Android Operating System
Priya Raghuvanshi¹, Swati Choudhary², Nidhi Singh³,Ms. Deepali Singhal 4
Department of Computer Science, Raj Kumar Goel Institute Of Technology For Women, Ghaziabad.
¹ priyaraghuvanshi21@gmail.com
² swatichoudhary568@gmail.com
³ nidhisingh366@gmail.com
4 deepalisinghal@rkgitw.edu.in
Abstract: Cellular telephony has had a significant worldwide
rate of acceptance, by year 2010 it is estimated that 3.5B of
the 6.s8B people in the planet will have access to a cell phone.
Smartphone devices such as iPhone, Blackberry, and those
that support the Android operating system are progressively
making an impact on society. In addition to their support for
voice and text exchange, smartphones are capable of
executing sophisticated embedded software applications, as
well as provide a simple link to the Internet and its resources.
1.INTRODUCTION
Android is a software stack for mobile devices that includes
an operating system, middleware and key applications.
Android's mobile operating system is based on a modified
version of the Linux kernel. The increasing interest from the
industry arises from two core aspects: its opensource
nature and its architectural model. Being an open-source
project, allows Android to be fully analysed and understood,
which enables feature comprehension, bug fixing, further
improvements regarding new functionalities and, finally,
porting to new hardware. On the other hand, its Linux kernelbased architecture model also adds the use of Linux to the
mobile industry, allowing taking advantage of the knowledge
and features offered by Linux. Both of these aspects make
Android an appealing target to be used in other type of
environments. Another aspect that is important to consider
when using Android is its own Virtual Machine (VM)
environment. Android applications are Java-based and this
factor entails the use of a VM environment, with both its
advantages and known problems. In computing, a solution
stack is a set of software subsystems or components needed to
deliver a fully functional solution, e.g. a product or service.
Middleware is computer software that connects software
components or some people and their applications. Software
that provides a link between separate software applications.
Middleware is sometimes called plumbing because it connects
two applications and passes data between them. Middleware
allows data contained in one database to be accessed through
another. The Android opensource software stack consists of
Java applications running on a Java-based, object oriented
application framework on top of Java core libraries running on
a Dalvik virtual machine featuring JIT compilation. Libraries
written in C include the surface manager, Open Core media
framework, SQLite relational database management system,
OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL
graphics engine, SSL, and Bionic libc.. The Android operating
system, including the Linux kernel, consists of roughly 12
million lines of code including 3 million lines of XML, 2.8
million lines of C, 2.1 million lines of Java, and 1.75 million
lines of C++. Android uses WAVE & CALFIT. WAVE is an
API for Android OS which allows easy management of by
sensor networks (BSNs) on mobile platforms. It present a
simple framework for health-oriented applications by
providing functionality for data collection from sensors and
data processing.
Keywords— Android, Dalvik virtual machine, linux, opensource system,nJIT compiler.
2. FEATURES
Handset layouts
The platform is adaptable to larger, VGA 2D graphics library,
3D graphics library based on OpenGL ES 2.0 specifications,
and traditional smartphone layouts.
Connectivity
Android supports connectivity technologies including
GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, WiFi, LTE, NFC and WiMAX.
Media support
Android supports the following audio/video/still media
formats: WebM, H.263, H.264 (in 3GP or MP4 container),
MPEG-4 SP, AMR, AMR-WB (in 3GP container), AAC, HEAAC (in MP4 or 3GP container), MP3, MIDI, Ogg Vorbis,
FLAC, WAV, JPEG, PNG, GIF, BMP, WebP.
Messaging
SMS and MMS are available forms of messaging, including
threaded text messaging and Android Cloud To Device
Messaging (C2DM) and now enhanced version of C2DM,
Android Google Cloud Messaging (GCM) is also a part of
Android Push Messaging service.
Multiple language support
Android supports multiple languages.
Streaming media support
RTP/RTSP streaming (3GPP PSS, ISMA), HTML progressive
download (HTML5 <video> tag). Adobe Flash Streaming
(RTMP) and HTTP Dynamic Streaming are supported by the
Flash plugin. Apple HTTP Live Streaming is supported by
RealPlayer for Android, and by the operating system in
Android 3.0 (Honeycomb).
Additional hardware support
Android can use video/still cameras, touchscreens, GPS,
accelerometers, gyroscopes, barometers, magnetometers,
dedicated gaming controls, proximity and pressure sensors,
thermometers, accelerated 2D bit blits (with hardware
orientation, scaling, pixel format conversion) and accelerated
3D graphics.
Multi-touch
Android has native support for multi-touch which was initially
made available in handsets such as the HTC Hero. The feature
was originally disabled at the kernel level (possibly to avoid
infringing Apple's patents on touch-screen technology at the
time). Google has since released an update for the Nexus One
and the Motorola Droid which enables multi-touch natively.
Bluetooth
Supports A2DP, AVRCP, sending files (OPP), accessing the
phone book (PBAP), voice dialing and sending contacts
between phones. Keyboard, mouse and joystick (HID) support
is available in Android 3.1+, and in earlier versions through
manufacturer customizations and third-party applications.
Screen capture
Android supports capturing a screenshot by pressing the
power and volume-down buttons at the same time. Prior to
Android 4.0, the only methods of capturing a screenshot were
through manufacturer and third-party customizations or
otherwise by using a PC connection (DDMS developer's tool).
These alternative methods are still available with the latest
Android.
External storage
Most Android devices include microSD slot and can read
microSD cards formatted with FAT32, Ext3 or Ext4 file
system. To allow use of high-capacity storage media such as
USB flash drives and USB HDDs, many Android tablets also
include USB 'A' receptacle. Storage formatted with FAT32 is
handled by Linux Kernel VFAT driver, while 3rd party
solutions are required to handle other popular file systems
such as NTFS, HFS Plus and exFAT
3. ANDROID ARCHITECTURE
The following diagram shows the major components of the
Android operating system.
Each section is described in more detail below. It consist of
four layers: Application,
Application framework, the layer below is divided in two
parts: libraries and Android
RunTime, and the last layer is Linux Kernel.
Video calling
Android does not support native video calling, but some
handsets have a customized version of the operating system
that supports it, either via the UMTS network (like the
Samsung Galaxy S) or over IP. Video calling through Google
Talk is available in Android 2.3.4 and later. Gingerbread
allows Nexus S to place Internet calls with a SIP account. This
allows for enhanced VoIP dialing to other SIP accounts and
even phone numbers. Skype 2.1 offers video calling in
Android 2.3, including front camera support.
Multitasking
Multitasking of applications, with unique handling of memory
allocation, is available.
Voice based features
Google search through voice has been available since initial
release. Voice actions for calling, texting, navigation, etc. are
supported on Android 2.2 onwards.
Tethering
Android supports tethering, which allows a phone to be used
as a wireless/wired Wi-Fi hotspot. Before Android 2.2 this
was supported by third-party applications or manufacturer
customizations.
.
4. ADVANTAGES
Advantages of Android operating System are :

