1. In IOS architecture there are 4 layers mainly Cocoa touch, Media player, Core services, Core Os.
This layer contains the low-level features on basis of which the other high-level features are built. Though we may not use these services directly, they used by the frameworks which are used by our application. We can make use of these features when we need to implement the security features or communicating with an external hardware accessory.
Core Service layer:
This Layer contains basic system services for apps. Core Foundation and Foundation Frameworks are the key services provided by this layer, which define the basic types that all apps use it also has the technologies which support the features like location, iCloud, social media and networking.
This 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.
Cocoa Touch mainly contains the classes implemented in Objective-C, an object-oriented language that is compiled to run at incredible speed, yet employs a truly dynamic runtime making it uniquely flexible. Because Objective-C is a superset of C, it is easy to mix C and even C++ into your Cocoa Touch applications
In Android, there are mainly 4 layers: Linux kernel, Libraries & Android Runtime, Application framework, and application.
Android is partly Linux with some changes. In this layer device drivers, memory management, process management, and networking. However, we will never be programmed to this layer directly.
Libraries & Android runtime:
This layer contains native libraries. They are all written in C/C++ internally, but you’ll be calling them through Java interfaces. In this layer, you can find the Surface Manager (for compositing windows), 2D and 3D graphics, Media codecs (MPEG-4, H.264, MP3, etc.), the SQL database (SQLite), and a native web browser engine (WebKit).
Next is the Android runtime, including the Dalvik Virtual Machine. Dalvik runs dex files, which are converted at compile time from standard class and jar files. Dex files are more compact and efficient than class files, an important consideration for the limited memory and battery-powered devices that Android targets. Java libraries are also part of the Android runtime. They are written in Java, as is everything above this layer.
Parts of this toolkit are provided by Google, and parts are extensions or services that you write. The most important component of the framework is the Activity Manager, which manages the lifecycle of applications and a common “back-stack” for user navigation.
This is the top layer. Most of our code will live here, alongside built-in applications such as the Phone and Web Browser.
Studies have found that a far higher percentage of mobile malware targets Android than iOS, the software that runs Apple’s devices. That’s down both to Android’s huge global popularity and its open approach. Plus, Apple tightly controls which apps are available on its App Store, vetting all apps to avoid allowing malware through.
Many threats to Android could be largely eliminated if all users upgraded their handsets to the latest version of the OS. The fragmentation of Android devices across old versions plays into the hands of malware creators, so it’s vital to keep your own devices up to date.
Apple has no similar problem, as each release of iOS quickly filters through to users. Indeed, iOS updates are big events that prompt mass upgrades, and that means significant security scares are rare enough to be big news when they occur. There are of course downsides to Apple’s tight grip over everything that occurs on its platform, but there’s no doubt it makes for a more secure environment for casual users.
Majority cellphone users are android and that is the reason that android phones are easy to hack as hacker target majority users. And you might have read articles about google, facebook collecting data. if you are using apple phones chances are less .