What directories can be shared between multiple distributions on the same machine??

[Zhao YouBing <zhaoyb@cad.zju.edu.cn>]

If I want to install multiple distributions on one machine, there should 
be some parts that can be shared,
such as SWAP, /tmp(if u made it a separate partition), but
can we share /usr, /var? What should be done carefully to share them?

thanks

--
Zhao YouBing, Ph.D student
State Key Lab of CAD&CG,Zhejiang University,
Hangzhou, 310027, P.R.China
Tel  : 0571-87951045(O), 87933444(H)
Email: zhaoyb@cad.zju.edu.cn
MSN  : zhaoyoubing@hotmail.com