"Unable to find device node" errors at install

[Brian Behlendorf]

I ran into this familiar problem tonight while trying to do a fresh 
install of 6.0 - the one where during the install process you can 
successfully create a slice, but then fail to create the partitions. The 
error when one attempts to write out the partition table is "Unable to 
find device node /dev/da0s1b in /dev!"  After successfully installing 
Ubuntu on the same box (and having run FreeBSD 4.x on it for years) I 
figured out it wasn't a hardware or even disk geometry problem.

The problem must lie in devfs or in the initialization of the miniroot 
environment.  After the successful disklabel (one big partition type 165) 
I skipped the partition editor and started a fixit shell.  /dev/md0 was 
mounted as /.  I don't know if that's how it is during a partition edit, 
but I noticed that the only da0 devices in /dev were da0s1a and da0s1c.

I don't know enough "mknod" magic or whatever is used to create additional 
device handles in /dev these days; as a naive installer I shouldn't have 
to.  I went back to the partition editor, created one big partition, 
da0s1a, and didn't bother creating a swap or secondary partition.  The 
write succeeded, and I could proceed to install FreeBSD 6.0.

Since none of the previous attempts at addressing this problem seemed to 
come up with a clear answer, I thought I would add this information to the 
fray; it's not a question to be answered but it might help someone who 
hits this problem again. Or it might even lead to a fix by someone who 
understands how the installation scripts are supposed to work.

 	Brian