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recoverdm(1) [debian man page]

RECOVERDM(1)						      General Commands Manual						      RECOVERDM(1)

NAME
recoverdm - recover filesdisks with damaged sectors SYNOPSIS
recoverdm -t type -i filedevicein -o fileout [-l list] [-n retries] [-s speed] DESCRIPTION
recoverdm This program will help you recover disks with bad sectors. You can recover files as well complete devices. In case if finds sec- tors which simply cannot be recoverd, it writes an empty sector to the output file and continues. If you're recovering a CD or a DVD and the program cannot read the sector in "normal mode", then the program will try to read the sector in "RAW mode" (without error-checking etc.). This toolkit also has a utility called 'mergebad': mergebad merges multiple images into one. This can be useful when you have, for example, multiple CD's with the same data which are all damaged. In such case, you can then first use recoverdm to retrieve the data from the damaged CD's into image-files and then combine them into one image with mergebad. OPTIONS
-t type is 1 for files, 10 for floppy disks and 40 for IDE disks (try -h for a complete list) -i filedevicein is the device or file you want to recover. -o fileout is the file where to write to. This file should not already exists. -l list This file will contain the offsets of the bad blocks as well as the size of the bad blocks. This file can be used together with the image with the mergebad utility. -n retries Number of retries before going on with next sector, defaults to 6. -r RAW read Number of retries while reading in RAW mode before going on with next sector, default to 6. -s rotation speed Speed of the CD-ROMDVD, defaults to 1. -h Gives the help message. SEE ALSO
gddrescue(1), dd_rescue(1), testdisk(1), gpart(1) AUTHOR
Folkert van Heusden <flok@xs4all.nl>, Home page is <http://www.vanheusden.com/recoverdm/> recoverdm Version 0.19 RECOVERDM(1)

Check Out this Related Man Page

BAD144(8)						      System Manager's Manual							 BAD144(8)

NAME
bad144 - read/write DEC standard 144 bad sector information SYNOPSIS
bad144 disktype disk [ sno [ bad ... ] ] DESCRIPTION
Bad144 can be used to inspect the information stored on a disk that is used by the disk drivers to implement bad sector forwarding. The format of the information is specified by DEC standard 144, as follows. The bad sector information is located in the first 5 even numbered sectors of the last track of the disk pack. There are five identical copies of the information, described by the dkbad structure. Only the first of these copies is used. Replacement sectors are allocated starting with the first sector before the bad sector information and working backwards towards the begin- ning of the disk. A maximum of 126 bad sectors can be supported. The position of the bad sector in the bad sector table determines which replacement sector it corresponds to. The bad sector information and replacement sectors are conventionally only accessible through the ``h'' file system partition of the disk. If that partition is used for a file system, the user is responsible for making sure that it does not overlap the bad sector information or any replacement sectors. The bad sector structure is as follows: struct dkbad { long bt_csn; /* cartridge serial number */ u_short bt_mbz; /* unused; should be 0 */ u_short bt_flag; /* -1 => alignment cartridge */ struct bt_bad { u_short bt_cyl; /* cylinder number of bad sector */ u_short bt_trksec; /* track and sector number */ } bt_bad[MAXBAD]; }; Unused slots in the bt_bad array are filled with all bits set, a putatively illegal value. MAXBAD (in <sys/dkbad.h>) may be tuned locally to reduce the space required to hold the bad-sector file in memory. It may not be greater than 126, which uses the whole disk sector. Bad sectors past MAXBAD may be included by the formatter, but replacement sectors will not be used until MAXBAD is increased. Bad144 is invoked by giving a device type (e.g. rk07, rm03, rm05, etc.), and a device name (e.g. hk0, hp1, etc.). It reads the first sec- tor of the last track of the corresponding disk and prints out the bad sector information. It may also be invoked giving a serial number for the pack and a list of bad sectors, and will then write the supplied information onto the same location. Note, however, that bad144 does not arrange for the specified sectors to be marked bad in this case. This option should only be used to restore known bad sector information which was destroyed. New bad sectors can be added by running the standard DEC formatter in section ``bad.'' SEE ALSO
badsect(8) BUGS
Not all drivers support bad-sector forwarding on the PDP-11. It should be possible to both format disks on-line under UNIX and to change the bad sector information, marking new bad sectors, without running a standalone program. The bootstrap drivers used to boot the system do not understand bad sectors or handle ECC errors. This means that none of these errors can occur when reading the file /unix to boot. Sector 0 of the disk drive and the file /boot in the root file system of that drive must also not have any of these errors in it. The drivers that write a system core image on disk after a crash do not handle errors; thus the crash dump area must be free of errors and bad sectors. 3rd Berkeley Distribution BAD144(8)
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