[K12OSN] Homework DropBox Idea

[Liam Marshall]

Here is what I have:

off of the /home/ dir I have created sub dirs for each of the classes, 
then inside those the home dirs for the individuals in the class.  For 
instance:

/home/compsci/user1
/home/compsci/user2
/home/compsci/user3

Now this worked for me last year, and as equiv to root I could go into 
each folder to mark.  But it took some time to go into each folder 
individually, looking for assignments

Here is what I would like:

directory structure like so   

/homework/compsci
/homework/saps
/homework/7a

one directory for each class, but no individual user folders inside. 

I want to give the kids responsibility to "hand-in" their assignments 
into the appropriate folders.  BUT:

I don't want other classes to be able to mess with their files.  so 
compsci kids can't mess with saps files, etc.  But I wanted to take it 
further and say that the compsci kids could hand in their finished work 
into the /homework/compsci folder, but not delete or change the file 
once it is there

in other words I want the class homework folders to have write once 
access/no read access/and no delete access.  So they can save/drop the 
file into the directory, but not change it or delete it once there

So after that long preamble, what rights do I set on a folder to 
acomplish this?  You should know that each class has a distinct gid so I 
can set rights using that, I think

I am thinking, if the rights can be set like I want, that users can drag 
their completed assignments into the appropriate homework "dropbox" and 
they are done, and can't cheat off of, or trash, other classmate's files


advise greatly appreciated