phpMan

/* Void Main's man pages */

{ phpMan } else { main(); }

BADBLOCKS(8) BADBLOCKS(8)

NAME
badblocks - search a device for bad blocks

SYNOPSIS
badblocks [ -svwnf ] [ -b block-size ] [ -c blocks_at_once ] [ -e max_bad_blocks ] [ -d read_delay_factor ] [ -i
input_file ] [ -o output_file ] [ -p num_passes ] [ -t test_pattern ] device [ last-block ] [ first-block ]

DESCRIPTION
badblocks is used to search for bad blocks on a device (usually a disk partition). device is the special file corre-
sponding to the device (e.g /dev/hdc1). last-block is the last block to be checked; if it is not specified, the last
block on the device is used as a default. first-block is an optional parameter specifying the starting block number for
the test, which allows the testing to start in the middle of the disk. If it is not specified the first block on the
disk is used as a default.

Important note: If the output of badblocks is going to be fed to the e2fsck or mke2fs programs, it is important that the
block size is properly specified, since the block numbers which are generated are very dependent on the block size in use
by the filesystem. For this reason, it is strongly recommended that users not run badblocks directly, but rather use the
-c option of the e2fsck and mke2fs programs.

OPTIONS
-b block-size
Specify the size of blocks in bytes. The default is 1024.

-c number of blocks
is the number of blocks which are tested at a time. The default is 64.

-e max bad block count
Specify a maximum number of bad blocks before aborting the test. The default is 0, meaning the test will continue
until the end of the test range is reached.

-d read delay factor
This parameter, if passed and non-zero, will cause bad blocks to sleep between reads if there were no errors
encountered in the read operation; the delay will be calculated as a percentage of the time it took for the read
operation to be performed. In other words, a value of 100 will cause each read to be delayed by the amount the
previous read took, and a value of 200 by twice the amount.

-f Normally, badblocks will refuse to do a read/write or a non-destructive test on a device which is mounted, since
either can cause the system to potentially crash and/or damage the filesystem even if it is mounted read-only.
This can be overridden using the -f flag, but should almost never be used --- if you think you're smarter than the
badblocks program, you almost certainly aren't. The only time when this option might be safe to use is if the
/etc/mtab file is incorrect, and the device really isn't mounted.

-i input_file
Read a list of already existing known bad blocks. Badblocks will skip testing these blocks since they are known
to be bad. If input_file is specified as "-", the list will be read from the standard input. Blocks listed in
this list will be omitted from the list of new bad blocks produced on the standard output or in the output file.
The -b option of dumpe2fs(8) can be used to retrieve the list of blocks currently marked bad on an existing
filesystem, in a format suitable for use with this option.

-n Use non-destructive read-write mode. By default only a non-destructive read-only test is done. This option must
not be combined with the -w option, as they are mutually exclusive.

-o output_file
Write the list of bad blocks to the specified file. Without this option, badblocks displays the list on its stan-
dard output. The format of this file is suitable for use by the -l option in e2fsck(8) or mke2fs(8).

-p num_passes
Repeat scanning the disk until there are no new blocks discovered in num_passes consecutive scans of the disk.
Default is 0, meaning badblocks will exit after the first pass.

-s Show the progress of the scan by writing out rough percentage completion of the current badblocks pass over the
disk. Note that badblocks may do multiple test passes over the disk, in particular if the -p or -w option is
requested by the user.

-t test_pattern
Specify a test pattern to be read (and written) to disk blocks. The test_pattern may either be a numeric value
between 0 and ULONG_MAX-1 inclusive, or the word "random", which specifies that the block should be filled with a
random bit pattern. For read/write (-w) and non-destructive (-n) modes, one or more test patterns may be speci-
fied by specifying the -t option for each test pattern desired. For read-only mode only a single pattern may be
specified and it may not be "random". Read-only testing with a pattern assumes that the specified pattern has
previously been written to the disk - if not, large numbers of blocks will fail verification. If multiple pat-
terns are specified then all blocks will be tested with one pattern before proceeding to the next pattern.

-v Verbose mode.

-w Use write-mode test. With this option, badblocks scans for bad blocks by writing some patterns (0xaa, 0x55, 0xff,
0x00) on every block of the device, reading every block and comparing the contents. This option may not be com-
bined with the -n option, as they are mutually exclusive.

-X Internal flag only to be used by e2fsck(8) and mke2fs(8). It bypasses the exclusive mode in-use device safety
check.

WARNING
Never use the -w option on a device containing an existing file system. This option erases data! If you want to do
write-mode testing on an existing file system, use the -n option instead. It is slower, but it will preserve your data.

The -e option will cause badblocks to output a possibly incomplete list of bad blocks. Therefore it is recommended to use
it only when one wants to know if there are any bad blocks at all on the device, and not when the list of bad blocks is
wanted.

AUTHOR
badblocks was written by Remy Card <Remy.CardATlinux.org>. Current maintainer is Theodore Ts'o <tytsoATalum.edu>.
Non-destructive read/write test implemented by David Beattie <dbeattieATsofthome.net>.

AVAILABILITY
badblocks is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.