Android: An overview

About Android

Android is an open-source and Linux-based Operating System for mobile devices such as smartphones and tablet computers. Android was developed by the Open Handset Alliance, led by Google, and other companies.

Android offers a unified approach to application development for mobile devices which means developers need only develop for Android, and their applications should be able to run on different devices powered by Android. The source code for Android is available under free and open-source software licenses.

Features of Android

Android is a powerful operating system competing with Apple 4GS and supports great features. Few of them are listed below −

1. Beautiful UI: Android OS basic screen provides a beautiful and intuitive user interface.
2. Connectivity: GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi, LTE, NFC and WiMAX.
3. Storage: SQLite, a lightweight relational database, is used for data storage purposes.
4. Media support: H.263, H.264, MPEG-4 SP, AMR, AMR-WB, AAC, HE-AAC, AAC 5.1, MP3, MIDI, Ogg Vorbis, WAV, JPEG, PNG, GIF, and BMP.
5. Messaging: SMS and MMS
6. Web browser: Based on the open-source WebKit layout engine, coupled with Chrome's V8 JavaScript engine supporting HTML5 and CSS3.
7. Multi-touch: Android has native support for multi-touch which was initially made available in handsets such as the HTC Hero.
8. Multi-tasking: User can jump from one task to another and same time various applications can run simultaneously.
9. Resizable widgets: Widgets are resizable, so users can expand them to show more content or shrink them to save space.
10. Multi-Language: Supports single direction and bi-directional text.
11. GCM: Google Cloud Messaging (GCM) is a service that lets developers send short message data to their users on Android devices, without needing a proprietary sync solution.
12. Wi-Fi Direct: A technology that lets apps discover and pair directly, over a high-bandwidth peer-to-peer connection.
13. Android Beam: A popular NFC-based technology that lets users instantly share, just by touching two NFC-enabled phones together.

Android Architecture

The android is an operating system and is a stack of software components which is divided into five sections and four main layers that is-

• Linux kernel
• Libraries
• Android runtime
• Application Framework
• Applications

Linux Kernel

The android uses the powerful Linux kernel and it supports a wide range of hardware drivers. The kernel is the heart of the operating system that manages input and output requests from the software. This provides basic system functionalities like process management, memory management, device management like camera, keypad, display, etc the kernel handles all the things.

Linux is really good at networking and it is not necessary to interface it to the peripheral hardware. The kernel itself does not interact directly with the user but rather interacts with the shell and other programs as well as with the hardware devices on the system.

Libraries

The on top of a Linux kennel there is a set of libraries including open-source web browsers such as WebKit, library libc. These libraries are used to play and record audio and video. The SQLite is a database that is useful for the storage and sharing of application data. The SSL libraries are responsible for internet security etc.

Android Runtime

The android runtime provides a key component called Dalvik Virtual Machine which is a kind of java virtual machine. It is specially designed and optimized for android. The Dalvik VM is the process virtual machine in the android operating system. It is software that runs apps on android devices.

The Dalvik VM makes use of Linux core features like memory management and multithreading which is in java language. The Dalvik VM enables every Android application to run its own process. The Dalvik VM executes the files in the .dex format.

Application Framework

The application framework layer provides many higher-level services to applications such as windows manager, view system, package manager, resource manager, etc. The application developers are allowed to make use of these services in their applications.

Applications

You will find all the android applications at the top layer and you will write your application and install it on this layer. Examples of such applications are contacts, books, browsers, services, etc. Each application performs a different role in the overall applications.

Android Versions

The different android versions from the beginning to the present are mentioned below from 1.0 to 2.0. Here is the android operating system list.

• Android Versions from 1.0 – 1.1: The first Android version like 1.0 was released in the year 2008 but it didn’t have any codename.
• Android Version – 1.5: In the year 2009, the 1.5 android version was released which is named Cupcake.
• Android Version – 1.6: The Android version – 1.6 was released in the year 2009 which is called Donut. The ability of this version is, it operates on different screen sizes as well as resolutions.
• Android Versions from 2.0 – 2.1: Éclair 2.0 version was released after six weeks of the Donut version.
• Android Version – 2.2: After four months of 2.1version invention, the Android 2.2 version was released which is called Froyo.
• Android Version 2.3: The first true visual identity of Android version 2.3 was released in the year 2010 namely Gingerbread.
• Android Version from 3.0 – 3.2: In the year 2011, the versions from 3.0 – 3.2 were released which is named Honeycomb
• Android Version 4.0: Android 4.0 was released in the year 2011 which is called Ice Cream Sandwich.
• Android Versions 4.1 – 4.3: Android Versions 4.1 to 4.3 were released between 2012 to 2013 which is called Jelly Bean.
• Android Version 4.4: Android Version 4.4 was released in Late-2013’s which is called KitKat.
• Android 5.0: The version of Android 5.0 was launched in the year 2014, Nov in the Nexus 6 device which is called Lollipop
• Android 5.1: This version of Android 5.1 was released in March 2015 called Lollipop
• Android 6.0: Android 6.0 Version like Marshmallow was released in Oct 2015.
• Android 7.0: Android 7.0 version was released by Google in Aug 2016 called Nougat.
• Android 7.1, 7.1.1 & 7.1.2 Nougat: Android 7.1 version was released in Oct 2016, called Nougat
• Android 8.0: Android 8.0 version was released in Aug 2017 called Oreo.
• Android 8.1.0: Android 8.1.0 version was released in Dec 2017, called Oreo
• Android Version 9 Pie: Android version 9 Pie was released in Aug 2018
• Android Version 10: Android version 10 was launched in September 2019
• Android Version 11: Android version 11 was released recently on September 8th, 2020

Advantages of Android

• Android is a Linux based open-source operating system, it can be developed by anyone
• Easy access to android apps
• You can replace the battery and mass storage, disk drive, and UDB option
• Its supports all Google services
• The operating system is able to inform you of a new SMS and Emails or the latest updates.
• It supports Multitasking
• Android phone can also function as a router to share the internet
• It’s free to customize
• Can install a modified ROM
• Its supports 2D and 3D graphics
• We can install Millions of apps-
• Backup and restore of apps can be possible
• It supports Third-party apps
• Addition & removal of unwanted features:-
• High job demands for Android developers
• Notifications can be displayed very clearly
• Huge community support
• The Internet can be shared from device to device
• It is an Open source
• Different types of mobile models you can select
• Add/ Remove Unwanted
• Internal memory is Expandable
• Cloud storage
• It supports big screens at a reasonable price
• Foldable Android devices
• Different apps can run at the same time
• Several widgets on display

Disadvantages of Android

• Apps work in the background
• Battery discharges easily due to a lot of processes within the background.
• Requires Google account
• Less security, so fake apps can be easily installed to steal your data from strange resources
• Mobiles with low specification run very slow
• Generally, you require additional code on Java language as compared to Objective-C.
• Android developers have a critical time
• Difficult layouts & animations are tough to code within Android.
• Protection of Virus is required
• For developers of the app, Google is strict
• Several ads within apps
• Some apps quality is not good
• For elders, it is not friendly

Conclusion

In this tutorial we saw what is android, what its features and its advantages and disadvantages. Android operating system is now becoming best among all the other mobile operating system. All Google services can you have with one operating system, namely “Android”. By Android versions its features are increased rapidly.