1.\" Copyright (c) 1985, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)badsect.8 8.1 (Berkeley) 06/05/93 7.\" 8.Dd 9.Dt BADSECT 8 10.Os BSD 4 11.Sh NAME 12.Nm badsect 13.Nd create files to contain bad sectors 14.Sh SYNOPSIS 15.Nm /etc/badsect 16.Ar bbdir sector ... 17.Sh DESCRIPTION 18.Nm Badsect 19makes a file to contain a bad sector. Normally, bad sectors 20are made inaccessible by the standard formatter, which provides 21a forwarding table for bad sectors to the driver; see 22.Xr bad144 8 23for details. 24If a driver supports the bad blocking standard it is much preferable to 25use that method to isolate bad blocks, since the bad block forwarding 26makes the pack appear perfect, and such packs can then be copied with 27.Xr dd 1 . 28The technique used by this program is also less general than 29bad block forwarding, as 30.Nm badsect 31can't make amends for 32bad blocks in the i-list of file systems or in swap areas. 33.Pp 34On some disks, 35adding a sector which is suddenly bad to the bad sector table 36currently requires the running of the standard 37.Tn DEC 38formatter. 39Thus to deal with a newly bad block 40or on disks where the drivers 41do not support the bad-blocking standard 42.Nm badsect 43may be used to good effect. 44.Pp 45.Nm Badsect 46is used on a quiet file system in the following way: 47First mount the file system, and change to its root directory. 48Make a directory 49.Li BAD 50there. Run 51.Nm badsect 52giving as argument the 53.Ar BAD 54directory followed by 55all the bad sectors you wish to add. 56(The sector numbers must be relative to the beginning of 57the file system, but this is not hard as the system reports 58relative sector numbers in its console error messages.) 59Then change back to the root directory, unmount the file system 60and run 61.Xr fsck 8 62on the file system. The bad sectors should show up in two files 63or in the bad sector files and the free list. Have 64.Xr fsck 65remove files containing the offending bad sectors, but 66.Em do not 67have it remove the 68.Pa BAD/ Ns Em nnnnn 69files. 70This will leave the bad sectors in only the 71.Li BAD 72files. 73.Pp 74.Nm Badsect 75works by giving the specified sector numbers in a 76.Xr mknod 2 77system call, 78creating an illegal file whose first block address is the block containing 79bad sector and whose name is the bad sector number. 80When it is discovered by 81.Xr fsck 82it will ask 83.Dq Li "HOLD BAD BLOCK ?" 84A positive response will cause 85.Xr fsck 86to convert the inode to a regular file containing the bad block. 87.Sh SEE ALSO 88.Xr bad144 8 , 89.Xr fsck 8 , 90.Xr format 8 91.Sh DIAGNOSTICS 92.Nm Badsect 93refuses to attach a block that 94resides in a critical area or is out of range of the file system. 95A warning is issued if the block is already in use. 96.Sh BUGS 97If more than one sector which comprise a file system fragment are bad, 98you should specify only one of them to 99.Nm badsect , 100as the blocks in the bad sector files actually cover all the sectors in a 101file system fragment. 102.Sh HISTORY 103The 104.Nm 105command appeared in 106.Bx 4.1 . 107