| AHDILABEL(8) | System Manager's Manual (atari) | AHDILABEL(8) | 
ahdilabel —
| ahdilabel | disk | 
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:
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:
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:
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).
ahdilabel sd0ahdilabel command first appeared in
  NetBSD 1.5.
ahdilabel only on a disk without any mounted or
  otherwise active partitions. This is not enforced by
  ahdilabel.
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.
| February 17, 2017 | NetBSD 10.1 |