As briefly noted in the introduction to this chapter, apps (applications) are full-fledged software programs. One major implication of this is that apps need to work on a specific operating system. Dreamweaver, for example, is an app (application). Dreamweaver runs on two operating systems: Microsoft Windows and Apple's OS X operating system. And again, apps are specific to an operating system, so you can't run the Windows version of Dreamweaver on a Mac (nor can you run the Mac version of Dreamweaver on a Windows machine). And neither the Mac nor the Windows version of Dreamweaver runs on a Linux machine.
The point? When you create apps for mobile devices, you have to create separate versions of your app for each mobile operating system. There are many mobile operating systems, including Google Android, Apple iOS, Microsoft's Windows Phone, HP's WebOS, Blackberry, and Symbian.
The dominant mobile operating systems that serve between them, the overwhelming majority...