Android Open Source Project

Android Open Source Project
Name	Android Open Source Project
Developer	Google, Open Handset Alliance
Released	21 October 2008
Programming language	C, C++, Java, Kotlin
Operating system	Linux
Genre	Mobile operating system
License	Apache License 2.0, GPLv2
Website	source.android.com

Android Open Source Project. The Android Open Source Project (AOSP) is the foundational, open-source codebase from which the commercial Android operating system is built. Maintained primarily by Google, it provides the core platform and system services that device manufacturers and developers can use and modify freely. The project is licensed permissively, allowing extensive customization and has led to a vast ecosystem of devices and derivative software distributions.

History and development

The project's origins trace back to Android Inc., a company founded in Palo Alto in 2003 by Andy Rubin, Rich Miner, Nick Sears, and Chris White. Google acquired the startup in 2005, and development continued in secret. The public unveiling occurred in 2007 with the formation of the Open Handset Alliance, a consortium of technology companies including HTC, Samsung, Motorola, and Qualcomm. The first public release, based on Linux kernel 2.6, was Android 1.0, which debuted on the HTC Dream (T-Mobile G1) in 2008. Key early figures in its engineering included Mike Cleron and Dianne Hackborn. Major version milestones have often been named after desserts, such as Cupcake, Donut, and Pie.

Architecture and components

The architecture is a layered software stack. At its base is the modified Linux kernel, which handles core system functions like memory management and process control. Above this lies the Hardware Abstraction Layer, which provides standard interfaces for hardware components like the Bluetooth radio or camera. The core runtime, historically powered by the Dalvik virtual machine and now Android Runtime (ART), executes application code. Critical native libraries, many from the Open Source Initiative, include OpenGL ES for graphics and SQLite for database management. The application framework exposes APIs for developers to build apps, managing fundamental elements like the Activity lifecycle and notifications.

Licensing and governance

The project uses a mix of open-source licenses. Most user-space code, including the application framework and standard apps, is released under the permissive Apache License 2.0. This allows manufacturers to modify and distribute code without being required to share their changes publicly. The underlying Linux kernel modifications, however, are licensed under the copyleft GNU General Public License version 2 (GPLv2), which requires derivative works to make their source code available. Governance is primarily overseen by engineers at Google, who manage the main code repository and decide on the integration of features into the official releases, though external contributions are accepted through a review process.

Device compatibility and certification

To ensure a consistent experience across devices, Google defines a Compatibility Definition Document and a suite of tests called the Compatibility Test Suite (CTS). Manufacturers whose devices pass the CTS can license Google's proprietary apps and services, such as the Google Play Store and Google Mobile Services. This certification is separate from the open-source project itself. The Google Play Services platform, which provides APIs for Google Maps, Google Sign-In, and Firebase Cloud Messaging, is a proprietary layer that runs on top of compatible AOSP builds.

Relationship with Google Android

The commercial "Google Android" found on most smartphones is a superset of the AOSP code. It combines the open-source base with Google's proprietary applications and services. While the AOSP includes essential system apps like a dialer and SMS messenger, it lacks the Google Play Store, Gmail, Chrome, and other Google-branded software. Manufacturers like Samsung with its One UI, Xiaomi with MIUI, and OnePlus with OxygenOS use AOSP as a starting point, then add their own custom interfaces and applications alongside Google's licensed suite.

Community and forking

The permissive licensing has fostered a large community of developers and enthusiasts who create modified versions, or "forks," of the AOSP code. Notable examples include LineageOS, a popular aftermarket firmware that succeeded CyanogenMod. Other significant forks include Replicant, which aims for a fully free software distribution, and CalyxOS, which focuses on privacy and security. Various Chinese technology firms, including Huawei with its HarmonyOS and Xiaomi, have also utilized AOSP code for devices in markets where Google Mobile Services are not available, creating distinct ecosystems.

Category:Android (operating system) Category:Open-source mobile operating systems Category:Google software Category:2008 software