Wide range of mobile application.

one will be able to customize a mobile phones using
Google Android platform , right down to the screen.
Features like weather details, opening screen, live
RSS feeds and even the icons on the opening screen
will be able to be customized.

In addition, as a result of many mobile phones
carrying Google Android, companies will come up
with such innovative products.

In addition the entertainment functionalities will be
taken a notch higher by Google Android being able
to offer online real time multiplayer games.
5. DISADVANTAGES
Some of disadvantages of Android Operating System are:


Rejection of Google Android by carriers who charge
a fee for some of the web based applications which
Google Android will enable mobile phone holders to
access free of charge.
Since Google Android is an open source platform
driving all Android phones, it could significantly
increase the risk of hacking these devices.
CONCLUSION
Now cell phone is the major part of everyone‘s life. Android
making them more and more users
interactive by providing lots of applications and services. Its
large touch pad and sensor mode
provide easy access to user. As all the mobile applications are
build in java but android does not
have any java virtual machine, there is a special virtual
machine which is built for Android that is
Dalvik virtual machine which compiles the code in .dev form.
Android support for real time
application, providing four different directions making it a
real time system.
6. REFERENCES
[1]
―About
the
Android
open
source
project‖http://source.android.com/about/index.html.
[2]
Android
Developers.
21
July
2009.
http://developer.android.com/guide/basics/what-isandroid.
html.
[3] "Google Projects for Android". www.code.google.com.
Google Inc. 2011. Archived from
the
original
on
2011-02-23.
http://www.webcitation.org/5wiw1JXa2.
[4] http://en.wikipedia.org/wiki/Android_(operating_system)
[5] http://www.lextrait.com/Vincent/implementations.html
[6] http://www.seeingwithsound.com/android.html
[7] Medical application for Android powered mobile systems
by Gray S. Tyson and Ford
Tyson in CSI communication 8 April 2011. Journal of the
American Geriatrics Society,
Vol. 58,No. 3, April 2010.
[8] Open Handset Alliance, ― Android overview,‖
http://www.openhandsetalliance.com/
[9] android_overview.html.
[10] Research paper on ―Evaluating Android OS for
Embedded Real-Time Systems‖.
CISTER Research Centre, School of Engineering of the
Polytechnic Institute of Porto in
Euromicro Conference on Real- time systems (ECRTS- 2010)
july 6, 2010.
[11] Technical trands – smart phones, smart people by
Harikumar P Travancore
Analytics, Technopark-Trivandrum, Kerala in CSI
communication11april2011.http://www.csiindia.org/c/docume
nt_library/.