What is Android?
Android is a software stack for mobile devices that includes an operating system, middleware and key applications. The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language.Features* Application framework enabling reuse and replacement of components
* Dalvik virtual machine optimized for mobile devices
* Integrated browser based on the open source WebKit engine
* Optimized graphics powered by a custom 2D graphics library; 3D graphics based on the OpenGL ES 1.0 specification (hardware acceleration optional)
* SQLite for structured data storage
* Media support for common audio, video, and still image formats (MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF)
* GSM Telephony (hardware dependent)
* Bluetooth, EDGE, 3G, and WiFi (hardware dependent)
* Camera, GPS, compass, and accelerometer (hardware dependent)
* Rich development environment including a device emulator, tools for debugging, memory and performance profiling, and a plugin for the Eclipse IDE
Android Architecture
The following diagram shows the major components of the Android operating system. Each section is described in more detail below.
Applications
Android will ship with 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.
Developers have full access to the same framework APIs used by the core applications. The application architecture is designed to simplify the reuse of components; any application can publish its capabilities and any other application may then make use of those capabilities (subject to security constraints enforced by the framework). This same mechanism allows components to be replaced by the user.
Underlying all applications is a set of services and systems, including:
* A rich and extensible set of Views that can be used to build an application, including lists, grids, text boxes, buttons, and even an embeddable web browser
* Content Providers that enable applications to access data from other applications (such as Contacts), or to share their own data
* A Resource Manager, providing access to non-code resources such as localized strings, graphics, and layout files
* A Notification Manager that enables all applications to display custom alerts in the status bar
* An Activity Manager that manages the lifecycle of applications and provides a common navigation backstack
For more details and a walkthrough of an application, see the Notepad Tutorial(I'll post another on this subject).
Libraries
Android includes a set of C/C++ libraries used by various components of the Android system. These capabilities are exposed to developers through the Android application framework. Some of the core libraries are listed below:
* System C library - a BSD-derived implementation of the standard C system library (libc), tuned for embedded Linux-based devices
* Media Libraries - based on PacketVideo's OpenCORE; the libraries support playback and recording of many popular audio and video formats, as well as static image files, including MPEG4, H.264, MP3, AAC, AMR, JPG, and PNG
* Surface Manager - manages access to the display subsystem and seamlessly composites 2D and 3D graphic layers from multiple applications
* LibWebCore - a modern web browser engine which powers both the Android browser and an embeddable web view
* SGL - the underlying 2D graphics engine
* 3D libraries - an implementation based on OpenGL ES 1.0 APIs; the libraries use either hardware 3D acceleration (where available) or the included, highly optimized 3D software rasterizer
* FreeType - bitmap and vector font rendering
* SQLite - a powerful and lightweight relational database engine available to all applications
Android Runtime
Android includes a set of core libraries that provides most of the functionality available in the core libraries of the Java programming language.
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 which is optimized for minimal memory footprint. The VM is register-based, and runs classes compiled by a Java language compiler that have been transformed into the .dex format by the included "dx" tool.
The Dalvik VM relies on the Linux kernel for underlying functionality such as threading and low-level memory management.
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. The kernel also acts as an abstraction layer between the hardware and the rest of the software stack.
Smartphone operating systems
Table showing most of the current mobile operating systems for smartphones, PDAs and netbooks in 2010
Share of 2010 Q2 smartphone sales to end users by operating system, according to Gartner.
Operating systems that can be found on smartphones like Nokia's Symbian OS, Apple's iOS, RIM's BlackBerry OS, Microsoft's Windows Phone OS, Linux, Palm WebOS, Google's Android, Samsung's Bada (operating system) and Nokia's Maemo. Android, Bada, WebOS and Maemo are in turn built on top of Linux, and the iPhone OS is derived from the BSD and NeXTSTEP operating systems, which all are related to Unix.
The most common operating systems (OS) used in smartphones by Q2 2009 sales are:
The Symbian OS and its successor Symbian platform from the Symbian Foundation (41.2% Market Share Sales Q2 2010)(open public license)
Symbian has the largest share in most markets worldwide, but lags behind other companies in the relatively small but highly visible North American market.This matches the success of its largest shareholder and customer, Nokia, in all markets except Japan. In Japan Symbian is strong due to a relationship with NTT DoCoMo, with only one of the 44 Symbian handsets released in Japan coming from Nokia. It has been used by many major handset manufacturers, including BenQ, Fujitsu, LG, Mitsubishi, Motorola, Nokia, Samsung, Sharp, and Sony Ericsson. Current Symbian-based devices are being made by Fujitsu, Nokia, Samsung, Sharp, and Sony Ericsson. Prior to 2009 Symbian supported multiple user interfaces, i.e. UIQ from UIQ Technologies, S60 from Nokia, and MOAP from NTT DOCOMO. As part of the formation of the Symbian platform in 2009 these three UIs were merged into a single platform which is now fully open source. Recently, though shipments of Symbian devices has increased, the operating system's worldwide market share has declined from over 50% to just over 40% from 2009 to 2010.
RIM BlackBerry OS (18.2% Market Share Sales Q2 2010)(closed source, proprietary)
This OS is focused on easy operation and was originally designed for business. Recently it has seen a surge in third-party applications and has been improved to offer full multimedia support. Currently Blackberry's App World has over 6,000 downloadable applications.
