Pervasive Computing is the main characteristic of the emerging fourth era of computer evolution. The paper discusses features of a new generation of intelligent sensor-based information appliances for distributed heterogeneous real-time applications. These appliances will be found in the intelligent homes, offices, automobiles and cities of the future. They will also offer higher mobility and convenience to professionals and open new avenues to many industrial and health applications. 1. Introduction Since its emergence, some forty years go, computing industry has passed through a rapid sequence of technological phases: central computing/mainframe (1950s-1980s), personal computer/PC (1980s-...), computer networks (1990s -...). A fourth era is emerging now, when computers become pervasive, i.e. a technology more noticeable by its absence than its presence [1], [6], [11], [14], [17], [22], [25]. The first mass-produced pervasive computing devices are starting to appear. The Clarion Au...