ubuntu-phone team mailing list archive

[Thomas Voß <thomas.voss@xxxxxxxxxxxxx>]

On Wed, Aug 14, 2013 at 4:08 PM, Roberto Colistete Jr.
<roberto.colistete@xxxxxxxxx> wrote:
>     Hi,
>
>     Please, let it be clear about Ubuntu Touch :
> - currently Apps screen shows "Running Apps" with (not live) miniatures of
> open softwares. These softwares are not-focused ? If so, they can be closed
> by the system ?

Right, none of them are guaranteed to be running and can be stopped or
killed by the system. At any rate, they will remain in the list of
recent applications. It is transparent to the user if an app is
running or not.

> - if the user have installed a mathematical application and want to let an
> integral calculation run (for 30s or even some minutes, it depends a lot on
> the complexity of the integral) while he/she can browse the web, etc. Will
> the mathematical application be stopped by the system even if it is shown as
> "Running Apps" miniature ?
>
Probably yes, the policy is free to decide to stop unfocused
applications to save resources.

>     About the link cited below, I am worried to see :
> a) no mention of Symbian, Maemo, MeeGo Harmattan, WebOS, BlackBerry OS in :
> "Write summary of how other OSes (iOS, Android, Windows) handle background
> activities: DONE
>   Write summary of how other OSes (iOS, Android, Windows) handle
> applications state preservation: DONE"
> As iOS, Android and Windows Phone have the most limited multitasking among
> the mobile OS, i.e., they don't let the user decides which softwares remain
> open or not. In the opposite side, Maemo 5 and MeeGo Harmattan even show
> live miniatures of running softwares (see the video of Maemo 5 on a Nokia
> N900 from 1min26s) :
> https://www.youtube.com/watch?v=mLuYmaM6J-c

Sure, and those are the mobile operating systems with the largest
exposure to users. Having live previews of (i.e., running)
applications is a nice effect, but not particularly thoughtful of the
scarcest resource on the phone, i.e, the battery. That being said, we
will keep exploring how we can cleverly adjust the policy for
different usage scenario over time, with a strict and rigid starting
point that prioritizes resource saving.

> b) in the document "Draft : Application Model", section "Application
> Lifecycle -> Meta State : Running -> State : Unfocused" :
> "Please note that the runtime system can decide to transition the
> application instance to not running at its own discretion and at any point
> in time.
> ... applications can not interfere with the runtime’s decision to transition
> an application instance to the “Not Running” meta-state."
>
>     It seems Canonical wants Ubuntu Touch to have multitasking à la Android,
> iOS and Windows Phone. Is it true ?
>

In version 1: yes. The lifecycle policy will be strict and the system
will provide background services that ensure a seamless operation
(e.g., downloads and music playback in background).

>         Regards,
>
>         Roberto
>
>
> Em 14-08-2013 05:34, Thomas Voß escreveu:
>
> Please also see:
>
>
> https://blueprints.launchpad.net/ubuntu/+spec/client-1303-add-app-model-and-lifecycle-to-platform-api
>
> and the linked documents for further details.
>
>   Thomas
>
> On Wed, Aug 14, 2013 at 10:33 AM, Thomas Voß <thomas.voss@xxxxxxxxxxxxx>
> 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.
>
> 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
>
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> 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.
>
>
>
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