Mobile computing, whether the ubiquitous laptop, smartphone or tablet, has become a necessary part of our lives, both for work and for leisure. Currently, smartphones and tablets dominate the market, even surpassing personal computers and laptops. The three main companies that develop the operating system used by software developers to allow us to send, receive and process data on the go are Apple, Google and Microsoft. Technology is constantly evolving. These companies, with the help of other partners, develop hardware, operating systems and programming solutions that allow us to break away from our desks. Their efforts also give individual developers the ability to develop games and apps, with the added benefit of selling them on an online marketplace. Below is an overview of the mobile computer operating system architecture, programming tools, and online application stores that developers can use to distribute their work. Apple's iPhone, iPad and iPod touch all use Apple iOS (operating system) which is based on a layered architecture consisting of four layers, cocoa touch, media, core services and core operating system. Most iOS development is done with frameworks that provide developers with the interfaces required to program applications. The cocoa layer is responsible for defining the look and feel of your application, providing touch input and many other high-level system services. The media layer allows programmers to add high-quality graphics, audio, and video to their applications. This layer also allows developers to create media streaming applications. The core services layer defines the basic types used by all apps and support for features like iCloud, social media, and network services. Finally, the O core...... middle of paper ....../features/android.html http://www.zdnet.com/blog/burnette/how-android-works-the-big- photo/515 http://developer.android.com/distribute/googleplay/publish/register.html http://developer.android.com/distribute/googleplay/publish/console.html https://developer.apple.com /library/ios/documentation/miscellaneous/conceptual/iphoneostechoverview/Introduction/Introduction.htmlhttp://www.zdnet.com/blog/burnette/how-android-works-the-big-picture/515 http://www. jetbrains.com/objc/ http://www.jetbrains.com/idea/features/android.html http://www.zdnet.com/blog/burnette/how-android-works-the-big-picture/515 http://developer.android.com/distribute/googleplay/publish/register.html http://developer.android.com/distribute/googleplay/publish/console.html https://developer.apple.com/library/ ios/documentation/miscellaneous/conceptual/iphoneostechoverview/Introduction/Introduction.html