:-) Bus Address Register (puts this address on the Bus) and yes there are two more bits in the CSR for XAD16 and XAD17 to tell it the upper two bits of the address (16 + 2 = 18) but no word on if there are four more bits squirrelled around somewhere to do it right for the 22 bit back planes. I can live with the 18 bit restriction on the VAX since the VAX will just create a copy buffer in a chunk of memory mapped into Q-bus space and then copy things in and out of it. Another idea I had was to hook up perhaps some M7941s to some solenoids, light bulbs, etc and have the local high school kids see what sort of effects they can create. --Chuck At 11:44 PM 5/12/01 -0600, you wrote: