Apple :: Disk UtilityVolume Header

to verify my USB External Harddrive using disk utility. during the verifying phase, the disk utilty stops and says that there is something wrong with the volume and cannot continue. so after thats done, i click "repair volume" during the checking, it founds and error "Volume Header needs minor repair". it repairs the problem and eventually it ends up with "1 volume passed verification". what could have caused this? anyone else ever got this? -how? is this means that there is something corrupt with the drive data? after i click repair; would everything be all right again? i found something on the net which i found interesting;

ref: [url]

Quote:

POWER USERS' CLINIC Journaling vs.fsck

Mac OS X 10.4 comes with journaling turned on. As noted on Section A.4, journaling means that the Mac keeps a diary about every tiny bit of hard drive activity. In event of a crash or freeze, the Mac knows precisely what was going on at the time, and precisely which files might have been damaged.....