Sowmya mathukumalli b. Tech., Sastra university, India, 2014

 
2.4 MySQL
 
This application uses MySQL as a back end database. MySQL is a fast, open source Relational 
database management system for developing web-based applications. Since it a relational based 
database, data is stored in the form of tables and relations are established between tables using 
primary keys, foreign keys.
 
2.5 Tomcat Web Server 
Tomcat is an open source Java Servlet Container by Apache Software Foundation for 
implementing Java Servlet, Java Servlet Pages (JSP). The web application is deployed into the 
Tomcat server. Using any web browser, we can run the web application that is deployed into the 
Tomcat Server. 
 
2.6 Android
Android is an open source Linux based operating system. It is used to create various mobile 
applications on various smart phones or tablets available and to customize the device in many 
ways. It provides various components for an optimal application development and execution 
environment for mobile devices.
Each layer in the Android OS shown above provides various functionalities to the layers above it.

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Figure 3: Android Architecture [9] 
https://developer.android.com/guide/platform/index.html
 

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In detail about each layer,
 
2.6.1 Linux Kernel 
The Linux Kernel is the bottom layer of the Android software stack that provides a level of 
abstraction between the device hardware and the upper layers of the software stack [4]. The 
functionalities of the kernel include memory, process and power management. It also provides 
various device drivers for display, Wi-Fi and audio.
 
2.6.2 Android Libraries
The Libraries layer provides a set of Java-based libraries that facilitates interface design, graphics 
drawing and database access to list a few and C/C++ libraries for 2D and 3D graphics drawing, 
SSL communication, graphic layer and SQLite database management etc.,