Part 4 Android Vs IOS , Simplified Version

Previous Link

https://hemchandralive.blogspot.com/2018/08/assignment-2-part-3-android-vs-ios.html

Now talk about IOS Technology  . IOS and iOS are interchangeble .

C. IOS Technologies

IOS is the operating system that runs on iPad, iPhone, and iPod touch devices. The operating system manages the device hardware and provides the technologies required to implement native apps. The operating system also ships with various system apps, such as Phone, Mail, and Safari that
provide standard system services to the user.

The iOS Software Development Kit (SDK) contains the tools and interfaces needed to develop, install, run, and test native apps that appear on an iOS device’s Home screen. Native apps are built using the iOS system frameworks and Objective-C language and run directly on iOS. 

Unlike web apps, native apps are installed physically on a device and are therefore always available to the user, even when the device is in Airplane mode. They reside next to other system apps, and both the app and any user data is synced to the user’s computer through iTunes.

D. The IOS Architecture Is Layered

As you write your code, it is recommended that you prefer the use of higher-level frameworks over lower-level frameworks whenever possible. The higher-level frameworks are there to provide object-oriented abstractions for lower-level constructs. 

These abstractions generally make it much easier to write code because they reduce the amount of code you have to write and encapsulate potentially complex features, such as sockets and threads.
You may use lower-level frameworks and technologies, too, if they contain features not exposed by the higher-level frameworks.

Apple delivers most of its system interfaces in special packages called frameworks. A framework is a directory that contains a dynamic shared library and the resources (such as header files, images, and helper apps) needed to support that library. To use frameworks, you add them to your app project from Xcode. 

i) Cocoa Touch Layer

The Cocoa Touch layer contains key frameworks for building iOS apps. These frameworks define the appearance of your app. They also provide the basic app infrastructure and support for key technologies such as multitasking, touch-based input, push notifications, and many high-level system services. When designing your apps, you should investigate the technologies in this layer first to see if theymeet your needs. 

ii) Media Layer

The Media layer contains the graphics, audio, and video technologies you use to implement multimedia experiences in your apps. The technologies in this layer make it easy for you to build apps that look and sound great. 

iii) Core Services Layer

The Core Services layer contains fundamental system services for apps. Key among these services are the Core Foundation and Foundation frameworks, which define the basic types that all apps use. This layer also contains individual technologies to support features such as location, iCloud, social media, and networking. 

iv) Core OS Layer

At the highest level, IOS acts as an intermediary between the underlying hardware and the apps you create. Apps do not talk to the underlying hardware directly. Instead, they communicate with the hardware through a set of well defined system interfaces. These interfaces make it easy to write apps that work consistently on devices having different hardware capabilities.

The implementation of IOS technologies can be viewed as a set of layers, which are shown in

Below Figure. Lower layers contain fundamental services and technologies. Higher-level layers build upon the lower layers and provide more sophisticated services and technologies

The Core OS layer contains the low-level features that most other technologies are built upon. Even if you do not use these technologies directly in your apps, they are most likely being used by other frameworks. And in situations where you need to explicitly deal with security or communicating with an external hardware accessory, you do so using the frameworks in this layer. 

https://hemchandralive.blogspot.com/2018/08/assignment-2-part-5-android-vs-ios.html