VirtualBox machines installation:
1. Run "create_network.sh" to create a NAT network for machines to communicate in
2. Copy "virtualbox/minix" and "virtualbox/ubuntu" directories somewhere to your drive
3. Copy Minix image from "disk_images/minix.7z" to your "minix" directory
4. Download and copy Ubuntu installation CD to your "ubuntu" directory
5. Open VirtualBox, choose "Add" and add both virtual machines.
6. To "ubuntu" machine add a new hard drive and a CD/DVD drive pointing to Ubuntu installation CD
7. Install Ubuntu. Configure Ubuntu according to "disk_images/INSTALLING_UBUNTU.txt. Close machine after installation.
8. Run both machines
Login and password for Minix machine is root:root

Make sure both machines have their network interfaces set to "NAT network -> natnet1", and that the adapter type is "PCnet-FAST III".
If something doesn't work, try to set up virtual machines yourself from scratch.