Linux Kernel

The Linux kernel forms the core of the Linux operating system family, which are Unix-like systems. It was created by Linus Torvalds in 1991 as part of a personal project. This free and open-source kernel is employed in a vast array of computer systems worldwide, from embedded systems to supercomputers.

Development and Structure

The development of the Linux kernel involves a global community of developers contributing to its source code, which is managed through version control systems like Git. The kernel's architecture is monolithic, meaning that it runs in a single address space, but it supports loadable kernel modules, allowing for dynamic enhancement of kernel functionalities.

The kernel provides essential services such as process management, memory management, device drivers, security, and file systems. It interfaces with hardware directly via device drivers, which provides a mechanism for the operating system to interact with the hardware components.

Features and Capabilities

Kernel-based Virtual Machine

The Linux kernel includes the Kernel-based Virtual Machine (KVM) module, which enables the kernel to act as a hypervisor. This functionality allows multiple isolated virtual machines to run on a physical host. KVM is integral to many major cloud computing platforms and virtualization solutions.

Kernel Interfaces

The Linux kernel provides a variety of interfaces to user-space applications and other kernel modules. These interfaces include the system call interface for process management and other operations, and application programming interfaces (APIs) for interacting with kernel functionalities. The robustness of these interfaces underpins the development of user-space applications and the integration of additional kernel features.

Documentation and Support

Comprehensive documentation for the Linux kernel can be built using commands like make htmldocs or make pdfdocs, and is available online. This documentation includes guides for both users and developers and covers everything from compilation requirements to troubleshooting common issues like a kernel panic, which is a critical error state that requires a system reboot.