Re: Creating /dev/dk* nodes so as to be persistent

[Alan Barrett <apb%cequrux.com@localhost>]

On Sat, 19 Oct 2013, Thomas Mueller wrote:
> How do I make device nodes in the underlying disk file system?
>
> How do I access the underlying file system and MAKEDEV?

Normally, /dev is on a disk file system.  However, in your case, 
I think you did not run MAKEDEV at the right point during the 
installation process, so the /dev on disk is missing some entries, 
or perhaps it's almost empty.  When you boot, /sbin/init notices 
that /dev/console is missing, and runs the moral equivalent of (cd 
/dev ; ./MAKEDEV -MM).  That creates a /dev file system in memory 
(using mount_tmpfs(8) or mount_mfs(8)) and populates it.  Anything 
in the memory file system is lost when you reboot.

You can run the "/sbin/mount" command, with no arguments, to check 
whether you have a memory file system mounted on /dev.  If so, then
there will be a line like "tmpfs on /dev type tmpfs (local)".

        /sbin/mount | grep /dev

You can unmount the tmpfs file system:

        /sbin/umount /dev

Now that the tmpfs file system has been removed, your /dev 
directory should be on the underlying disk.  To make device nodes 
there, use commands like this:

        cd /dev ./MAKEDEV all ./MAKEDEV dk16 dk17 dk18 dk19

You need to do all this as root, and some things might fail during 
the time that /dev is not fully populated (between the umount and 
the MAKEDEV).  I'd probably do it in single user mode.

Instead of all the above, if you are able to access your disk from 
some other working NetBSD system, then you can mount it as /mnt, 
and run commands like (cd /mnt/dev ; ./MAKEDEV all; ./MAKEDEV dk16 
dk17 dk18 dk19).


> Now I don't know if fsck_root would run if root is above the 
> /dev/dk* range.

I don't know.

> NetBSD 6.1_STABLE hung on boot on MSI Z77 MPOWER motherboard, 
> every time, most of the time reaching login prompt but hanging 
> there.

Perhaps that could be fixed.  You could report the problems via 
send-pr.

> I could run fsck_ffs from FreeBSD.

There are some differences between NetBSD and FreeBSD's FFS file 
systems.  I would probably not run the fsck from one OS on a disk 
from another OS.

> Most valuable part of this USB-stick NetBSD installation is 
> subversion (svn), which I don't want to disable by high-risk 
> fixes to /dev.

I don't think the /dev fixes are high risk.

--apb (Alan Barrett)