In the late 80's and early 90's Mark Weiser published a vision for the next generation of computing which he termed ubiquitous computing. In the last few years a number of research projects in areas of ubiquitous computing (Weiser, 1991; Weiser, 1993), proactive computing (Tennenhouse, 2000, Borriello and Want, 2000), wearable computing (Siewiorek, Smailagic, Bass, Siegel, Martin, and Bennington, 1998; Sunkpho, Carrett, Smailagic, and Sieworek, 1998) and context-aware (Schilit, 1995, Schilit, Adams, and Want, 1995) computing have begun. In this article I'll [discuss some of these efforts and how they relate to the concept of" aware information" which I use to describe the focus that will make" computing" truly useful to the" man on the street." I'll describe some exploratory research efforts partially funded through the Defense Advanced Projects Research Agency (DARPA) as well as other efforts funded by research agencies and industry. Let's start with Weiser's vision of ubiquitous computing. Consider a world where the desktop computer is replaced with computing embedded in typical physical objects without interfering with the current functionality of those objects. The computers would be small enough to be invisible inside the physical objects and would enhance the original functionality of the physical objects. In Weiser's vision, people would do their work assisted by computer technology, but without having to focus on the computers. Some of the early work at Xerox PARC included the PARCTABs (Want, Schilit, Adams, Gold, Petersen, Goldberg, Ellis & Weiser, 1995) Project. Xerox PARC developed computer prototypes in three sizes corresponding to whiteboard, a pad of paper, and a post-it note size. The PARCTABs project focused on communication and context. Communication (wireless, in this case) let the system share information about users, state, and context. Context acquired by the devices included the user's current location, the identities of people close by, the identities and status of computing devices close by, and physical properties of the environment such as light level, temperature, etc. The goals for the PARC Tabs project were to:

• design a mobile hardware device, the PARCTAB

, that enables personal communication;• design an architecture that supports mobile computing;• construct context-sensitive applications that exploit this architecture;• test the entire system in an office community of people acting as both users and developers of mobile applications.

Use of the system in a test bed was an important part of the project and gave usage data as well as technical data. The usage data showed that a number of factors affect whether or not such a product will be used including form factor, size, peer pressure, and the critical mass of applications available. People are reluctant to change their normal routine and a compelling use case as well as ease of use has to be present in such a product for this to occur. While much of this work has found it's way into the current mobile computing work, we are still far from the original vision of moving the digital world out into the physical world. The work in Virtual Reality or Virtual Environments (Bullinger, Bauer, and Braun, 1997) is orthogonal to ubiquitous computing. Virtual Reality constructs a digital model of the physical world and-humans are immersed in this digital world by using specially developed input and output devices. In this world, users manipulate digital objects. Real-world feedback is simulated using haptic, visual, and olfactory technologies to mimic manipulation of the actual physical objects. Virtual Environments differ from computer-based simulations in the following five basic …