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Our lives are being surrounded by a growing number of digital gadgets. Mobile phones, set-top boxes, e-book readers, netbooks digital photo frames (DPF), and a host of other devices are getting connected to Internet for content such as photos, weather, maps, traffic, music, videos, news, etc. As many of these devices are portable; low power consumption, small form factor, intuitive UI and time-to-market become major differentiators. simplicity and user-friendliness are the keywords for these gadgets.

The challenge for the device manufacturer is to provide increasingly more featured, low power, robust user-friendly devices at low price point. Developing interesting applications on top of proprietary systems across a range of hardware platforms and architecture is an expensive proposition and requires significant time for an increasingly small window of market opportunity. Currently, due to the nature of fragmented platforms, applications are usually device-specific and only large companies can afford to port applications across multiple devices.

Moving Beyond
Android presents a compelling value proposition in bringing Internet connectivity and a broad range of applications to consumer devices. It helps device manufacturers to build innovative products faster. Since Android was designed for low CPU usage and memory constrained mobile phones, it is well suited for consumer devices.

The Android application framework and SDK now extend beyond the handset assumptions for which it was initially developed.

Android provides an open source, unified software stack which is fully customizable platform for product vendors/OEMs. The well defined application framework and application lifecycle management on top of Linux allows developers to write applications easily on various devices. Device manufacturers get a license and royalty-free platform to create simple user-intuitive interfaces for various consumer devices.

Google has made several critical enhancements for the Linux Kernel subsystems and libraries for embedded usage. Some of the enhancements include:

Bionic: a compact and fast C run-time library with fast thread implementation

Power management: Aggressive power management policy on top of Linux power management. Application components can request to keep partial power on. This is very important for power sensitive consumer devices

AshMem: Ashmem is an anonymous shared memory system that adds interfaces so that processes can share named blocks of memory across various processes. It provides a means for the kernel to reclaim these shared memory blocks if they are not in use

Binder IPC: A shared memory based IPC system providing higher level APIs that allows processes to provide services to other processes

Eclipse based graphical IDE for application development and tools for debugging reduce development time. Consumer device vendors can now readily leverage these features and up-to-date kernel and run-time libraries using well defined application framework.

Android provides a flexible, powerful OpenCore based multimedia subsystem. This allows developers to build applications supporting audio/video capture, playback, streaming, special effects and multiple data formats faster. Pluggable OpenMax based framework allows platform providers to easily integrate multimedia codecs implemented in hardware and software. The Skia graphics engine in Android is capable of rendering high quality visual effects even on constrained devices.

Thus for consumer devices like cameras, music/video players, camcorders which require rich multimedia features, Android platform can accelerate time-to-market with its multimedia subsystem.

All these features make Android a well suited platform for embedded devices like set-top boxes, tablets, e-book readers, digital media devices, digital dashboards, MIDs. It creates a level playing ground where small consumer device vendors with innovative applications and features can compete against the largest OEMs.

By providing a single platform for various devices, Android provides an opportunity for application developers to re-use application across devices thus enabling wider market reach and cost reduction. However, effort would be needed to integrate Android seamlessly to take advantage of various hardware specific features for different type of consumer devices.

For long, original OEMs have been searching for a platform on which a product can be developed quickly at lower costs (without the hassles of licensing costs), and that which consumes low power and can be customized easily. Android meets most of these requirements of the OEMs.

Android offers a full platform stack which consists of an operating system (OS), middleware, application framework, rich set of APIs, and key applications. Ease of application development, open source licensing, good tooling, broad industry support backed by Google, well-designed application framework and middleware have helped create a large developer base. These attributes have contributed in wider acceptance of Android as a popular mobile platform with players like HTC, Motorola, Samsung, LG, and Acer.

Overview and Architecture

• The Android platform consists of the following components:
• Linux Kernel
• Native Libraries + Android Runtime (Dalvik Virtual Machine + Core Libraries)
• Application Framework
• Applications

Android uses an enhanced Linux 2.6.x for core OS services like memory management, process management, network services, power management, driver model, and hardware drivers. There is no native windowing support. Android includes a rich set of C/C++ libraries including an compact and fast C run-time library (Bionic), media framework based on PacketVideo OpenCore platform, surface manager, LibWebCore, SGL (2D graphics engine), OpenGLes based 3D graphics, FreeType and SQLite library. Android HAL is a user space C/C++ library that defines the interface that hardware drivers need to implement.

Android provides a well defined application framework and services for user application. Android provides core platform services like window manager, activity manager, resource manager, view manager, etc.

It also provides hardware services to access to low level services like telephony service, location service, sensor service, Wi-Fi service, USB and Bluetooth service. Android applications are written in the Java language on top of the application framework. The Java syntax provides the developers with a simple familiar environment with great tooling and library support. Parts of the applications can be developed using native-code languages such as C and C++. The native code can be called using JNI. Google provides native development kit (NDK) to provide tooling support to develop native libraries.

Android includes a set of core applications including a browser, email client, contacts, SMS program, calendar, maps, and others, all written in Java. Most of the Android code are released under the Apache free-software and open source license. Some of the Android applications however are not open source. Android also comes with a comprehensive set of development tools which include a SDK QEMU based emulator, eclipse plug-ins, debugger, and libraries.

Amit Modak
The author is project lead at MindTree
maildqindia@cybermedia.co.in

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