Strange fdisk behavior on 5.4-STABLE

[Jerry McAllister]

> 
> I have a hard drive in my laptop with a 30GB FreeBSD partition and a 
> few gigabytes of unused space (40GB hard drive).
> I wanted to make another FreeBSD partition but when I run fdisk I get 
> this following error:
> fdisk: cannot open disk /dev/ad0: No such file or directory
> 
> /dev/ad0 does exist and fdisk has no problem printing the partition table, 
> but when run with -u it pretends
> the disk doesn't exist.

Well, are you trying to make fdisk write to the slice table of
a drive that you have mounted - the one with ad0s1 on it which is
probably where you are booted?   That isn't allowed.   
Try it from a fixit disk boot.   That is disk 1 in the 5.xxx ISO set.

////jerry

> I had no problems partitioning a USB flash drive.
> 
> Any suggestions?
> 
> Baldur
>