Problems with booting & MBR

[Vittorio De Martino]

Alle 11:16, giovedì 28 luglio 2005, vdm.fbsd at virgilio.it ha scritto:
> In the first disk ad0 (master) of a computer at office I had installed
> linux to be used as a postgresql server. Later I installed FreeBSD 5.4
> (just to have a go at it)  on a partition of the second disk ad1 (slave) to
> be a postgrresql server too.
> Linux lilo was the boot loader, booting linux by default and freebsd.
> Now, convinced of the high quality of the latter I eliminated linux from
> the first disk unfortunately without modifying lilo, and reshuffled the
> FreeBSD filesystem as in my latest /etc/fstab using also the first disk:
>
> # Device                Mountpoint      FStype  Options         Dump   
> Pass# /dev/ad1s2b             none            swap    sw              0    
>   0 /dev/ad1s2a             /               ufs     rw              1      
> 1 /dev/ad0s1a             /usr/local      ufs     rw              0       0
> /dev/ad0s1d             /var            ufs     rw              0       0
> /dev/ad0s1e             /tmp            ufs     rw              0       0
> /dev/acd0               /cdrom          cd9660  ro,noauto       0       0
>
> Now, even though I read the booting procedure in the handbook and somewhere
> else in the internet, issuing the various "fdisk -b B", "disklabel -b ..",
> "boot0cfg ..", I was completely unable to modify the MBR and make this
> FreeBSD only computer boot directly into this OS.
>
> What should I do with the configuration I have?
> A straightforward and step by step explanation is highly appreciated.
>
> P.S. Is it possible that some problems can arise by the fact that I used
> an "a" slice (ad0s1a)for mounting /usr/local and freebsd starts from
> ad1s1a?
>
>  


Friends, 
as suggested in the docs in the internet I tried both with
                                                                                
# fdisk -B -b /boot/boot0 ad0
fdisk: cannot open disk /dev/ad0: No such file or directory

and with
                                                                                
# fdisk -B -b /boot/boot0 ad1
fdisk: cannot open disk /dev/ad1: No such file or directory

WHILST
my working /etc/fstab is, as I mentioned before:
# Device                Mountpoint      FStype  Options         Dump    Pass#
/dev/ad1s2b             none            swap    sw              0       0
/dev/ad1s2a             /               ufs     rw              1       1
/dev/ad0s1a             /usr/local      ufs     rw              0       0
/dev/ad0s1d             /var            ufs     rw              0       0
/dev/ad0s1e             /tmp            ufs     rw              0       0

Why FreeBSD 5.4 cannot find /dev/ad0 and ad1?
What should I do?          

A baffled and frustated Vittorio again