[sugar] perceived sugar performance

[Gary C Martin]

On 1 May 2008, at 16:24, Albert Cahalan wrote:

> For other reasons (GUI complexity and the OOM killer), the ability
> to launch multiple activities should be disabled by default.


Do you mean 2+ instances of one activity, or multiple activities?

I do agree that UIs that support multiple activities (and switching)  
will be more complex than one that is completely modal. The iPhone and  
iPod Touch are the best current examples I can think of, though they  
clearly have some areas still to solve in terms of using several  
applications together to achieve something no single one could alone.  
Current lack of Copy/Paste is a well cited complaint (but I can see  
Apple solving/fixing that at some point, at least I hope so). There's  
also the whole conversation going on about will Apple allow developers  
to create background applications. These devices are currently more  
about accessing than creating, the XO is about creating and accessing  
– I think that changes the UI game enough to warrant activity instance  
switching.

Preventing multiple activities on the XO would be too extreme, I  
think, though it would be the next logical step down for UI  
simplification. For the younger end of the target audience I can see  
this being a positive (an assumption, I have no proof), but it would  
reduce the utility of the XO over a range of learning usage scenarios  
for everyone else. You loose much of the combinatorial effect of using  
several activities to achieve an end goal – can you imaging trying to  
write homework that need a photo added, images from the web, reading a  
pdf with the homework assignment/questions, or how an invitation to  
participative in another's activity would be very disruptive (say a  
friend wanted to use chat and ask you something about the homework  
assignment you were doing).

Preventing 2+ instances of the same activity would be less disruptive,  
but would not solve kids launching multiple other activities as they  
click about with the interface.

Devils advocate: Now if activity launch + state restoration, and  
activity closing + state saving, was as fast as iPhone/iPod Touch,  
then my opinion could** start to swing in favour of a UI that  
presented a, one activity running at a time, view. You wouldn't so  
much quit an activity, as return to the Home view. Switching via the  
frame would be gone, you'd just return to the Home view.

** I say 'could' because some actions that require two or more  
activities to complete would still be sub optimal relative to a UI  
that allowed instant switching between running instances (example,  
trying writing an essay about a Shakespeare play you have in pdf  
format, lot's of back and forwards referencing and copy/paste).

--Gary