technologies that can be used to support 2D/3D visualization, and audio or video playback. Cocoa Touch is the top layer. Although iOS was derived from Mac OS X, there was no Cocoa Touch layer in Mac OS X architecture. Cocoa Touch was derived from Cocoa in Mac OS X, and was uniquely designed for touch-based interfaces. Code libraries at this layer provide fundamental infrastructure for developers (Boudreaux, 2009; Buck and Yacktman, 2009). (Apple refers to these code libraries as frameworks. Since in the paper, the term “framework” refers to application architecture, the term “library” is used instead to avoid confusion.)