Features
The Android Emulator default home screen (v1.5)
Architecture diagram
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
Connectivity
Android supports connectivity technologies including GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi (no connections through Proxy server[65] and no Ad hoc wireless network),[66] 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.
Multiple language support
Android supports multiple human languages. The number of languages more than doubled for the platform 2.3 Gingerbread. Android lacks font rendering of several languages even after official announcements[citation needed] of added support (e.g. Hindi).
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 a 93/100 on the Acid3 Test.
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 (though earlier versions do not support animated GIFs),[67] BMP.[64]
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.[68] Apple HTTP Live Streaming is supported by RealPlayer for Mobile,[69] and by the operating system in Android 3.0 (Honeycomb).[55]
Additional hardware support
Android can use video/still cameras, touchscreens, GPS, accelerometers, gyroscopes, 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).[70] Google has since released an update for the Nexus One and the Motorola Droid which enables multi-touch natively.[71]
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 through manufacturer customizations and third-party applications. Full HID support is planned for Android 3.0 (Honeycomb).[55]
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 is available.[72]
Voice based features
Google search through voice has been available since initial release.[73] Voice actions for calling, texting, navigation, etc. are supported on Android 2.2 onwards.[74]
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.[75]
Screen capture
Android does not support screenshot capture as of 2011. This is supported by manufacturer and third-party customizations. Screen Capture is available through a PC connection using the DDMS developer's tool.[76]
Hardware
Main article: List of Android devices
The Android operating system is used on smartphones, netbooks, tablet computers, Google TV, and other devices.[77][78]The main hardware platform for Android is the ARM architecture. There is support for x86 from the Android-x86 project,[79] and Google TV uses a special x86 version of Android.
The first commercially available phone to run Android was the HTC Dream, released on 22 October 2008.[80] In early 2010 Google collaborated with HTC to launch its flagship[81] Android device, the Nexus One. This was followed later in 2010 with the Samsung-made Nexus S.
iOS and Android 2.3.3 'Gingerbread' may be set up to dual boot on a jailbroken iPhone or iPod Touch with the help of OpeniBoot and iDroid.[82][83]
Applications
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++, and Google App Inventor, a visual environment for novice programmersSecurity
In August 2010, an SMS Trojan called Trojan-SMS.AndroidOS.FakePlayer.a infected a number of mobile devices, according to security firm Kaspersky Lab. Disguised as a harmless media player application, the trojan, once installed sends out SMS text messages without the user's knowledge or consent. According to Denis Maslennikov, Senior Malware Researcher at Kaspersky Lab, an exact number of devices infected is not available at present, but the outbreak is currently regional. For now, only Russian Android users can actually lose money after installing the Trojan, but anyone can be infected.[91] Android users were advised not to use the Android web browser until Google issues a security patch. The Android Security Team responded and developed a fix on February 5 2011 and patched Open Source Android two days later.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.[92] These apps were malicious applications in the Android Market which contained trojans hidden in pirated versions of legitimate apps.[93] The malware (called DroidDream) exploited a bug which was present in versions of Android older than 2.2.2.[94] Android device manufacturers and carriers work in tandem to distribute Android based updates and had not uniformly issued patches to their customers for the DroidDream exploit, leaving users vulnerable.[95] 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.[96] Within days, Google remotely wiped the apps from infected users and rolled out an update that would negate the exploits that allowed the apps to view information. They also announced that they would be resolving the issue to ensure that events like this did not occur again.[97] Security firms such as AVG Technologies and Symantec have released "antivirus" software for Android devices.
In August 2011, Security firm Lookout estimated that between half a million to one million Android users have been affected by malicious software in the first half of 2011. Lookout also reported that there was an increase of applications infected with malware, from 80 to 400 in the first six months of 2011.[98]
Linux compatibility
Android's kernel is derived from the Linux kernel. Google contributed code to the Linux kernel as part of their Android effort, but certain features, notably a power management feature called wakelocks, were rejected by mainline kernel developers, so the Android kernel is now a separate version or fork of the Linux kernel.[115][116][117]Google announced in April 2010 that they would hire two employees to work with the Linux kernel community.[118] 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.[116] 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.[119]
Android does not have a native X Window System nor does it support the full set of standard GNU libraries, and this makes it difficult to port existing GNU/Linux applications or libraries to Android.[120] However, support for the X Window System is possible.[121
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