Another way to do this, 2 oracle instances in 2 different OS on single system,
that are working in same time.

I was using VMware package.
1. I installed Win2000 as host OS.
2. In Win2000 i installed VMware and created vitual network.
3. Under VMware i installed RH 7.2
4. Under Win2000 i installed Oracle 8.1.7 and in Linux i installed Oracle 9.0.1,
5. Next I (optional) install samba package on linux
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Now I have 2 oracle instances (8.1.7 and 9.0.1) in 2 different OS (Win2000 and Linux RH 7.2) on single system.

But perfomance!!! (very bad on linux instance).