Path: utzoo!censor!geac!torsqnt!lethe!yunexus!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ukc!newcastle.ac.uk!sylvaner!q1aqf From: A.Waterworth@newcastle.ac.uk (A Waterworth) Newsgroups: comp.realtime Subject: Re: AmigaDOS as realtime system? Message-ID: <1991Feb27.090231.5412@newcastle.ac.uk> Date: 27 Feb 91 09:02:31 GMT References: <1566@swrinde.nde.swri.edu> Sender: news@newcastle.ac.uk Organization: University of Newcastle upon Tyne, UK, NE1 7RU Lines: 50 kent@swrinde.nde.swri.edu (Kent D. Polk) writes: >In article tims@infidel.lanl.gov (Tim Sullivan) writes: >>I just saw a posting in which AmigaDOS was described as a realtime >>multitasking operating system. Can anyone shed light on its realtime >>abilities? >> >>Tim Sullivan (tims@infidel.lanl.gov) > . > . >The Amiga is so quick, responsive and easy to program compared to any >other real-time system... > . > . >Even after reading this simple example, wouldn't you agree that Amigas >qualify as having a real-time OS? I probably won't be the only one to mention this, but here goes anyway... Being quick, responsive, etc. is not necessarily being real-time. The important characteristic of a real-time computer system is that it must be _predictable_. That is to say, it must be able to offer guarantees of a specified level of service provision under specified timing constraints. Simply being fast or responsive isn't enough, although such features often make the job of meeting those 'specified timing constraints' so much easier. For example, supposing that you have a process control task which absolutely must be performed within 750ms. Can the Amiga OS _guarantee_ that that task will never (in the absence of faults or failures) miss its deadline? If it cannot make such a guarantee, then it isn't a real-time OS - although it might act as a decent starting point from which to develop one. Profound apologies to all of those people out there who are sick of listening to the constant "What is/isn't real-time?" bickering which seems to be affecting the field at the moment, but I honestly think that the common misconceptions about real-time being the same thing as blindingly fast should be cleared up. Adrian. P.S. If the last paragraph sounds a bit pompous, I'm sorry - no offence was intended to anyone. (So we'll all forget about any little flame wars before they even start. Won't we?) ______________________________________________________________________________ FROM : Adrian Waterworth. JANET : A.Waterworth@uk.ac.newcastle ARPA : A.Waterworth@newcastle.ac.uk PHONE : +44 91 222 6000 UUCP : ...!ukc!newcastle.ac.uk!A.Waterworth POST : Computing Lab. University of Newcastle upon Tyne, UK. NE1 7RU.