An object-oriented software architecture interacts with "real" input/output devices exclusively through "virtual" input/output devices. Since all human interface with the operating system is performed through such virtual devices, the system can accept any form of real input or output devices. The lowest...http://www.google.com/patents/US5502839?utm_source=gb-gplus-sharePatent US5502839 - Object-oriented software architecture supporting input/output device independence
