Simon Burge wrote:
> 	230 User C797061 logged in.
> 	ftp> pwd
> 	257 "/sys" is current directory.
> 	ftp> cd ..
> 	200 CWD command okay.
> 	ftp> pwd
> 	257 "/" is current directory.
> 	ftp> cd data/users/c797061
> 	200 CWD command okay.
> 	ftp> pwd
> 	257 "/data/users/c797061" is current directory.

An URL that expresses the idea 
	First "CWD .."
	then "CWD data/users/c797061"
	then "RETR file"
would be
	ftp://host/../data%2Fusers%2Fc797061/file
		   ~~ ~~~~~~~~~~~~~~~~~~~~~~ ~~~~
   first CWD ------^  ^                      ^
   second CWD --------^                      ^
   RETR -------------------------------------^

The part between the hostname and the filename in an FTP URL
is a slash-separated list of args to be passed (one at a time)
to a set of CWD commands.  (See RFC 1734 section 3.2.3.)

--apb (Alan Barrett)