IBM OS AT

IBM OS/AT is a never released operating system, created by pythonProgrammer in Alternative History of the Operating System video. Released first version in 1917 and last version in 1985.
== History ==
In real life, IBM was founded in 1911. So in a world where operating systems were invented before then, IBM would get a head start, releasing OS/AT in 1917. Note that the Bennett-Robertson patent only applied to Great Britain, so IBM was free to create their own monopoly over North America.
Category:Fictional OS