Xref: utzoo comp.sys.amiga:23830 comp.sys.amiga.tech:2078 Path: utzoo!attcan!uunet!super!udel!gatech!rutgers!bellcore!tness7!tness1!sugar!peter From: peter@sugar.uu.net (Peter da Silva) Newsgroups: comp.sys.amiga,comp.sys.amiga.tech Subject: Re: Next Amiga system Keywords: real-time unix Message-ID: <2773@sugar.uu.net> Date: 9 Oct 88 13:30:11 GMT References: <3678.AA3678@heimat> <2756@sugar.uu.net> <4964@cbmvax.UUCP> Followup-To: comp.sys.amiga Organization: Sugar Land Unix - Houston, TX Lines: 75 In article <4964@cbmvax.UUCP>, ditto@cbmvax.UUCP (Michael "Ford" Ditto) writes: > In article <2756@sugar.uu.net> peter@sugar.uu.net (Peter da Silva) writes: > >Give the man a cigar. Yes, this is what I want to do. To be precise, I want > >to run UNIX *under* AmigaDOS. I want a real-time UNIX. > Running Unix under AmigaDOS would certainly not make it real-time Unix; it > would be less real-time than if it were running directly on the machine. I'm not talking about having a big program that was the UNIX kernel running under AmigaDOS. I'm talking about making each process a seperate Exec task, subject to Exec scheduling, but with protection. Make each a big contiguous lump of memory with a virtual zero origin, etc... but handled by Exec. > If a real-time Unix did exist for the Amiga, then it would make more sense > to run Exec under Unix than the other way around. The only way to get a *real* real-time UNIX is to replace MOST of the UNIX kernel with a real-time executive. Abandon the UNIX coroutine model, make device drivers tasks (not UNIX processes, maybe, but tasks within the kernel). Make UNIX processes protected tasks. Protected from each other, at least. Why look, the Amiga Exec is a real-time kernel! What a convenient happenstance... > ... except reliability. It could work, but it would give me > the willies. All that nice memory protection gone to waste as soon as > you run a buggy AmigaDOS program. (Oops! Guru meditation!? Now I > have to sit through another fsck!) So if you want reliability don't run buggy AmigaDOS software. I have never gurud since I've gotten 1.2 except when I was running a known buggy program, such as something I'm developing or Manx VI. > Another possibility is to run Exec under Unix in a virtual machine... > sounds awful, but that's what the Ms.Dos folks do with VP/IX and such. This is totally out of the question. The Amiga Exec's primary advantage is that it's small and fast. Running it in a virtual machine is unreasonable. I would not WANT AmigaDOS on these terms... all its advantages would be gone. > Yet another possibility is to run them almost side-by-side -- have Unix at > the core, but Exec tasks could be Unix processes. Again, out of the question. UNIX tasks have too much overhead. > If enough of the graphics > library & intuition were in the Unix kernel, they could achieve real-time > response. Sticking more things in the UNIX kernel is a bad thing to do. There's too much pure garbage in there already. The UNIX kernel is a nightmare. The UNIX programming environment is a dream. On the other hand, the Amiga Exec is beautiful and the Amiga programming environment is, well, too many pizzas before bedtime. You'd get something, but real-time response isn't it. Look at a Sun some time. I'm not bashing Suns, but the display can be slow. This isn't their fault, it's UNIX's. There really hasn't been any fundamental change in how UNIX works in 10 years. And the AT&T/Sun merge, or the OSF effort, is just more of the same. > And there are at least half a dozen other interesting ways to combine Unix > and Amiga software... the above is just idle speculation. I agree with > Peter da Silva that something really exciting could and should be done > in this area, but I suppose we have to start with the essentials. The essentials are there already. A good real-time kernel. If you've ever done unprotected realtime work you would be amazed how *stable* the Amiga Exec is. It's a *lot* less likely to toss its cookies than even some protected realtime systems I've used. Don't throw out the best parts of this system just for the sake of a buzzword. -- Peter da Silva `-_-' peter@sugar.uu.net Have you hugged U your wolf today?