Developed by: Berkeley Softworks
Launched: 1986

GEOS (Graphic Environment Operating System) was a graphical operating system developed by Berkeley Softworks (later Geoworks) for the Commodore 64. This was the best-selling computer of all time, and would become the third most popular operating system in the world, after MS-DOS and Mac OS, in the late 1980s.

Enhanced versions were later released for the Commodore 128 and the Apple II range of computers.

In 1990, the company made the leap to 16-bit systems with a version for PCs and MS-DOS called PC/GEOS, later renamed Geoworks Ensemble.
Despite being incompatible with the 8-bit version, it retained many of its features, such as multitasking and scalable fonts.

GEOS came with a suite of productivity applications: GeoWrite, GeoDraw, GeoManager, Geoplanner, GeoDex, and GeoComm.
It was included with many PCs at the time, but like other graphical environments for the PC platform, such as Graphics Environment Manager (GEM), it ultimately proved less successful in the market than Windows.
The former CEO of GeoWorks claims that GEOS faded away "because Microsoft threatened to withdraw MS-DOS support from hardware manufacturers who included Geoworks with their machines."

GEOS versions

Year	Ver.
1985	1.0
1987	1.5Support for 1571 and 1581 units is added
1988	2.0
2001	4.0It was renamed Breadbox Ensemble