I've seen many posts concerning Apple's decision to ship Mac OS X 10.4 exclusively on DVD. While I understand that Apple has offered its customers a $10 exchange option to "downgrade" to CDs, I would like to post a second option for those more adventurous types. You can actually install Mac OS X Tiger from your iPod! What does this require?
1. Tiger install DVD
2. A friend's Mac with a DVD drive
3. An iPod with a firewire cable (not sure about USB2.0... haven't tested it).
I should also add that any external hard drive will also work for this. The data currently stored on the hard drive your your iPod will not be modified. Anyway, without further adieu, the steps:
1. Connect your iPod to a Mac with a DVD drive and ensure that you have enabled mounting of your iPod as a disk. You should also insert the Tiger DVD.
2. Launch Apple's Disk Utility applet, found in /Applications/Utilities/
3. Choose any disk listed on the left hand side and select the "Restore" tab.
4. Here you will see a "Source:" field and a "Destination:" field. On the left you should be able to find your iPod drive and your Tiger DVD. You want to drag the Tiger DVD to the "Source:" field and the iPod drive to the "Destination:" field.
5. Next click Restore. You need not check "Erase Destination" unless you just want to.
Once that process has completed, your iPod will be a fully bootable Tiger installation image. Simply plug your iPod into the system onto which you'd like to install Tiger, pull up the Startup Disk applet in the System Preferences, and the iPod will appear in the list of available start up volumes (assuming once again you have enabled mounting of your iPod as a hard drive). Select it, click restart and proceed with installation.
There are a few additional nuances and implications to this method. First of all, you can also use a disk image to restore your iPod. If you have trouble using the aforementioned methodology you can first generate an image of your install DVD, then mount that image and then use the mounted volume as the source.
Second, since most external hard drives, iPod included, are faster than most internal DVD-rom drives (my iBook's included), this method can greatly decrease the requisite install time (not taking into account the time invested preparing the volume). If you must install Tiger on multiple machines and would like to avoid the dangers of scuffing the disk or would like to decrease the wait time, this is also a viable option.
Lastly, and in my opinion most interestingly, this is a good method of making an install partition. Once you get the system to boot off the iPod (or external hard drive), if you have made a disk image of your install DVD you can easily use Apple's disk tools to format a small 3 gig-or-so partition and restore it with the install DVD's image. This way if in the future you need to do a fresh Tiger install, you can simply boot off of this partition and zap, new system in no time.
Alright... that's it.
Hope this wasn't too confusing or too obvious. Happy Tiger'ing.