Corrupted partition table

[M. Schatzl]

    Generally when installing DragonFly on a partition that is not
    at the beginning of the disk, packet mode is required.  Packet mode
This is not directly related to what happened. The point is that I 
installed DFly on /dev/ad0s2 while Windows was at /dev/ad0s1. The 
first time I reviewed the partition table (after a reboot), I found 
the following:

. ..
cylinders=116280 heads=16 sectors/track=63 (1008 blks/cyl)
Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
<UNUSED>
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
sysid 165,(DragonFly/FreeBSD/NetBSD/386BSD)
    start 63, size 117210177 (57231 Meg), flag 80 (active)
        beg: cyl 0/ head 1/ sector 1;
        end: cyl 567/ head 15/ sector 63
Partition 4 is marked active
. ..