According to Wikipedia (http://en.wikipedia.org/wiki/Logic_Pro), Emagic and Logic weren't around until the 90's, even though Logic was based on ideas from previous software. It's stated there that Emagic and Logic, as software named "Logic" didn't exist until '93. Then Emagic was acquired by Apple in 2002 at which point the Windows version was discontinued. The information there, if factual, would mean that Logic was only being developed by Emagic for about 10 years before they were acquired by Apple.
Information here implies (http://www.tweakheadz.com/history_of_notator_and_logic3.html) that the Mac version came in '93 followed by the PC/Windows version in '95 or '96 which would mean that Logic wasn't being used on PC/Windows for more than 6 or 7 years or so before the Windows version was discontinued by Apple. Logic and all the previous software whose ideas it was based on were also originally on Atari.