What is Android ? What are its Features and Applications ?

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About an Android Operating System

Android is an operating system based on the Linux kernel and designed primarily for touchscreen mobile devices such as smartphones and tablet computers. Initially developed by Android, Inc.and now google is takeover this.

Android

• Now a days 70% of the smartphones is using this operating system.
• Except the Apple company all the other companies are using this operating system.
• The apps which are working based upon this operating system are available at “Googleplay”.
• In googleplay upto now 7lakhs apps will be available here.
• The user interface of Android is based on direct manipulation, using touch inputs that loosely correspond to real-world actions,      like swiping, tapping, pinching and reverse pinching to manipulate on-screen objects.
• Internal hardware such as accelerometers, gyroscopes and proximity sensors are used by some applications to respond to additional user actions, for example adjusting the screen from portrait to landscape depending on how the device is oriented.
• Android allows users to customize their home screens with shortcuts to applications and widgets, which allow users to display live  content, such as emails and weather information, directly on the home screen. Applications can further send notifications to the  user to inform them of relevant information, such as new emails and text messages.
• Android’s source code is released by Google under the Apache License this permissive licensing allows the software to be freely  modified and distributed by device manufacturers, wireless carriers and enthusiast developers. Most Android devices are ship  with a combination of open source and proprietary software.
• Now it is very popular with technology companies which require a ready-made, low-cost and customizable operating system for  high-tech devices. Despite being primarily designed for phones and tablets, it also has been used in televisions, games consoles,  digital cameras and other electronics.
Android became the most popular mobile OS, having the largest installed base, and is a market leader in most countries including the United States; there it has had the highest installed base of mobile phones for years.

Features in Android:

Interface

android interface

  • Android’s user interface is based on direct manipulation, using touch inputs that loosely correspond to real-world actions, like swiping, tapping, pinching and reverse pinching to manipulate on-screen objects. The response to user input is designed to be immediate and provides a fluid touch interface, often using the vibration capabilities of the device to provide haptic feedback to the user.
  •  Internal hardware such as accelerometers, gyroscopes and proximity sensors are used by some applications to respond to additional user actions, for example adjusting the screen from portrait to landscape depending on how the device is oriented, or allowing the user to steer a vehicle in a racing game by rotating the device, simulating control of a steering wheel.
  •  Android devices boot to the homescreen, the primary navigation and information point on the device, which is similar to the desktop found on PCs. Android homescreens are typically made up of app icons and widgets; app icons launch the associated app, whereas widgets display live, auto-updating content such as the weather forecast, the user’s email inbox, or a news ticker directly on the homescreen.
  •  A homescreen may be made up of several pages that the user can swipe back and forth between, though Android’s homescreen interface is heavily customisable, allowing the user to adjust the look and feel of the device to their tastes. Third-party apps available on Google Play and other app stores can extensively re-theme the homescreen, and even mimic the look of other operating systems, such as Windows Phone. Most manufacturers, and some wireless carriers, customise the look and feel of their Android devices to differentiate themselves from their competitors
home page
pic credits: www.wikihow.com
  •  Present along the top of the screen is a status bar, showing information about the device and its connectivity. This status bar can be “pulled” down to reveal a notification screen where apps display important information or updates, such as a newly received email or SMS text, in a way that does not immediately interrupt or inconvenience the user.
  •  Notifications are persistent until read (by tapping, which opens the relevant app) or dismissed by sliding it off the screen. Beginning on Android 4.1, “expanded notifications” can display expanded details or additional functionality; for instance, a music player can display playback controls, and a “missed call” notification provides buttons for calling back or sending the caller an SMS message.
  •  Android provides the ability to run applications which change the default launcher and hence the appearance and externally visible behaviour of Android. These appearance changes include a multi-page dock or no dock, and many more changes to fundamental features of the user interface.

