A1200 - 1994 to 2004, 2011-now.
The gap from 2004 to 2011 is when I ran my BBS from first an A4000 (2004-2009) then under UAE (2009-2011).
I would say the A1200 is the same machine, but I've upgraded so much on it that I lose track of what is original.
I guess you mean continuously powered, so perhaps I've hit a year with just reboots. The machine has had many breaks for power cuts, fiddling with the hardware, etc.
