Can a Sun2/120 take SunOS 4.x and/or Unix 4.3 ?

[Aaron Y. T. Cheung]

Anyone could help give information regards whether a Sun2/120 can take
SunOS 4.x or any Unix 4.3?  If not, what's the latest SunOS release for
the Sun2?  

How compatible is SunOS 3.5 and SunOS 4.x ?  Can I expect 4.x binaries to
run under 3.5?  If not, how about at source level?

Thanks for any information.

Aaron Cheung
<cs519905 at caesar.cs.umn.edu>