Maintain a devtmpfs filesystem to mount at /dev

modulename: devtmpfs.ko


Linux Kernel Configuration
└─>Device Drivers
└─>Generic Driver Options
└─>Maintain a devtmpfs filesystem to mount at /dev
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  
This creates a tmpfs/ramfs filesystem instance early at bootup.
In this filesystem, the kernel driver core maintains device
nodes with their default names and permissions for all
registered devices with an assigned major/minor number.
Userspace can modify the filesystem content as needed, add
symlinks, and apply needed permissions.
It provides a fully functional /dev directory, where usually
udev runs on top, managing permissions and adding meaningful
In very limited environments, it may provide a sufficient
functional /dev without any further help. It also allows simple
rescue systems, and reliably handles dynamic major/minor numbers.

Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs
file system will be used instead.

source code: