A wearable computer is a computer that is subsumed into the personal space of the user, controlled by the user, and has both operational and interactional constancy, i.e. is always on and always accessible. Most notably, it is a device that is always with the user, and into which the user can always enter commands and execute a set of such entered commands, and in which the user can do so while walking around or doing other activities". 
One of the first technologists to pioneer the idea of being able to compute anywhere and be connected was professor and wearable computing pioneer Steve Mann. Mann thought that humans should not contort to computers, but that computers should contort to humans. While enrolled in classes at MIT, Mann wore 80 pounds of computing equipment almost everywhere he went. As time progressed, computing became lighter, and Steve Mann’s load became less burdensome while still retaining the same functionality. In December 1994, Steve Mann developed the "Wearable Wireless Webcam." Webcam transmitted images point-to-point from a head-mounted analog camera to an SGI base station via amateur TV frequencies. The images were processed by the base station and displayed on a webpage in near real-time.
Steve Mann envisioned a future in which hardware could be downloaded in as easily as software. Where one’s contact lens prescription could change during the day based on one’s needs. A future where a device morphs is the most fluid and liquid that an interface can become. Interfaces today are limited by their external structure. This limitation will dissolve when the hardware dissolves. Computers have diminished in volume from gymnasiums to desktops to pockets, and computer screens have become liquid, allowing buttons to appear anywhere they are needed. Although the Internet is invisible and seemingly omnipresent, it is only accessible by two-dimensional interfaces on physical machines in connected fields.
It has only been a recent occurrence that we’ve been able to carry around complex computational interfaces in our pockets, increasing technological capabilities into our everyday lives. Until this point, one had to be in a certain time and place in order to access computing power. This usually meant a college or university, and sometimes between the hours of 3 and 6 AM.
Dr. Mann's WearComp invention dates back to his high school days in the 1970s and early 1980s, where he was experimenting with wearable computing and personal imaging as a hobby . "Unlike other wearable devices (wristwatches, regular eyeglasses, wearable radios, etc.), a WearComp is as reconfigurable as the familiar desktop or mainframe computer. Unlike other computers (including laptops and PDAs), a WearComp is inextricably intertwined with its wearer - WearComp's "always ready" characteristic leads to a new form of synergy between human and computer".
Operational Modes of Wearable Computing
Mann defined three operational modes in this new interaction between human and computer, and six informational flow paths. The three operational modes and their attributes will be listed here. For further reading, see the references section of this entry. It is recommended that anyone working on wearable computing read Mann's work on the Eyetap and follow the full set of guidelines for wearable computing.
Constancy Augmentation Mediation Solitude Privacy The computer runs continuously, and is always ready to interact with the user. Unlike a hand-held device, laptop computer, or PDA, it does not need to be opened up and turned on prior to use. The signal flow from human to computer, and computer to human runs continuously to provide a constant user interface. Traditional computing paradigms are based on the notion that computing is the primary task. Wearable computing, however, is based on the notion that computing is NOT the primary task. The assumption of wearable computing is that the user will be doing something else at the same time as doing the computing. Thus the computer should serve to augment the intellect, or augment the senses. Unlike hand held devices, laptop computers, and PDAs, the wearable computer can encapsulate us. It doesn't necessarily need to completely enclose us, but the concept allows for a greater degree of encapsulation than traditional portable computers. It can function as an information filter, and allow us to block out material we might not wish to experience, whether it be offensive advertising, or simply a desire to replace existing media with different media. In less severe manifestations, it may simply allow us to alter our perception of reality in a very mild sort of way. Mediation allows us to block or modify information leaving our encapsulated space. In the same way that ordinary clothing prevents others from seeing our naked bodies, the wearable computer may, for example, serve as an intermediary for interacting with untrusted systems, such as third party digital anonymous cash "cyberwallets".
Future of Wearable Computing
The whole of the Internet is an invisible, 4th dimensional potentiality with portals of different sizes, shapes, and capabilities. The hardware determines the size of the portal, the connection determines the rate of information flow, and the software/web browser and the sites within that web browser determine the rate of information absorption into the mind. The rate of information absorption is dependent upon the format of the information presented. The best wearable computers will evaporate over time until they are no longer noticeable or are proper ubiquitous extensions of the self, as valuable and as iconic as sports cars and external transport structures for the physical body. Their interfaces will be invisible. All that is solid will melt into air.
- Mann, Steve. Definition of "Wearable Computer". Wearable Computer Definition taken from Steve Mann's Keynote Address entitled "WEARABLE COMPUTING as means for PERSONAL EMPOWERMENT" presented at the 1998 International Conference on Wearable Computing ICWC-98, Fairfax VA, May 1998. Published to Wearcomp.org. Accessed Jul 2011. http://wearcomp.org/wearcompdef.html
- Kieffner, Tara. Wearable Computers: An Overview. Published to Indiana State University personal website of Professor Jeffrey S. Harper. Accessed Jul 2011. http://misnt.indstate.edu/harper/Wearable_Computers.html
- Mann, Steve. I AM A CAMERA: Humanistic Intelligence is the medium; our everyday living is the message. Keynote Address at the McLuhan Symposium on Culture and Technology, Friday, October 23, 1998. Posted to Wearcam.org Accessed Jul 2011. http://wearcam.org/mcluhan-keynote.htm
- Mann, Steve. WhereComp. Glossary of Definitions. Eyetap.org. Adapted from Steve Mann's address Wearable Computing as Means for Personal Empowerment. Keynote Address for The First International Conference on Wearable Computing, ICWC-98, May 12-13, 1998. Fairfax, VA. Accessed Jul. 2011. http://www.eyetap.org/defs/glossary/wearcomp/
- Mann, Steve. Definition of Wearcomp. EyeTap.org. Accessed Jul 2011. http://www.eyetap.org/defs/glossary/wearcomp/
- Adapted from Steve Mann's address. Wearable Computing as Means for Personal Empowerment Keynote Address for The First International Conference on Wearable Computing, ICWC-98, May 12-13, Fairfax, VA. Published by S. Mann to eyetap.org. Accessed Jul 2011. http://www.eyetap.org/defs/glossary/wearcomp/
- Mann, Steve. Definition of "Wearable Computer". Wearable Computer Definition taken from Steve Mann's Keynote Address entitled "Wearable computing as means for personal empowerment" presented at the 1998 International Conference on Wearable Computing ICWC-98, Fairfax VA, May 1998. Published to Wearcomp.org. Accessed Jul 2011. http://wearcomp.org/wearcompdef.html