In this article, Mark Weiser (a researcher at Xerox Parc) explains his ideas and the Parc's realizations in Ubiquitous Computing, which he defines as "getting the computer out of the way". Weiser first explains why Ubiquitous Computing is important, and how far it is from what was known at the time (1992). He then talks about three devices designed at the Parc, which were prototypes demonstrating what could be achieved in different form-factors. The ultimate goal was to obtain a set of devices of all sizes and shapes, intuitive, easy to use, with very long battery lives, connected using a wireless network and present everywhere (hundreds of the smallest devices per person). After this general discussion, the implementation of Ubiquitous Computing is discussed : the problem of power consumption, the design of a wireless network with the adequate protocols (and discussion of why classical protocols such as IP are not good candidates), the design of appropriate input methods, and two examples of applications. The problem of privacy in a wireless network is also raised. The main interest of this paper is that it gives a complete overview of how Ubiquitous Computing was seen in 1992, shows the path to follow and lets us see how far we have gone since that time. Some technical innovations outlined here are also very interesting, and could still be used today (position-independent networking, "remote" pen, ...).

I think the major weakness of this paper is that it does not really show how Ubiquitous Computing would be useful, and why it is worth becoming universal. For example, the applications enabling the user to take notes with a pen, to display data on a board, or to use Post-Its seem quite useless because this can already be done without computers. I think the first part of the article should have focused on what Ubiquitous Computing can offer (high connectivity, interactive displays, networking, information redundancy, ...). I am also not really convinced by the experimental protocol outlined here. The applications presented (locating people and shared drawing) are not something everybody would use, which restricts the use of these devices. Furthermore, I am not sure that top Computer Science Researchers are the best testers for devices supposed to be used by everybody (in terms of user interface and intuitivity for example). However, the devices show here are part of research projects and are for demonstrating purposes, and I think this goal is reached.

Weiser's article is now almost 12 years old. Did we get closer to his vision of Ubiquitous Computing? We don't have hundreds of computers around us, and I believe we won't in a near future. However, more and more applications and devices use the same kind of technology as a computer (MP3 player, digital camera, cell phones, PDA, ...) and are more and more popular. Shared drawing, virtual dashboard, and some other applications are now a reality, but are not used everyday. More and more people own computers, and they can be found in libraries, bookstores, supermarkets, ..., however Weiser's dream of using a computer without knowing it is still to come. I think he had a very good point about wireless networking. In the last few weeks, WiFi (802.11) has reached a large adoption, and it is now possible to imagine to be able to have access to Internet or a local network from almost anywhere. This has definitely changed the way we use computers, together with the rapid growth of Internet access. I think Ubiquitous Computing is still far from being a reality, and I don't think computers will be forgotten in the next ten years, but increased connectivity and wireless networking are clearly a huge progress and will radically change the way we use computers. It is interesting to note that some of the problems that Weiser raised, such as using appropriate protocols for wireless networking and privacy, are not always taken into account. IP has been chosen as the routing protocol of 802.11, and it is not possible to move from one network to another without losing one's connection. Privacy has only recently become a major concern for wireless networks, leading to 802.1x.