Why Android?

android-mobile-phone-cell

Android™ delivers a complete set of software for mobile devices: an operating system, middleware and key mobile applications. The Android Software Development Kit (SDK) is now available.

Open

Android was built from the ground-up to enable developers to create compelling mobile applications that take full advantage of all a handset has to offer. It was built to be truly open. For example, an application can call upon any of the phone’s core functionality such as making calls, sending text messages, or using the camera, allowing developers to create richer and more cohesive experiences for users. Android is built on the open Linux Kernel. Furthermore, it utilizes a custom virtual machine that was designed to optimize memory and hardware resources in a mobile environment. Android is open source; it can be liberally extended to incorporate new cutting edge technologies as they emerge. The platform will continue to evolve as the developer community works together to build innovative mobile applications.

All applications are created equalandroid

Android does not differentiate between the phone’s core applications and third-party applications. They can all be built to have equal access to a phone’s capabilities providing users with a broad spectrum of applications and services. With devices built on the Android Platform, users are able to fully tailor the phone to their interests. They can swap out the phone’s homescreen, the style of the dialer, or any of the applications. They can even instruct their phones to use their favorite photo viewing application to handle the viewing of all photos.

Breaking down application boundaries

Android breaks down the barriers to building new and innovative applications. For example, a developer can combine information from the web with data on an individual’s mobile phone — such as the user’s contacts, calendar, or geographic location — to provide a more relevant user experience. With Android, a developer can build an application that enables users to view the location of their friends and be alerted when they are in the vicinity giving them a chance to connect.

Fast & easy application development

Android provides access to a wide range of useful libraries and tools that can be used to build rich applications. For example, Android enables developers to obtain the location of the device, and allows devices to communicate with one another enabling rich peer-to-peer social applications. In addition, Android includes a full set of tools that have been built from the ground up alongside the platform providing developers with high productivity and deep insight into their applications.

What is Android?

android-logo

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.

android-system-architecture

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

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
  • Resource Manager, providing access to non-code resources such as localized strings, graphics, and layout files
  • 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.

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.

Cheers…

Can Microsoft’s Bing, or Anyone, Seriously Challenge Google?

Google vs BingEvery year, the market-research firm Millward Brown conducts a survey to determine the economic worth of the world’s brands — in other words, to put a dollar value on the many corporate logos that dominate our lives. Lately the firm’s results have been stuck on repeat: Google has claimed the top spot for the past three years. The most recent report values Google’s brand — those six happy letters that herald so many of our jaunts down the Web’s rabbit hole — at more than $100 billion.

What’s astonishing about this stat is how effortlessly Google seems to have earned the public’s affection. Other companies — Microsoft, Coke, IBM, McDonald’s — spend enormous sums to stay in the consciousness. Google, which makes most of its money from ads, rarely advertises itself. Telling the world how well it does what it does just isn’t Google’s way. (See pictures of work and life at Google.)

But Google’s humility is being tested as never before. The firm’s headquarters in Mountain View, Calif., seem besieged by competitors gaining new momentum. Even nominal allies are questioning the company’s motives and long-term plans. In July, Google’s largest competitors, Microsoft and Yahoo!, agreed to work together in an attempt to dethrone it as the world’s dominant search engine. The deal, which awaits government approval, would create a first: a tenacious, well-financed search rival.

Conflicts are beginning to take place in other areas where Google has ventured. That includes e-mail and office programs (Gmail, Google Docs), a cell-phone operating system (Android) and a Web browser (Chrome). Google scans and sells books, runs a phone system and is even working on a desktop operating system to rival Windows. CEO Eric Schmidt recently stepped down from Apple’s board of directors because the two companies now compete in so many areas. The U.S. Justice Department is investigating a legal settlement between Google and the publishing industry over the company’s book-scanning service, and Christine Varney, Justice’s antitrust chief, said she sees Google as a “problem.”

At the moment, Google’s most pressing problem is Microsoft. The software giant is spending $100 million to market its new search engine, Bing — and in the process, to get us all bummed about Google. Bing’s slick ads are unavoidable and blistering. They suggest that Google is broken, that it rarely leads us to what we’re looking for and turns us all into blathering zombies who spew out search keywords in casual conversation. (See the top 10 TV ads of 2008.)

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