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ANDROID Computer Science
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Contents What is an Operating System ? What Is Android ? History Of Android Various
Versions Logos Features Of Android Android Architecture Security Issues Comparison With
Other OS Disadvantages Conclusion References
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What is an Operating System ? An operating system is the program that, after being initially
loaded into the machine by a boot program, manages all the other programs in a machine. The
other programs are called applications or application programs.
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What Is Android ? Android is a Linux-based mobile phone operating system developed by
Google. Android is a software stack for mobile devices that includes an operating system and
applications .
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History Of Android Android Inc. was founded in 2003 . It was founded in Palo Alto, California,
United States in October, 2003 by Andy Rubin, Rich Miner, Nick Sears and Chris White. Google
Inc. purchased the initial developer of the software, Android Inc., in 2005 .
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Vari ous Versions Android has seen a number of updates since its original release. These updates
focus on fixing bugs as well as adding new features. The most recent released versions of
Android are: 2.0/2.1 (Eclair) , which revamped the user interface and introduced HTML5
and Exchange ActiveSync 2.5 support. 2.2 (Froyo) , which introduced speed improvements
with JIT optimization and the Chrome V8 JavaScript engine, and added Wi-Fi hotspot and
Adobe Flash support. 2.3 (Gingerbread) , which refined the user interface , improved the soft
keyboard and copy/paste features , and added support for Near Field Communication. 3.0
(Honeycomb) , a tablet-oriented release which supports larger screen devices and many new user
interface features, and supports multicore processors and hardware acceleration for graphics. The
Honeycomb SDK has been released and the first device featuring the Motorola Xoom tablet,
went sale in Feb 2011.
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2. Logos The Android logo was designed with the Droid font family made by Ascender
Corporation. Android Green is the color of the Android Robot that represents the Android
operating system. Android Robot Android Eclair Android Froyo Android Honeycomb Android
Gingerbread
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Features Of Android Connectivity Android supports connectivity technologies including GSM /
EDGE , IDEN , CDMA , EVDO , UMTS , Bluetooth , Wi-Fi , LTE , NFC and WiMAX .
Messaging SMS and MMS are available forms of messaging, including threaded text messaging
and now Android Cloud to Device Messaging Framework ( C2DM ) is also a part of Android
Push Messaging service. 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 the Dalvik virtual machine . Dalvik is a
specialized virtual machine designed specifically for Android and optimized for battery-powered
mobile devices with limited memory and CPU .
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Media support Android supports WebM , H.263 , H.264 , MPEG-4 , AMR , AMR, AAC , HE-
AAC , MP3 , MIDI , Ogg Vorbis , WAV , JPEG , PNG , GIF , BMP . Additional Hardware
support Android can use video/still cameras , touchscreens , GPS , accelerometers , gyroscopes ,
magnetometers , dedicated gaming controls, proximity and pressure sensors , thermometers and
accelerated 3D graphics. Market The Android Market is a catalog of applications that can be
downloaded and installed to Android devices over-the-air, without the use of a PC. Multi-touch
Android has native support for multi-touch which was initially made available in handsets such
as the HTC Hero . Multitasking Multitasking of applications is available.
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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. Storage
SQLite , a lightweight relational database , is used for data storage purposes. Tethering Android
supports tethering, which allows a phone to be used as a wireless/wired hotspot. Prior to Android
2.2 this was supported by third-party applications or manufacturer customizations. Web browser
The web browser available in Android is based on the open-source WebKit layout engine,
coupled with Chrome 's V8 JavaScript engine. These are some main features. Apart from these
there are many other features .
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Android Architecture
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3. Applications Android has a set of core applications including an email client, SMS program,
calendar, maps, browser, contacts, and others. All applications are written using the Java
programming language. Application Framework By providing an open development platform,
Android offers developers the ability to build extremely rich and innovative applications.
Developers are free to take advantage of the device hardware, access location information, run
background services, set alarms, add notifications to the status bar, and much, much more.
Libraries Android includes a set of C/C++ libraries used by various components of the Android
system. Some of the core libraries are listed below: System C library Media Libraries SGL - the
underlying 2D graphics engine 3D libraries - an implementation based on OpenGL SQLite - a
powerful & lightweight relational database engine.
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Android Runtime Every Android application runs in its own process, with its own instance of the
Dalvik virtual machine. Dalvik has been written so that a device can run multiple VMs
efficiently. The Dalvik VM executes files in the Dalvik Executable (.dex) format. Linux Kernel
Android relies on Linux version 2.6 for core system services such as security, memory
management, process management, network stack, and driver model.
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Security Android is a privilege-separated operating system. Each application runs with a distinct
system identity (Linux user ID) Parts of the system are also separated into distinct identities. So
Linux isolates applications from each other and from the system. All Android applications (.apk
files) must be signed with a certificate. Security Problems Android Faced In March 2011, Google
pulled 58 malicious apps from the Android Market, but not before the 58 apps were downloaded
to around 260,000 devices. These apps contained Trojans hidden in pirated versions of legitimate
apps. Trojan was Droid Dream. Google said the exploit allowed the apps to gather device
specific information, as well as personal information. The exploit also allowed the apps to
download additional code that could be run on the device .
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In August 2010, an SMS Trojan called Trojan. SMS. Android OS. FakePlayer.a infected a
number of mobile devices. The Trojan, once installed sends out SMS text messages without the
users knowledge or consent. Almost six months ago, popular Voice over Internet Protocol
company Skype unveiled the Skype for Android App . Android Police discovered a security
issue with Skype for Android App. According to Android Police, the latest version of Skype for
Android stores chats logs and other information on the microSD card un-encrypted.
Android v/s Symbian:
4. Android v/s Symbian Multiple Home Screens. You can change the base firmware. Android
Market has around 200,000 apps. Great processing power based on modern processors like
Cortex-A8 and Cortex-A9 giving 1GHz speed. 512MB RAM is normal for Androids goes up to
1 GB in Atrix . No Multiple Home Screens. You can never change the base firmware. OVI store
has around 40,000 apps only. Processor like OMAP2420 running at only 330 MHz . Symbian
have to leave with 256MB RAM. Android Symbian
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Android is its Open Source Platform. Android Market has around 200,000 apps. Association
with Google has made it more powerful with Google Maps and Google Voice Apps. Large
market share. Full, Multiple Account Sync, no outlook required . Windows Mobile is similar to
Windows and has a lot of legal bindings. Windows Mobile have only around 800 applications
and no gaming apps. No such features here. Market share fall by 70%. Gmail Support only
through outlook.
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Disadvantages There are various security issues that plague users of Google Android operating
system, if the users are not so savvy. Where Android identities are not secured, thefts and hacks
are possible. Its open security free business model lacking security keys and code-signing
certificates allows any application to install and run, which is perhaps the biggest drawback. The
Java enabled system cannot be installed on the memory card. Thus apps and software have to be
downloaded direct onto the phone’s own memory, which obviously takes up much-needed space.
The system shows up only the first frame. It does not support animated .gif files. Nokia
Criticized Google’s Android System Is Not Open. The Google Android system, despite claims of
being an open source, does not make the source code completely available to all.
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Conclusion So besides having too many advantages of Android over little disadvantages its up to
the user to chose according to his needs, to chose Android over other Operating systems.
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References http://www.wikipedia.org/ http://developer.android.com http://www.techtree.com
http://www.readwriteweb.com http://phandroid.com