Ok I have read lotsa postingss about Tiger and installation.
My theoretical proceedure is as follows:
Clone my 80gb h/d to an external FWD with Super Duper.
Clean my internal Drive and reformat.
Install Tiger
Copy over my files and apps from the FWD.
Now, that all sounds very simple but I...
Verrrry Interrresting !
I used UNIX a little on a Sun Sparstation at college in the early nineties but have since forgotten it completely.
If I remember it takes learning a lot of commands.
I'm sure there is a wealth of info on the Sun and Apple sites which I shall investigate but maybe there...