Install or upgrade to ubuntu 8.04 on linux with no media

I had a problem, my ubuntu server was too old for automatic updates, and the CD-ROM drive was broken and I'm allergic to floppies. A quick internet search lead to three options:

• instlux, a nice graphical installer to run under windows
• UNetbootin, a really nice graphical installer for linux and windows
• A grub trick for booting the installer from grub under windows described in detail for any linux, and in less detail but for ubuntu.

The first option was no good, because it only ran on windows. The second looked really neat and easy, and is probably the best, but being the geek that I am, I wanted to try the ideas in the third option, but 'translated' to work on my old linux (in my case ubuntu 5.04). It turned out to be pretty easy. Here are the steps I used:

• I opened my downloaded ubuntu 8.04.1 server ISO image in archive manager and extracted the 'install' directory to /boot/install on my old computer. I did this with another 8.04 desktop, but could just as easily done it with the old computer itself.
  
• I edited /boot/grub/menu.lst, adding the following lines at the bottom:

  title           Ubuntu 8.04.1 Installer (hd0,0)
  kernel          (hd0,0)/boot/install/netboot/ubuntu-installer/i386/linux vga=normal ramdisk_size=14972 root=/dev/rd/0 rw --
  initrd          (hd0,0)/boot/install/netboot/ubuntu-installer/i386/initrd.gz
  

  (I actually first tried the vmlinuz and initrd.gz I found in the installer directory, but that insisted on a CD, and I did not want to try faking that with a raw partition, so I changed to the netboot option in the text above.)
• I also commented out 'hiddenmenu' and added 'timeout 10' to menu.lst so that I would actually get to see the menu choice when I rebooted.
  
• Finally I rebooted and choose the new installer, and, after answering a bunch of question, viola, I had a new Ubuntu 8.04.1 server!
  

These instructions assume a decently fast internet access, since everything installed is downloaded. If you have the CD already (as I had), and no internet, or slow internet, you can also copy the CD to a local hard-drive partition and install from there. That was too much trouble for me, so I did not try it :-)