The purpose of zdisk is to have a kernel of your choice and a rescue system on one floppy or cdrom 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 1070Kb in size. Ramf-117.exe at the same site has a similar rescue system, except it comes with a IDE kernel.