QEMU is an open-source alternative to VirtualBox (etc.)—A tool i use for running other operating systems within Linux. this is useful if you for example, want to run a program that needs 16-bit Windows, or if you want to try out another operating system without a messy uninstall. Dunno why it's taken me this long to use it, was using VB for a while for the same purpose ;3

• Migrate a VirtualBox Disk Image (.vdi) to a QEMU Image (.img)
• Convert from VirtualBox to KVM/Qemu

• Qemu