Uncertain whether it's related to VirtualBox or Ubuntu.
Uncertain whether it's related to VirtualBox or Ubuntu.
It’s just Windows following its own conventions. In Windows, what appears as "GB" (giga bytes) is actually GiB (gibibytes). The hierarchy goes 1 GiB = 1024 MiB, 1 MiB = 1024 KiB, etc. On the other hand, Ubuntu shows in GB, meaning 128 GiB equals about 137.4 GB. This isn’t an issue; it’s simply a difference in units between the operating systems. With Windows, the SI suffix is different, which explains the discrepancy. Regarding your Ubuntu setup being smaller than expected, the EXT4 filesystem allocates space for journaling—used for recovery after power loss. It consumes roughly 2.7 GB here, which isn’t available for regular use, so it doesn’t count toward usable storage. Additionally, some partitions might be partially occupied.
You're not able to. Unless you're ready to fully change the Nautilus/GNOME files and recompile everything, plus any programs that show file sizes... I believe KDE (Dolphin file manager) offers a setting to go to base-2, so if you truly wanted this, you could swap GNOME for KDE and make the switch.