Many people have asked me that question. My answer usually results in a blank stare or a Pong joke. No, it doesnt run DOS and Windows it runs TOS and GEM, I relate, trying to explain the obscure operating system and graphical user interface my Atari TT uses. When I say Atari, some people just assume it is a PC clone which the company also made and I am off the hook for further explanations. First appearing in early 1985, TOS stands for The Operating System, with the distinction of being one of the few mainstream operating systems burned into ROM. GEM stands for Graphic Environment Manager, Digital Researchs graphical user interface that Atari licensed and burned into ROM as well collectively known as TOS. There were GEM applications for DOS, the best known being Ventura Publisher, but Windows would takeoff and now very little is heard of the GEM interface. Legend has it that TOS really stands for Tramiel Operating System, named after Ataris boss at the time, but this was probably more of an inside joke than anything else: the early Atari manuals make direct references to The Operating System. TOS itself originated from the landmark CPM operating system created by Gary Kildall who would later form Digital Research by modifying CPM68, a version for the Motorola 68000 processor which Atari was to use in its new 16bit computer. Competing with MSDOS at the time, Digital Researchs Intelbased operating system was known as DRDOS, with their own GEM being the counterpart to Microsofts Windows. Apple took legal action on Digital Research for the look and feel of its desktop, forcing GEM for the PC to be somewhat crippled. Indeed, GEM was written by someone who had just left the Xerox PARC lab where the concept of the GUI was born and, from Steve Jobs visits there, subsequently borrowed by Apple. Ataris use of GEM, however, was not restricted by these early legal wranglings.

Website: http://www.vanc.igs.net/~roughley/tos_main.htm