Turn off periodic FSCK at booting time.

Forces drives to be checked once for every 30 times the filesystem is mounted. This means that on an average, once every 30 times you bootup your computer, the filesystem integrity is checked.
To disable filesystem integrity check forever do:

$sudo tune2fs -c -1 `mount | awk '$3 == "/" {print $1}'`

or

$sudo tune2fs -c -1 /dev/yourhdd

but if you don’t want disable filesystem check forever, only for the next bootup, create a file called /fastboot.

$sudo touch /fastboot

will disable filesystem check for the next time you bootup. Since the /fastboot file is removed during bootup, this will disable filesystem check only once – for the one time you bootup after you create the /fastboot file
On the contrary to force a filesystem check the next time you bootup, create a file called /forcefsck by doing

$sudo touch /forcefsck