need help repairing this system... mount issues

Matthew Seaman m.seaman at
Mon May 19 01:07:52 PDT 2003

On Sun, May 18, 2003 at 04:54:12PM -0700, Bsd Neophyte wrote:
> --- Matthew Seaman <m.seaman at> wrote:
> > Uh -- which sort of disk drive do you have? IDE/ATA use the 'ad'
> > driver, SCSI use 'da'.  You seem to be confusing the two.  If you've
> > got SCSI disks, then you'ld have to boot from ufs:/dev/da4s1a and try
> > and mount /dev/da4s1e.  On the other hand if you've dot IDE drives
> > then you should be looking for the device files matching /dev/ad4* If
> > the device files are missing, you can generate them from single user
> > mode by:
> > 
> >     # cd /dev
> >     # ./MAKEDEV ad4
> > 
> > which should create a whole set of device files ad4, ad4s1, ad4s1a,
> > ad4s1b etc.
> thanks for that da/ad clarification, that's something that will stay with
> me now. :)
> i tried the "sh MAKEDEV all" earlier after reading something on
>, but that didn't work.  i guess it's good it didn't because i
> doubt i need to remake all the files.
> however, i'm still getting the same issue with your method.  the following
> errors appear:
> mknod: ad4: Read-only file system
> /sbin/mknod ad4
> this happens about 5 times starting with ad4 and ending with ad4s4.  how
> can i resolve this?

You need to re-mount the root partition read-write first.  Booting
into single user mode gets you a read-only root partition, because the
system hasn't been able to run the usual filesystem checks on it.  You
should be able to run:

    # mount -o rw -u /

to get the root partition read-write.  That may fail if the system
thinks the filesystem is dirty, in which case, you need to run fsck(8)
to clean it.  However, catch22 here: you need the /dev/ad4* device
files in order to run fsck(8), and you can't create those without a
writable filesystem, and you need to run fsck(8) to get the filesystem
to a writable state.

In this case, you've got to boot either the fixit floppy, which you
can create from the floppy images on the ftp site:

or you can use the 'live filesystem' Disk 2 CDRom.  See:

Use either of these by booting up your installation media in the usual
way, then choose the 'Fixit' option from the top level menu in
> > However, that's unlikely as most systems can only take 4 ATA drives
> > (ad0, ad1, ad2 and ad3).
> what has happend is that i've added a maxtor ata/100 controller.  this
> older BX board only supports ata/33 so i figure i might as well use the
> full potential of this drive.  the odd thing is that i've disabled native
> motherboard controllers, so why is this drive still listed as ad4?

Right --- that's a pretty good way to add extra ata busses to your
system.  If you're using the GENERIC kernel or your custom kernel
configuration contains "options ATA_STATIC_ID" (which it should unless
you have a compelling reason to take it out), then the fact that the
system sees your disk as ad4 means that it recognises your add-on card
as the third ata bus on the system: whether the older ata/33 busses
are usable is another question.  The dmesg(8) output will show you
what ATA controllers your system knows about.



Dr Matthew J Seaman MA, D.Phil.                       26 The Paddocks
                                                      Savill Way
PGP:         Marlow
Tel: +44 1628 476614                                  Bucks., SL7 1TH UK
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