The Linux kernel is the central engine of Linux. It starts during boot and stays running while the computer is on. How it works Applications usually cannot access hardware directly. Instead, they request services from the kernel through system calls. For example: A text editor asks to open a file. The kernel checks whether the user has permission. The kernel communicates with the storage device. The file’s contents are returned to the text editor. Main responsibilities Process management: Starts, stops, and schedules programs. Memory management: Gives programs memory and prevents them from interfering with one another. Device management: Uses device drivers to communicate with hardware. File systems: Manages files, folders, permissions, and storage. Networking: Handles Wi-Fi, Ethernet, internet protocols, and connections. Security: Controls users, permissions, isolation, and access to resources. Power management: Helps control sleep, batteries, and energy usage. Kernel mode and user mode Linux separates computer activity into two main areas: User mode: Where ordinary applications run, such as browsers and media players. Kernel mode: Where the kernel runs with powerful access to hardware and system resources. This separation helps prevent one faulty application from crashing or controlling the entire system. Linux kernel versus Linux distribution The kernel alone is not a complete desktop operating system. A Linux distribution combines the kernel with other components: System utilities A command-line shell Software libraries Package managers Optional desktop environments Applications For example: Ubuntu = Linux kernel + GNU tools + desktop and applications Fedora = Linux kernel + system tools + desktop and applications Android = Linux kernel + Android framework and applications Is the Linux kernel an operating system? Strictly speaking, the kernel is the core of an operating system, not the entire operating system by itself. However, people often use “Linux” to refer to a complete Linux-based operating system. What is a kernel module? A kernel module is an add-on that can be loaded into the kernel when needed. Hardware drivers are often implemented as modules. This allows Linux to support new devices without rebuilding the entire kernel. You can view your kernel version in a Linux terminal with: bash uname -r To see more detailed information: bash uname -a In short, the Linux kernel manages the computer’s hardware and provides the essential services that all other software depends on. #linux - @math_its_my_wife