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Expanding width\height of VM without X installed?

Posted: 26. Apr 2015, 19:04
by gibbsw
I have a Virtualbox based Virtual Machine (VM) where the guest is 'Oracle Enterprise Linux', the host is 'Windows 8.1 Professional'. The Linux guest does not have X Windows (Gnome, etc...) installed. Please see the inline attachment, I think this will help you understand what I'm wanting to do and am asking below. Notice how the Virtualbox software window will expand the entire width/height of my monitor if I maximize the window.... Even if I maximize the Virtualbox window, the 'Linux VM' portion of the winodow does not expand along with it. How can I somehow get the Linux VM portion of the window to be a greater width/height without installing X windows on this guest VM?
Virtualbox Based VM - Oracle Enterprise Linux.png
Virtualbox Based VM - Oracle Enterprise Linux.png (31.46 KiB) Viewed 2473 times
Thank you in advance

Re: Expanding width\height of VM without X installed?

Posted: 27. Apr 2015, 11:40
by mpack
If the guest is running in text mode, and the guest OS doesn't let you change display resolutions, then the only option VirtualBox can offer you is scale mode (View | Switch to scale mode while the VM is running).

Re: Expanding width\height of VM without X installed?

Posted: 27. Apr 2015, 13:58
by Perryg
Goggle "vga=791"
What you are wanting requires that you set the framebuffers at boot time. Usually in gurb/grub2, by adding a definition to the boot line.

Re: Expanding width\height of VM without X installed?

Posted: 29. Apr 2015, 16:17
by gibbsw
Perryg wrote:Goggle "vga=791"
What you are wanting requires that you set the framebuffers at boot time. Usually in gurb/grub2, by adding a definition to the boot line.
I ended up seeing this recommendation based on the Google search you recommended at http://pierre.baudu.in/other/grub.vga.modes.html

I went to the menu.lst file located at /boot/grub on my guest VM, looked at the contents of this file with the vi editor and see the contents below.
menu-lst-screenshot.png
menu-lst-screenshot.png (16.5 KiB) Viewed 2431 times
The vga= syntax doesn't look to be located within this file. I'm still researching based on your recommendation.

Re: Expanding width\height of VM without X installed?

Posted: 29. Apr 2015, 16:20
by gibbsw
mpack wrote:If the guest is running in text mode, and the guest OS doesn't let you change display resolutions, then the only option VirtualBox can offer you is scale mode (View | Switch to scale mode while the VM is running).
Thank you for this feedback. I will end up using this solution if this guest OS doesn't support the resolution change that perryg is suggesting. I was able to use the 'Switch to Scale' option as you suggested. It definitely is better then what I had, not the preferred solution since the resolution doesn't get better, it only increases the font size of everything on the screen.

After getting into 'Switch to Scale' mode, how do you get back out of it... nevermind see the solution to this new at: http://stackoverflow.com/questions/1071 ... virtualbox

Re: Expanding width\height of VM without X installed?

Posted: 29. Apr 2015, 16:21
by Perryg
The vga= syntax doesn't look to be located within this file
That's because you have to add it. Find the line that resembles the following and add the proper value I have indicated in red.

kernel /boot/vmlinuz-2.6.18-6-686 root=/dev/sda7 ro vga=791

Re: Expanding width\height of VM without X installed?

Posted: 29. Apr 2015, 16:44
by gibbsw
Thank you perryg. Your suggestion took effect after I restarted the guest VM. On Oracle Enterprise Linux I just needed to add vga=791 right before the "initrd" syntax in the /boot/grub/grub.conf file. Screenshot of working file is inline below for anyone else trying to do this.
solution.png
solution.png (86.92 KiB) Viewed 2429 times
mpack: Thank you also for your feedback, this will also come in use, I wasn't aware that this feature existed.