Hey, I used to do distribution centers: sortation conveyors, vertical and horizontal carousels, pick stations, etc. We used Quatech boards with Opto 22 modules stuffed in IBM PS/2 Model 80s which we stuffed in turn in big Hoffman cabinets, and, contrary to my specs, unventilated. They ran like gangbusters! We'd gone in to Rose's Distribution center down in Raleigh-Duram area, and found they had to keep a $250,000 inventory of spares *just* for the custom controllers they used. We figured it would be a lot cheaper to keep a couple Model 80s and some Quatech I/O boards around. We were told that if we botched the timing of the sortation conveyor, that the whole line could "explode"; the contractor said he'd seen conveyor rollers embedded in a warehouse ceiling, once... Lights going on and off, arms swinging lanes shut, packages shuttling off into other lanes, etc. Some of the most fun I've had in computing! And all on-topic, as everything described in the list is > 10years old. Regards, -doug q