I often start with Wiki to get info on the different Mac models:
re: the G3: here is some info from wiki:
Maximum Operating System Mac OS X 10.2.8 "Jaguar" and Mac OS 9.2.2^*
^*Unofficially possible to install up to Mac OS 10.4.9 or 10.4.11 on these systems with help of third-party software. See "Upgradability" below.
go to this Wiki page for more info: http://en.wikipedia.org/wiki/Power_Macintosh_G3
(This page also explains different G3 models and their corresponding hardware/operating system)
Now, we were negotiating a price for that 35/2.8 Summaron ..............
good luck, Gary