locked
Windows Metro - Snapped view and multi-taskings

    Question

  • The snapped view seems to suggest that user can put more than one app on screen to run concurrently.  What are the rules regarding

    1. Which app is considered foreground if say, I have 3 Metro apps snapped together on screen and they all active.

    2. The suspended background app rule - which app will be subjected to this background suspending rule?

    3. What is the multi-task scheduler timeslide per task? 

    4. Is there a good explanation of the Metro multi-tasking architecture/model for Metro Apps and Metro+Desktop apps? 


    Codemaniac


    • Edited by codemaniac Wednesday, February 8, 2012 1:18 AM typo
    Wednesday, February 8, 2012 1:17 AM

All replies

  • Hi codemaniac,

    the app visible on the screen is the only one that's not in the suspended state, suspended apps do use your ram but have little impact on CPU. If you open your Task Manager, you will see what I mean. At the moment I have IE, One Note, Outlook, Note Pad, Piano, Stocks and Task Manager open, the metro apps, Piano and Stocks are in suspended state, taking 60.3 and 36.1 MB of Ram, while my total CPU usage varies between 0 and 4%, while memory usage is 56% of 2 GB. 


    Irfan


    • Edited by Irfanfare Wednesday, February 8, 2012 3:11 AM to make clear
    Wednesday, February 8, 2012 2:58 AM
  • So there can be maximum a single one foreground app at a time, correct?

    Any good source that explains HOW does the OS manage this? Like what apps get suspended and what are skipped, what's the time to suspend them, etc.


    Well this is the world we live in And these are the hands we're given...

    Wednesday, February 8, 2012 11:32 AM
  • Please read the reply by Andy Cadley and the thread links given by Marilyn at:
    http://social.msdn.microsoft.com/Forums/en-US/windowsdeveloperpreviewgeneral/thread/14a760cf-8045-485c-8abf-b5eaad5a0228

    Irfan

    Wednesday, February 8, 2012 4:25 PM
  • Thanks for links, but they don't quite give an answer. Indeed, what does this exactly mean: "If memory comes under pressure, suspended Metro applications will simply be killed by the OS". What's under pressure here? Something like "Your system is low on virtual memory"? What are the absolute or at least relative measures taken by the OS to consider the app ready for abrupt closing?

    Thank you, anyways.


    Well this is the world we live in And these are the hands we're given...

    Wednesday, February 8, 2012 8:54 PM
  • Any situation in which the OS decides it needs to reclaim memory for some other purpose. Any Metro application that is suspended must assume that it will be killed without being given any further notice (as this will happen in any situation the OS needs to close it, such as a system restart) and should be prepared to resume from place it was left at when restarted.

    I would strongly recommend watching the BUILD videos on the fundamentals of Windows 8 development, especially How and When Your App Will Run as this explains the changes in application lifecycle very well.

    Wednesday, February 8, 2012 11:51 PM
  • For instance, AndyCadley, in my first reply here, if I open a program, say a high memory-using game, which consumes nearly all of my 2 GB Ram, will my 2 suspended apps Piano and Stocks, which together consume 96.4 MB Ram, be closed down by the OS ?

    Irfan

    Thursday, February 9, 2012 2:25 AM
  • Thanks, Andy, I'll give it a look at.

    Well this is the world we live in And these are the hands we're given...

    Thursday, February 9, 2012 1:48 PM
  • Right, Irfan, that's pretty what you come up with when you start thinking of it.

    Well this is the world we live in And these are the hands we're given...

    Thursday, February 9, 2012 1:54 PM
  • When you snap applications on the screen, they are all visible.  the screen split and shared between the 2 apps.   I want to know if this model the Metro brokers allows the 2 app to multitasks.  I am awared of the foreground running app rule of Metro and what the OS does with suspended apps.  This is not the same operation model. 


    Coder


    • Edited by codemaniac Wednesday, February 15, 2012 12:10 AM
    Wednesday, February 15, 2012 12:10 AM