To echo what others have said, when you say 'emulator', do you mean hardware (the usual meaning of emulator), or software (which would be a simulator)? And if you mean hardware, are you going to emulate the bus as well? Having said that, I think you should ask yourself 'what do you want to do with it'? The thing is there are a lot of DEC machines which are 'interesting', and have a lot of software available for them: the -8, -10, 11, -15 and VAX (dunno if you consider that a 'PDP') are all in that category. They aren't really that different; many of them are more 'the optimal technology to implement in' changed over the (fairly) long life of the architecture, so many of models are where an earlier one was replaced by a more cost-effective equivalent. E.g. for one 'class', the /20 (TTL SSI) was followed by the /05 (microcoded TTL SSI), and then the /04 (TTL MSI), and then the /03 (LSI); in another the /40 was followed by the /34 and then the /23. Etc. There are really only 3 kinds of -11: - Those without memory management (the /20, etc) - Those with 'simple' memory management (the /40, etc) - Those with 'complex' memory management (all the others) Simple software will run on all three; more complex (e.g. Unix) only on the latter two. The very earliest version of their BASIC was done on PDP-10's running TOPS-10 - first the one at Harvard, and then some commercial time-sharing system in the Boston area. OK, so it's going to be just running a simulator? Well, for good reason, I think. It was at one point (1980), the best-selling computer, and really made the minicomputer (yes, I know the -8 was the first successful mini, but their size/computing power range was a lot smaller than the -11, and so it didn't have as widespread a utilization as with the -11). It's also the machine that Unix was developed on, so if you want to play around with the 'classic' early Unixes (e.g. Version 6), you'll be wanting to go with the -11. Finally, it is to me the finest architecture ever, in terms of elegance, and bang/buck - the power they squeezed into a 16-bit instruction is pretty mind-blowing. If you want to see a really elegant design, look at the -11. A lot of later architectures stole a lot of ideas from the -11. If you want to go the -11/V6 route, there are instructions for doing so here: http://gunkies.org/wiki/Running_Unix_v6_in_SIMH http://gunkies.org/wiki/Installing_UNIX_Sixth_Edition_on_Ersatz-11 and I have a very detailed page for doing so with the Ersatz-11 simulator (which is _very_ fast, and easy to work with), with a lot of useful pre-built disks, and tools, here: http://www.chiappa.net/~jnc/tech/V6Unix.html The other one I would point to as 'interesting' is the PDP-10, _especially_ if you run ITS on it. There's a very complete and detailed page here: https://www.cosmic.com/u/mirian/its/itsbuild.html for bringing it up under SIMH. There's also KLH10 as a simulator, which I know a lot of people like for running ITS; instructions here: http://its.victor.se/wiki/setup which has a lot of detail about how to get things running _on_ your ITS once you have it up. Please let us know what you decide... :-) Noel