>>32835682If you're talking about DOS, it's actually Seattle Computer Systems who wrote the DOS which Microsoft then bough, renamed, and then sold to the IBM.
If you're talking about Widows, it's actually IBM made the OS (OS/2). And Microsoft worked with the UI. And when Microsoft and IBM got in to a debate over it, Microsoft stole the OS/2, renamed it into Windows NT, and then continued as if nothing had happened.
Oh and about the UI, check the consepts from Xerox and you know where the Microsoft stole their UI design, and if you know how IBM influenced the design later on with the Presentation Manager you know that Microsoft is full of shit taking innovations of others into their own name with a minimal amount of work.