Came up with a silly but ultimately successful workaround for installing Mac OS X 10.4 onto that ancient G3 tower. What should be a simple process was complicated by a confluence of awkward limitations:

• My copy of 10.4 is on DVD, while the G3 only has a CD-ROM drive. A new DVD drive would cost more than the computer is worth, so I’m not buying one.
• The B&W (blue and white) G3s don’t support booting from either USB or FireWire devices, thus preventing me from installing via my external USB DVD drive. This also ruled out using the G5’s DVD drive in Target Disk Mode.
• Speaking of Target Disk Mode, the B&W G3s don’t support it, so I couldn’t install from the G5 to the G3 by mounting the G3’s disk as an external hard drive.
• The OS X installer doesn’t seem to support installing onto external USB hard drives, which foiled plan #3: pulling the hard drive from the G3, putting it into an external enclosure, and installing OS X onto the drive from my G5 system. This probably would have worked if I’d had a FireWire-equipped enclosure handy, which of course I did not.

So, here’s what I ended up doing:

1. Install 10.3 from CDs, with the hard drive divided into a large main partition and a little 3 GB partition.
2. Hook up the external DVD drive and use Disk Utility to “restore” the 10.4 install DVD onto the 3-gig partition.
3. Wait for-EVAR for the copy to finish. I was copying a 2.8 GB disk image onto a hard drive via a USB 1.1 connection. Ponderous, man. Fuckin’ ponderous. (someone please get that reference!)
4. Set the Mac to boot from the second partition.
5. Reboot and use the 10.4 installer to put 10.4 on the main partition.
6. Use the little 3-gig partition for an OS 9 installation. Duke Nukem, Carmageddon, Shadow Warrior, and Warcraft II, here I come!

This 9-year-old box actually provides useable performance with 10.4. It’s not blazing fast, by any means, but it’ll do basic web browsing/email/IMing. I can easily overclock it from 350 MHz up to a blazing 400 MHz once I dig out the appropriately-sized jumper from my spare parts bin, and I’m sure I have a few sticks of suitable RAM lying around somewhere. Right now it’s running on 512 MB. Or perhaps “walking” is the more appropriate term.

In any case, I managed to get it working without spending a dime, so I’m happy.