GEOS is a loosely connected family of operating systems / environments.

GEOS for the Commodore 64

GEOS was a graphical environment for the C64 made by Berkeley Softworks. The first version appeared in 1985:

GEOS 2.0 running in vice under Mac OS X

It brought many abilities to the 64K machine that were at the time only available for much more powerful (and expensive) machines, like WYSIWYG word processing:

geoWrite 2.1

Other programs available for the environment provided paint, spellcheck, music, laser printing, and even an assembly language IDE.

Resources

• download
  While the software remains protected by copyright, it is free to download

GEOS for the IBM PC (& compatibles)

Known as GeoWorks Ensemble when I bought it. It was around at the same time as Microsoft Windows 3.0 and outperformed it on the same hardware. GeoWorks Ensemble even ran on XT class and would multitask on XT and AT machines. I pre-purchased it solely on the strength of the C64 version.

Resources

• Breadbox Computer Company owns it now.