Multi-tasking

[Rich Caloggero]

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" <akp at eznet.net>
To: <speakup at braille.uwo.ca>
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 at 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 at braille.uwo.ca
> http://speech.braille.uwo.ca/mailman/listinfo/speakup
>