On two different types of motherboards, RH6.1 incorrectly recognized my
Pentium-Pro motherboards as having 2 CPUs, and used the SMP version of the
vmlinuz files in /boot.
This caused the system to fail/lockup on first reboot. Luckily I made an
emergency floppy, and was able to manually softlick the correct UP vmlinuz
Post-boot (when the installer runs), it's not possible to tell with 100%
accuracy if a machine is UP or SMP. When an SMP install is done incorrectly, you
can boot into Linux UP by specifying "linux-up" at the lilo prompt.