I have three harddisks. The first one is Windows, second Suse 9.3 and third all my data. I want to put Suse and Xandros on the second harddisk. How do I resize and/or install the two operating systems on the second harddisk?

Thanks in advance.

The resizing is up to you. A "safe" size would be 5GB, but it could but smaller or bigger, depending what you want to install (full system or just the base?).
The installing will not be any different than the usual, but make sure you choose the correct drive/partition (otherwise you will destroy your other OSes). The only tricky part is about the boot loader, make sure it contains an entry for every OS you may have before rebooting or you won't be able to boot other system. Usually Linux is bright enought to find other system and to make you a working configuration of the boot loader, but a tri-os is maybe something it won't expect.

Half_Elf is right, but I would just add that tri- (or more) booting is made easier if when you are first partitioning your disks, you have one (small eg 20MB) partition for /boot that is shared between the different distros.

Each distro can share the same swap partition, so you only need one of those.

Each distro needs its own / partition (obviously!).

If you share /home between distros, make sure you have different usernames for each distro eg: /home/suse-me and home/xandros-me because of course each distro will set up your "home" slightly differently.

Hope this makes sense.

One option to get tri boot to work (as far as the boot loader is concerned) is to not allow the setup to install the boot loader when you install the sys. It will still write a grub.conf file (if that's the default for the system). Then you simply reboot into your existing linux installation and mount the new partitoin which contains /boot. You read grub.conf from that partition and add the necessary lines to your own grub.conf.

I have managed to install Xandros and Suse on the same disk, but grub (suse's bootloader) does not recognise Xandros. How do I add it to the bootloader's configuration?

have you mounted the partition that contains the xandros /boot folder?
cd to xandros's /boot/grub and the open grub.conf in your favourite text editor. You should find a couple of lines not very different from:

title Fedora Core (2.6.13-1.1526_FC4)
root (hd0,1)
kernel /vmlinuz-2.6.13-1.1526_FC4 ro root=/dev/hda9 rhgb quiet
initrd /initrd-2.6.13-1.1526_FC4.img

copy it into Suse's grub.conf (and check the device naming is correct, that is the partitions it points to are the ones where the xandros kernel and initrd are located) That should do it.

I am new to this stuff, so I don't know how to mount the partition. At this time I can't get into Xandros's operating system.

as root: make a mount point

#mkdir /mnt/xandros

mount the xandros partition:

#mount -t ext3 /dev/hdx? /mnt/xandros (hdx? -> x should be a for first ide master, bfor 1st ide slave etc, ? corresponds to the number of the partition. If you don't know, run cfdisk and try to figure it out from there. Change ext3 for the filsystem type you chose during setup if necessary)

#fdisk -l (try '/sbin/fdisk -l' if your system complains it can't find fdsik) will give you a list of all available devices.

I've entered the following into grub's configuration:
root (hd1,2)
kernel /boot/vmlinuz-2.6.9-reiser root=dev/hdb1,2 rw acpi=on noapic
initrd /bootinitrd-2.6.9-x1

I then get the following message when trying to boot:

Filesystem type is reiserfs, partition type 0x83
kernel /boot/vmlinuz-2.6.9-reiser root=dev/hdb1,2 rw acpi=on noapic
Error 15: File not found

There's slash missing in the root designation. Also hd1,2 is the grub way of saying hdb3 (grub starts counting at 0). So it should be /dev/hdb3.
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