Problem in the G4 is online, the G3 Stays offline since it is me financial records machine.
Looking at a used G3 since all local techs want $100+ to just check it out.
can you tell model# from serial #? ie. 300, 350, 450 mhz?
Your M8493 G4 is a Quicksilver. It can run 10.1. You can put the hard drive from the G3 into the G4 and boot off of either HD. I can talk you through how install it, boot from both HDs, and how to turn off internet on the G3 boot drive.
I provided a video below on how to install the HD. You only need to watch Part One, it ends at 4:00. If you give me the model and make of the G3 HD I can talk you through setting the jumpers to Slave.
Although you're being kind of paranoid about the offline thing IMO. It's a Mac, they can't get in unless you have File Sharing or Screen Sharing turned on in Sharing preferences. Plus if you are connected to a router that is another layer of protection.
Go to System Preferences/Network on the G4. If your IP address is 192.168.x.x or 10.x.x.x you are behind the firewall of the router and no one could get in unless you have set the router up to forward the sharing ports to the IP address of the G4, plus, you would have to have File Sharing and/or Screen Sharing turned on.
I can save you a lot of money and you can get rid of the G3 computer set up and save space, if you have the patience.
No, I was looking to see what the Mhz speed was on the G3. I have no display at the moment but I could read the Ser# of the back. I was thinking of buying a used G3 since I use this offline for my accounting machine.