NAME
edahdi
- modify AHDI partition identifiers
SYNOPSIS
edahdi
device
DESCRIPTION
edahdi
allows you to modify the partition identifiers on a disk partitioned with
AHDI or an AHDI compatible formatter. An 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.
edahdi
supports the following options:
- device
-
The name of the raw device you want to edit.
The following partition identifiers are recognized by
NetBSD:
- 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 partition
a
in
NetBSD.
The following NBD partitions will be mapped from
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.
- NBR
-
NetBSD
root partition (deprecated).
- NBU
-
NetBSD
user partition (deprecated).
- NBS
-
NetBSD
swap partition (deprecated).
EXAMPLES
Say, you have a disk with that is partitioned like:
Number Id
1 GEM
2 GEM
3 GEM
4 GEM
This partitioning will show up in
NetBSD
as (Number refers to the first table):
Partition Fstype Number
c (whole disk) unused
d (user part) MSDOS 1
e (user part) MSDOS 2
f (user part) MSDOS 3
g (user part) MSDOS 4
Now you decide to change the id of partition 2 and 3 to NBD. Now
NetBSD
will show the partitioning as (Number refers to the first table):
Partition Fstype Number
a (root) 4.2BSD 2
c (whole disk) unused
d (user part) MSDOS 1
e (user part) 4.2BSD 3
f (user part) MSDOS 4
You will notice that the order of the partitions has changed! You will have
to watchout for this. It is a consequence of
NetBSD
habit of assigning a predefined meaning to the partitions
a/b
and
c.
SEE ALSO
disklabel(8),
installboot(8)
HISTORY
The
edahdi
command first appeared in
NetBSD1.2.
BUGS
The changes made to the AHDI partitions will become active on the next
first open
of the device. You are advised to use
edahdi
only on a device without any mounted or otherwise active partitions. This
is not enforced by
.
This is particularly confusing when your change caused partitions to shift,
as shown in the example above.
As soon as a disk contains at least one NBD partition, you are allowed to
write disklabels and install bootstraps.