vm-guest:~/driver# make
make -C /lib/modules/2.6.5/build SUBDIRS=/root/driver modules
make[1]: Entering directory `/usr/src/linux-2.6.5'
*** Warning: Overriding SUBDIRS on the command line can cause
***          inconsistencies
make[2]: `arch/i386/kernel/asm-offsets.s' is up to date.
  CC [M]  /root/driver/hello2.o
  LD [M]  /root/driver/module.o
  Building modules, stage 2.
  MODPOST
  CC      /root/driver/module.mod.o
  LD [M]  /root/driver/module.ko
make[1]: Leaving directory `/usr/src/linux-2.6.5'
vm-guest:~/driver# insmod module.ko
vm-guest:~/driver# cat /proc/devices | grep test
254 test_dev
vm-guest:~/driver# mknod ser0 c 254 0
vm-guest:~/driver# cat <ser0;echo
abcde
vm-guest:~/driver# cat <ser0;echo
fghij
vm-guest:~/driver# echo "foobar" >ser0
vm-guest:~/driver# rmmod module