GEOS (Graphic Environment Operating System) is an operating system from Berkeley Softworks (later GeoWorks). Originally designed for the Commodore 64 and released in 1986, it provided a graphical user interface for this popular 8-bit computer.

GEOS closely resembled early versions of Mac OS and included a graphical word processor (geoWrite) and paint program (geoPaint). For many years, Commodore bundled GEOS with its redesigned and cost reduced C64, the C64C. At its peak, GEOS was the third most popular operating system in the world in terms of units shipped, trailing only MS-DOS and Mac OS.

Other GEOS-compatible software packages were available from Berkeley Softworks or from third parties, including a reasonably sophisticated desktop publishing application called geoPublish and a spreadsheet called geoCalc. While geoPublish was not as sophisticated as Aldus Pagemaker and geoCalc not as sophisticated as Microsoft Excel, the packages provided reasonable functionality, and Berkeley Softworks founder Brian Dougherty claimed the company ran its business using its own software on Commodore 8-bit computers for several years.

Enhanced versions of GEOS later became available for the Commodore 128 and the Apple II family. A lesser-known version was also released for the Commodore Plus/4.

Written by a group of programmers, led by Dougherty, who cut their teeth on limited-resource video game machines such as the Atari 2600, GEOS was revered for what it could accomplish on machines with 64–128 kB of RAM memory and 1–2 MHz of 8-bit processing power.

Reference Number : 11-0101-0120 A

Date Published : 1986

Manufacturer : Berkeley Softworks

Platform : Commodore 64, 64C and 128 computers

Format : Paperback: 308 Pages