One handy tool for booting linux systems and mounting the root partition is Loadlin. Now, Loadlin is *really* old, but there have been many times it has saved our sorry arses. You can get loadlin here. Loadlin needs some kind of *DOS on the floppy to boot from. MS-DOS 6.22 works fine; however, if you would like something that is maintained and free, you might try FreeDOS. [DR-DOS? Was it because the DR dudes were relaxing by the pool and didn’t want to talk to the IBM suits when they called? That is how Agatha remembers hearing the story. Hats off to Bill for keeping us from all running Display Writer for fifteen years!!] Cough… this is a story about Booting. Anyway, you need some kind of DOS. Snag a floppy boot image of FreeDOS here. Create the diskette:
bash-2.05a# cat BTFDOSB7.IMG > /dev/fd0 bash-2.05a# mount -t vfat /dev/fd0 /mnt bash-2.05a# ls /mnt autoexec.bat config.sys fdkernel.lsm kernel.sys readme command.com copying.txt fdos kernel16.sys bash-2.05a#
Copy your kernel, loadlin.exe, and edit a linux.bat:
bash-2.05a# cp loadlin.exe /mnt bash-2.05a# cp vmlinuz /mnt bash-2.05a# cat /mnt/linux.bat loadlin vmlinuz root=/dev/sda3 ro vga=3 bash-2.05a# ls /mnt autoexec.bat copying.txt kernel.sys loadlin.exe command.com fdkernel.lsm kernel16.sys readme config.sys fdos linux.bat vmlinuz bash-2.05a#
Modify linux.bat for the location of your root partition. This also assumes that your kernel has the correct drivers built in. Loadlin does have options for an initrd file if you need it. There are also some utilities included with FreeDOS:
bash-2.05a# ls /mnt/fdos Xkeyb.txt fdiskhlp.txt ldxkeyb.bat te.exe attrib.com fdiskpt.ini listxdef.exe xkeyb.exe choice.exe format.exe more.exe xkeybres.exe drvmngr.exe keyb.bat scankbd.exe fdisk.exe keydefs sys.com fdisk.ini keyman.exe te.doc bash-2.05a#
One cool utility is te, an editor quite similar to the Borland C++ 3.1 IDE. Another cool thing is that the FreeDOS fdisk sees Linux partitions correctly. Might be useful in a pinch. To boot your system using the above diskette, just boot and type linux. Create a floppy like this for every system!! For an alternate approach, see our SysLinux article.