Android is a software package that contains an operating system, middleware, and various applications.6 It allows developers to create their applications using the Java programming language through the Android software development kit (SDK). It provides the following features: allows components to be reused or replaced, contains Dalvik virtual machine which is designed specifically for mobile devices, contains a web browser, allows the display of both two and three dimensional graphics, contains SQLite for database management, supports audio, video, and images in various formats including JPG, GIF, and MP3, and supports hardware components with features such as Bluetooth, Wi-Fi, camera, global positioning systems, accelerometer, and compass.
Android operating system is developed with the key applications such as short messages service program, calendar, browser, contacts etc. The applications are coded in the Java programming language. The application platform allows creators to develop their applications and provide them with access to application programming interface that core applications utilize. It allows the reuse and the replacement of application components.
Android library contains a set of C or C++ library functions that are used by various layers. It contains a system C library which is designed specifically for systems using Linux, media libraries which allow playing of audio and video of various formats, SGL for display and manipulation of two dimensional image, SQLite for storage and retrieval of data.8 Android run time contains Dalvik virtual machine which enables applications to run on their own different virtual machines.
Android Linux kernel acts as an interface between hardware and applications. It provides Android operating systems with functionalities such as memory management and security.
iPhone operating system allows creators to develop applications that run on iPhones, iPad Touch, and iPod. Since it is based on Mac operating system, it isolates and separates its applications through a “sandbox mechanism” similar to the one used by Mac operating system.9 In this mechanism, the access to some device features and applications are restricted by a program. It restricts third party applications from reading or writing data outside their directory. The data includes system files, resources, and the kernel.
Developers wishing to make their applications available in iPhone operating system are required to submit them to Apple for approval. Apple digitally signs applications, it deems as suitable to be distributed to the public and rejects any application that violets intellectual property right or developers terms of service.
Android uses a standard Unix user identification and Dalvik virtual machine to separate applications. It allows applications to read and write files in their own directory. It gives permissions to applications to access resources and requires developers to specify the functionalities that their applications may require. They then specify permission levels that protect their own interfaces. Processes can communicate only if the calling process has not restricted access to its interface or when it has defined permissions to access other applications. Android applications can be got through Google controlled sites or developers sites. Google removes applications that violets the terms of service or those which are involved in malicious activity from market.
The key difference between iPhone and Android operating systems is that iPhone’s application developers have to wait to be digitally signed by Apple to get in the market while Android’s developers do not.
iPhone OS 4.0 has many features that make it easy for both users and application developers to use. It enables users to multitask various applications including VoIP and global positioning system. It also allows fast switching of applications. If there is a problem in an application that was previously opened, iPhone OS 4.0 is able to notify users using pop up in any application they are applying to. It allows applications to be grouped into folders which allow an easy retrieval. The operating system offers the mail application that allows users to view all their email messages in one inbox. Other features of iPhone OS 4.0 include iBook, iAd advertising, and Bluetooth keyboards.10
Android operating system features include Google maps navigation, support for Bluetooth, the search function that allows searching of short messages service, multimedia messages service, email messages, world wide web, phone book, web browser, that supports HTML 5, high quality camera, and different screen resolutions.