Emulation vs. Simulation (was: Fun with Lisp: Programming the NES)

Well, I dunno about "many", but I've done an emulator or two in my day. I'll be happy to answer any questions you have (that I can answer), but you'll need to use some other sending path for your mail for me to see them; Yahoo is too much of an abuse sewer for me to be willing to listen to them directly, and your list mail comes through a webmail system from a host with no rDNS and I thus don't see it either. (You may note I'm replying to someone else's reply to you.) I agree, though it's really two extremes of a difference of degree, which amounts in practice to a difference of kind. (The difference of degree lies in how much of the emulated system can be handled directly by the real hardware.) Indeed. One of those emulators I mentioned is for the KA630. I tried to run the ROM code from a real KA630 under emulation and, upon finding that it didn't work, investigated and discovered that the real hardware has a prefetch buffer which isn't flushed when MAPEN is turned on (or, probably, off). The ROM code enables MAPEN and depends on executing the next instruction or two out of the prefetch buffer. I had to add a prefetch buffer to my emulator to make it work. (That project is currently blocked on a different problem: serial I/O timing.) I agree. Parsing can refer to either of two closely related things in my experience, but neither one is such as to make it true that "emulation [is] basically just parsing". (Loosely put, they are the theoretical and practical versions of the same thing.) They amount to syntax-checking and de-serializing some kind of serialization; in practice, this most often is converting a text representation of something to a data-structure representation of the same thing. Well...more to the point, it's a rather nonstandard use of the verb "parse" and thus isn't too useful if you want to actually communicate with other people. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mouse at rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B