FPGA's, Emulators, Simulators Vs real hardware (was Re: Somewhat OT: FPGA Develpment Kits)

9000 VAX wrote: I don't think that this will be the case. We should have replicas and emulators, and the more the merrier. I think that emulators and replicas are an important step in preserving old hardware. Over time, it will get progressively harder to keep old machines running. At least with emulators and replicas you have some way to access the old software and get a feel of what it was about. Otherwise, you lose an important part of history, with no way to replace it. There are probably two schools of thought on this. The purist collector would rather have the machine as is, even if non-functional. The pragmatic collector would want it working. I'm leaning towards the latter. :-) There will always be folks such as ourselves who want the old hardware anyway, and will maintain it, despite the existence of emulators. As far as I know, no one is producing new PDP11's, in their original form nor IBM/360's. Having emulators for them is important, at least in that respect. Having access to replacement parts, whether they are in FPGA's or other modern components, or in the form of whole replica's is also important. Being able to keep the old machines running is the goal (at least my goal), but in the long view, they won't last forever. There are lots of things we can do to keep them running, and we should - but sometimes, that means replacing failed components. I don't view replacing components with modern equivalents any worse than replacing dried up capacitors. We should of course be honest and realize that replacing a part was done and that the machine is no longer in the original state. For example, replacing an old MFM hard drive with a CF card may keep a machine running, but it is no longer in the original state. This isn't to say that we should discard the original non-functioning components either - if you're a purist, you could always replace the failed components back, and return the machine to it's original, but non-functional state. At some point, once you've replaced most of the original parts, it's no longer the original machine, but rather an equivalent in the same case. But unlike old vases, statues, chairs, tapestry, or what not, with machines, the goal isn't to keep them in the exact state you've found them in, but rather to keep them running. A powered off computer that's on display in a museum is in a state that you cannot interact with it, and is no longer useful in the sense that you can't experience interacting with it. Knowing that a given CRT was amber or green isn't the same as seeing it, or feeling the heat and static electricity (and even smells) it gives off , or what happens when there's a magnet nearby, versus seeing output on a modern LCD display. Seeing an old model-m keyboard isn't the same as typing on it, getting tactile and auditory feedback from it, versus a doing the same with a modern cheapo keyboard. It's ok to see something powered off behind a glass window, in a protected environment but the experience is lacking in a lot of ways. Of course, I don't expect that a museum would let us go into some gallery and let us cut our steak with ancient knives, etc., but at least with emulators and replicas, we can do the equivalent of just that - even if it's only a partial experience. More importantly, it will keep the memories of these machines alive - even if we can't share our knowledge and experiences with future generations, at least they may stumble upon some future ftp site that has emulators along with the original software and, manuals and might spend some time learning from them. Replicas are even more important for those who weren't born in the early days and have never built a computer from parts, not just in using the replica computer, but also in building one and understanding how and why it worked. I don't know whether there are some exceedingly wealthy folks on this mailing list, but I certainly can't afford to build my own fab and thus replicate 6502's or am2901's for example. I'm sure if we looked hard enough, we could find modern replacements for some of those chips, but at some point, when that isn't possible, what would you do? An FPGA on a board wired to fit a 6502 socket would sound very good if you were in that situation. One issue with emulators is that they may differ from the original hardware in subtle ways that make them incompatible with the original hardware (aka bugs). If you have accurate schematics, at least you can build FPGA's that are near identical to the original hardware, and even slow the timing down to match it. At the same time, regarding emulators, I can load up my notebook with hundreds if not thousands of emulators and fire them up at will anytime and anywhere. It won't be the same as having access to a large building full of working machines, but close enough to keep me smiling. :-)