Compile the “net-boot” programs that are located in /usr/src/sys/i386/boot/netboot. You should read the comments at the top of the Makefile. Adjust as required. Make a backup of the original in case something goes wrong. When the build is done, there should be 2 MS-DOS® executables, nb8390.com and nb3c509.com. One of these two programs will be what you need to run on the diskless server. It will load the kernel from the boot server. At this point, put both programs on the MS-DOS boot floppy created earlier.