On a hard disk when a file is written on it, it’s just a long sequence of bits. You’ll need a system in place to identify where a file begins and ends, who owns it, what type it is, and stuff like that. The system that handles your files is the filesystem. In other words, it literally means a system for storing and managing your files. Think of it as a huge file cabinet with all your files in it.
If you are Windows user, you’d be used to the partition system of directories like
D:, and more drives for removable and network shared directories. They all form their own trees of hierarchy.
But in the Linux operating system the filesystem is one big tree. You have the root folder at the top level that holds all of your files in different sub folders. And these subfolders would then have their own files and subfolders and so on. Additional devices can be ‘mounted’ on to this heirarchy and accessed under the same tree as well.
It’s okay if you don’t get the filesystem yet. In the next lesson, once you practically view the hierarchy and make sense of what the folder layout is like and what sort of directories they hold, things will start clicking.