# mknod /dev/name type major minor
[fs/devices.c]:
int register_blkdev(unsigned int major, const char * name,
struct file_operations *fops)
int register_chrdev(unsigned int major, const char * name,
struct file_operations *fops);
int unregister_blkdev(unsigned int major, const char * name);
int unregister_chrdev(unsigned int major, const char * name);