new world is a type of hardware or software?

Before I thought Mac OS X is "new world", being a software thing. Mac OS
9 is "old world".

Now I am a bit confused. If I wish to run a 3-OS system with Mac OS 9 +
Mac OS X + Gentoo Linux, should I partition my harddisk in old world?

I suspect I should do the following (currently I am already using Gentoo
Linux on my iBook/G3)

   1. backup my Linux
   2. Install Mac OS 9
   3. Install Mac OS X. It should help me to configure it as dual boot.
      while leave some empty space;
   4. restore the Linux backup and run yaboot.

Is this correct?

Best regards
Zhang Weiwu