The purpose of 'zdisk' is to have a kernel of you choice and a rescue system on one floppy disk. Zdisk copies a kernel of your choice to a floppy and puts a rescue system on the same floppy, creating a boot-rescue floppy. The kernel can't be more than 730Kb in size. Zdisk contains the same rescue system as ramf.exe, except ramf.exe comes with a kernel.