If you have a Fedora 8 or above installation, you can upgrade it to the latest release 13 easily with an application called PreUpgrade. The application supports direct upgrade from Fedora 11 or Fedora 12, so you only have to run it once.

Here is the official HOW TO page for  PreUpgrade.

How to use PreUpgrade

The page also offers troubleshooting tips on how to solve your common upgrading errors. When I tried to follow the instructions to upgrade my Fedora 12 installation, I ran into a problem where the /boot partition was low in space. I followed the troubleshooting section to delete some older kernels, but it still was not enough. The problem is that the default installation of Fedora has 200MB allocated to /boot, but the installer image is huge and also requires additional space for installation. I finally solved the problem by letting PreUpgrade  download the installer image when the computer reboots. This is a screenshot for the dialog where you should click on Continue. Note that this requires a wired connection to the network.

To install VirtualBox 3.0 Guest Additions on a Fedora 12 virtual machine, follow these steps.

1. In the virtual machine’s menu, click on Devices -> Install Guest Additions .
2. The guest additions CD image is mounted. A message pops up asking about autorun. Click on Cancel.
   
3. Click on the Applications -> System Tools -> Terminal to bring up a terminal window.
4. Now you do the following steps in the terminal. Enter su and press enter. Enter root’s password to get a root prompt.
5. We need two extra packages to install the guest additions. Enter the following commands.
   yum -y install gcc kernel-devel
6. Now change the directory to the guest additions media. The path is different, if you use a different version of VirtualBox.
   cd /media/VBOXADDITIONS_3.0.12_54655/
7. Run the guest additions script for 32bit machines. If you use a 64bit VM, use VBoxLinuxAdditions-amd64.run instead.
   sh VBoxLinuxAdditions-x86.run
8. Reboot the VM and it’s done.

I do not have a full guide on installing Fedora 12 on VirtualBox, but the whole process is very similar to installing Fedora 11. Please see this post for reference.

To install VirtualBox 2.2 Guest Additions on a Fedora 11 virtual machine, follow these steps.

1. In the virtual machine’s menu, click on Devices -> Install Guest Additions .
2. Click anywhere inside the VM. Click on the Fedora -> Computer. Scroll down and click on the VBOXADDITIONS CD.
   
3. Click on the Fedora icon again. Enter konsole and press enter to bring up a terminal(konsole).
   
4. Now you do the following steps in the terminal. Enter su and press enter. Enter root’s password to get a root prompt.
   
5. We need two extra packages to install the guest additions. Enter the following commands.
   yum -y install gcc kernel-devel
6. Now change the directory to the guest additions media. The path is different, if you use a different version of VirtualBox.
   cd /media/VBOXADDITIONS_2.2.4_47978/
7. Run the guest additions script for 32bit machines. If you use a 64bit VM, use VBoxLinuxAdditions-amd64.run instead.
   sh VBoxLinuxAdditions-x86.run
8. Reboot the VM and it’s done.

If you are interested in the full guide on installing Fedora 11 on VirutalBox. Please follow this link.

If you want to try Fedora 11 without buying a new machine or partitioning your hard drive, VirtualBox is a good choice. This guide assumes you have downloaded the Fedora 11 KDE iso and you also have installed VirtualBox 2.2 or above. You also need enough disk space to hold the virtual disk on your hard drive.

1. Run VirtualBox and Click on New to create a new virtual machine.
   
2. Click on Next to continue.
   
   
3. Name your virtual machine and select the proper OS Type. Click on Next to continue.
   
4. Set the memory size for the virtual machine. I used 512MB. Click on Next to continue.
   
5. Click on Next to create a new virtual disk.
   
   
6. Create New Virtual Disk Wizard starts, click on Next to continue.
   
   
7. Select Dynamically expanding storage and click on Next to continue.
   
   
8. Specify a location for the disk image and size. If your system drive is low on space, you might want to use a different drive. Click on Next to continue.
   
9. Click on Finish to finish creating a new virtual disk.
   
10. Click on Finish to finish creating of the new virtual machine.
    
11. Now back to the main windows of VirtualBox with the newly created virtual machine for Fedora. Double click on CD/DVD-ROM. Note that a lot of features are turned off by default. If you want to change the settings, click on Settings to modify them.
    
12. Check Mount CD/DVD Drive and select ISO Image File. Click on the folder icon.
    
13. Click on the Add icon to locate the iso image you downloaded. Click on Select and you will be brought back to the dialog in previous step. Click on OK.
    
14. Click on Start icon in the upper left corner to start installation.
    
15. Click anywhere inside the virtual machine window, so that you can use your keyboard and mouse inside the virtual machine. If you ever want to release the mouse and keyboard from the virtual machine, press right Ctrl key. Double click on Install to Hard Drive.
    
16. The installer runs. Click on Next.
    
    
17. Select the language and click on Next.
    
18. A warning dialog shows. Click on Re-intialize drive to continue.
    
19. Set a hostname and click on Next.
    
    
20. Select a time zone and click on Next.
    
21. Create a user and click on Forward.
    
22. Enter root’s password and click on Next.
    
23. Use the default scheme for partitioning. Click on Next.
    
    
24. A confirmation dialog shows. Click on Write changes to disk.
    
25. The installer copies the live image to the virtual disk. When the installation is done. Click on Close.
    
    
26. Click on the Fedora icon -> Leave -> Shutdown.
    
27. When the virtual machine is in the shutdown state. We want to un-mount the Live CD, so the virtual machine won’t boot to it again. Double click on CD/DVD-ROM and uncheck Mount CD/DVD Drive. Please see the screenshots for step 11 and 12.
    
    
28. Start the virtual machine.
29. When the VM boots up the first time, a setup wizard runs. Click on Forward.
    
30. Click on Forward.
    
31. Create a user and click on Forward.
    
32. Click on Network Time Protocol and check Enable Network Time Protocol. Click on Forward.
    
33. Click on Finish.
    
34. The basic installation is done!
    

In my next post, I’ll show you how to install the VirtualBox Guest Additions. Stay tuned. Ok, here is the link to the guide on Guest Additons.