I test a lot of software on virtual machines, especially boot disks as booting my real computer is inconvenient. To that end I'm looking for a program that could create virtual USB flash disks and writable cd images (a writable iso of an empty cd/dvd?). For example, I don't have a floppy drive on my laptop, so I use a program called Virtual Floppy Drive. If a program can create a bootable floppy (think of Image for Windows or Drive Snapshot), I just let it write to the virtual floppy drive. I then save the virtual floppy as an img-file, and I can boot from it (as well as from iso files) using grub boot loader. (Booting from virtual floppies is also much faster than from real floppies). I'm looking for software that could do the same for CD/DVD images and USB flash disks.