Path: utzoo!attcan!uunet!crdgw1!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!ncar!gatech!mcnc!duke!mdl From: mdl@duke.cs.duke.edu (Michael D. Landis) Newsgroups: comp.sys.next Subject: Re: Mac emulator Message-ID: <656892267@macbeth.cs.duke.edu> Date: 25 Oct 90 22:04:28 GMT References: Organization: Duke University Computer Science Dept.; Durham, N.C. Lines: 43 In article Anthony Berno writes: >>>> I'm wondering if there has been any news about a mac emulator >Keith Perkins >Texas A&M University > >I gravely doubt if we will ever see a Mac emulator for the NeXT, for the >same reason that there are no Mac clones. The Mac toolkit, for that >matter the entire operating system, is entirely proprietary. >Furthermore, the way Mac toolbox calls are executed (direct ROM >addressing to the routines on the ROM chips) makes me doubt that it >would be feasible. I know nothing about emulating other computers, but >it seems to me that it would be especially difficult for the Mac >even if you did know their secret ROM code and had a license to boot. > >I may be wrong here, though... any feedback? Seems like, if you had a set of routines that did the equivalent of Mac things, but in the NeXT environment, and if you knew the entry points in the roms, then you could write a program to load a Mac binary file, re-link the entry points to transfer control to the new routines, and possibly do some other address translation, etc for IO, and then run the program. You may also need another process running to map the "Mac" screen memory onto the NeXT display, and to do any other memory- mapped IO. This memory-mapped IO would be slow, but the new routines should not have a speed problem. Seems I recall someone mentioning a DOS program loader for UNIX systems that did the same sort of thing to get PC compatability. Only there, they had to translate instructions as well. All of this assumes that no one does code modification anymore. I don't know whether or not people out there in the real world still do such nasty things or not. In any case, I feel that you could probably make a Mac Emulator without in any way using the Mac roms. For that matter, you might as well change some of the "look-and-feel" as well, but maintain compatability of course. Am I being foolish?? -- mike -- Mike Landis, Dept. of Computer Science, Duke Univ., Durham, NC 27706 Internet: mdl@cs.duke.edu Phone: 919-660-6520 or 919-493-0559