File System
https://tldp.org/LDP/sag/html/filesystems.html
The methods and datastructures that allow for organising and accessing data on disk.
Filesystem-like structures exist including Pseudo File Systems and Virtual File Systems. These typically allow working with objects in a file-like manner, even if they don’t represent an actual file underneath
Most filesystems (except, notably, FAT/FAT32 and ntfs) use a tree-like structure for recording file layouts
Types
There are many types of filesystems, each with their own specific advantages and disadvantages. The most common kinds are: