Mounting folders error

Question

I work for a school division where we needed a script that logs the user on to the servers User folder and Assignment folder. We had one that worked last year on the iBook carts but now our staff have macbooks and the original script no longer fuctions.
Each school has a different IP so we used linux calls netstat through awk command like so:
set the IPID to (do shell script "netstat -nr | grep default |awk '{print $2}' | awk -F \".\" '{print $2}'")
to obtain the second IP number. All the other numbers are constant ie: 169.1.41.0, 169.2.41.0, 169.3.41.0 ...
The first mount is the 169.(#).41.0 /username and the second would 169.(#).41.0/Assignments ( not the real IP of course)
-- this works fine
What happens though is if there is already one of the mounted drives on the laptop the script errors out, so we tried using a:
tell application "Finder" to eject (every disk whose local volume is false)
This removes the mounts off the desktop but it causes the script to error. After much searching we found out it is because Linux still thinks one of the drives is mounted. I did a df in terminal to see and its listed there so eject is not removing them entirely just their visiblity from the desktop.
I tried using:
set the nameHolder to (do shell script "logname")
and unmounting the drivers using umount:
do shell script ("umount /Volumes/169." & IPID & ".41.0/" & nameHolder)
delay 5
do shell script ("umount /Volumes/169." & IPID & ".41.0/Assignments")
which worked if the teacher logs in or they haven't any other folders already mounted. But students who log on with a local generic user "Student" have to use the same script to get to their private folders on the server to save their work using a seperate username and password.
So unlike the teachers who have mobile accounts they log in with a generic local account and then log into the server through the script to save their work. We have worked out most of it except unmounting the existing drives.
Compounded the teachers can also pick other folders to mount after they are logged in.
Is there a applescript command that will unmount every network mounted drive? Eject and unmount did not work. umount -A causes permission errors on all the other mounts so the script again fails.
here is the script:
set the IPID to (do shell script "netstat -nr | grep default |awk '{print $2}' | awk -F \".\" '{print $2}'")
-- we tried eject here: tell application "Finder" to eject (every disk whose local volume is false)
if IPID = "" then
display dialog "Sorry... You do not have a network connection. Network volumes cannot be mounted at this time." buttons {"OK"} with icon stop
-- we also tried the eject script here.
else
repeat
set the userid to text returned of (display dialog "Please enter your School Network User ID:" with icon note default answer "")
set the pass to text returned of (display dialog "Please enter the password for account ID: " & userid with icon note default answer "" with hidden answer)
if userid = "" or pass = "" then
display dialog "You must enter both a User ID and password in order to log on to the network." with icon caution giving up after 10
else
exit repeat
end if
end repeat
mount volume "afp://" & userid & ":" & pass & "@169." & IPID & ".41.0/" & userid
mount volume "afp://" & userid & ":" & pass & "@169." & IPID & ".41.0/Assignments"
end if

Answer 1

I'm not sure I follow the entire thread but the upshot is you're occassionally getting errors unmounting drives.
The first, and most obvious solution, is to find out which files are open and close off whatever processes are using those files, but that's not a trivial task to script.
The alternative is to force-unmount the volume. This will ensure the volume is unmounted but has potential hazards if it's run when there are files in use - they risk becoming corrupted.
If you want the force approach, just:
<pre class=command>do shell script ("umount -f /Volumes/169." & IPID & ".41.0/" & nameHolder)</pre>
The addition of the -f switch forces the unmount.