort, but is in the woodwork everywhere.
For thirty years most interface design, and most computer design, has been headed down the path of the "dramatic" machine. Its highest ideal is to make a computer so exciting, so wonderful, so interesting, that we never want to be without it. A less-traveled path I call the "invisible"; its highest ideal is to make a computer so imbedded, so fitting, so natural, that we use it without even thinking about it. (I have also called this notion "Ubiquitous Computing", and have placed its origins in post-modernism.) I believe that in the next twenty years the second path will come to dominate. But this will not be easy; very little of our current systems infrastructure will survive. We have been building versions of the infrastructure-to-come at PARC for the past four years, in the form of inch-, foot-, and yard-sized computers we call Tabs, Pads, and Boards. Our prototypes have sometimes succeeded, but more often failed to be invisible. From what we have learned, we are now explorting some new directions for ubicomp, including the famous "dangling string" display.
Ubiquitous computing and virtual reality certainly relate to mobile computing, but there are mobility applications, such as cellular telephony, that involve neither ubiquitous computing nor virtual reality — even though cell phones are becoming ubiquitous, and one's dinner partner may be in a reality of his or her own, texting or in a call. The blurred line among these is nowhere more evident than finding one's friend's face go blank, until you see the blinking blue light in her ear and realize she is in a cellular call with a wireless Bluetooth interface.
- Mark Weiser, Ubiquitous Computing, Xerox