BADSECT(8) BSD System Manager's Manual BADSECT(8) NNAAMMEE bbaaddsseecctt - create files to contain bad sectors SSYYNNOOPPSSIISS //eettcc//bbaaddsseecctt _b_b_d_i_r _s_e_c_t_o_r _._._. DDEESSCCRRIIPPTTIIOONN BBaaddsseecctt makes a file to contain a bad sector. Normally, bad sectors are made inaccessible by the standard formatter, which provides a forwarding table for bad sectors to the driver; see bad144(8) for details. If a driver supports the bad blocking standard it is much preferable to use that method to isolate bad blocks, since the bad block forwarding makes the pack appear perfect, and such packs can then be copied with dd(1). The technique used by this program is also less general than bad block forwarding, as bbaaddsseecctt can't make amends for bad blocks in the i-list of file systems or in swap areas. On some disks, adding a sector which is suddenly bad to the bad sector table currently requires the running of the standard DEC formatter. Thus to deal with a newly bad block or on disks where the drivers do not sup- port the bad-blocking standard bbaaddsseecctt may be used to good effect. BBaaddsseecctt is used on a quiet file system in the following way: First mount the file system, and change to its root directory. Make a directory BAD there. Run bbaaddsseecctt giving as argument the _B_A_D directory followed by all the bad sectors you wish to add. (The sector numbers must be relative to the beginning of the file system, but this is not hard as the system re- ports relative sector numbers in its console error messages.) Then change back to the root directory, unmount the file system and run fsck(8) on the file system. The bad sectors should show up in two files or in the bad sector files and the free list. Have fsck remove files containing the offending bad sectors, but _d_o _n_o_t have it remove the _B_A_D_/_n_n_n_n_n files. This will leave the bad sectors in only the BAD files. BBaaddsseecctt works by giving the specified sector numbers in a mknod(2) system call, creating an illegal file whose first block address is the block containing bad sector and whose name is the bad sector number. When it is discovered by fsck it will ask ``HOLD BAD BLOCK ?'' A positive re- sponse will cause fsck to convert the inode to a regular file containing the bad block. SSEEEE AALLSSOO bad144(8), fsck(8), format(8) DDIIAAGGNNOOSSTTIICCSS BBaaddsseecctt refuses to attach a block that resides in a critical area or is out of range of the file system. A warning is issued if the block is al- ready in use. BBUUGGSS If more than one sector which comprise a file system fragment are bad, you should specify only one of them to bbaaddsseecctt, as the blocks in the bad sector files actually cover all the sectors in a file system fragment. HHIISSTTOORRYY The bbaaddsseecctt command appeared in 4.1BSD. 4th Berkeley Distribution June 5, 1993 1