Timo's Rescue CD Set
Build Your Bootable Rescue CD

Howto make 2.88MB el torito floppy disk images

Preface:

I wrote that little recipe because i did not find any useful information on that title on the net. So maybe that will be useful for someone else.

Do it with lilo
Do it with syslinux
Do it with grub
Or do it with isolinux
Multi boot images

1. Use lilo as the bootloader

First make a 2.88MB zeroed image file.
dd if=/dev/zero of=/tmp/boot288.img bs=512 count=5760

Then set up the loop device.
losetup /dev/loop0 /tmp/boot288.img

Then format it with a filesystem.
mkfs.minix /dev/loop0

Mount it at /mnt.
mount /dev/loop0 /mnt

Assemble your boot floppy at /mnt.
-----<snip>------

# lilo.conf
boot	=/dev/loop0
disk	=/dev/loop0
bios	=0x00	# 2.88MB disk geometry
sectors	=36
heads	=2
cylinders	=80
install	=/mnt/boot/boot.b
map	=/mnt/boot/map
backup	=/dev/null
default	=RescueSystem
prompt
delay	=50
timeout	=50
image	=/mnt/bzImage	# your kernel image
label	=RescueSystem
initrd	=/mnt/initrdfs.gz	# initial ramdisk
root	=/dev/ram0
append	="ramdisk_size=40960"	# initial ramdisk size

-----<snap>------

Now execute lilo.

Last but not least copy the initrdfs.gz to /mnt and unmount /mnt.

Detach the loop device: losetup -d /dev/loop0.

Voila, that's it.

I got that out of the scripts from tomsrootboot disk - http://www.toms.net/rb.

1.2 Use syslinux as the bootloader

Syslinux will maybe work on systems where the lilo bootloader does not work.
That's because there are some buggy bioses out in the universe which does not implement the full el torito standard. And BTW syslinux is a lot easier to set up then lilo.

First make a 2.88MB zeroed image file.
dd if=/dev/zero of=/tmp/boot288.img bs=512 count=5760

Then set up the loop device.
losetup /dev/loop0 /tmp/boot288.img

Then format it with the fat filesystem because syslinux only operate from dos formatted disks.
mkfs.msdos /dev/loop0

Mount it at /mnt.
mount /dev/loop0 /mnt

-----<snip>------

# syslinux.cfg

DEFAULT	RescueSystem
PROMPT	1

LABEL	RescueSystem
KERNEL	bzImage
APPEND	initrd=initrdfs.gz ramdisk_size=40960 root=/dev/ram0
TIMEOUT	100

-----<snap>------

Now copy the initrdfs.gz and the kernel to /mnt and unmount /mnt. Now you execute:
syslinux -s /tmp/boot288.img
And detach the loop device:
losetup -d /dev/loop0

Voila, that's it.

1.3 Use grub as the bootloader

This recipe is heavily based on information provided to me by Petr Konecny .

First make a 2.88MB zeroed image file.
dd if=/dev/zero of=/tmp/boot288.img bs=512 count=5760

Then set up the loop device.
losetup /dev/loop0 /tmp/boot288.img

Then format it with the ext2 filesystem.
mke2fs /dev/loop0

Mount it at /mnt.
mount /dev/loop0 /mnt

Create a directory named grub.
mkdir /mnt/grub

Copy the grub stage files onto the floppy image.
cp /usr/lib/grub/i386-pc/stage[12] /mnt/grub

Create a device map file.
echo "(fd0) /dev/loop0" > /tmp/dev.map

Install grub to the image.
/sbin/grub --device-map=/tmp/dev.map <<END
root (fd0)
setup (fd0)
END

-----<snip>------

# grub menu file menu.lst

timeout	5
title	Rescue System
root	(fd0)
kernel	/vmlinuz root=/dev/ram0 ramdisk_size=4096 init=/linuxrc rw

-----<snap>------

Now copy the initrdfs.gz and the kernel to /mnt and unmount /mnt. Finally detach the loop device:
losetup -d /dev/loop0

Voila, that's it.

1.4 Use isolinux as the bootloader

Nothing easier than that.

First make a direcory isolinux in the root tree of your rescue system:
mkdir $ROOTFS/isolinux

Copy the kernel image, the gzipped initrd image, isolinux.bin and isolinux.cfg to $ROOTFS/isolinux

Make the cd image with the following command:
mkisofs -R -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table $ROOTFS > cd.iso

-----<snip>------

# isolinux.cfg

DEFAULT	RescueSystem
PROMPT	1

LABEL	RescueSystem
KERNEL	/isolinux/vmlinuz
APPEND	initrd=initrdfs.gz ramdisk_size=40960 root=/dev/ram0
TIMEOUT	100

-----<snap>------

Voila, that's it.

2. Multi boot cdrom images

You can use isolinux in conjunction with memdisk to create multi boot cds. You can also take a look at nu2.nu, where you will find additional information on how to create multi boot cds.

The following recipe is based on information provided to me by Ralf Moll.

2.1 Tree hierarchy

2.2 isolinux.cfg

The rescuecd image is a special case 'cause we don't want to load the whole iso into RAM, so there is a special initrdfs.gz which takes care of starting it. The other images will all straightforward booted by the memdisk tool.
------ DEFAULT 1 DISPLAY /isolinux/txt/message.txt PROMPT 1 LABEL 1 KERNEL /isolinux/vmlinuz APPEND initrd=initrdfs.gz init=/linuxrc ramdisk_size=5000 root=/dev/ram0 TIMEOUT 100 LABEL 2 KERNEL /isolinux/vmlinuz APPEND initrd=initrdfs.gz init=/linuxrc ramdisk_size=5000 root=/dev/ram0 cd_into_ram TIMEOUT 100 LABEL 3 KERNEL /isolinux/memdisk APPEND initrd=images/dr_image.img TIMEOUT 100 LABEL 4 KERNEL /isolinux/memdisk APPEND initrd=images/part_img.img TIMEOUT 100 LABEL 5 KERNEL /isolinux/memdisk APPEND initrd=images/win_95a.img TIMEOUT 100 LABEL 6 KERNEL /isolinux/memdisk APPEND initrd=images/win_95b.img TIMEOUT 100 LABEL 7 KERNEL /isolinux/memdisk APPEND initrd=images/win_98.img TIMEOUT 100 LABEL 8 KERNEL /isolinux/memdisk APPEND initrd=images/win_98se.img TIMEOUT 100 LABEL 9 KERNEL /isolinux/memdisk APPEND initrd=images/win_me.img TIMEOUT 100 ------

2.3 Creating the image

mkisofs -R -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table cd_root > rescuecd.iso

homepage

top

24. October 2002

Timo's Rescue CD Set Build Your Bootable Rescue CD