To update the files in a directory, one would want to copy over the new 
binaries and tar & compress them with steps like:

cd /u/ftp/pub/mx/unix/irix6.4/mx-1.42
ftp hercules (or wherever)
cp ../digitalunix4.0B/mx-1.42/INSTALL .
cd ..
tar cvfb ./mx-1.42.tar 20 mx-1.42/*
compress mx-1.42.tar