Tiger is running on my iMac DV (G3 350Mhz) featuring 128MB of RAM, and no FireWire ports (despite what is claimed by Apple)! Of course it is not super fast, but I guess if I had a bit more RAM it should run faster.
Well, Apple is not totally wrong when stating that one can not install Tiger on a Firewire-less iMac (the display freeze 3 minutes after installation from the DVD; according to my own test).
What I have done to make it running: I have installed a HD (originating from a Firewire enclosure HD used to backup my iBook's HD.), and the iMac booted straight from the new HD without any probems!
The reason of such behavior: Tiger is checking hardware compatibility only during installation. Once installed (on a supported hardware), it boots on FireWire-less G3-based iMac as well as on computers featuring only 64MB of RAM. But for sure Apple did not test Tiger on those computers.
If you have an even older computer such as a G3 Beige, or a computer with a G3/G4-based upgrade card, XPostFacto 4 can help you to install Tiger on your computers.
To conclude, Apple's License Agreement states that one should have one license per computers. Apple is proposing a Family Pack including 5 licenses for 199 Euros.
