Also known as: Linux kernel · monolithic kernel · kernel space
The kernel is the core of an operating system, responsible for managing memory, scheduling processes, and mediating all access between software and hardware. The Linux kernel is the component that makes a system 'Linux'.
Linux uses a monolithic design, meaning device drivers and filesystem code run in kernel space with full privileges rather than as isolated user-space processes. This yields performance advantages and is a large part of why memory-safety bugs in drivers are so consequential — a flaw there is a flaw with total system authority.
Loadable kernel modules soften the monolithic model by allowing drivers to be added and removed at runtime, so a general-purpose kernel need not be recompiled for every hardware combination.
Kernel Module
A kernel module is a piece of code that can be loaded into and unloaded from a running Linux kernel on demand, extending its functionality — most commonly with device drivers — without requiring a reboot or recompilation.
System Call
A system call is the mechanism by which a user-space program requests a service from the kernel — such as opening a file, allocating memory, or sending network data — crossing the privilege boundary between application and kernel.
Memory Safety
Memory safety is the property of a program being unable to access memory outside the bounds of what it legitimately owns, preventing entire vulnerability classes such as buffer overflows, use-after-free, and data races.
Rust
Rust is a systems programming language that guarantees memory safety without garbage collection, using a compile-time ownership and borrowing model to eliminate entire classes of bugs including use-after-free and data races.
Linux Distribution
A Linux distribution is a complete operating system built around the Linux kernel, bundling it with system libraries, a package manager, default utilities, and a curated set of software, along with policies for how all of it is maintained and updated.
Long-Term Support
Long-term support (LTS) designates a software release that will receive security patches and critical bug fixes for an extended period — typically several years — without introducing new features or breaking changes.
SELinux / AppArmor
SELinux and AppArmor are Linux mandatory access control systems that confine processes to explicitly permitted actions, so that even a process running as root is limited to what its policy allows.