mounting CDs? and emacs under SU?

[Peter Christensen <christensen@gtcinternet.com>]

I'm still learning about the basics of Linux, so please excuse a very
basic question:  If I want to access a CD do I need to add a line to
/etc/fstab:

  /dev/cdrom /cd iso9660 ro,user,noauto,unhide

and then under superuser type:

  mount -t iso9660 /dev/cdrom /cdrom

This is how I did it (I think!) before my hard drive crashed and I had
to replace it.  Now that I've reloaded Linux I can't edit /etc/fstab
with emacs.  Emacs works OK with a normal signon, but under SU I get the
following messages:

  Xlib:  connection to ":0.0" refused by server
  Xlib:  Invalid MIT-MAGIC-COOKIE-1 key
  emacs:  Cannot connect to X server :0.0
  check the display environment variable or use "-d"
  Also use the 'xhost' program to verify that it is set to permit
connections from your machine

So...  two questions:  Do I always need to type the full mount command,
or is there a shortcut for this?  And how can I get emacs to work under
Superuser?

Thanks,
Peter Christensen