Tell us about file systems — how does the path from device to file work in Linux

In Linux, the file system is a hierarchical structure where all devices and files are mounted into a single directory tree, starting from the root /.

The path from a device to a file passes through several levels:

1. Device — a physical medium (hard drive, SSD, flash drive, etc.)
2. Device driver — interacts with hardware at the kernel level
3. File system — a logical structure that organizes data on the device (e.g., ext4, xfs, btrfs)
4. Mount point — a directory in the overall tree where the device's file system is attached
5. Path to the file — a sequence of directories from the root / to the target file

When a user accesses a file by path, the kernel processes each component of the path sequentially, using inode tables and directories to locate the corresponding file or directory. The entire Linux file system is perceived as a single tree, where devices are represented as subtrees mounted at specific points.

For example, if a hard drive is mounted at /mnt/disk, and a file is located at /mnt/disk/docs/report.txt, then:

• /mnt/disk — the mount point of the device's file system
• docs/report.txt — the path within this file system

Thus, the path from the device to the file is the path from the root of the tree through mount points and directories to the specific file.