I installed Debian Lenny (amd64) on the HDD. It was a bit of PITA, because I used my USB key as an installation medium. After a bit of googling I learned I need to use the 4th primary partition in order to boot from a USB device. There's also a small catch, the configuration of GRUB need to be changed after installation, because the HDD is sdb during install, but sda after the OS is installed (and USB key removed).
Here's the list of web pages that helped me during the install:
- Debian etch on ThinkPad X31 via USB stick (for dummies like me)
- Boot grml from usb-stick/firewire-device
- Grub Error 24: Attempt to access block outside partition
- Editing /boot/grub/menu.lst to change the GRUB boot menu
- chroot then "update-grub" gives errors
The PC is now up and running, I just configured munin on it, here are some resources: