The definition of GEOS

The graphic environment operating system is a lightweight OS with a GUI. It runs on several different processors, including the 65xx (different versions for different machines -- there are versions for the C64, the C128, and the Apple ][, each utilizing the relevant custom chip sets), the x86 (although the x86 version is made to run on top of MS-DOS (or PC-DOS or DR-DOS) and is not strictly a full OS or a window manager, rather it is somewhat in between, like Windows 3.1) and numerous different PDAs, embedded devices, and hand-held machines. It was originally designed by Berkeley Softworks (no real relation to the Berkeley of UNIX fame) but is currently in a more interesting state: the company GeoWorks develops and promotes development of GEOS for hand-held devices, PDAs, & and embedded devices and owns (but has ceased further development on) the x86 version. The other versions are owned (and possibly still being developed) by the company CMD.