Linux Kernel

April 19, 2023

What Is a Linux Kernel?

Serving as the principal interface between a computer’s hardware and its programs, the Linux kernel is a key part of the Linux operating system (OS) that provides a stable and reliable foundation, enabling it to perform a wide range of tasks efficiently and effectively. 

Similarly to a seed inside of a shell, the Linux kernel exists inside of the operating system. This gives the kernel power to control the hardware of the device. In order to manage resources as effectively as possible, the Linux kernel communicates between the device’s hardware and its processes.  

Linux Kernel Functions

The kernel oversees all essential hardware functions, regardless of the device type, and is designed to prioritize critical functions such as:

  • Memory management - Tracks how much memory is used and how it is utilized.

  • Process management - Determines which processes can access the central processing unit (CPU) and how they can access it.

  • Device drivers - Serve as an intermediary component between the hardware and various applications and processes that operate on a system.

  • System calls and security - Responsible for receiving requests for services from various processes.

Types of Kernels

Kernel design is essential to developing operating systems, with various approaches adopted to address different needs. Each approach has benefits and drawbacks, and choosing the appropriate kernel design is important for developing effective operating systems. The different types of kernels are:

  • Monolithic kernels - Larger than microkernels as they house both the kernel and user services in the same space. They use a faster system than microkernels to implement processes between hardware and software. However, they are less flexible, requiring administrators to redesign the entire kernel to support a new service.

  • Microkernels - Use message passing for a communication protocol to all services which are located within the kernel address space. Administrators can alter the user address space to add new services more flexibly than in a monolithic kernel. Due to their isolated nature, microkernels are considered more secure than monolithic kernels because they remain unaffected by failures of a single service within the address space.

Hybrid kernel - Combines both the monolithic kernel and the microkernel. It has greater modularity and provides more memory protection for some OS components due to its combination of monolithic and microkernel architectures.