EMA (without some of the timeshare wizzies) is not bad really in TTL. You need two three bit and one 6 bit register and the mux logic. Around that goes the IOT decode. And you can cheat and only implement an 8I and trim the IF and DF register to one bit for only 8kw ram. Which really reduces the hardware. It's also possible to extend it as there was a 8A version that could address 64kW (4 bit IF and DF). A few gals would make short work of it all. Like I'd said about the Intersil Sampler board, 4kW is not enough sometimes. so I did do the 8I minimal EMA (8k). The IF and DF regiser is a single 74ls74 and the SF register is also a 74ls74 the rest is interrupt logic (1ff) and addressing mux the IOTs are per DEC save for the active bits. By reducing the number of bits the logic needed (raw chip count) goes way down. However the 6120 really does make it a lot easier and it's faster too. Allison