Before taking this course, I only knew how to simply change permissions using the chmod command. However, through this lecture, I was able to gain a deep understanding of the detailed internal processes and the permission systems involved when an executable binary file is loaded into memory as a process and accesses actual files. Beyond simple permission management, the course covered essential practical topics such as setting up Apache web servers and DB servers, efficient disk management, and firewall settings for security, making it the perfect lecture for grasping the overall context of Linux operations. It was a beneficial time that allowed me to build both a solid foundation and practical skills simultaneously. I am so satisfied with this lecture that I am truly looking forward to the next follow-up course!