I think when we are using the Mac, we can't choose "Repair Disk" in Disk Utilty to repair the current hard drive, as the drive is being used.
If "Verify Disk" is used, it only takes about 3 to 5 minutes for a 120GB hard drive, so it seems not the whole drive is scanned.
It seems that we can boot up using the OS X Installation DVD and use Disk Utility to do Repair Disk. But is it equally possible to boot up the Mac in a single user mode (or is it called the command line mode), and use fsck or diskutil to do it?
The use is mainly to repair the hard drive (just to double check) that the whole hard drive is ok, after the Macbook is dropped from the bed about 3 feet tall.