ubuntu-phone team mailing list archive

[Michael Zanetti <michael.zanetti@xxxxxxxxxxxxx>]

On Wednesday 14 August 2013 10:33:34 Thomas Voß wrote:
> The state of an application is transparent to the user. Behind the
> scenes, the system can decide to stop/kill non-focused apps at its own
> discretion. Whenever the system alters the state of an app to "not
> running" it offers an archive such that the app can persist its state.
> With that, a user ideally never realizes that an app has been stopped
> or killed.

Take for example this use case:

A remote control application for a media center might have a feature to pause 
the running movie/song/whatever in case of an incoming phone call. This 
obviously only works while the application is running and will break when the 
app gets paused. 

Another one: A sports tracker tracks my way while running. I still want to 
listen to music while running and have the music app focused. If that kills 
the sports tracker app this won't work.

I guess both use cases could be implemented by the app starting a background 
task for that given job and stop the background task again when it is closed 
by the user (as opposed of being suspended/killed by the system) or when the 
user manually stops the task (disconnect from media center, stop sports 
tracking etc).

Thanks,
Michael

> 
> Thomas
> 
> On Wed, Aug 14, 2013 at 10:08 AM, Tobias Havla <tbhavla@xxxxxxxxx> wrote:
> > On 14.08.2013 10:04, Thomas Voß wrote:
> >> On Wed, Aug 14, 2013 at 9:56 AM, Tobias Havla <tbhavla@xxxxxxxxx> wrote:
> >>> On 14.08.2013 09:54, Thomas Voß wrote:
> >>>> On Wed, Aug 14, 2013 at 9:41 AM, Michael Zanetti
> >>>> 
> >>>> <michael.zanetti@xxxxxxxxxxxxx> wrote:
> >>>>> On Wednesday 14 August 2013 09:31:31 Daniel Holbach wrote:
> >>>>>> Hello,
> >>>>>> 
> >>>>>> On 14.08.2013 09:29, Michael Zanetti wrote:
> >>>>>>> On Wednesday 14 August 2013 09:07:52 Thomas Voß wrote:
> >>>>>>>> Hey Fabio,
> >>>>>>>> 
> >>>>>>>> no, applications are not allowed to run in background. Our
> >>>>>>>> application
> >>>>>>>> lifecycle is strict in this respect and we only guarantee focused
> >>>>>>>> applications to be running.
> >>>>>>> 
> >>>>>>> Does that mean I will have an Ubuntu Edge phone with 4GB of RAM, 8
> >>>>>>> CPU
> >>>>>>> cores and cannot do multitasking on it?
> >>>>>> 
> >>>>>> I don't think anyone specified the phone to have 8 CPU cores - where
> >>>>>> did
> >>>>>> you read that?
> >>>>> 
> >>>>> Nowhere... I think you get my point...
> >>>>> 
> >>>>>> How is "app authors can write daemons" = multitasking?
> >>>>> 
> >>>>> How does this relate? Thomas said there will be no running apps in the
> >>>>> background / minimzed apps, which to me means there will be no
> >>>>> multitasking.>>>> 
> >>>> We have had this conversation multiple times in the past, and version
> >>>> 1 of our application lifecycle will not allow to run arbitrary
> >>>> applications in the background. Instead, we will provide selected
> >>>> services to hand over to the system for certain tasks, e.g.,
> >>>> downloads, alarms, music playback. Please note that this is a policy
> >>>> targetted towards the "mobile phone" usage scenario and swapping
> >>>> policies at runtime when transitioning to different usage scenarios is
> >>>> one of the primary goals of the lifecycle architecture.
> >>>> 
> >>>> Version 2 of the lifecycle will then allow applications to run their
> >>>> own background tasks, UI less, with restrictions on
> >>>> CPU/Memory/resources in general.
> >>>> 
> >>>> Thomas
> >>>> 
> >>>>> --
> >>>>> Mailing list: https://launchpad.net/~ubuntu-phone
> >>>>> Post to     : ubuntu-phone@xxxxxxxxxxxxxxxxxxx
> >>>>> Unsubscribe : https://launchpad.net/~ubuntu-phone
> >>>>> More help   : https://help.launchpad.net/ListHelp
> >>> 
> >>> If Ubuntu Touch doesn't support multi task it is far behind iOS,
> >>> Android, Windows Phone and Blackberry. Sorry, I thought it would be a
> >>> modern system that requires a lot of power, so we can do the same things
> >>> as on our PCs.
> >> 
> >> Okay, let's be clear here: Multitasking and application lifecycle are
> >> related but distinct topics. Obviously, Ubuntu Touch will support
> >> multi-tasking, but an application lifecycle architecture that allows
> >> for controlling resource consumption of applications by the system is
> >> sorely needed to ensure a long-running _mobile_ device. It is not
> >> sufficient to assume that app authors will get it right and it is
> >> important to note that users always "blame" the platform for bad
> >> battery life. And that is for a good reason: It's the platform's/OS's
> >> responsibility to put mechanisms in place to manage a device's
> >> resources!
> >> 
> >> Our application lifecycle policies and state machines allow us to
> >> exercise this level of control for specific usage scenarios, but they
> >> do not touch on general multi-tasking capabilities and we can leverage
> >> the full process state spectrum to ensure a seamless operation.
> >> 
> >>   Thomas
> > 
> > So can two or three applications run at the same time and other gets
> > closed/suspended or can I switch between two applications only with
> > reloading the application?
> > We have a gesture to quick switch between apps, so if we have to reload
> > apps while we are multitasking this gesture makes no sense. A good way
> > would be suspending apps like Android does (/Greenify). The doesn't
> > notice that and the battery life is good.