The Emulation Rambler: Useful and Ridiculous Emulator Tricks
Jason Compton

Rather than profile any specific emulator in this issue, I'd like to explore a few highlights and "dubious-lights" of what you can do with emulators on the Amiga. Next issue: FUSION 2.0 gets the works, and a look at what PC-Task 4.3 promises to add to our PC emulation repertoire.

Stick It To Microsoft!

Ah yes. You've already told the PC industry what it can go do with itself by buying PCx, PC-Task, or maybe a second-hand bridgeboard. But how to get around Microsoft? It seems that the best you can do is find an old copy of MS-DOS somewhere...but wait!

Caldera has purchased the rights to Novell DOS, formerly known as DR DOS, which is now called OpenDOS. And...wait for it...Caldera has made OpenDOS free to most comers! (If you're planning to use OpenDOS commercially, they'll gladly sell you a license.) But for regular old evaluation or educational use, OpenDOS is yours for the asking.

At, OpenDOS can be yours by simply filling out a short questionnaire for the folks at Caldera to look at. (Mostly, they want to know if you want to hear about their Linux products.) Then you get a passcode and the ability to download the encrypted OpenDOS archive. There is a slight catch in that you need a previously bootable DOS in order to de-archive the OpenDOS archive...a bit of a snag for getting completely around Microsoft, although you can always carry out this part of the operation on some other machine which has already paid its dues. Once installed, OpenDOS functions virtually the same as MS-DOS. There are a few quirks and additional features available: OpenDOS has built-in task-switching and multitasking, for starters. Neither work quite 100% with PCx and PC-Task, although they're worth investigating. PCx has a couple of issues that I've found--the special PCXANSI driver seems to be incompatible and a video bug occurs when exiting most applications to DOS. Microcode Solutions was unaware of OpenDOS until my bug report to them, but they assured me that they are working on the problems. The author and publisher of PC-Task 4 have been informed of their program's clashes with OpenDOS, but have not yet replied.

Both get strange video blackouts when task switching is enabled--curiously enough, the solution Jim Drew of Microcode Solutions suggested I use for PCx only worked for PC-Task: blindly entering a "CLS" to reset the video display. There may be some additional issue on my machine keeping it from working properly for PCx.

OpenDOS also offers a DOS-based HTML 3 web browser dubbed WebSpyder. We'll take a look and tell you how it fares next issue, as well as keep you up to date on how well the PC emulators are handling OpenDOS. I've installed it to both of my emulation partitions and haven't looked back.

Two Ridiculous Things Done With Emulation

We all know that emulation can lead to some crazy notions. Of course, there's the classic "run UAE on UAE" (which works), or the oft-practiced "Run Shapeshifter on UAE" (because the PC barely has a decent Mac emulator, and that only recently). But just iterating two common emulators isn't truly novel. No, to be really ridiculous takes some hard work. Here are some examples I've come across, in no particular order:

- A64's GEOS emulation mode. Don't get me wrong, I don't have a death wish for C64 GEOS. It's actually ok once you get some decent speed into it. The real problem with this GEOS implementation was that it only ran on 68000 Amigas, meaning that you got no major benefits over running on a real 64. If it had supported 030s and 040s, it would have been worthwhile, but it was just another misguided effort from A64's author.

- The Gameboy Infocom interpreter. For those of you unfamiliar with the technology behind the Infocom text games, Infocom was able to port them to so many platforms because what they did was to establish a specification for a mythical computer called the "Z-Machine" and then emulate it on various computers ranging from 8-inch floppy CP/M computers all the way up to Amigas. These emulators all read the same game data file. So in effect, playing an Infocom game involves using an emulator. Implementing this emulator on a Gameboy took some real gall--and, of course, you can use it on a Gameboy emulator. (So far, I've only had success with AmigaVGB by ignoring the CRC checking. AmiGameBoy and WzonkaLad seem not to be able to actually give a display, although it sometimes is visible for a second when breaking out of the emulator.

With this 8k of Gameboy code, you're able to play almost all of the Infocom games and even some new creations on a Gameboy or emulator, on a 39 wide by 9 row text screen. You use the directional pad and buttons to select letters "high-score style", but a neat feature lets you pick words off of the display as well. It's beyond ridiculous--but it's very, very clever.

Come On, Amiga MAME, Catch Up!

The latest version of MAME, the multi-machine arcade emulator, supports such classics as Tron and Spy Hunter. Our port is still one revision behind. Come on!

Things You Should Own For Emulation

Here's a brief, and not by any means exhaustive, summary of the sort of hardware you might want to have if you're going to approach emulating a certain machine or platform.

PC and Mac emulation hopefuls should get a CD-ROM drive or high density floppy drive. Preferably both.

Mac emulators match up pretty well for CPU power, so you need a CPU as powerful as the Mac you want to emulate--although video is a different issue. If you don't have a graphics card and can't afford one or don't have a good way to hook one up, you should at least have AGA and a lot of memory to burn.

PC emulators require a lot of CPU power and work better (PCx and PC-Task 4) when given lots of memory.

To get good Apple II emulation on an Amiga is simple--030/25. That buys you about 100% performance using any Amiga system.

64 emulation, in my opinion, is best done through Frodo if you have the machine for it--and that would be an 060 with graphics card. Magic64 is pretty good for reliability with a somewhat slower machine, but Frodo's color choices are a lot better, I feel.

Gameboy emulation can be pulled off on 030 machines.

Atari 2600 emulation: Trust me, you want a fast machine. It seems ironic, I know.

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