Android from Google Inc. (17.2% Market Share Sales Q2 2010) (open source, Apache)
Android was developed by a small startup company that was purchased by Google Inc., and Google continues to update the software. Android is an open source, Linux-derived platform backed by Google, along with major hardware and software developers (such as Intel, HTC, ARM, Samsung, Motorola and eBay, to name a few), that form the Open Handset Alliance.This OS is fairly new, though has a following among programmers. There have been six releases of Android- Android 1.0, 1.5, 1.6, 2.0, 2.1 and 2.2. All are nicknamed after a dessert item like Cupcake (1.5) or Frozen Yogurt (2.2). Most major mobile service providers carry an Android device.
The Apple iPad tablet computer uses a version of iOS.
Since the HTC Dream (T-Mobile G1) was introduced, there has been an explosion in the amount of devices that carry Android OS. From Q2 of 2009 to the second quarter of 2010, Android's worldwide market share rose 850% from 1.8% to 17.2%.
iOS from Apple Inc. (14.2% Market Share Sales Q2 2010)(closed source, proprietary)
The Apple iPhone, iPod Touch and iPad all use an operating system called iOS, which is derived from Mac OS X. Third party applications were not officially supported until the release of iOS 2.0 on July 11th 2008. Before this, "jailbreaking" allowed third party applications to be installed, and this method is still available. Currently all iOS devices are developed by Apple and manufactured by Foxconn or another of Apple's partners.
Windows Mobile from Microsoft (5% Market Share Sales Q2 2010)(closed source, proprietary)
The Windows CE operating system and Windows Mobile middleware are widely spread in Asia. The two improved variants of this operating system, Windows Mobile 6 Professional (for touch screen devices) and Windows Mobile 6 Standard, were unveiled in February 2007. It has been criticized for having a user interface which is not optimized for touch input by fingers; instead, it is more usable with a stylus. However, unlike iPhone OS, it does support both touch screen and physical keyboard configurations.
Windows Mobile's market share has sharply declined in recent years to just 5% in Q2 of 2010. Microsoft is phasing out the Windows Mobile OS to specialized markets and is instead focusing on it's new platform, Windows Phone.
Windows Phone from Microsoft (negligible Market Share Sales in October 2010)(closed source, proprietary)
On February 15th, 2010 Microsoft unveiled its next-generation mobile OS, Windows Phone 7. The new mobile OS includes a completely new over-hauled UI inspired by Microsoft's "Metro Design Language". It includes full integration of Microsoft services such as Windows Live, Zune, Xbox Live and Bing, but also integrates with many other non-Microsoft services such as Facebook and Google accounts. The new OS platform has received some positive reception from the technology press.Windows Phone 7 is a new platform, there is no backwards compatibility with Windows Mobile applications and some power-user features that were in Windows Mobile will not be present until near-future updates.
The Palm Pre running HP (formerly Palm) webOS. HP purchased Palm in 2010.
Linux operating system (open source, GPL) (2.4% Market Share Sales Q2 2010)
Linux is strongest in China where it is used by Motorola, and in Japan, used by DoCoMo.[15][16] Rather than being a platform in its own right, Linux is used as a basis for a number of different platforms developed by several vendors, including Android, LiMo, Maemo, Openmoko and Qt Extended, which are mostly incompatible. PalmSource (now Access) is moving towards an interface running on Linux. Another platform based on Linux is being developed by Motorola, NEC, NTT DoCoMo, Panasonic, Samsung, and Vodafone.
Palm webOS from HP (certain parts open sourced) and Palm OS/Garnet OS from Access Co. (closed source, proprietary)
Palm webOS is Palm's next generation operating system. PalmSource traditionally used its own platform developed by Palm Inc. Access Linux Platform (ALP) is an improvement that was planned to be launched in the first half of 2007. It will use technical specifications from the Linux Phone Standards Forum. The Access Linux Platform will include an emulation layer to support applications developed for Palm-based devices.
bada from Samsung Electronics (closed source, proprietary)
This is a mobile operating system being developed by Samsung Electronics. Samsung claims that bada will rapidly replace its proprietary feature phone platform, converting feature phones to smartphones.The name 'bada' is derived from ?, the Korean word for ocean or sea. The first device to run bada is called 'Wave' and was unveiled to the public at Mobile World Congress 2010. The Wave is a fully touchscreen phone running the new mobile operating system. With the phone, Samsung also released an app store, called Samsung Apps, to the public. It currently has 300 mobile applications.
Samsung has said that they don't see Bada as a smartphone platform, but as a platform with a kernel configurable architecture, which allows the use of either proprietary Real-time operating system (RTOS) kernel, or the Linux kernel. Though Samsung plans to install bada on many phones, the company still has a large lineup of Android phones.
MeeGo from Nokia and Intel (open source, GPL)
At the 2010 Mobile World Congress in Barcelona, Nokia and Intel both unveiled 'MeeGo' a brand new mobile operating system which would combine the best of Moblin and the best of Maemo to create a truly open-sourced experience for users across all devices.
Maemo from Nokia (open source, GPL)
Maemo is a software platform developed by Nokia for smartphones and Internet Tablets. It is based on the Debian operating system.
Maemo is mostly based on open source code, and has been developed by Maemo Devices within Nokia in collaboration with many open source projects such as the Linux kernel, Debian and GNOME.
Maemo is based on Debian GNU/Linux and draws much of its GUI, frameworks and libraries from the GNOME project. It uses the Matchbox window manager and the GTK-based Hildon as its GUI and application framework.Source URL: http://gbejadacosta.blogspot.com/2010/11/smartphone-operating.html
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