Android utilizes a kernel based on the well-established Linux operating system kernel.
The Foundation: A Linux-Based Kernel
At its core, Android relies on the powerful and flexible Linux kernel. This provides Android with a stable and robust foundation for managing hardware, processes, memory, and networking. Leveraging the Linux kernel allows Android to benefit from decades of development, testing, and security improvements contributed by a vast global community.
Upstream Linux Long Term Supported (LTS) Kernel
Specifically, the Android kernel is derived from a particular type of Linux kernel. As stated in the provided reference:
- The Android kernel is based on an upstream Linux Long Term Supported (LTS) kernel.
Let's break down what this means:
- Upstream Linux: This refers to the standard, main development branch of the Linux kernel source code maintained by the global Linux community. Android starts with this widely accepted base rather than creating a kernel entirely from scratch.
- Long Term Supported (LTS): This is a crucial aspect. LTS kernels are versions of the Linux kernel that are designated to receive security updates and bug fixes for a much longer period than typical releases. This commitment to long-term support provides stability and enhances the security posture for devices running Android, which have extended lifespans in the market.
Why Use an LTS Kernel?
Using an LTS version from the upstream Linux project offers significant advantages for the Android ecosystem:
- Stability: LTS kernels are more mature and extensively tested compared to mainline or short-term releases.
- Security: Regular security patches are backported to LTS versions, protecting devices from known vulnerabilities over time.
- Maintainability: Having a consistent, well-supported base simplifies ongoing maintenance and updates for device manufacturers.
- Driver Support: While Android adds its own hardware abstraction layer (HAL) and drivers, starting with a stable Linux base means leveraging existing driver models and infrastructure.
Android-Specific Modifications
While based on the upstream Linux LTS kernel, the Android kernel includes specific modifications and additions necessary for the mobile environment. These include:
- Wake locks: A mechanism to manage device power states more granularly than standard Linux.
- Low Memory Killer (LMK): A system to manage memory pressure by selectively killing processes when memory runs low.
- Binder IPC: Android's inter-process communication system, crucial for how different parts of the Android framework communicate.
- Specific hardware drivers: Code written to interact with mobile-specific components like cameras, sensors, battery controllers, etc., which may not be part of the standard upstream kernel initially but are often contributed back over time.
Key Characteristics Summarized
Here's a quick overview of the Android kernel's key traits:
| Characteristic | Description |
|---|---|
| Base | Linux Operating System Kernel |
| Source | Derived from Upstream Linux |
| Version Type | Long Term Supported (LTS) for stability and security |
| Includes | Android-specific additions and drivers |
In summary, the Android kernel is a specialized adaptation of an upstream Linux LTS kernel, balancing the benefits of a mature, well-supported base with the unique requirements of mobile and embedded devices.
