The Android OS
Open Operating System for
Mobile Devices, This Guide By Saikrishna.
Google announced
Android , a Java/Linux-based mobile phone
and tablet operating system. As of July
2012, the latest version is 4.1, code
named “Jelly Beans”, which succeeds the
previously popular versions 4.0 (Ice Cream
Sandwich) and 2.3 (Ginger Bread).
There
are now some 600,000 applications ( apps)
available for devices running Android.
The basic functionality of the Android OS
includes:
Major mobile phone companies have joined
the Open Handset Alliance to promote the
development of Android, which is intended
to be a "truly open platform for mobile
devices.
" The objective of Google's mobile
operating system is to simplify software
development for wireless devices, make it
freely accessible to everybody, and promote
improved services to the estimated three
billion mobile phone users on the planet.
Android is a Linux-based operating system
designed primarily for mobile phones,
although it is also being adopted for other
small devices such as netbooks and
tablets.
As of February 2012, number of devices
running Android has reached 70, and the
total number of Android activations (users)
has exceeded 300 million.
Among the most popular Android phones
are the HTC One S and HTC Rezound,
the Samsung Galaxy Nexus, and the T-
Mobile MyTouch 4G.
Google and the Open Handset Alliance are
providing a Software Development Kit (SDK)
that is available to anybody free of
charge. The SDK includes all the
information, API libraries, and tools you
need to write, build, test, and debug
applications for Android.
The SDK allows developers to write
software for Android devices in Java .
The
system is designed for platform
independence, so that no or little
adjustments are required to run the same
applications on different devices.
However, there is also a Native
Development Kit (NDK), which enables
Andoid developers to access native code,
which in general is not platform
independent, but may be more efficient in
some cases.
More details and download information for
the SDK and NDK is available at the
Android web site .
Since Android OS version 4.1 (Jelly
Beans), the system includes advanced
natural language recognition, voice command
and anticipatory functionality call Google
Now.
While it provides powerful voice
search capabilities similar to Apple's Siri,
the main idea behind Google Now is to
replace the static main menu with
"context" dependent options and
information, that is, options and
information that are relevant based on your
current location and current time.
It combines information from various sources
to predict what information would be useful
or valued by you at any given time. For
example, at the start of the day it may
give you the weather forecast and traffic
conditions between your home and office.
If you are standing at bus stop or train
station it may tell you when the next bus
or train comes. It may also proactively
keep you up to date on your favorite
teams scores. While on the road you may
get recommendations for restaurants, hotels,
etc.
With both Siri and Google Now still at
the beta stage, head to head comparisons
indicate that the voice search function of
Google Now easily beats Siri on the iPhone
in terms of responsiveness and information
content. For more information about Google
Now see the official project site .
Another advanced Android application is
Google Maps for Android , which includes a
free but first-class navigation system
providing voice-guided turn-by-turn
instructions for driving, walking, or using
public transportation. You can also search
for nearby business, schools, or other
locations of interest.
Top Features of Android
* User interface
* Multitasking
* Widgets
* Folders
* Camera/video
* Network data monitoring
* Wi-Fi direct
* Developer tools
• 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.
• Storage
SQLite , a lightweight relational
database , is used for data storage
purposes.
• Connectivity
Android supports connectivity
technologies including GSM/ EDGE ,
IDEN, CDMA , EV-DO , UMTS ,
Bluetooth , Wi-Fi , LTE , NFC and
WiMAX .
• 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.
• Web browser
The web browser available in
Android is based on the open-
source WebKit layout engine,
coupled with Chrome's V8 JavaScript
engine. The browser scores 100/100
on the Acid3 test on Android 4.0.
• Java support
While most Android applications are
written in Java , there is no Java
Virtual Machine in the platform and
Java byte code is not executed.
Java classes are compiled into Dalvik
executables and run on Dalvik, a
specialized virtual machine designed
specifically for Android and optimized
for battery-powered mobile devices
with limited memory and CPU.
J2ME support can be provided via
third-party applications.
• Media support
Android supports the following
audio/video/still media formats:
WebM , H.263 , H.264 , AAC , HE-
AAC (in 3GP or MP4 container),
MPEG-4 SP , AMR, AMR-WB (in
3GP container), MP3 , MIDI , Ogg
Vorbis , FLAC , WAV, JPEG , PNG,
GIF , BMP , WebP.
• 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). [8] 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.
• 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. Users with the Google+
android app can video chat with
other google+ users through
hangouts .
• Multitasking
Multitasking of applications, with
unique handling of memory
allocation, is available.
• Accessibulity
Built in text to speech is provided
by Talk back for people with low
or no vision. Enhancements for
people with hearing disabilities is
available as is other aids.
• 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.
As of Android 4.1, Google
has expanded Voice Actions with
the ability to talk back and read
answers from Google's Knowledge
Graph when queried with specific
commands. The ability to control
hardware has not yet been
implemented.
• 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.
• 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.
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