Linux guests in full screen on Arch Linux and Slackware

[Luck]

Good morning everyone. I just signed up for the Forum, I've been a Virutalbox user for a year, and linuxuser. I always have two distributions, dual boot, on my PC, and both have Virtualbox installed. For some time, I used Arch Linux / Debian and my experiences with virtual machines were almost always done in Debian. In Debian, most distributions that I installed, as a virtual machine, the monitor screen automatically resized itself, taking up the entire screen area. One of the only exceptions was Slackware 14.2, which required a series of adjustments and installation of packages, such as a kernel, to work in full screen. Well, for a while now I replaced Debian for Slackware current, on the PC, and started to have my dual boot with Arch Linux with Slackware, in both Virtualbox is installed (installed correctly, with extension package, vboxdrv activated at startup ...). What I have noticed is that using Arch as a host, like Slackware, the systems I install as virtual machines do not work automatically in full screen, as was the case, for example, in Debian (as a host). I can make adjustments inside the guest, resizing to 1400x1050 (example), but it is not the same as the full screen. I do not know if I was clear, my command of English is not the best ... I ask, if anyone would have any suggestions of what I could do, given this limitation that I am observing? Because Debian, as a host, allowed guest Linux systems, for the most part, to automatically boot to full screen, and on Arch and Slackware this is not happening. Thanks for listening.

[Pernat1y]

Check that you have enough video memory and guest additions installed.

[scottgus1]

Also, be aware that many Linux distros fork Virtualbox and become responsible for their forked versions. You would need to be sure you personally installed official Virtualbox on the host PC from https://www.virtualbox.org/wiki/Linux_Downloads, and the Guest Additions inside the guest from the ISO that came with official Virtualbox, not a separate download from the Linux distro's repository.

And to get the best help, see Minimum Info Needed for Assistance. When you need to post a log (usually a good thing for every issue you need to post about), start the guest from full power off, not save-state. Run until you see the problem happen, then shut down the guest from within the guest OS if possible. If not possible, close the Virtualbox window for the guest with the Power Off option set. Then right-click the guest in the main Virtualbox window's guest list, choose Show Log. Save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.

[Luck]

Thank you for answering my question, taking the opportunity to apologize for perhaps not knowing for sure yet, the right places for posts here on the Forum. So, I always set the maximum video memory (128 mb), always (my CPU is very fast, it has 16 GB of RAM, and every machine I create I put 5 GB of dedicated RAM). Yes, I only install Virtualbox directly from the official website, as well as the extension package. Regarding guest add-ons, I haven't tried installing on my Slackware yet, but I'm trying to understand how Debian, without installing guest add-ons, provided the system graphic in full screen in almost all distributions.
I will try to install these extras, in one of the Virtual Machines, and watch what happens. And I will perform this operation that was suggested to obtain the log of this occurrence that I am quoting here.



I appreciate the prompt response. Thank you.

[scottgus1]

If you are always installing Linux for your guests, Linux tends to add Virtualbox Guest Additions to their distros, too, so the OS might work better if out in a Virtualbox guest. This is what probably helps your Linux guests work correctly on the Debian host.

A guest log would be necessary to find out why the Arch host acts differently.

Those Guest Additions are also a fork. If they work OK with your host, then they can stay. But if you have issues with Virtualbox that depend on the Guest Additions (like Full-screen) you may have to uninstall them and put in the official GAs on the ISO that comes with official Virtualbox.