Today, I have tried to used VirtualBox to use Linux Red Hat (RHEL5) as guest on my Windows XP as host. I have created fixed 30GB (quite small) space for the Linux RHEL5 installation. I don’t want to write about the installation process of RHEL5 into my VirtualBox but, I just want to share about the small resolution on my guest OS (RHEL5) in my VirtualBox.

Surprisingly, once completed RHEL5 installation on VirtualBox, found that the resolution is too small. There is only one resolution that I can use. That is 800 x 600. Even I click on the drop down menu, it only show 800×600 resolution. Its pain for me, it is too small on my WVGA screen.

As usual, Google is the first place I go to find the solution how to drag my VirtualBox screen resolution to 1280 x 800 or at least 1024 x 768. Again, there are crappy suggestion on this matter. They said to do this, and this, then this. But ended with nothing. My VirtualBox resolution still at 800 x 600.

The actual solution is very easy. Just install the “Install Guest Additions”. The way how to do it is, press Right Ctrl+F (if you are already in Full screen mode on your VirtualBox). There three menus on top of your VirtualBox menu i.e: Machine, Devices and Help. Click on Devices > Install Guest Additions as shown in picture below:

Then, the Install Guest Additions will automatically mounted into your VIrtualBox (RHEL5 guest) environment. Click OK as shown in picture below:

After that, open your terminal. Change directory to your mounted CD-ROM. Mine is:

#cd /media/VBOXADDITIONS_2.0.6_39755

Then execute as root the following:

sh ./VBoxLinuxAdditions-x86.run (FOR 32-bit)

sh ./VBoxLinuxAdditions-amd64.run (FOR 64-bit)

After that, recompile the guest kernel modules by using the following command:

/etc/init.d/vboxadd setup

and reboot.

Now, you can choose 1024 x 768 as your resolution by using KDesktop – right click on your Desktop and choose Configure Desktop..

In case you are not satisfied with 1024 x 768 resolution and want to use even more larger screen resolution, type the following command:

vi /etc/X11/xorg.conf (or you can use your own favourite editor such as nano, but I prefer vi)

Scroll down until you see phrase something like this:

Section "Screen"
Identifier "Screen0"
Device "Virdeocard0"
Monitor "Generic Monitor"
DefaultDepth              24
SubSection "Display"
View port       0  0
Depth 24
Modes "1280x800" "1024x768" "800x600" "640x480"
EndSubSection
EndSection

Notice that I have added the code as below, just after Depth 24 i.e

Modes "1280x800" "1024x768" "800x600" "640x480"

That means, when I open my KDesktop, I can see four type resolution:

1280×800, 1024×768, 800×600, and 640×480 as shown in the picture below:

You can also list all the resolution you needs if you want, something like this:

Modes "2048x800" "1280x800" "1024x768" "800x600" "640x480"

Hope this solve the problem, enjoy with big screen resolution