page.title=Android Technical Information
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    <h2>In this document</h2>
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<p>Welcome to the Android technical documentation section of the site. Here you
can find technical information useful to people and organizations who are
looking to modify, contribute to, or port the Android software. This is "under
the hood" information intended for engineers.</p>

<h2 id="accessory-protocol-information">Accessory Protocol Information</h2>
<p>Android devices can connect to hardware accessories, such as audio docks,
keyboards and custom hardware, through USB or Bluetooth. This document
describes the Android Open Accessory protocol for accessory hardware builders.</p>
<p><a href="{@docRoot}accessories/index.html">&raquo; Accessory Protocol Information</a></p>

<h2 id="dalvik-technical-information">Dalvik Technical Information</h2>
<p>The Dalvik Virtual Machine is the heart of Android. It's a fast, just-in-time
compiled, optimized bytecode virtual machine. Android applications are
compiled to Dalvik bytecode and run on the Dalvik VM. This section includes
detailed information such as the Dalvik bytecode format specification,
design information on the VM itself, and so on.</p>
<p><a href="{@docRoot}devices/tech/dalvik/index.html">&raquo; Dalvik Information</a></p>

<h2 id="data-usage-technical-information">Data Usage Technical Information</h2>
<p>Android's data usage features allow users to understand and control how their
device uses network data. This document is designed for systems integrators
and mobile operators, to help explain technical details they should be aware
of when porting Android to specific devices.</p>
<p><a href="{@docRoot}devices/tech/datausage/index.html">&raquo; Data Usage Information</a></p>

<h2 id="debugging">Debugging and Tuning</h2>
<p>Android is a large and complex system. This section includes tips and tricks
about debugging at the platform level.</p>
<p><a href="{@docRoot}devices/debugtune.html">&raquo; Debugging Information</a></p>

<h2 id="HAL-technical-information">HAL File Reference</h2>
<p>Android's Hardware Abstraction Layer (HAL) provides the interface between
software APIs and hardware drivers. This section contains the commented code
files of the HAL.</p>
<p><a href="{@docRoot}devices/halref/files.html">&raquo; HAL Reference</a></p>

<h2 id="kernel-technical-information">Kernel Technical Information</h2>
<p>The kernel configuration settings in this document are meant to be used as a base
for an Android kernel configuration. All devices should have the options in android-base
configuration enabled.</p>
<p><a href="{@docRoot}devices/tech/kernel.html">&raquo; Kernel Information</a></p>

<h2 id="power-technical-information">Power Technical Information</h2>
<p>Battery usage statistics are tracked by the framework. This involves keeping track of 
time spent by different device components in different states.</p>
<p><a href="{@docRoot}devices/tech/power.html">&raquo; Power Information</a></p>

<h2 id="tradefed-test-infrastructure">Trade Federation Testing Infrastructure</h2>
<p>Trade Federation is a continuous test framework for running tests on Android devices. 
Trade Federation's modularity makes it straightforward to slot into environments with existing build, 
test, and reporting infrastructures.</p>
<p><a href="{@docRoot}devices/tech/test_infra/tradefed/index.html">&raquo; Trade Federation Testing Infrastructure Overview</a></p>