Applications:

Android software development and Google Play

google play

  •  Android has a growing selection of third party applications, which can be acquired by users either through an app store such as Google Play or the Amazon Appstore, or by downloading and installing the application’s APK file from a third-party site. The Play Store application allows users to browse, download and update apps published by Google and third-party developers, and is pre-installed on devices that comply with Google’s compatibility requirements.
  •  The app filters the list of available applications to those that are compatible with the user’s device, and developers may restrict their applications to particular carriers or countries for business reasons.
  • Applications (“apps”), that extend the functionality of devices, are developed primarily in the Java programming language. language using the Android software development kit (SDK). The SDK includes a comprehensive set of development tools, including a debugger, software libraries, a handset emulator based on QEMU, documentation, sample code, and tutorials. The officially supported integrated development environment (IDE) is Eclipse using the Android Development Tools (ADT) plugin. Other development tools are available, including a Native Development Kit for applications or extensions in C or C++, Google App Inventor, a visual environment for novice programmers, and various cross platform mobile web applications frameworks.

Memory management:

Since Android devices are usually battery-powered, Android is designed to manage memory (RAM) to keep power consumption at a minimum, in contrast to desktop operating systems which generally assume they are connected to unlimited mains electricity. When an Android app is no longer in use, the system will automatically suspend it in memory – while the app is still technically “open”, suspended apps consume no resources (e.g. battery power or processing power) and sit idly in the background until needed again.

This has the dual benefit of increasing the general responsiveness of Android devices, since apps don’t need to be closed and reopened from scratch each time, but also ensuring background apps do not consume power needlessly.

Android manages the apps stored in memory automatically:

When memory is low, the system will begin killing apps and processes that have been inactive for a while, in reverse order since they were last used (i.e. oldest first). This process is designed to be invisible to the user, such that users do not need to manage memory or the killing of apps themselves. However, confusion over Android memory management has resulted in third-party task killers becoming popular on the Google Play store; these third-party task killers are generally regarded as doing more harm than good.

Android hardware requirements:

  •  The main hardware platform for Android is the 32-bit ARMv7 architecture. The Android-x86 project provides support for the x86 architecture, and Google TV uses a special x86 version of Android. current versions of Android recommend at least 512 MB of RAM (with 340 MB as a requirement), and require a 32-bit ARMv7, MIPS or x86 architecture processor (latter two through unofficial ports), together with an OpenGL ES 2.0 compatible graphics processing unit (GPU).
  •  Android supports OpenGL ES 1.1, 2.0 and 3.0. Some applications explicitly require certain version of the OpenGL ES, thus suitable GPU hardware is required to run such applications.
  •  Android devices incorporate many optional hardware components, including still or video cameras, GPS, hardware orientation sensors, dedicated gaming controls, accelerometers, gyroscopes, barometers, magnetometers, proximity sensors, pressure sensors, thermometers and touchscreens.
  •  For example, as Android was developed initially as a phone OS, hardware such as microphones were required, while over time the phone function became optional. Android used to require an autofocus camera, which was relaxed to a fixed-focus camera if it is even present at all, since the camera was dropped as a requirement entirely when Android started to be used on set-top boxes.

Development:

Android is developed in private by Google until the latest changes and updates are ready to be released, at which point the source code is made available publicly. This source code will only run without modification on select devices, usually the Nexus series of devices.
The source code is, in turn, adapted by OEMs to run on their hardware. Android’s source code does not contain the often proprietary device drivers that are needed for certain hardware components.The green Android logo was designed for Google in 2007 by graphic designer Irina Blok.

Android version history:

  • Google provides major updates, incremental in nature, to Android every six to nine months, which most devices are capable of receiving over the air. The latest major update is Android 4.4 KitKat.
  • Compared to its chief rival mobile operating system, namely iOS, Android updates are typically slow to reach actual devices. For devices not under the Nexus brand, updates often arrive months from the time the given version is officially released.
  • In 2012, Google began decoupling certain aspects of the operating system (particularly core applications) so they could be updated through Google Play Store, independently of Android itself. One of these components, Google Play Services, is a system-level process providing APIs for Google services, installed automatically on nearly all devices running Android version 2.2 and higher.
  • With these changes, Google can add new operating system functionality through Play Services and application updates without having to distribute an update to the operating system itself. As a result, Android 4.2 and 4.3 contained relatively fewer user-facing changes, focusing more on minor changes and platform improvements.

