objective: Create a boot floppy for a Redhat installation.
what you need: High Density Floppy... Redhat 6.2 to 7.x installed
note: any line that starts with "#" means you should type that in a console logged in as root

log in as root
Insert floppy
format the floppy ( the example is for a 1.44 meg floppy, but you can format at higher capacities)

# fdformat /dev/fd0H1440

use mkbootdisk to create a boot floppy
note: you need to know what your kernel version is. There are probably many ways to get this info. I just cat'd my /etc/lilo.conf
It looked like this

boot = /dev/sda1
timeout = 50
prompt
message = /boot/message
default = linux
vga = normal
read-only
map=/boot/map
install=/boot/boot.b
image = /boot/vmlinuz-2.2.16-22
label = linux
initrd = /boot/initrd-2.2.16-22.img
root = /dev/sda5

the version number in the image line is what you need to know.
If you are running Xwindows with gnome you can find system in the foot button/system/System Info. It's the operating system release number.

#mkbootdisk version number goes here
example below is using kernel version 2.2.16-22
#mkbootdisk 2.2.16-22

If your systems bios is set to boot from a floppy disk, reboot and see if it works.