Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!texbell!sugar!ficc!peter From: peter@ficc.uu.net (Peter da Silva) Newsgroups: comp.realtime Subject: Re: Realtime and UNIX (Re: An opportunity for Commodore (Re: Windows without Front/Back gadgets)) Keywords: unix Message-ID: <6969@ficc.uu.net> Date: 14 Nov 89 22:39:57 GMT References: <22175@gryphon.COM> <4537@sugar.hackercorp.com> <788@jc3b21.UUCP> <4679@cbnewsc.ATT.COM> <4532@sugar.hackercorp.com> <104@amix.commodore.com> <8552@cbmvax.UUCP> Reply-To: peter@ficc.uu.net (Peter da Silva) Organization: Xenix Support, FICC Lines: 96 I said: > >>UNIX is not real time. Many of the things we now take for granted would just > >>not be possible under UNIX, or would be unbearably slow. It would kill the > In article <104@amix.commodore.com> ford@amix.commodore.com (Mike "Ford" Ditto) flames: > >Everything in the above paragraph is false. Peter doesn't seem to > >know a trademark from an operating system implementation. There are Get off your high horse and listen up. First of all, I have carried on many debates over the years supporting the position you're espousing here: that UNIX is a family of operating systems that share a common program interface etcetera, etcetera, etcetera. Secondly, insulting someone is not a good way to carry on a discussion. Even if I were a slimy Atari-ST user, it wouldn't be appropriate, but I've been a vocal supporter of the Amiga almost since its inception, I've sold at least 4 of the beasts that I know of, and I've recommended it far and wide (just ask anyone here). I've written a fairly popular utility and co-authored a critically acclaimed game, as well as providing a moderated sources group and contributing a lot of code to the freeware kitty. In short, I've done my share and more of helping pay your salary. I'm not an uncritical sycophant, though, and I have a good idea of the sort of resources Commodore enjoys. They're not enough to properly develop a real-time UNIX, let alone do this while expanding the Amiga product line in other areas and maintaining AmigaDOS. And it's not within the apparent goals of the company to do so, or else AMIX would be based on Mach rather than V.4. So, in context of what is visible of Commodore's UNIX development, everything in my article is true. We're talking about what Commodore is likely to do in future Amiga system software, not what they would do with unlimited time and resources. > >"Unix" and "real-time" are orthogonal concepts. You can have either > >one without the other, or neither, or both. Of course. This is intuitively obvious to the most casual observer. But you can't do it under the V.4 platform Commdoore is working with. In article <8552@cbmvax.UUCP> valentin@cbmvax.UUCP (Valentin Pepelea) writes: > For a Unix wizard like you, having ported Unix to our platform this is exact. > For a guy like me and Peter, this is fresh news. Actually, it's not "fresh news" to me. Masscomp has a workable realtime UNIX, though it's tied to their hardware (:-<). Venturcom and others have done decent real-time patch jobs to UNIX. Personally I'd rather see a from-scratch realtime system with a UNIX program interface built on top of it. Say, starting in the vicinity of Mach... > >With AmigaDos we technically have neither, although we are close enough on > >both sides to do some good things. It's possible to write programs under AmigaOS that meet very stringent realtime constraints. It's not always easy: you may have to write interrupt handlers, run stuff off the copper list, and so on. But it's possible, and these applications remain well-behaved and don't interfere overly with other tasks on the system. And often just careful coding *under* the exec is sufficient. The only way to achieve this sort of response in a conventional UNIX system is to put your real-time stuff in the lower half of a device driver. That's how you get the sort of real-time response things like dumb streaming-tape boards require. > >If you mean there aren't enough programmers here to implement a > >real-time OS from scratch in this decade, you're probably right. That's what I mean. That's almost exactly what I said. > Another option though is to simply provide a library which runs under AmigaDOS > and emulates Unix functions as well as it can. I remember that Deven Cervone > had volunteered to do just that. It sound like an interesting university > student project. Another option I thought of would be to run UNIX tasks as AmigaDOS tasks with appropriate hooks to go into and out of protected mode when you enter and leave the UNIX task's context. This would make AmigaOS a real-time kernel for UNIX. I once wrote this up at great length and posted it to comp.sys.amiga. It was met with a resounding thud (though Deven was interested, as I recall). I think this would be MUCH more promising than writing an AmigaOS emulator for UNIX. But, hey, what of the original plan that started this message chain: using Amiga 500s and 2000s as smart NeWS/X terminals for a 2500UX? This is a niche that's currently only filled by the Sun/Graphon combination, and an Amiga is much more capable than the PC-type platform that the Graphon uses. -- `-_-' Peter da Silva . 'U` -------------- +1 713 274 5180. "*Real* wizards don't whine about how they paid their dues" -- Quentin Johnson quent@atanasoff.cs.iastate.edu