Linux Kernel :
The operating system is the software package that communicates directly to the hardware and our application. The kernel is the lowest level of the operating system. The kernel is the main part of the operating system and is responsible for translating the command into something that can be understood by the computer. Android mobile operating developed by Google, based on a modified version of the Linux kernel and other open source software and designed primarily for touchscreen mobile devices such as smartphones and tablets.The kernel is the essential center of a operating system, the core that provides basic services for all other parts of the operating system. … A kernel can be contrasted with a shell, the outermost part of an operating system that interacts with user commands.
A kernel in an operating system – in this case Android – is the component responsible for helping your applications communicate with your hardware. It manages the system resources, communicates with external devices when needed, and so on. Android uses a variation of the Linux kernel.
Android uses the Linux kernel under the hood. Because Linux is open-source, Google’s Android developers could modify the Linux kernel to fit their needs. Linux gives the Android developers a pre-built, already maintained operating system kernel to start with so they don’t have to write their own kernel
Libraries
An Android library project is a container of shareable Android source code and resources that can be referenced from Android app projects. A library project is merged into an Android PacKage (APK) file (with file extension .apk ) when an app project is built.When you develop an app on a latest version of android like 5.x and you also want it to run on those devices which are running older versions of android like 3.2 e.t.c. you can’t do that until you add backward compatibility to your code. To provide this backward compatibility android provides you the Android Support Library package. The Android Support Library package is a set of code libraries that provide backward-compatible versions of Android framework APIs as well as features that are only available through the library APIs. Each Support Library is backward-compatible to a specific Android API level. Including the Support Libraries in your Android project is considered a best practice for application developers, depending on the range of platform versions your app is targeting and the APIs that it uses.
The Android Support Library package contains several libraries that can be included in your application. Each of these libraries supports a specific range of Android platform versions and set of features. In order to effectively use the libraries, it is important to consider that which API level you want to target as each library supports different API level.
Following is a brief description of android support libraries and API level they support.
| Sr.No |
Version & Features
|
| 1 | v4 Support Library This library is designed to be used with Android 1.6 (API level 4) and higher. |
| 2 | v7 Support Library There are several libraries designed to be used with Android 2.1 (API level 7) and higher. |
| 3 | v8 Support Library This library is designed to be used with Android (API level 8) and higher. |
| 4 | v13 Support Library This library is designed to be used for Android 3.2 (API level 13) and higher. |