If your CMU account is in the ANDREW or ECE domains, you will not be able to access the CS AFS volumes without a cross-realm authentication ticket. To create a cross-realm ID, execute the following commands in a Unix shell:
cklog cs.cmu.edu touch /afs/cs/academic/class/15612-s98/class
Don't worry about the error message that the touch command gives you. To ensure that your cross-realm ID is active whenever you log in, add the above lines to your .profile (sh/ksh/bash users) or .login (csh/tcsh users). For more information on AFS and cross-realm authentication, see:
file:/afs/cs/help/www/01-Documentation/02-AFS_Getting_Started_Doc/TOC.html