missing initrd image

[Matthew Bennett <bennettm@hotpop.com>]

I'm using 3.0r1 with a custom 2.4.22 kernel. /boot/grub/menu.lst contains:

title Debian
   root (hd0,6)
   kernel /vmlinuz root=/dev/hda7
       initrd /initrd

However, /initrd is an empty directory on my system, so it complains and 
I have to manually enter the first two lines in the grub shell to boot. 
Booting this way causes a lot of 'modprobe: Can't locate module 
char-major-xyz' errors, and although I can ping localhost, trying 
anywhere else fails with 'network unreachable.

From what I've read, loading initrd seems to be necessary for loading 
modules, but I don't really know what its function is. Should I have an 
initrd image, and why is /initrd an empty directory? Thanks for any help.