The Semi-Virtual Disk, a hardware interface that you can copy a disk image onto using a serial port on a PC, then use the SVD as if it were a floppy disk drive on your computer. The Apple II support is nearly complete; you can now boot software from the SVD, although you can’t yet write to the emulated disk. The SVD is available as a complete product for $110, or you can buy various combinations of parts to build one yourself.