Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!brl-adm!rutgers!mit-eddie!husc6!husc4!grunau_b From: grunau_b@husc4.harvard.edu (justin grunau) Newsgroups: comp.sys.atari.st Subject: Re: software Mac and rudeness Message-ID: <920@husc6.UUCP> Date: Thu, 18-Dec-86 16:38:27 EST Article-I.D.: husc6.920 Posted: Thu Dec 18 16:38:27 1986 Date-Received: Fri, 19-Dec-86 00:24:56 EST References: <8612181103.AA02378@ucbvax.Berkeley.EDU> Sender: news@husc6.UUCP Reply-To: grunau_b@husc4.UUCP (justin grunau) Organization: Harvard Science Center Lines: 53 I agree 100% with MARKS-ROGER@YALE.ARPA on his response to Patrick@ark (Paul Molenaar?) regarding the Magic Sac and this alleged "new European emulator". It was offensive to imply that David Small is trying to boost his profits by using hardware instead of software; it is, however, probably based on a gross misunderstanding. In no rational sense can David Small's cartridge be called a "hardware emulator". The cartridge itself does not contain any of the emulation ware at all -- the emulation, if you can call it that, is done by software that you get on a little TOS diskette. A good example of a hardware emulator is Atari's upcoming Big Blue Box: they use hardware (an 8088, amongst many other things) to convince the MS-DOS software that it is running on an MS-DOS machine. The better the emulator, the closer the software actually IS to running on an MS-DOS machine: the MacCharlie emulator is supposed to be an IBM clone without the keyboard and screen. A good example of a software emulator is Paradox's MS.EM. -- it is software that runs on the 68000 that emulates the hardware activities that an 8088 would perform: in other words, it is just an 808X instruction set interpreter, no different in principle from a BASIC interpreter. I think we can rule this definition of software emulation out for the European Mac emulator: it would be foolish (and very slow) to write a 68000 interpreter that would run on a 68000. In any event, the Magic Sac is neither version of emulator, least of all a hardware emulator, because you have the most relevant piece of hardware there already: the 68000! The only emulation ware he sells you is his set of patches to the MacIntosh OS that re-route hardware references to the ST hardware, which is of course quite different from the Mac's. Any software that bypasses calls to the OS and directly references hardware will of course fail miserably on the Magic Sac, and unfortunately more applications do that than we would like. The ROM cartridge isn't really "hardware emulation" -- it's just a legal way to get the SOFTWARE contained in the Apple ROMs into your machine. Copying the contents of the ROMs onto disk and selling them would be highly illegal, and I doubt the Europeans are doing that. Also, it is hard to see an advantage to loading the ROM software into your RAM -- if you use the cartridge, you don't use up any RAM, which is a clear advantage! Now that we have cleared this up, perhaps the original note writer would like to elaborate on his report, and/or direct us to the original sources? I would speculate that if the European approach is truly different, it must be a rewrite of the Apple ROMs (a la Phoenix's version of the IBM BIOS). It is hard to see offhand how this would be any better than using the real ROMs -- here, too, I would expect that applications which directly access hardware would fail, and I don't think it would be cheaper to develop such a product than what David Small has done ... JJMG { seismo OR rutgers OR decvax!ihnp4 } !husc6!husc4!grunau_b