Linux kernel:

  • Android’s Linux kernel has further architecture changes by Google outside the typical Linux kernel development cycle. Certain features that Google contributed back to the Linux kernel, notably a power management feature called “wakelocks”, were rejected by mainline kernel developers partly because they felt that Google did not show any intent to maintain its own code.
  • The flash storage on Android devices is split into several partitions, such as /system for the operating system itself, and /data for user data and application installations. In contrast to desktop Linux distributions, Android device owners are not given root access to the operating system and sensitive partitions such as /system are read-only.
  • However,the root access can be obtained by exploiting security flaws in Android, which is used frequently by the open-source community to enhance the capabilities of their devices, but also by malicious parties to install viruses and malware.

Software stack:

  • Historically, device manufacturers and mobile carriers have typically been unsupportive of third-party firmware development. Manufacturers express concern about improper functioning of devices running unofficial software and the support costs resulting from this.
  • Moreover, modified firmwares such as CyanogenMod sometimes offer features, such as tethering, for which carriers would otherwise charge a premium. As a result, technical obstacles including locked bootloaders and restricted access to root permissions are common in many devices.
  • However, as community-developed software has grown more popular, and following a statement by the Librarian of Congress in the United States that permits the “jailbreaking” of mobile devices, manufacturers and carriers have softened their position regarding third party development, with some, including HTC, Motorola, Samsung and Sony, providing support and encouraging development.
  • As a result of this, over time the need to circumvent hardware restrictions to install unofficial firmware has lessened as an increasing number of devices are shipped with unlocked or unlockable bootloaders, similar to the Nexus series of phones, although usually requiring that users waive their devices’ warranties to do so. However, despite manufacturer acceptance, some carriers in the US still require that phones are locked down.
  • The unlocking and “hackability” of smartphones and tablets remains a source of tension between the community and industry, with the community arguing that unofficial development is increasingly important given the failure of industry to provide timely updates and/or continued support to their devices.

Security and privacy Mobile security:

Permissions are used to control a particular application’s access to system functions.
Android applications run in a sandbox, an isolated area of the system that does not have access to the rest of the system’s resources, unless access permissions are explicitly granted by the user when the application is installed. Before installing an application, the Play Store displays all required permissions: a game may need to enable vibration or save data to an SD card, for example, but should not need to read SMS messages or access the phonebook. After reviewing these permissions, the user can choose to accept or refuse them, installing the application only if they accept.

  • The sandboxing and permissions system lessens the impact of vulnerabilities and bugs in applications, but developer confusion and limited documentation has resulted in applications routinely requesting unnecessary permissions, reducing its effectiveness.
  • Google currently uses their Google Bouncer malware scanner to watch over and scan the Google Play store apps.It is intended to flag up suspicious apps and warn users of any potential issues with an application before they download it.

Android version 4.2 Jelly Bean was released in 2012 with enhanced security features, including a malware scanner built into the system, which works in combination with Google Play but can scan apps installed from third party sources as well, and an alert system which notifies the user when an app tries to send a premium-rate text message, blocking the message unless the user explicitly authorises it. Several security firms, such as Lookout Mobile Security,AVG Technologies, and McAfee, have released antivirus software for Android devices.

This software is ineffective as sandboxing also applies to such applications, limiting their ability to scan the deeper system for threats.

Android versions:

Every time the Android is releasing new versions by adding more features and that its very easy to the user to follow those all. Where upto now the Android has released so the next version will be release in few days.
Any guesses what will be the next Android version name . Here the version names are in Alphabetic order g,h,I,j So the K

Donut,Eclair,Froyo,Gingerbread,Honeycomb,jellyBean Android version names , next version will be starts with K. So guess the next Android version name.
We’ve been tipped by a reliable source today that Google will be using the name “Key Lime Pie” for the version of Android that comes after Jelly Bean.

So, Next Android version name is Key Lime.

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