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RE: [Widgets] R21. Resource Declarations. Was RE: Request for Comments on Widgets 1.0 Requirements Last Call WD

From: Sullivan, Bryan <BS3131@att.com>
Date: Wed, 3 Sep 2008 16:06:06 -0700
Message-ID: <8080D5B5C113E940BA8A461A91BFFFCD0B4881BD@BD01MSXMB015.US.Cingular.Net>
To: "Marcos Caceres" <marcosscaceres@gmail.com>, "public-webapps" <public-webapps@w3.org>

Hi Marcos,
My response is late (the review happened just before vacation and other things...), but here it is:

I'm not sure there is a semantically useful way to declare/assess resource dependencies (currently), but that would be the goal. In the meantime simple disclosure is better than the "use it if it works for you, otherwise get rid of it" approach. At least the user may be able to understand the significance of the disclosure. 

The examples I provided in the proposal illustrate common resource constraint cases:

a) automated operation

a.1) network-intensive applications can cost users a lot of money (a critical resource) or drain the device battery (another critical resource). Applications that are designed to operate all the time or in the background (e.g. using Ajax methods) should disclose this so that the user can decide if that's what they want to allow. If possible, the extent of resource usage (frequency of network requests, typical amount of data exchanged) should be disclosed.
a.2) screen updates (e.g. for phonetop widgets) and memory updates (e.g. managing content and variables) can be battery-affecting. Application designers should have some understanding of the typical effect that their applications will have on the devices they target, and make at least useful disclosures of such effects. 

b) storage requirements: Web applications may manage local persistent (e.g. flash) storage of content related to the application, and may have a significant impact on the operating memory (e.g. ram) of the device. While user choice in use of the application may significantly affect the storage requirements, the developer should have some understanding of the typical storage requirements. The user could then decide based upon the disclosure, whether they want to allocate a potentially significant amount of storage to this application.

The real goal as I mentioned would be that a policy management engine could use the declarations to determine if the application would exceed a certain policy (which the user could manage as preferences). Semantic assessment of impact would resolve the variable "relative" impact problem (or at least reduce it), since the assessor would know how to relate the resource declarations in the context of the host device.

In the meantime however at least some schema-defined disclosure of resource impacts could be used in a widget installer UI to inform the user of the impacts that the developer is aware of.

Best regards,
Bryan Sullivan | AT&T
-----Original Message-----
From: Marcos Caceres [mailto:marcosscaceres@gmail.com] 
Sent: Thursday, August 07, 2008 10:05 PM
To: Sullivan, Bryan; public-webapps
Subject: [Widgets] R21. Resource Declarations. Was RE: Request for Comments on Widgets 1.0 Requirements Last Call WD

Hi Bryan,
I'm wondering if you could help me understand "R21. Resource
Declarations", which was proposed in your feedback [1]:

> R21. Resource Declarations
> A conforming specification must specify a means for declaring that the
> instantiated widget will have an impact on sensitive device or network
> resources, which may impact device performance or the user experience.
> Motivation:
> Security, current development practice or industry best-practices.
> Rationale:
> To declare the resource requirements of the widget, allowing the
> widget user agent to respond accordingly by adjusting its resource
> policies and warning the end-user. Example of resource sensitive
> services that could require notification are automated operation
> involving network access or screen display, which can impact overall
> service cost and device battery life; or persistent storage
> requirements, which can affect device performance and reliability of
> the environment for other applications.

I'm not sure I understand, from a developer's perspective, how I would
declare resource use particularly because it seems so relative and
subjective. For example, if I had created a widget and tested it on my
super-phone I might think that it is not very resource demanding (this
might be because the widget implementation running on my phone is very
efficient and light weight). However, another widgets implementation
might not be as efficient and hence it may use a lot of resources (but
this is not the fault of the widget, it is the fault of the
implementaiton). Another problem is that one phone might have limited
resources by design (eg. limited RAM and storage) or because other
applications are hogging resources.

Maybe the requirement should be that the user agent should report to
the user when a widget is hogging resources; however this seems more
like something that would be best left to implementers.

Can you maybe show us a usage scenario for what you have in mind for
this requirement. How do you envision this would work?

Kind regards,

[1] http://lists.w3.org/Archives/Public/public-webapps/2008JulSep/0298.html

Marcos Caceres
Received on Wednesday, 3 September 2008 23:07:35 UTC

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