From: Stuffed Crust on 18 Apr 2010 22:44
In rec.photo.digital.slr-systems John A. <john(a)nowhere.invalid> wrote:
> True enough. I wonder why MS decided preemptive was the way to go when
> they already had cooperative.
Because cooperative requres the processes to behave themselves and
explicitly hand off execution, while in a preemptive model, the OS
schedules execution and cuts off the process when it's used up its
timeslice, scheduling the next one that's ready to go. The individual
processes don't know or care about how they're scheduled and take as
much processing time as they're given.
What Apple's done here is set things up such that a process has to
explicitly say what it wants to do in the background, otherwise it's
suspended and not re-scheduled until the user brings that process back
to the foreground.
The downside of Apple's model is that all apps have to be coded
to work in the background by explicitly registering what they want to
do (and with what) in advance. One can make a good case why this is a
good thing -- or a bad thing.
Solomon Peachy pizza at shaftnet dot org
Melbourne, FL ^^ (mail/jabber/gtalk) ^^
Quidquid latine dictum sit, altum viditur.
From: nospam on 18 Apr 2010 23:27
In article <3sens5d7arlm0kilun7givd2fosnde5qfj(a)4ax.com>, John A.
> >> And if you have true multitasking you can set a complex filter working
> >> on your image in the background while you switch over to checking
> >> email while you wait for it to finish.
> >who runs complex filters on a phone?
> Maybe some day you will. How many things do you do on a phone now that
> you never thought you would, even just five years ago? :)
then i'll worry about its multitasking abilities *then*.
> Or a jazz ensemble, or a remix. Yeah, those are intentional. But then
> there are other unintentional combinations like watching a video of
> the Wizard of Oz while listening to Dark Side of the Moon. :)
heh, that's easily done on a computer which can then be played on the
From: David J. Littleboy on 18 Apr 2010 23:32
"Stuffed Crust" <pizza(a)spam.shaftnet.org> wrote in message
> In rec.photo.digital.slr-systems John A. <john(a)nowhere.invalid> wrote:
>> True enough. I wonder why MS decided preemptive was the way to go when
>> they already had cooperative.
> Because cooperative requres the processes to behave themselves and
> explicitly hand off execution, while in a preemptive model, the OS
> schedules execution and cuts off the process when it's used up its
> timeslice, scheduling the next one that's ready to go. The individual
> processes don't know or care about how they're scheduled and take as
> much processing time as they're given.
Good description. Just an addendum: as your description implies, cooperative
is a disaster in the presence of badly behaved processes, and since all
software has bugs, cooperative is a seriously bad idea. I worked on a CDC
3600 the summer of '72. It was supposed to be used for patient monitoring,
but since the OS was cooperative, it couldn't be used. I just assumed that
no one would make that mistake again. Wrong.
> What Apple's done here is set things up such that a process has to
> explicitly say what it wants to do in the background, otherwise it's
> suspended and not re-scheduled until the user brings that process back
> to the foreground.
> The downside of Apple's model is that all apps have to be coded
> to work in the background by explicitly registering what they want to
> do (and with what) in advance. One can make a good case why this is a
> good thing -- or a bad thing.
David J. Littleboy
From: Ray Fischer on 19 Apr 2010 00:21
John A. <john(a)nowhere.invalid> wrote:
> nospam <nospam(a)nospam.invalid>
>>> Multitasking on the computer is something people do all the time.
>>> Just because you have a mobile version of a computer, that's no reason
>>> to stop multitasking.
>>actually no. most people use one application at a time. if you are
>>watching a movie, are you also reading an ebook? if you are playing a
>>game are you also editing images in photoshop?
>>you might have an email app running in the background and if it beeps
>>for new email, you *switch* to it, read the email, then switch back to
>>photoshop or whatever and continue working.
>And if you have true multitasking you can set a complex filter working
>on your image in the background while you switch over to checking
>email while you wait for it to finish.
On a PHONE?!?
From: sobriquet on 20 Apr 2010 13:40
On 20 apr, 17:03, Allen <all...(a)austin.rr.com> wrote:
> whisky-dave wrote:
> > "Alan LeHun" <t...(a)reply.to> wrote in message
> >> In article <hqhk2p$qum$1(a)qmul>, whisky-d...(a)final.front.ear says...
> >>> There's little proof that the human brain can mulititask, what is does is
> >>> ignore whatever other inmut is present, it's more time slicing than
> >>> multitasking.
> >> There is plenty proof that the human brain can multi-task on two tasks.
> >> This is due in no small part to the fact that our brain is in fact a
> >> pair of brains.
> > No, that's still time slicing.
> > One of the basic laws of physics is that two things can not occur at the
> > same instance in time.
> > One of the reasons you have a clock frequency in electronic devices is to
> > make sure everything
> > has it's own time slot and is 'clocked properly.
> > In the human world magicians use this 'trick' as the human eye can not see
> > everything at the same time i.e it can;t multitask, humans can't multitask.
> > They just think they can because they aren't clever enough to realise they
> > can't.
> You mean no one can ride a bicycle and chew gum at the same time?
That's one thing... but think about riding a bicycle and listening to
It depends how much attention is needed to keep track of the traffic
and to what degree
the audiobook requires your full attention to follow.
However, with an audiobook, it doesn't really matter that you can't
follow the story in full detail, as you can listen to the same book
repeatedly. In this fashion render the story in your mind as fragments
that gradually expand to cover the complete contents of the book as
you've been listening to it repeatedly.
Some books are well worth to re-read and every time you'll discover
new things. It doesn't really matter if you miss out on certain parts
the first few times you skim it over.
Also, you can add music to the mix of activities competing for your
attention.. some kinds of music are very meditative and can induce a
kind of meditative state of mind. In this state of mind, your mind is
more receptive and this alters the way in which you process and digest