NAME
ahdilabel
- modify AHDI partitions
SYNOPSIS
ahdilabel
disk
DESCRIPTION
ahdilabel
allows you to modify the AHDI partition table on a disk partitioned with
AHDI or an AHDI compatible formatter. The AHDI partition format is usually
only present on disks shared between
NetBSD
and some other OS. The partition identifiers are used by
NetBSD
as a guideline to emulate a disklabel on such a disk.
ahdilabel
supports the following options:
- disk
-
The name of the disk you want to edit.
ahdilabel
will first try to open a disk of this name. If this cannot
be opened, it will attempt to open
r<disk>c.
Finally, if this also cannot be opened, it will attempt to open
/dev/r<disk>c.
ahdilabel
will display information about the number of sectors, tracks
and sectors on the disk, as well as the current AHDI partition information.
It will then prompt for input. The input choices are:
- a-p
-
Modify a partition. You will be prompted for a partition id, root, start
and size.
NetBSD
recognises the following partition id's:
- NBD
-
Partition is reserved for
NetBSD.
This can be either a root or an user partition. The first NBD
partition on a disk will be mapped to
NetBSD
partition letter
a.
The following NBD partitions will be mapped from letter
d
up.
The filesystem type is ffs by default.
- SWP
-
The first SWP partition is mapped to partition
b.
- GEM or BGM
-
These partitions are mapped from
d
up. The filesystem type is msdos.
The root, start and size parameters can be entered using sector,
cylinder/track/sector or megabyte notations. Whole numbers of cylinders can
be entered using the shorthand <cylinder>/. Likewise, whole numbers of tracks
can be entered using the shorthand <cylinder>/<track>/. Megabytes are entered
using the suffix
M.
The following can also be used to enter partition parameters:
- -N (root)
-
Position the root sector for this partition immediately after partition N.
- -N (start)
-
Make this partition start after partition N (leaving a gap of 1 sector for a
root sector, if necessary).
- -N (size)
-
Make this partition end immediately before partition N.
- -1 (size)
-
Make this partition extend to the end of the disk.
The sector holding the primary AHDI partition table only has space for four
partitions. Thus, if a disk has more than four partitions, the extra
partition information is held in auxiliary root sectors. There is one
auxiliary root for each additional partition (and also for the fourth
partition, if the disk has more than four partitions).
- r
-
Recalculate the root sectors. This will automatically assign auxiliary
root sectors if the disk has more than 4 partitions. The auxiliary root
sectors will be positioned in a default location preceding the relevant
partition.
- s
-
Show the current partition information.
- u
-
Toggle the unit display between sector and cylinder/track/sector notation.
- w
-
Write the AHDI partition table to the disk.
- z
-
Options for zero'ing the boot sector and bad sector lists. The default is to
preserve them both.
- q
-
Quit
EXAMPLES
ahdilabel
sd0
Edit the AHDI label for disk sd0.
SEE ALSO
bootpref(8),
disklabel(8),
installboot(8)
HISTORY
The
ahdilabel
command first appeared in
NetBSD1.5.
BUGS
The changes made to the AHDI partitions will become active on the next
first open
of the disk. You are advised to use
ahdilabel
only on a disk without any mounted or otherwise active partitions. This
is not enforced by
.
Because of way
NetBSD
interprets AHDI partition tables to create the
NetBSD
disklabel, the
NetBSD
partition ordering may change if partitions labelled NBD are created or
removed.
Creating an AHDI partition table on a disk that previously did not have
one will almost certainly overwrite any existing partition information
and/or data on that disk. This is especially the case if auxiliary root
sectors are needed for the AHDI partition table.
As soon as a disk contains at least one NBD partition, you are allowed to
write
NetBSD
disklabels and install bootstraps.