On Tue, Sep 24, 2019 at 9:13 AM Bill Degnan via cctalk <cctalk at classiccmp.org> wrote: I think with that many address switches, a 'vector' switch, the grant jumpers and the connector at that end it's Unibus. -tony

On 9/24/2019 3:15 AM, Tony Duell via cctalk wrote: Assuming UNIBUS... Looking at the address switches, I see 11 selectable bits out of how many we don't know. If at one extreme, the bits start at bit 15 (MSB) [assuming bits 16 and 17 are also 1], then the address of the ports on the board would be 77744X - 77747X - that seems like a lot. (They might start at bit 17, but then the space used by the board gets absolutely crazy). If, on the other extreme, we suppose that the top 4 bits are 17 (along bit bits 17 and 16), then we get 777762 - 777763. That might actually be possible. One might continue the exercise one bit at a time between the two to see if the address lands anywhere "interesting". 777762 777744 777710 Not here (Conflict with CPU registers) 777620 Unlikely (memory management) 777440 A more sure way would be to find the address line to which the first address switch corresponds. JRJ