For very good reasons (i.e. we never know when the power is going to go) the disks are mounted read-only in-car. Various workarounds for this are theoretically possible, but they're all either really icky (ioctl(FIBMAP) + open("/dev/hda4")) or really inconvenient (fdisk, mkreiserfs).

Peter

PS. Nobody heard me say ioctl(FIBMAP) + open("/dev/hda4"), right?