2. An d r o i d i s a L i n u x -b a s e d
ope r a t i ng s y s t e m f or
mo b i l e de v i c e s s uc h a s
S ma r t phone a nd t a bl e t
c o mp ut e r s , de v e l ope d by
Go o g l e i n c onj unc t i on
wi t h t h e Op e n Ha n d s e t
Al l i a n c e . An d r o i d wa s
i ni t i a l l y de v e l ope d by
An d r o i d I n c ., w h o m G o o g l e
f i na nc i a l l y ba c k e d a nd
l a t e r p u r c h a s e d i n 2005. T h e

3. Android, Inc. founded in Palo Alto, California, United
States in October 2003 by Andy Rubin(co-founder of
Danger), Rich Miner (co-founder of wildfire
communications. Inc.), Nick Sears(once VP at T-mobile),
and Chris White (headed design and interface
development at WebTV) to develop, in Rubin’s words
“….smarter mobile devices that are more aware of its
owner’s location and preferences”. That same year,
Rubin ran out of money. Steve Perlman, a close friend of
Rubin, brought him $10,000 in cash in an envelope and
refused a stake in the company.

4. Each version after "Astro" and "Bender" is named in alphabetical
order after a dessert or sugary treat, with 1.5 "Cupcake" being the
first and every update since following this naming convention.
• 1.0 Astro
• 1.1 Bender
• 1.5 Cupcake
• 1.6 Donut
• 2.0/2.1 Eclair
• 2.2 Froyo
• 2.3 Gingerbread
• 3.x Honeycomb
• 4.0 Ice Cream Sandwich
• 4.1 Jelly Bean

5.  Android 1.0, the first commercial version
of the software, was released on
September 23, 2008. This release was
robot-related codename, "Astro",
internally at Google, but the name could
not be used officially for trademark
reasons. The first Android device, the HTC
Dream, incorporated the following.

6.  On February 9, 2009, the Android 1.1
update was released, initially for
the HTC Dream only. Like 1.0, this release
continued the robot naming theme, with
"Bender" chosen, but again this was used
internally only. The update resolved bugs,
changed the API and added a number of
features

7.  On April 30, 2009, the Android 1.5 update
was released, based on Linux kernel 2.6.27. This
was the first release to use a name based on a
dessert ("Cupcake"), a theme which would be
used for all releases henceforth. The update
included several new features and UI
amendments.

8.  On September 15, 2009, the Android 1.6
SDK – dubbed Donut – was released, based
on Linux kernel 2.6.29. Included in the
update were numerous new features.

9.  On October 26, 2009, the Android 2.0 SDK –
codenamed Eclair – was released, based
on Linux kernel 2.6.29. Changes included

10.  On May 20, 2010, the Android 2.2 (Froyo)
SDK was released, based on Linux kernel
2.6.32

11.  On December 6, 2010, the Android 2.3
(Gingerbread) SDK was released, based on
Linux kernel 2.6.35. Changes included.

12.  On February 22, 2011, the Android 3.0
(Honeycomb) SDK – the first tablet-only
Android update – was released, based on
Linux kernel 2.6.36. The first device
featuring this version, the Motorola
Xoom tablet, was released on February 24,
2011. Changes included.

13.  The SDK for Android 4.0.1 (Ice Cream Sandwich),
based on Linux kernel 3.0.1, was publicly
released on October 19, 2011. Google's Gabe
Cohen stated that Android 4.0 was "theoretically
compatible" with any Android 2.3.x device in
production at that time. The source code for
Android 4.0 became available on November 14,
2011. The update introduced numerous new
features, including

14. • On June 27, 2012, at the Google I/O conference, Google
announced Android 4.1 (Jelly Bean). Based on Linux
kernel 3.1.10, Jelly Bean is an incremental update with
the primary aim of improving the user interface, both in
terms of functionality and performance. The
performance improvement involves "Project Butter",
which uses touch anticipation, triple buffering,
extended vsync timing and a fixed frame rate of 60fps
to create a fluid and "buttery"-smooth UI.[ Android 4.1
Jelly Bean was released to AOSP on July 9, 2012, and
an OTA update for the Nexus 7 to Android 4.1.1 was
released on July 11, 2012, making it the first device to
run Jelly Bean.

15. • Android consists of a kernel based on the Linux kernel
2.6 and Linux Kernel 3.x (Android 4.0 onwards),
with middleware, libraries and APIs written
in C and application software running on
an application framework which includes Java-
compatible libraries based on Apache Harmony.
Android uses the Dalvik virtual machine with just-in-
time compilation to run Dalvik dex-code (Dalvik
Executable), which is usually translated from Java byte
code. The main hardware platform for Android is
the ARM architecture. There is support for x86 from
the Android x86 project, and Google TV uses a special
x86 version of Android.

16. Android's kernel is based on the Linux kernel and has further architecture
changes by Google outside the typical Linux kernel development
cycle. Android does not have a native X Window System by default nor does
it support the full set of standard GNU libraries, and this makes it difficult to
port existing Linux applications or libraries to Android.
Certain features that Google contributed back to the Linux kernel, notably a
power management feature called wake locks, were rejected by mainline
kernel developers, partly because kernel maintainers felt that Google did
not show any intent to maintain their own code. Even though Google
announced in April 2010 that they would hire two employees to work with
the Linux kernel community, Greg Kroah-Hartman, the current Linux kernel
maintainer for the -stable branch, said in December 2010 that he was
concerned that Google was no longer trying to get their code changes
included in mainstream Linux.

17. Some Google Android developers hinted that "the Android team was
getting fed up with the process", because they were a small team and
had more urgent work to do on Android.
Linux included the auto sleep and wake locks capabilities in the 3.5
kernel, after many previous attempts at merger. The interfaces are
the same but the upstream Linux implementation allows for two
different suspend modes: to memory (the traditional suspend that
android uses), and to disk (hibernate, as it is known on the
desktop). In August 2011, Linus Torvalds said that "eventually Android
and Linux would come back to a common kernel, but it will probably
not be for four to five years".
In December 2011, Greg Kroah-Hartman announced the start of the
Android Mainlining Project, which aims to put some Android drivers,
patches and features back into the Linux kernel, starting in Linux 3.3.
further integration being expected for Linux Kernel 3.4.

18. • 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.

19. • 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 (in 3GP or MP4 container), MPEG-4 SP, AMR,
AMR-WB (in 3GP container), AAC, HE-AAC (in MP4 or 3GP
container), MP3, MIDI, Ogg Vorbis, FLAC, WAV, JPEG, PNG, GIF, BMP, WebP.

20. • 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.

21. • 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.
• 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.

22. • 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.
• 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.

23. • 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.

24. • Applications are usually developed in
the Java language using the Android Software
Development Kit, but other development tools are
available, including a Native Development Kit for
applications or extensions in C or C++, Google App
Inventor, a visual environment for novice programmers
and various cross platform mobile web applications
frameworks.
• Applications can be acquired by end-users either
through a store such as Google Play or the Amazon
Appstore, or by downloading and installing the
application's APK file from a third-party site.

25. • http://en.wikipedia.org/wiki/Android_(opera
ting_system)
• http://en.wikipedia.org/wiki/Astro_(operatin
g_system)#cite_note-eclair-highlights-21