Confused about fdisk -A option

[Hugo Silva <hugo%barafranca.com@localhost>]

Hello,

I'm trying to specify a partition alignment and offset for SSD disks
(apparently it makes quite a difference & wanted to test that) (it also
doesn't work on the sata disks attached, same behavior), but there's
something strange happening:


(note use of -A)

# fdisk -A 2048/64 -0ua /dev/rwd1d


fdisk: primary partition table invalid, no magic in sector 0
Disk: /dev/rwd1d
NetBSD disklabel disk geometry:
cylinders: 62003, heads: 16, sectors/track: 63 (1008 sectors/cylinder)
total sectors: 62500000

BIOS disk geometry:
cylinders: 1023, heads: 255, sectors/track: 63 (16065 sectors/cylinder)
total sectors: 62500000

***** Partitions aligned to 2048 sector boundaries, offset 64 *****

Do you want to change our idea of what BIOS thinks? [n]

Partition 0:
<UNUSED>
The data for partition 0 is:
<UNUSED>
sysid: [0..255 default: 169]
start: [0..3890cyl default: 64, 0cyl, 0MB]
size: [0..3890cyl default: 62499936, 3890cyl, 30518MB]
bootmenu: []
Do you want to change the active partition? [n] y
Choosing 4 will make no partition active.
active partition: [0..4 default: 0]
Are you happy with this choice? [n] y

We haven't written the MBR back to disk yet.  This is your last chance.
Partition table:
0: NetBSD (sysid 169)
    start 64, size 62499936 (30518 MB, Cyls 0-3890/113/31), Active
        PBR is not bootable: All bytes are identical (0x00)
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
Bootselector disabled.
First active partition: 0
Should we write new partition table? [n] y



But then..

# fdisk wd1
Disk: /dev/rwd1d
NetBSD disklabel disk geometry:
cylinders: 62003, heads: 16, sectors/track: 63 (1008 sectors/cylinder)
total sectors: 62500000

BIOS disk geometry:
cylinders: 1023, heads: 255, sectors/track: 63 (16065 sectors/cylinder)
total sectors: 62500000

Partitions aligned to 16065 sector boundaries, offset 63

Partition table:
0: NetBSD (sysid 169)
    start 64, size 62499936 (30518 MB, Cyls 0/1/2-3890/113/31), Active
        PBR is not bootable: All bytes are identical (0x00)
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
Bootselector disabled.
First active partition: 0
root@xen:/root# fdisk wd1
Disk: /dev/rwd1d
NetBSD disklabel disk geometry:
cylinders: 62003, heads: 16, sectors/track: 63 (1008 sectors/cylinder)
total sectors: 62500000

BIOS disk geometry:
cylinders: 1023, heads: 255, sectors/track: 63 (16065 sectors/cylinder)
total sectors: 62500000

***** Partitions aligned to 16065 sector boundaries, offset 63 *****

Partition table:
0: NetBSD (sysid 169)
    start 64, size 62499936 (30518 MB, Cyls 0/1/2-3890/113/31), Active
        PBR is not bootable: All bytes are identical (0x00)
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
Bootselector disabled.
First active partition: 0



Now it's been a while since I set up raidframe on NetBSD (pretty much
the only time when fdisk crosses my path) so it's possible that I'm
doing something incredibly stupid.


Shouldn't it say 2048/64 above, where it says 16065/63, as specified in
the first command given?


If it matters, this is NetBSD 6.0/amd64.