Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!sugar!peter From: peter@sugar.hackercorp.com (Peter da Silva) Newsgroups: comp.sys.amiga.advocacy Subject: Re: Amiga basher Message-ID: <1991Jun16.040300.17455@sugar.hackercorp.com> Date: 16 Jun 91 04:03:00 GMT References: <22362@cbmvax.commodore.com> <1991Jun13.042836.8112@marlin.jcu.edu.au> <1991Jun13.065150.3529@cs.mcgill.ca> Organization: Sugar Land Unix -- Houston, TX Lines: 52 In article <1991Jun13.065150.3529@cs.mcgill.ca> genius@cs.mcgill.ca (Michel NGUYEN) writes: > What makes the Amiga so great > is the software, not the hardware (at least not anymore) It always *was* the software. > Do you know why "they" spend 3/4s of the CPU for graphics and I/O and the > Amiga's don't? I want to know why they spend the remaining 25% for context switching. Even UNIX does a better job than that. Actually, I know why... because they have so much context to switch, and because the context switching is under control of the application (both Multifinder and Windows use polled multitasking). > Or add the appropriate > coprocessors to the other ones (system) and compare. OK, a blitter is roughly on a par with a 68020 (both can keep the bus saturated 100%, so any additional speed is irrelevant). Given that, an Amiga 1000 and a basic Mac II should be equivalent. In fact, under a moderate load (say, 3-4 applications) Multifinder acts like an 11/70 with 60 users. Performance drops off faster than linearly with the number of apps because of the high cost of context switching. > About multitasking, I want to know what you are using multitasking for?? Everything. > Do you use it a lot?? I know I could not live without multitasking, but > very often (when I do serious work), I want my computations to take > exactly 20 minutes and not 30-40 minutes because I am playing some > chess or tetris games in another window. So run chess at -1 priority and it will *never* chew up any CPU time when your application is ready to run. You will have a few extra context switches... maybe 10-20 per second. I've run processes that required 1200 context switches per second on a 1000 and watched Perfmeter drop by about 7%, so 10-20 aren't going to be noticed. > As I said, go look around. Check out the softwares and hardwares of the other > systems (especially the Mac and PeeCee) NOW on the market. You will > be surprised. I have. Gorgeous graphics. But they're about as responsive as a deaf cat. When I want to switch to another window I want it *now*, not after every app on the screen has been scheduled, cleaned up its damage list, done its housekeeping, and so on. -- Peter da Silva. `-_-' . 'U` "Have you hugged your wolf today?"