Checking for disk errors with badblocks
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It can be a good idea to periodically check for bad blocks.
This is done with the badblocks command. It outputs
a list of the numbers of all bad blocks it can find. This list
can be fed to fsck to be recorded
in the filesystem data structures so that the operating system
won't try to use the bad blocks for storing data.
The following example will show how this could be done.
$ badblocks /dev/fd0H1440 1440 > bad-blocks
$ fsck -t ext2 -l bad-blocks /dev/fd0H1440
Parallelizing fsck version 0.5a (5-Apr-94)
e2fsck 0.5a, 5-Apr-94 for EXT2 FS 0.5, 94/03/10
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Check reference counts.
Pass 5: Checking group summary information.
/dev/fd0H1440: ***** FILE SYSTEM WAS MODIFIED *****
/dev/fd0H1440: 11/360 files, 63/1440 blocks
$
If badblocks reports a block that was already used, e2fsck
will try to move the block to another place. If the block was really
bad, not just marginal, the contents of the file may be corrupted.
Lars Wirzenius
Sat Nov 15 02:32:11 EET 1997
