The Linux Kernel

The Linux kernel is the core of the Linux operating system: the low-level software that sits between a computer's hardware and the programs running on it. It manages the system's memory, schedules processes on the CPU, controls hardware through device drivers, and mediates every request that applications make for system resources. All Linux distributions, from Rocky Linux to Android, are ultimately built on the same open-source kernel, which is why they share a common foundation despite their differences.

What is the Linux kernel?

The kernel runs in a privileged part of the system known as kernelspace, where it has direct control over hardware and administrative functions. Applications run separately in userspace, an unprivileged environment that must ask the kernel, through system calls, to perform operations such as reading a file, sending network data, or allocating memory. This separation protects the system: a misbehaving application cannot directly corrupt hardware or other programs because the kernel controls access.

The Linux kernel is free and open source, with its canonical source tree maintained by Linus Torvalds and hosted publicly (github.com/torvalds/linux). It is developed by thousands of contributors, past and present, individual volunteers and companies alike, with coordination happening largely on the long-running Linux kernel mailing list. This open, collaborative model is a major reason Linux runs on everything from embedded devices to the world's largest supercomputers.

What the kernel does

The kernel is responsible for a set of essential functions on every Linux system:

• Memory management, tracks how memory is allocated and used, and reclaims it when it is no longer needed.
• Process management, decides which processes run on the CPU and when, sharing the processor fairly among many tasks.
• Device drivers, act as the intermediary between hardware devices and the software that uses them.
• System calls and security, receive and validate requests from userspace programs for privileged services, enforcing access controls.

Types of kernel architecture

Operating system kernels are designed in different ways, each trading off speed, modularity, and security:

Kernel type	Design	Trade-off
Monolithic	Kernel and system services share one address space	Fast, but less modular; Linux is essentially monolithic (with loadable modules)
Microkernel	Minimal core; services run separately and communicate by message passing	More isolated and secure, but higher communication overhead
Hybrid	Combines monolithic and microkernel ideas	Balances modularity and memory protection

The Linux kernel is fundamentally monolithic but supports loadable modules, letting drivers and features be added or removed at runtime without rebuilding the whole kernel.

Why the kernel matters in Enterprise Linux

Because the kernel controls hardware and enforces security boundaries, its stability and patch cadence are central to Enterprise Linux. Distributions such as Rocky Linux and the other RHEL forks ship a specific, extensively tested kernel version and backport security and stability fixes to it over the release's lifetime, rather than always shipping the newest upstream kernel. The kernel also underpins containerization: containers share the host's single kernel while each presenting its own userspace, so the operating environment an application sees can be swapped without changing the running kernel. CIQ provides commercial support for Rocky Linux, including its kernel and long-term maintenance.