The Plop boot managers are very useful tools for both physical hardware and for VMs. I used to use these tools a lot, for booting Linux from USB on machines th

The Plop boot managers are very useful tools for both physical hardware and for VMs. I used to use these tools a lot, for booting Linux from USB on machines that only supported floppy/CD boot, and occasionally for booting from CD on machines that only supported floppy boot. Note: this does not just mean physical machines. I have used several hypervisors in which VMs could not boot from USB devices, well within the last decade. You can boot the Plop boot manager from a virtual floppy or virtual CD, and then start the VM from a real physical USB key that is attached to a physical USB port which is assigned to the VM. This is a useful function: for instance, one can install DOS onto a USB key from inside a VM, then stop the VM to readily put files onto, or take them off, the key. That works with a physical partition too but most modern OSes do not play nicely with DOS. Linux does, but Windows doesn't. You can install Linux onto a USB key and boot it both from within the VM and on bare metal. Note, not copy an ISO image, I mean a fully-installed Linux system. The VM continues to be useful because if you update the Linux-on-a-key, it will tend to add any OSes on the hard disk in the PC you are using, which you probably do not want. Update in a VM and this doesn't happen.