EDAHDI(1) | General Commands Manual (atari) | EDAHDI(1) |
edahdi
— modify
AHDI partition identifiers
edahdi |
device |
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:
The following partition identifiers are recognized by NetBSD:
Say, you have a disk 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.
The edahdi
command first appeared in
NetBSD 1.2.
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
edahdi
. 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.
September 1, 2019 | NetBSD 10.99 |