Search This Blog

Showing posts with label what is an android. Show all posts
Showing posts with label what is an android. Show all posts

Saturday, August 27, 2011

Android Overview and History


Back in July 2005, when Google seemed to have so much money it didn't know what to do with, it quietly went about buying up a load of start-up companies.
Some of these never really saw the light of day: for instance, Dodgeball, a service that allowed you to text a group of friends in a similar way to Twitter, has never really appeared anywhere in Google's stable.
But at the same time, it also bought a little-known company called Android Inc, co-founded by Andy Rubin, now director of mobile platforms at Google.
Little was known about this company even within its own industry: in fact, all that was available in terms of description was it was 'it developed software for mobile phones.'
In 2003, before getting involved with Android, Rubin conducted an interview with Business Week:
"Rubin said there was tremendous potential in developing smarter mobile devices that are more aware of its owner's location and preferences.
'If people are smart, that information starts getting aggregated into consumer products,' said Rubin"
The gPhone
Hot on the heels of the iPhone launch, rumours began to increase of Google bringing out its own handset, to help leverage its burgeoning mobile search functions.
Widespread reports of Google hawking its wares round to all the major manufacturers and carriers began to circulate; it was believed the new handset would be designed to work around location-based services and implement a whole host of Google Labs' ideas, as well as the old favourites Maps and Mail.
In fact, the fact Google was spotted more times than a Big Brother reject in the media meant it became a matter of when and not if a gPhone would be announced.
Remember, remember the 5 November (2007)
And then the Californians went and sprang a huge surprised on the world: not only had it not been working on a handset, it had been developing the core of a whole new open-source OS to rival the likes of Symbian, Microsoft et al.
And all those clandestine meetings? The beginnings of what we now know as the Open Handset Alliance (OHA), including HTC, LG, Samsung, T-Mobile and a whole host of other names.
And what many people fail to realise, especially those who call it 'Google's Android', is that the new platform was born out of this group, not Google incorporating the help of others.
Well, that's not strictly true - Google is clearly the main driving force behind the new system, but all factions of the OHA stand to do well from the success of the OS.
Many people had trouble understanding the benefits of what Google Android actually was, and what made it special compared to the raft of other rival OS systems out there.
Lego
The best way to describe it was making all sections of the system like Lego bricks. Where before developers might have struggled to break down the bits of a mobile phone OS, and even if successful, would find that getting one part of the system to talk to another was very difficult indeed, as they were packaged up in their own little programmes.
But with Android, the rules were changed. Fancy making a GPS application that used SMS location updates? The two sections would fit together nicely. If you wanted to add in some location data from the net too? Just pop on a web piece, too.
OK, it may not be that simple, but to the developer community, it represented a big step forward. While the above may have been possible through things like Linux for Mobiles (LiMO), Google Android aims to provide the same thing on a larger, more unified scale, thus bringing a wider audience in the future.
The theory behind the system is very similar to that which has made Google such a success so far: mobile advertising and revenue share are likely to become the big buzzwords for such a platform, and will need to be leveraged well to make Android a success for Google and the OHA.
The aftermath
So now the secret was out, the pressure really was on to actually get Android to market in enough time that other companies and organisations wouldn't be able to steal a march.
Here's a quick run down of the highlights of the Android development in the last 10 months:
* The OHA releases the Android developers SDK on the 12 November, just a week after announcement. The development community gets its first glimpse of what is capable, and likely begins working out the most efficient way to get adult content on a mobile handset.
* In February, a number of companies including Qualcomm and Texas Instruments had chipsets working on very basic versions of the Android OS, giving the world its first sneak preview of OS.

Wednesday, August 17, 2011

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
  • 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
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.