devtmpfs
also: devtmpfs filesystem
A virtual filesystem that automatically creates and manages device files in /dev at boot time, replacing the static device files of earlier Linux systems.
devtmpfs is a lightweight, kernel-managed filesystem that dynamically populates the /dev directory with device nodes as hardware is detected. Unlike older methods that required pre-created static device files, devtmpfs automatically creates these files on-the-fly when devices are plugged in or initialized.
When your system boots, the kernel mounts devtmpfs at /dev before userspace tools start. As devices are discovered (via udev or similar mechanisms), device files like /dev/sda, /dev/tty0, and /dev/null appear automatically. This eliminates the need to manually create or maintain hundreds of device files.
Most modern Linux distributions use devtmpfs by default. You can verify it's mounted by running mount | grep devtmpfs, which typically shows output like: devtmpfs on /dev type devtmpfs (rw,nosuid,size=1966936k,...)