BTW, if it wasn't implicit (it is to me), I wouldn't have much of a need for an emulator for a machine that's readily available, or if rare, easy on the pocketbook to keep running (parts, electricity, etc). We can't all be Megan Gentry, Eric Smith, or Daniel Seagraves (owners of DEC-10&20s who come immediately to mind)... Now, Jim Battle's doing a SOL emulator. Great idea, I might want to play with a SOL at work. But my SOL was the machine I did exactly the kinds of things you describe. Unlike many, I didn't buy even the complete SOL kit. I bought only the motherboard and a folder of schematics and instructions for component assembly. By December 1976, all it could do was display a test pattern consisting of essentially a dump of the character generator ROM. As time went by, I continued buying components. It was getting close to being finished, but I needed a keyboard. I bought one surplus, taken from a TI Silent 700. However, the strobe was inverted and either too long or too short (can't recall). So I fingered through Don Lancaster's TTL Cookbook until I came across the 74121, which I hadn't used yet. I used it to change the strobe width, and one gate in a NAND wired as an inverter to flip the logic direction. Next, I needed some kind of key-repeat. Like many early terminals, there was no auto-repeat, but instead, the keyboard included a REPEAT key. A couple of 555s and some more gates from the NAND, and I was almost done. I ended up adding a lightpen interface to the design, then built it up permanently using a Rat Shack proto board. Stuck that inside a generic keyboard enclosure along with the TI keyboard, and I could now talk to my SOL. For a monitor, I followed Lancaster's instructions on how to take an old B&W TV set and pull the unneeded circuitry (except for the tubes; they stayed in, heaters wired in series). The mods all helped boost the bandwidth of the monitor a bit. The image quality ended up being quite good, and I sold it to another guy who'd bought a complete SOL kit sans monitor (I'd bought an actual monitor by this time). I enjoyed every minute of the 18 months it took me to make that forty-dollar naked PC board into a usable computer. Or termninal, actually... its raison d'etre was to hook up to my beloved and much missed CDC 6600 & DEC-10! And I think I even got to like the smell of solder.. especially the Ersin Multicore stuff made in the U.K... why, there's some now, and no iron in sight... But as much as I enjoyed fooling with hardware, the software had an even stronger draw. Just as you can only erase a piece of paper so many times before it disintegrates, you can only re- solder a PC board so many times before you've fried it. And yes, I've used all kinds of techniques to repair such damage. But you can't damage software... which is one of the things that I find attractive about it. Emulators represent the ultimate convergence of hardware and software... Hey, I just had an idea... how about an emulator that goes all the way down to the component level? One which actually emulates resisters, capacitors, transistors, and 7400-series chips. It could also have an emulated soldering iron & solder. Ever wish you had three hands for a difficult assembly? No problem in this proposed emulator! We'll just add an emulated hand... or two... or... ;-) -dq