Does a Northstar S-100 Bus Horizon Classify as a Classic

Hi Bob, You and I have corresponded before, and I believe regarding your Horizon. I would certainly count any S-100 system as Classic, and the N*Horizon is one of the biggies IMHO. I do have a Horizon running with the Double- Density N* controller, and one my my Altair's is running with the Single- Density N* controller. It's not clear from your message ... is your Horizon complete? (at least CPU, Memory and FDC), or does "No FDC's" apply to the Horizon as well? I assume it does have the standard Horizon mainboard which also includes a couple of serial ports. The Horizon can be a bit difficult to get up and running from a non- functional state, because it does not have a front panel. If you have a N* CPU board, you do at least have a 1K ROM socket (2708 or something newer adapted to a 2708 read pinout). Do you have the capability to program EPROMs? If so, I can give you a little (~500 byte) monitor that will run from the Horizon CPU ROM socket and does not need ANY RAM. This gives you a "window" into the system and lets you check out the RAM, disk controller registers etc. and makes it *MUCH* easier to bring the system up. Even if it doesn't run at first, it sits in a tight loop polling the UART - you can capture the first few bus cycles with a scope to see if it's getting there, and once you have the loop running, the repeating select for the UART makes it pretty easy to debug that. A little more info on exactly the condition and and debugging progress on your system would be helpful. Dave -- dave09 (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Classic Computers: http://www.classiccmp.org/dunfield/