It's most certainly derived. The kernel, system libraries and frameworks are common between Mac OS X and iOS (except for Appkit and UIKit) This article covers

It's most certainly derived. The kernel, system libraries and frameworks are common between Mac OS X and iOS (except for Appkit and UIKit) This article covers some of the Apple internal history of iOS http://www.gizmodo.com.au/2010/09/the-history-of-ios/ http://www.gizmodo.com.au/2010/09/the-history-of-ios/