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The forgotten GUIs
While Apple and Microsoft would go on to dominate the world of windowed user interfaces, other systems also experimented with the paradigm in the early days of the PC. One prominent example was GEM, a windowing system originally built for the CP/M OS that was later ported to DOS, among other systems. The screenshot above shows GEM running on the ST, Atari's ultimately failed attempt to enter the higher-end computing market. The similarity to the Mac was so strong that the Atari ST was dubbed the "Jackintosh" (after then Atari head Jack Tramiel), and indeed GEM ended up being watered down as a result of a lawsuit filed by Apple.