I mean , sometimes vbox warns about wrong chipset or dislay settings. It could say something about that caching thing too...

Maybe i'll try that "hostiocache off"-thing. Hopefully usb keeps working without problems... or i have to start to use GitHub or Dropbox or something.

Hey, any ideas about editors that a) are available for Devuan and b) have an autosave function? I mean editors for coders....

Just use Emacs.

When i shut down a vm by clicking it's window's close button i get options to a) save machine state b) send shutdown signal c) send power off. Anything but a) could undo the changes.

But I usually shut down vm by saying sudo /sbin/shutdown or sudo /sbin/halt inside tah vm. So vbox should commit changes into the virtual hd.

Has Oracle changed vbox's behaviour concerning shutting down a vm , after 6.0 ? Or is it just a bug that reveals itself in the situation where the backing fs is almost full ?

#!/bin/bash
# /home/glenn/bin/vbox_load
/etc/init.d/vboxdrv setup
# echo "load modules for vbox."
# sudo modprobe -f vboxdrv
# sudo modprobe -f vboxnetadp
# sudo modprobe -f vboxnetflt
echo "list vbox modules"
lsmod | grep vbox
ls -l /dev/bus/usb/001
chown -hR glenn:vboxusers /dev/bus/usb/001/005
chmod -R 775 /dev/bus/usb/001/005
ls -l /dev/input/js0
# total 0
# crw-rw-r-- 1 root root 189, 0 Aug 27 22:07 001
# crw-rw-r-- 1 root root 189, 1 Aug 27 22:07 002
# crw-rw-r-- 1 root root 189, 2 Aug 27 22:07 003
# crw-rw-r-- 1 root root 189, 3 Aug 27 22:07 004
# crw-rw-r-- 1 root root 189, 4 Aug 28 10:40 005
# [root@GamesBox ~]# chown -hR glenn:vboxusers /dev/bus/usb/001/005
# [root@GamesBox ~]# chmod -R 775 /dev/bus/usb/001/005
# [root@GamesBox ~]# ls -l /dev/input/js0
# crw-rw-r--+ 1 root root 13, 0 Aug 28 10:40 /dev/input/js0

I'm not sure if this is any good, it's been a long time since DiD F22 flight sim broke (after sept 11 2001).

Speaking of "doing non-default-things with vbox", i have tried virtual machine files on usb harddrive and virtual machine files on samba share, with just a .vbox-file on /home. It was a bit difficult but kind of worked. The most recent version of vbox then was 5.something.

I think running some light software inside vm wouldn't cause problems. I mean not eating too much storage or ram or processor capacity.

For some reason i would like to mention another non-default-thing i did with virtualbox 5.x. I tried doing dd if=/dev/usb-disk or dd of=/dev/usb-disk and managed to froze the host machine so badly that i had to turn it off by pushing powerbutton.

With vbox 6.0 that usb-situation got little better. Don't remember freezing my machine with dd after that.

I always manage to try Things That Are Forbidden.

... and the next funny thing was that usb devices stopped working properly. Vm couldn't find any usb stick at all although usb filters should "capture" all devices.
...and mouse not working either. Had to log out and in again to make usb work in the host side.

Today managed to reproduce the "mouse not working"-situation. Just add the usb mouse into vm's usb filters. And mouse pointer almost froze after that.
That may or may not explain why usb stick could not be found. A fair warning from vbox would be nice.

And that still wouldn't explain the missing files nor wrong content. Nor why there is 3 weeks of commits missing in git log. Didn't mention that detail week ago.
I still suspect that in some situations, vbox doesn't commit changes into virtual hd properly.

I started using VBox with Squeeze if I remember correctly, and I haven't got any issues with "disk full" or access problems to USB drives.

Well, I have always avoided the default of using my home drive to store the VMs. From the beginning I have had a separate partition or drive for them. Its easy to configure in the options of the Virtualbox Manager.

Beside the point. Haven't yet confirmed what happens if /mnt/vbox runs out of storage but i wouldn't trust the .vdi-files to propertly store my files on that situation either.

Speaking of "doing non-default-things with vbox", i have tried virtual machine files on usb harddrive and virtual machine files on samba share, with just a .vbox-file on /home. It was a bit difficult but kind of worked. The most recent version of vbox then was 5.something.

I think running some light software inside vm wouldn't cause problems. I mean not eating too much storage or ram or processor capacity.

But couple of months a go it seemed like a good idea to install Docker inside a vm instead of outside. The iptables rules that Docker insists on wouldn't interfere with the iptables rules i wrote. And problems with dns and Docker would go away also. (Dockerd sees only the dns server that vbox runs, not dnsmasq or anything like that.)
On the other hand, you can fill up your /var very fast by pulling all kinds of images and building containers.

Maybe the usb-problem is not fully vbox's fault. Recently bought a new usb-mouse and found out that the older one co-operates little better with Fujitsu.
I also run apt-get install and apt-get upgrade -u  recently, so some package may have broken usb somehow. On the other hand, problems with external mouse start after starting virtualbox.

Same here.
Mine is on Devuan Beowulf with a 5.10 kernel.
ie: same VBox version from their repository.

Only use it for two things: an old XPSP3 I need for my Blackberry* software (no web access) and running Devuan Chimaera for Pi-hole + Unbound recursive DNS.

Pass through of USB devices and shared folders works fine once you get the hand of configuring it properly.

Never thought of that.
No web access for XP and the Chimaera VM runs headless, updates only from the Devuan repository. 
Should I?

Best,

A.

* a basic but well working Linux application by the name of Barry was abandoned ~10 years ago.

I started using VBox with Squeeze if I remember correctly, and I haven't got any issues with "disk full" or access problems to USB drives.

Well, I have always avoided the default of using my home drive to store the VMs. From the beginning I have had a separate partition or drive for them. Its easy to configure in the options of the Virtualbox Manager.

In last 4 months i have encountered 2 times "VDI_DISK_FULL"-complaint.
The second time it became clear to me that cause was /home running out of space.

One nice thing related to that:at least when /home is full or almost full, i cannot trust virtual harddrives of vbox.
First found out that there was some files missing inside the vm. Copied them from another vm's vhd.
Next thing i found out that the contents were wrong. I know i commented out that part of script but now i have to comment that out again. And try to remember what other changes i have made after commenting out that particular part.

Luckily i have made backups into usb stick.

... and the next funny thing was that usb devices stopped working properly. Vm couldn't find any usb stick at all although usb filters should "capture" all devices.
...and mouse not working either. Had to log out and in again to make usb work in the host side.

Maybe it is just this particular hw+sw that is the problem. Unfortunately i have only 1 computer with recent enough processor to run vbox.

I'll try 6.1 if that co-operates better. If that doesn't work, i'll have to move to Xen or something.