河南科技学院河南科技学院20152015 届本科毕业设计届本科毕业设计外文资料及翻译外文资料及翻译An Analysis and Comparison of Open and Closed Mobile 1. Introduction In recent years, the popularity of smart phone kept going up. More an d more smart phones are sold anda lot of people are embracing them. S mart phones brought great convenience to users, as well created opportunities for smart phone researchers. Thats to say, the wide spread of smart phones benefited both sides. At the same time, developing ofsmart phone OS becomes one of the smartest industry. To be a smart p hone OS, the system should: 1. Provide services like a PC. 2. Work wi th a GPU for better visual effects. 3. Allow the user to surf on Internet freely. And apparently, therere also some weaknesses:1.Limited battery. 2. Poor CPU performance against PC CPU. 3. Small storage. 4.The use of RAM may leads to loss of data when the phone runs out of battery Now the 2 giants of smart phone OS are Android and iPhone OS. On one side, Android is based on Linux kernel and Dalvik virtual machine, an d it is open sourced. The upper layer of Android is Java based,allowi ng developers to develop Android applications with Google SDK and sel l their software in Android Market. On theother side, iPhone OS, whic h bases on Unix kernel and Darwin model but is closed sourced,evolvesfrom Mac OS X and is the default OS of iPhone, iPod Touch and iPad. Objective C based software can run in iPhone OS, and just like Androi d, you can develop your own iPhone applications and upload them onto Apples App Store for sale 1 2 3 4. By comparing the latest Android and iPhone OS, Android 2.2 Froyo and iOS 4, we can take a glimpse at the main feature of open and closed s mart phone OSs. While the 2 OSs are designed in rather different mentality and functionality, its a little early to tell which one is better. 2. Smart Phone OS 2.1. Android The system architecture of Android consists of 5 layers, which are Li nux Kernel, Android Runtime, Libraries, Application Framework and Ap plications, from bottom to top. Android provides core services like security, memory management, proc ess management, network stack and drivers, basing on Linux 2.6. Beingthe abstract layer between software and hardware, the layer of LinuxKernel hides the implementing details of hardware and provides integ rated services for upper layer. Dalvik virtual machine and Java core libraries are included in the layer of Android Runtime, providing most functions in Java core librari es. The layer of Libraries contains a class of C/C+ libraries for Androi d components. Those libraries are integrated by the layer of Applicat ion Framework and then provided to developers. The layer of Application Framework provides all kinds of modules for program initialization to simplify the use of components, allowing de velopers do whatever they want and provide services for other softwar es, under the limitation of security, of course. Mainstream applications are located in the layer of Application, incl uding e- mail, SMS, calendar, Google map, Web browser and contacts. Users inte ract directly with this layer 1 2. The latest version of Android, Android 2.2 Froyo, puts on some new fe atures. They are: 1. Support Flash 10.1, enables user to watch flash on the phone. 2. V8 JavaScript engine in web browser leads to faster Internet data transportation. 3. Big advance in network sharing. You can use the phone as a 3G NIC,or convert 3G signalto Wi- Fi. 4. Automatically software update. 5. Softwares can be setup in SDcard to extend file storages. 2.2. iPhone iPhone OS is consist of 4 abstract layers: Core OS, Core Service, Med ia and Cocoa Touch respectively. Layers of Core OS and Core Service are designed in C language to hand le core system services, enabling developers to perform file access,sockets calling and data handling. CFNetwork and SQLite are also par ts of these 2 layers. The layer of Media, according to its name, this layer is used to cont rol video and audio, as well handle 2D and 3D images. The Open GL- ES Quratz part of the layer is coded with C language, while the part of Core-Audio and Core-Animation is Objective C based. The layer of Cocoa Touch builds a basic framework for all kinds of programs in iPhone. Most programs run in Cocoa Touch layer, and its surely Objective C based 3 4. The latest iPhone OS is iOS 4. It includes the following new features: 1.Software classification. This feature enables user to place sorted softwares into different documen ts, making it clearer to manage. 2. Email integration. One account isfor all e- mails from different providers. 3. iBook, originally from iPad, is bu ilt in iOS. 4. A brand new Apple Game Center makes iPhone a tremendou s entertainment platform. 2.3. Android vs. iPhone Being the top 2 smart phone OSs, were sure that both Android and iPhone have their own advantages and disadvantages. Now lets take a look at each of them, and see what unique feature they have