bad Command bad Maintain list of bad blocks bad option filesystem [ block ... ] A hard disk or floppy disk may have bad blocks on it: a ``bad block'' is a portion of disk that cannot be used reliably because read or write errors occur on them. The COHERENT system keeps a list of bad blocks so it can avoid using them. The command bad maintains the bad-block list for the given filesystem, which must be a block-special file. option must be exactly one of the characters acdl, which tell bad to do one of the following: a Add each given block to the bad-block list c Clear the bad-block list d Delete each given block from the bad-block list l List all blocks on the bad-block list bad does not deallocate any i-node associated with a block when adding it to the bad-block list. You should run the command icheck with the -s option immediately after bad to correct the problem, or run the command fsck. filesystem should be unmounted if possible. The user who invokes bad must have appropriate permissions for the given filesystem. For many file systems, only the superuser may use bad to change the bad-block list. Use the command badscan to create a prototype file. When the mkfs command creates a file system, the prototype specification may include a bad block list for the new file sys- tem. ***** See Also ***** badscan, commands, icheck, mkfs, umount COHERENT Lexicon Page 1