Mobile information and communication systems in clinical routine have the potential to greatly improve communication, facilitate information access, eliminate double documentation, and increase quality of patient care in the long run. Projects to date have focused, for the most part, on highly specialized applications of the mobile computer. In our research project, 'Cooperative Problem Solving in Health Care', we have, among other things, designed a multifunctional mobile information and communication assistant. A prototype version of this system was implemented. This article outlines the close-to-reality evaluation of our prototype in a 1-week simulation study in a Heidelberg University hospital. We describe methods, aims, design and results of the simulation study, as well as discuss our methodology and the results we have obtained. We argue that the diverse requirements of different professional groups cannot be fulfilled by a single multifunctional device and propose, therefore, a 'multi-device mobile computer architecture'. Finally, we present consequences for the future computing infrastructure.