linux red hat computing free software linux distributions red hat linux debian cross-platform software dpkg deb (file format) package management system gnu rootstrap enterprise fedora fedora project red hat enterprise linux fedora (operating system) comparison of windows and linux mandriva linux java object object oriented object-oriented software design software engineering unified modeling language java platform java (programming language) modeling language class (computer science) rhce storage education audio storage compact disc digital media cd-rom flashcard cd-r red hat certified engineer