The Personal Server is a mobile device that enables you to readily store and access the data and applications you carry with you through interfaces found in the local environment. Unlike conventional mobile computers with relatively poor user interfaces, it does not have a display at all, instead wirelessly utilizing displays, keyboards and other IO devices found nearby. By co-opting large screens such as those found on desktop PCs, public display monitors, information kiosks, and other computers, a Personal Server is more effective than relying on a small mobile screen. This model goes beyond the mobile context and has wider implications for how we think about computing in general. A prototype system, including applications, system infrastructure, and a mobile platform, has been built to fully explore this model. This prototype sheds light on the suitability of standard components to support such a computing model, and from this illuminates directions for the design of future ubiquitous computing systems.