Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!ucsd!ucbvax!hplabs!nsc!pyramid!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga Subject: Re: Multitasking vs MultiFinder (was Amy 68030 vs Mac IIcx) Keywords: Oranges are better than Apples. Message-ID: <10143@cbmvax.commodore.com> Date: 13 Mar 90 23:15:14 GMT References: <3137@bingvaxu.cc.binghamton.edu> <21904@watdragon.waterloo.edu> Reply-To: daveh@cbmvax (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 56 In article <21904@watdragon.waterloo.edu> bmacintyre@watdragon.waterloo.edu (Blair MacIntyre) writes: >consp11@bingsunm.cc.binghamton.edu (Brett Kessler) writes: >>> [...] >>> Does AmyOs multitask as well as Multifinder? Are most Amy programs >>> pretty reliable when multi-tasking? >>> [...] >>This is the only question of the bunch that I can answer of the few you asked, >>but I must say, quite simply, that Apple's MultiFinder is a joke, basically >>because the hardware itself is still not capable of true multitasking. >_BUT_, where in the world did you come up with a conclusion that the >*hardware* can't multitask?!?! The OS, perhaps, but _not_ the hardware. The Amiga OS is better designed for multitasking than the Mac OS, basically because the Mac OS was never designed for multitasking in the first place. The basic fact that Mac people find the performance of Multifinder acceptible in the first place is a credit to the original Mac OS. You certainly wouldn't find as fluid an add-on multitasking system under MS-DOS if it weren't for the 640K physical limitations and hardware support for multiple virtual 8086s under the management of a '386. The best multitasking OS is one designed to do so, but there are varying degrees of How Good Is This Multitasking; it's not a 1 or 0 situation. As for the second comment, I imagine that Brett was thinking of the Amiga's support hardware, rather than the CPU. All 68030s multitask equally well at the base level, though the OS that they're running has alot to do with efficiency. The Amiga's use of preemptive task switching, interrupts, DMA slots, and bus DMA make it more efficient in a multitasking environment. However, to a degree, this would also help out in a non-multitasking environment -- in terms of raw transfer, for instance, the Amiga hard disk interface is about 4x the speed of most Macs. In real life, disk speed is the bottleneck, you really won't notice much difference in disk transfer. However, with a multitasking system, the CPU will get all the cycles the hard disk controller can't use on the Amiga, so your throughput is better -- the Mac would simply wait for the transfer to complete. Folks who don't always completely understand it say that the Amiga was designed for multitasking and the Mac wasn't. That's not true, since the capability for real multitasking lies in the CPU more than anything -- as proof, the Mac II machines run the same basic UNIX that the Amiga 25xx machines run. However, there's quite a bit of the Amiga system design that makes things much faster under multitasking by eliminating CPU waits in several different places. Macs currently don't do these kind of things, though other 680xx machines like Suns and NeXTs do, so I would expect it's only a matter of time before we see thing like peripheral DMA and video coprocessors in a Mac family machine. But expect to PAY for it. >-- Blair MacIntyre, Professional Leech on Society ( aka CS Graduate Student ) -- Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Too much of everything is just enough