Understanding LTSP and NFS mount of /

[Rodney Williams]

I'm working on getting a bunch of labs setup and I have been reading the LTSP 
docs and playing with Knoppix.  In the LTSP docs "Chapter 1. Theory of 
operation" (http://www.ltsp.org/documentation/ltsp-3.0.0/ltsp-3.0.html) the 
following point is made:

18.
Up to this point, the root filesystem has been a ram disk. Now, the /linuxrc 
script will mount a new root filesystem via NFS. The directory that is 
exported from the server is typically /opt/ltsp/i386. It can't just mount 
the new filesystem as /. It must first mount it as /mnt. Then, it will do a 
pivot_root. pivot_root will swap the current root filesystem for a new 
filesystem. When it completes, the NFS filesystem will be mounted on /, and 
the old root filesystem will be mounted on /oldroot.

I follow the big picture here but my question is what exactly is the mounting 
via NFS doing?  And if it is doing what I think it is, could I put the 
knoppix root from its CD in /opt/ltsp/i386?  I think something along these 
lines was asked in the following post and thread:
http://www.debianplanet.org/node.php?id=690

The point of this exercise is that the lab will have servers sufficiently 
beefy enough but will generally have lower end systems for 
workstation/network clients (Pentium Pro 200's w/ @64-128Mb RAM) and run by 
brain dead M$ admins. I was thinking if this could be done the on-site admins 
would be hard pressed to make a mess of things because the Knoppix root would 
always be easily recreated and the server could itself be backed up.  This 
also (with Knoppix as the final mounted root on the network client) has the 
added advantage that the lab users could be given an exact working Linux OS 
to take with them. 

I know there is a learning curve to getting home to function as the lab will 
but I've been working on the workstation/desktop floppyconfig save and it 
works pretty good especially if you setup some simple shell scripts on the 
floppy to make sure things return to a previous state the way you want.

If anyone has thoughts on this I will appreciate the input.

rbw