I tried to compile kernel with the newly installed NetBSD/vax 1.6.1 on
a VAX3900. The process stopped and complained that it could not create
files in /tmp directory. I am root in the single user mode. I tried to
"chmod" the /tmp directory but failed. Could somebody
let me know how to solve the problem? Thanks.

Then I tried NetBSD/vax 1.6.1 on SIMH3.30, and the samething happened.
Take a look of the screen shot for details. Is it because I am in
single user mode? I didn't change rc.conf file. I tried to modify the
file, but since /tmp is not usuable, I could not bring up "vi" or
"ed".
 
# cd /
# ls
.cshrc     boot       home       netbsd     sbin       usr
altroot    dev        kern       pcs750.bin stand      var
bin        etc        mnt        root       tmp
# mkdir /tmp/test
mkdir: /tmp/test: Read-only file system
# ls -al /tmp
total 4
drwxrwxrwt   2 root  wheel  512 Dec  5  2002 .
drwxr-xr-x  15 root  wheel  512 Oct 29  2002 ..
# chmod 777 /tmp
chmod: /tmp: Read-only file system
# df
Filesystem  512-blocks     Used     Avail Capacity  Mounted on
root_device      39742    32094      5660    85%    /
#
 
--vax, 9000