I'm setting up a NetBSD 1.4 box for amanda backups, and I'm
curious about a permissions thing. I'm using default
install sets, so the permissions should be default as
well.

The disk devices are owner and group readable

    # ls -l /dev/rwd0a 
    crw-r-----  1 root  operator  3, 0 Jun  8 04:31 /dev/rwd0a

while /sbin/dump is

    -r-xr-sr-x  2 root  tty  241664 May  7 13:08 /sbin/dump

So: unless the dumper is root, doesn't the g+s keep a
legitimate user (belonging to operator group) from making
dumps?

According to the amanda logs, dump reports

    DUMP: Cannot open /dev/rwd0a

WL