1page.title=Android Technical Information 2@jd:body 3 4<!-- 5 Copyright 2014 The Android Open Source Project 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18--> 19<div id="qv-wrapper"> 20 <div id="qv"> 21 <h2>In this document</h2> 22 <ol id="auto-toc"> 23 </ol> 24 </div> 25</div> 26 27 28<p>Welcome to the Android technical documentation section of the site. Here you 29can find technical information useful to people and organizations who are 30looking to modify, contribute to, or port the Android software. This is "under 31the hood" information intended for engineers.</p> 32 33<h2 id="accessory-protocol-information">Accessory Protocol Information</h2> 34<p>Android devices can connect to hardware accessories, such as audio docks, 35keyboards and custom hardware, through USB or Bluetooth. This document 36describes the Android Open Accessory protocol for accessory hardware builders.</p> 37<p><a href="{@docRoot}accessories/index.html">» Accessory Protocol Information</a></p> 38 39<h2 id="dalvik-technical-information">Dalvik Technical Information</h2> 40<p>The Dalvik Virtual Machine is the heart of Android. It's a fast, just-in-time 41compiled, optimized bytecode virtual machine. Android applications are 42compiled to Dalvik bytecode and run on the Dalvik VM. This section includes 43detailed information such as the Dalvik bytecode format specification, 44design information on the VM itself, and so on.</p> 45<p><a href="{@docRoot}devices/tech/dalvik/index.html">» Dalvik Information</a></p> 46 47<h2 id="data-usage-technical-information">Data Usage Technical Information</h2> 48<p>Android's data usage features allow users to understand and control how their 49device uses network data. This document is designed for systems integrators 50and mobile operators, to help explain technical details they should be aware 51of when porting Android to specific devices.</p> 52<p><a href="{@docRoot}devices/tech/datausage/index.html">» Data Usage Information</a></p> 53 54<h2 id="debugging">Debugging and Tuning</h2> 55<p>Android is a large and complex system. This section includes tips and tricks 56about debugging at the platform level.</p> 57<p><a href="{@docRoot}devices/debugtune.html">» Debugging Information</a></p> 58 59<h2 id="HAL-technical-information">HAL File Reference</h2> 60<p>Android's Hardware Abstraction Layer (HAL) provides the interface between 61software APIs and hardware drivers. This section contains the commented code 62files of the HAL.</p> 63<p><a href="{@docRoot}devices/reference/files.html">» HAL Reference</a></p> 64 65<h2 id="kernel-technical-information">Kernel Technical Information</h2> 66<p>The kernel configuration settings in this document are meant to be used as a base 67for an Android kernel configuration. All devices should have the options in android-base 68configuration enabled.</p> 69<p><a href="{@docRoot}devices/tech/kernel.html">» Kernel Information</a></p> 70 71<h2 id="power-technical-information">Power Technical Information</h2> 72<p>Battery usage statistics are tracked by the framework. This involves keeping track of 73time spent by different device components in different states.</p> 74<p><a href="{@docRoot}devices/tech/power.html">» Power Information</a></p> 75 76<h2 id="tradefed-test-infrastructure">Trade Federation Testing Infrastructure</h2> 77<p>Trade Federation is a continuous test framework for running tests on Android devices. 78Trade Federation's modularity makes it straightforward to slot into environments with existing build, 79test, and reporting infrastructures.</p> 80<p><a href="{@docRoot}devices/tech/test_infra/tradefed/index.html">» Trade Federation Testing Infrastructure Overview</a></p> 81 82