CRChris Royinfreecodecamp.org·3d ago · 17 min readHow to Write a Linux Kernel Module That Actually BuildsA Linux kernel module is a small piece of code that can be loaded into the running kernel without rebuilding the entire kernel. That sounds simple enough, but even a minimal module produces a surprisi00
JSJayakumar Sakthivelincloudwithjk.hashnode.dev·Sep 11 · 15 min readTetragon: Kubernetes Runtime Security at the Kernel Level — Theory and ArchitectureIntroduction You've hardened your container images. You've written Network Policies. You've configured RBAC. You've scanned your CI/CD pipeline for vulnerabilities. And yet—a compromised container is 00
CRChris Royinfreecodecamp.org·Sep 11 · 13 min readHow to Sandbox a Linux Process with Landlock, No Root RequiredHere's a program restricting itself, then trying to read two files: without landlock: read /etc/hostname ok read /tmp/secret.txt ok with landlock, /etc allowed: read /etc/hos00
CRChris Royinfreecodecamp.org·Sep 9 · 17 min readHow Linux Actually Boots: From Firmware to the Login ScreenOpen a terminal on any systemd machine and run this: systemd-analyze On the laptop I'm writing this on, it says: Startup finished in 5.855s (firmware) + 8.469s (loader) + 3.106s (kernel) + 12.181s (u00
CRChris Royinfreecodecamp.org·Sep 7 · 21 min readHow a System Call Actually Works in LinuxHere's a small C program. It calls clock_gettime() three times, then writes five bytes to standard output. #include <stdio.h> #include <time.h> #include <unistd.h> int main(void) { struct timespe00
SSaguninsagunwrites.hashnode.dev·Sep 1 · 7 min readWindows APIs and System Calls: How Applications Reach the Operating SystemWhen a Windows application wants to perform an operation, it cannot simply control the operating system directly. For example, an application may want to: Create a process Open a file Allocate memo00
Kkanikasaikalyaninkanikasaikalyan.hashnode.dev·Aug 26 · 7 min readUnderstanding Linux Architecture: User Space, Kernel Space and HardwareA beginner-friendly journey into how Linux is structured internally Introduction When I first started working with Linux, I spent most of my time running commands, managing services, checking logs, a00
Kkanikasaikalyaninkanikasaikalyan.hashnode.dev·Aug 26 · 8 min readLinux Kernel Explore Dive: Processes, Memory Management and System CallsUnderstanding what happens behind the scenes when Linux is running your applications. Introduction In the previous article, we explored Linux architecture and learned that the operating system can be00
SSaguninsagunwrites.hashnode.dev·Aug 24 · 5 min readUser Mode vs Kernel Mode in Operating SystemsA computer runs many different types of software. Some programs are ordinary applications, such as text editors and web browsers. Other software, especially the operating system kernel, needs much gre00
SSaguninsagunwrites.hashnode.dev·Aug 24 · 4 min readWhat Are System Calls?Applications need the operating system to perform many tasks. For example, a program may need to create a file, allocate memory, create a process, or communicate with a device. But applications normal00
