Each Soekris has a CompactFlash slot into which we insert a 64MB CompactFlash card. This is the system disk. It is mounted read-only during normal operation and we use a custom built LinuxDistribution. The Soekris BIOS supports PXE booting. The solution that I came up with PXE-boots the Soekris, copies a basic system onto the flash card, reboots the biscuit PC and configures it automatically. Minimal user interaction is required.
You need two components to get PXE to boot successfully:
# Address of the tftp server next-server 10.1.224.254; # Filename to load off the tftp server filename "pxelinux.0";
If you are running Debian, make sure you are using the tftpd-hpa package. Set tftproot to /tftproot. Inside tftproot you need to put the pxelinux.0 image and create a pxelinux.cfg directory. Inside this directory place a configuation file called default. It should contain the following:
SERIAL 0,19200 DEFAULT soekris TIMEOUT 30 PROMPT 1 IPAPPEND 1 label soekris kernel bzImage-2.4.26-bpc-pxe append root=/dev/nfs nfsroot=10.1.224.254:/exports/soekris ip=:::::eth0:dhcp panic=10 ramdisk_size=32768 console=ttyS0,19200n8
You also need to ensure the kernel image referenced above (in the kernel line) is in your tftproot.
Once you have the system PXE-booting successfully and loading the NFS FileSystem you are almost home and hosed. To achieve the configuration of the machine and install the flash card I simply editted the inittab(5) file on the NFS root to load a Shell script rather than spawning a getty. This script mounts the flash card read-only and copies a base image across on to it. This step is likely to be very user specific. Once the installation and configuration is complete the biscuit PC can be rebooted and it's up and running.