Xref: utzoo comp.sys.amiga.programmer:41 comp.sys.amiga.misc:21 Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!think.com!samsung!usc!sdd.hp.com!decwrl!pa.dec.com!bacchus!mwm From: mwm@raven.relay.pa.dec.com (Mike (My Watch Has Windows) Meyer) Newsgroups: comp.sys.amiga.programmer,comp.sys.amiga.misc Subject: Re: How do we change the scheduler? (Was Re: Multitasking at home...) Message-ID: Date: 10 Jan 91 20:09:36 GMT References: <17210@cbmvax.commodore. <1991Jan10.130741.11570@ux1.cso.uiuc.edu> Sender: news@pa.dec.com (News) Followup-To: comp.sys.amiga.misc Organization: Missionaria Phonibalonica Lines: 64 In-Reply-To: burley@geech.ai.mit.edu's message of 10 Jan 91 16:16:57 GMT In article burley@geech.ai.mit.edu (Craig Burley) writes: In article <1991Jan10.130741.11570@ux1.cso.uiuc.edu> lrg7030@uxa.cso.uiuc.edu (Loren Rittle) writes: I'm confused -- is the issue that AmigaDOS' scheduling algorithm allows low-priority tasks to be starved when higher-priority tasks stay eligible? Of course you're confused - you've walked into the middle of a discussion, and have no idea what we're talking about. Loren Rittle was asking if it was possible to change the Amiga's multitasking so that user processes can't be starved, based on commentary in an ongoing discussion of the phrase "true multitasking". He quite correctly moved the discussion to .programmer from .misc. I'll try and fill you in, and point followups to comp.sys.amiga.misc, where this belongs. True multitasking, as I believe it is defined, means preemptive scheduling. Actually, "true multitasking", as it is commonly _used_, means preemptive multitasking. If you've got a reference to a textbook that defines the term (in any way), I'd appreciate hearing about it. As I've just pointed out, there's a perfectly adequate term preemptive multitasking, without the derogatory implication that someone else's multitasking is "fake" or "false" in some way. The first uses I saw were from insecure Amiga owners trying to demonstrate the inferiority of someone else's machine. As such, the terminology is bad, and should be avoided. That is a hard thing to introduce to an operating system with a large installed base including 3rd-party applications. Multifinder is not true multitasking, period. Bullshit. Explain to a user who doesn't have the foggiest idea what a scheduler is why his machine - which, as far as he can tell, behaves exactly like an Amiga under normal operation - has "fake" multitasking. Especially when (from what I hear of the Mac world) the percentage of commercial programs that are multitasking friendly on the Mac is larger than on the Amiga. In summary, I don't think it is at ALL silly to define true multitasking to exclude Multifinder, and I doubt that even Apple Marketing would disagree -- and I do agree it IS silly to claim that true multitasking includes meeting any particular set of requirements for task scheduling, especially since "priority levels" are used to mean so many different things in different situations. Actually, I think it's silly to define "true multitasking" at all. Either something is multitasking, or it isn't. I've already explained how to tell which is which. If you insist on defining "true multitasking", do it in non-technical terms. How about "no non-privileged task can starve any other task"? Please note I don't define single-tasking, cooperative multitasking, or true multitasking as GOOD or BAD. They all have their advantages and disadvantages, and I have done lots of useful work in all three environments (the bulk under true multitasking) and had problems with all three. I take it that the bulk wasn't done on the Amiga - it doesn't have "true multitasking" by the definition I'm going to use until an authoritative source appears.