From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fort-point-station.mit.edu ([18.72.0.53]) by speech.braille.uwo.ca with esmtp (Exim 3.22 #1 (Debian)) id 15H7wf-0004dz-00 for ; Mon, 02 Jul 2001 13:57:13 -0400 Received: from grand-central-station.mit.edu (GRAND-CENTRAL-STATION.MIT.EDU [18.7.21.82]) by fort-point-station.mit.edu (8.9.2/8.9.2) with ESMTP id NAA03516 for ; Mon, 2 Jul 2001 13:56:08 -0400 (EDT) Received: from melbourne-city-street.mit.edu (MELBOURNE-CITY-STREET.MIT.EDU [18.7.21.86]) by grand-central-station.mit.edu (8.9.2/8.9.2) with ESMTP id NAA22398 for ; Mon, 2 Jul 2001 13:56:08 -0400 (EDT) Received: from vantaa ([18.81.1.76]) by melbourne-city-street.mit.edu (8.9.2/8.9.2) with SMTP id NAA05028 for ; Mon, 2 Jul 2001 13:52:39 -0400 (EDT) Message-ID: <002001c10320$22d0ca70$4c015112@vantaa> From: "Rich Caloggero" To: References: <000e01c0fe5e$80797bc0$c52b893e@essex.ac.uk><003d01c0fe6c$e6f96140$2cf60141@mtgmry1.md.home.com><20010626204432.C611@lpwh.pwh.com><001f01c10035$b068a800$0100a8c0@cybertsar> <15164.26693.159819.537401@akp.selfhost.com> Subject: Multi-tasking Date: Mon, 2 Jul 2001 13:55:09 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.3018.1300 X-Mimeole: Produced By Microsoft MimeOLE V5.00.3018.1300 Sender: speakup-admin@braille.uwo.ca Errors-To: speakup-admin@braille.uwo.ca X-BeenThere: speakup@braille.uwo.ca X-Mailman-Version: 2.0.4 Precedence: bulk Reply-To: speakup@braille.uwo.ca X-Reply-To: "Rich Caloggero" List-Help: List-Post: List-Subscribe: , List-Id: Speakup is a screen review system for Linux. List-Unsubscribe: , List-Archive: Well, as far as I know, both windows and linux multi-task; linux has the added advantage of being fully memory managed. Note, windows refers to the consumer versions of windows (win95, 98, and milinium); NT and 2k are memory managed, preemptive scheduling operating systems. The lack of memory management is why, in most cases, windows becomes so unstable after being "up" for a while. In a memory managed environment, the hardware actually checks each memory reference to make sure that the correct virtual address (the one supplied with the referencing instruction) is mapped to a physical address. If no physical address is mapped to that virtual address, it figures out whether a mapping is possible by checking to see if the virtual address given is in the correct range for the currently executing process. If yes then it loads the appropriate page from disk and continues; if not, it generates a page fault and terminates the process. Note: this process is far more complex than this; I'm sure I'm over simplifying and leaving a lot of stuff out. Windows probably does some bound checking and it can swap, however it does not make use of the memory management hardware on the processor; it does not check every memory reference. As far as scheduling goes, I believe they both do some sort of round robbin preemptive scheduling, but linux probably has a better algorithm. ----- Original Message ----- From: "Ann Parsons" To: Sent: Friday, June 29, 2001 7:36 AM Subject: Re: New Braille Notetaker From Papenmeier > Hi all, > > Well, Vic, you know that Windows is not a true multitasking > invironment. the processor pauses between tasks in order to allocate > resources and memory while Linux and Unix really *are* multitasking > environments. they actually do run processes simultaneously and there > is no pausing or checking of resources. > > Ann P. > > -- > Ann K. Parsons > email: akp@eznet.net ICQ Number: 33006854 > WEB SITE: http://home.eznet.net/~akp > "All that is gold does not glitter. Not all those who wander are lost." JRRT > > > _______________________________________________ > Speakup mailing list > Speakup@braille.uwo.ca > http://speech.braille.uwo.ca/mailman/listinfo/speakup >