ralphw@IUS3.IUS.CS.CMU.EDU (Ralph Hyre) (04/18/88)
In article <347@caldwr.caldwr.gov> ack@caldwr.caldwr.gov (David Ackerman) writes: >I saw a lot of potential in the version of A/UX I used. But potential doesn't >develop by itself. A/UX should be to the Mac OS what the Roadrunnner is to DOS. >If Apple doesn't understand what I mean, they should go play with a Roadrunner. I saw a RoadRunner the other day, and I understand. I don't work for Apple, though, and I'm not a 680X0 hacker. Ideally, you want to be able to run any 'reasonable' Mac application under A/UX. The good news is - theoretically you can! The 68020 supports the idea of a virtual machines, you can run any number of independent 680X0 programs in user mode, even if they want to run in supervisor mode. The 80386 has virtual 8086es, so I imagine that the RoadRunner is somewhat limited in the type of Intel-based software it can run. (ie no '286 or '386 software). When you try to do something which requires supervisor priviledges, you get a priviledge exception (or something like it), which the code running in supervisor mode (A/UX) can deal with. I Imagine that you could even work out memory access problems by setting up the PMMU to generate exceptions for accesses to certain areas (like the screen). (You'd want them to use A/UX windows, whatever those are.) So, by redirecting and possibly recoding some toolbox calls, and adding some code to the A/UX kernel - you can run even more Mac applications. I've been thinking of doing this to the Sun-3 on my desk - wouldn't that be embarassing for Apple, to have MacOS software running on a competitor's Unix box, while A/UX doesn't even grok HFS. -- - Ralph W. Hyre, Jr. Internet: ralphw@ius2.cs.cmu.edu Phone:(412)268-{2847,3275} CMU-{BUGS,DARK} Amateur Packet Radio: N3FGW@W2XO, or c/o W3VC, CMU Radio Club, Pittsburgh, PA
sas1@sphinx.uchicago.edu (Stuart Schmukler) (04/19/88)
In article <1451@pt.cs.cmu.edu> ralphw@IUS3.IUS.CS.CMU.EDU (Ralph Hyre) writes: >Ideally, you want to be able to run any 'reasonable' Mac application under >A/UX. The good news is - theoretically you can! > >The 68020 supports the idea of a virtual machines, you can run any >number of independent 680X0 programs in user mode, even if they >want to run in supervisor mode. The 80386 has virtual 8086es, >so I imagine that the RoadRunner is somewhat limited in the type of >Intel-based software it can run. (ie no '286 or '386 software). One of the problems (I think) is that both the MacOS and its programs are running in supervisor mode. Some programs take advantage of that fact even tho Apple has told them that it is not wise to rely on supervisor mode instructions. SaS
ralphw@IUS3.IUS.CS.CMU.EDU (Ralph Hyre) (04/22/88)
In article <4036@sphinx.uchicago.edu> sas1@sphinx.uchicago.edu.UUCP (Stuart Schmukler) writes: >In article <1451@pt.cs.cmu.edu> ralphw@IUS3.IUS.CS.CMU.EDU (Ralph Hyre) writes: > ... >>The 68020 supports the idea of a virtual machines, you can run any >>number of independent 680X0 programs in user mode, even if they >>want to run in supervisor mode. ... [386 stuff deleted] > >One of the problems (I think) is that both the MacOS and its programs >are running in supervisor mode. Some programs take advantage of that >fact even tho Apple has told them that it is not wise to rely on >supervisor mode instructions. This was part of my point, the Apple software will have no way of knowing it's not running in supervisor mode, since executing a priviledged instruction in user mode will cause a priviledge violation, which will invoke the (mythical) A/UX handler for that which will provide the proper results to the MacOS for the 'illegal' instruction. [This all presumes that you can control whether something runs in user or supervisor mode (on the Mac ][, I presume you can since it's running Unix)] [apologies for terminology wierdness - I'm not a 680X0 hacker] -- - Ralph W. Hyre, Jr. Internet: ralphw@ius2.cs.cmu.edu Phone:(412)268-{2847,3275} CMU-{BUGS,DARK} Amateur Packet Radio: N3FGW@W2XO, or c/o W3VC, CMU Radio Club, Pittsburgh, PA