The Limits of Running Fsck: What to Do When It Can't Help You Anymore
If you have a bad sector that cannot be unmounted while Ubuntu is running, such as ''root'', you will not be able to run fsck. Don't panic. You can always run fsck normally on root through a live Ubuntu disk (just load your install CD, restart, select ''test Ubuntu'' and proceed with ''root'' the same way as directed with ''home''.
This tool is great for extending the file of older machines, but remember that when it comes to magnetic hard drives, you're fighting a losing battle against time. The need to repair bad sectors is minimal in Ubuntu due to the very tough architecture of the ext3 and ext4 folders where most data is stored. If you need to run this command regularly, chances are that your hard drive is failing and has to be replaced.
If fsck is able to restore your data, the wisest thing to do is to back up everything you want to keep. You should also do this if fsck is unable to restore the corrupted drive. If you have a persistently irreparable sector, then its time to enter emergency data-rescue mode. Disk failure spreads like a cancer: It will spread bit by bit throughout the sectors until your system won't even have enough good memory to boot anymore. There is no reliable fix for hard drive failure. Programs that claim to ''isolate'' bad sectors generally only buy you time.
To avoid a loss of data, today's modern PC users simply need to follow the same backup practices we did in the days of the old black-and-yellow screens, which is to keep a copy of everything worth keeping. After all, if you take precautions to secure your computer against theft, it only makes sense to secure yourself against data loss--not as difficult a task as it used to be. With my first computer, in the old cave-dwelling days, I needed a stack of floppy disks that reached to the roof to back up what today would fit in a bog-standard usb drive!