Does Windows Requires Reboot after Format

Hi all,
I am working on SCSI miniport driver for windows 2000. I am seeing a
strange behaviour when i create a extended partition and then create a
logical drive on it. The system asks for a reboot. I have no idea why does
it do it.

Can anyone give some pointers here.
Any help is highly appriciated.
Thanks,
Ajitabh