GEOS stands for Graphical Environment Operating System, a compact, efficient, fast, stable OS available for several platforms: Brother GeoBook, Commodore 64/128, Intel PCs, Nokia Communicator. NewDeal GEOS and all NewDeal GEOS software (applications) are written in assembly language, using an object-oriented component architecture. Third party GEOS software can be written in other languages, which may not be object-oriented.