Constructed on a system in the DOM
Kernel: 2.6.30 busybox: 1.7.1 use the grub bootloader
Core has include the usbstorage, vfat support.
busybox, also mdev support.
google the web how to use mdev
Write / etc / init.d / rcS
mount-t tmpfs mdev / dev
mount-t sysfs sysfs / sys
mkdir / dev / pts
mount-t devpts devpts / dev / pts
/ Bin / echo / sbin / mdev> / proc / sys / kernel / hotplug
mdev-s

/ Etc / mdev.conf content:
null 0:0 666
zero 0:0 666
urandom 0:0 444

kem 0:9 000
mem 0:9 640
port 0:9 640

console 0:5 600
ptmx 0:5 660
tty [0-9] * 0:5 660

ttyS [0-9] 0:20 640
fd [0-9] * 0:11 660

sd [a-z] * 0:6 660
hd [a-z] * 0:6 660

After reboot, plug in usb storage device can not create a node in /dev directory
# Mount
rootfs on / type rootfs (rw)
none on / sys type sysfs (rw ,......)
none on / proc type proc (rw ,.....)
udev on / dev type tmpfs (rw ,...)
mdev on / dev type tmpfs (rw ,...)
devpts on / dev / pts type devpts (rw, ..)

Can not understand why udev, recalled by a mdev, and also why the plug plate Why do not u / dev node created automatically?
U disk, plug in the information when prompted:
[323.540054] usb 1-8: New USB device found, idVendor = 0951, idProduct = 160b
[323.674156] usb 1-8: New USB device strings: Mfr = 1, Product = 2, SerialNumber = 3
[323.674232] usb 1-8: Product: USB Mass Storage
[323.674299] usb 1-8: Manufactuer: GENERIC
[323 .............] usb 1-8: SerialNumber: USB000000001
[323 .............] usb 1-8: configuration # 1 chosen from 1 choice

Have been engaged in busybox, to help a hand
Sorry for my poor English!Thanks!