[syslinux] PXELINUX 2.0 diskless booting RedHat 9.0

[John R. Menig]

I'm trying to boot RedHat 9.0 on a diskless PC from a head machine 
running Redhat 9.0.

The network appears to be setup correctly. I can boot the installation 
disk image fine using pxelinux.

What I am trying to setup is a number of  different Linux systems each 
with its own root directory on the head machine. I am hoping that I 
don't have to modify the kernel for any of these systems.

To test this out, I have exported the head machine's root directory, 
which I want NFS mounted as root on the diskless machine, and I'm using 
its /boot/vmlinuz kernel.

My configuration file is
label linux
kernel RedHat/vmlinuz
append nfsroot=160.2.200.2:/

The errors I get on the diskless machine are

kmod: failed to exec/sbin/modprobe -s -k block-major-72, errno = 2
VFS: Cannot open root device "" on 48:05
Please append correct "root=" boot option
Kernel panic VFS: Unable to mount root fs on 48:05

I believe pxelinux can be used to do this, and I don't need to use a 
initrd disk image.
 
What changes are need to the configuration file? How is swap space setup 
the diskless machine?