You dont need to unlock a drive to format it you can fit a chip, format it from an auto installer,(like mine) directly in your xbox. You dont need to unlock it, done it mannnnnnnnnnny times, saves having to relock it again
yes you do need to unlock it then you can put it in your pc and format it. I did mines yestoday it work but my xbox harddrive was only a 7.754gig hdd and that suck later man...Era
Xbox format is different from pc format so you can't read a pc formatted drive in an xbox and vice versa. Do it through the modchip BIOS.