mbrlabel(8) [netbsd man page]

MBRLABEL(8)						    BSD System Manager's Manual 					       MBRLABEL(8)

NAME

     mbrlabel -- update disk label from MBR label(s)

SYNOPSIS

     mbrlabel [-fqrw] [-s sector] device

DESCRIPTION

     mbrlabel is used to update a NetBSD disk label from the Master Boot Record (MBR) label(s) found on disks that were previously used on
     DOS/Windows systems (or other MBR using systems).

     mbrlabel scans the MBR contained in the very first block of the disk (or the block specified through the -s flag), then walks through every
     extended partition found and generates additional partition entries for the disk from the MBRs found in those extended partitions.

     Each MBR partition which does not have an equivalent partition in the disk label (equivalent in having the same size and offset) is added to
     the first free partition slot in the disk label.  A free partition slot is defined as one with an fstype of 'unused' and a size of zero
     ('0').  If there are not enough free slots in the disk label, a warning will be issued.

     The raw partition (typically partition c, but d on i386 and some other platforms) is left alone during this process.

     By default, the proposed changed disk label will be displayed and no disk label update will occur.

     Available options:

     -f 	Force an update, even if there has been no change.

     -q 	Performs operations in a quiet fashion.

     -r 	In conjunction with -w, also update the on-disk label.

     -s sector	Specifies the logical sector number that has to be read from the disk in order to find the MBR.  Useful if the disk has remapping
		drivers on it and the MBR is located in a non-standard place.  Defaults to 0.

     -w 	Update the in-core label if it has been changed.  See also -r.

SEE ALSO

     disklabel(8), dkctl(8), fdisk(8), mbr(8)

HISTORY

     The mbrlabel command appeared in NetBSD 1.4.

BSD
								   April 5, 2010							       BSD

disklabel(4)						     Kernel Interfaces Manual						      disklabel(4)

NAME

       disklabel - Disk pack label

SYNOPSIS

       #include <sys/disklabel.h>

DESCRIPTION

       Each disk or disk pack on a system may contain a disk label which provides detailed information about the geometry of the disk and the par-
       titions into which the disk is divided.	It should be initialized when the disk is formatted, and may be changed later with  the  disklabel
       program.   This	information is used by the system disk driver and by the bootstrap program to determine how to program the drive and where
       to find the file systems on the disk partitions.  Additional information is used by the file system in order to use  the  disk  most  effi-
       ciently	and  to locate important file system information.  The description of each partition contains an identifier for the partition type
       (standard file system, swap area, etc.).  The file system updates the in-core copy of the label if it contains incomplete information about
       the file system.

       The label is located in sector number LABELSECTOR of the drive, usually sector 0 (zero) where it may be found without any information about
       the disk geometry.  It is at an offset LABELOFFSET from the beginning of the sector, to allow room for the  initial  bootstrap.	 The  disk
       sector  containing  the	label  is normally made read-only so that it is not accidentally overwritten by pack-to-pack copies or swap opera-
       tions; the DIOCWLABEL ioctl, which is done as needed by the disklabel program, allows modification of the label sector.

       A copy of the in-core label for a disk can be obtained with the DIOCGDINFO ioctl; this works with a file descriptor for a block or  charac-
       ter  (raw)  device for any partition of the disk.  The in-core copy of the label is set by the DIOCSDINFO ioctl.  The offset of a partition
       cannot generally be changed, nor made smaller while it is open.	One exception is that any change is allowed if no label was found  on  the
       disk,  and  the	driver was able to construct only a skeletal label without partition information.  Finally, the DIOCWDINFO ioctl operation
       sets the in-core label and then updates the on-disk label; there must be an existing label on the  disk	for  this  operation  to  succeed.
       Thus,  the  initial  label for a disk or disk pack must be installed by writing to the raw disk.  All of these operations are normally done
       using the disklabel program.

RELATED INFORMATION

       Files: disktab(4)

       Commands: disklabel(8) delim off

																      disklabel(4)