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Re: Comments on http://www.w3.org/TR/2010/WD-system-info-api-20100202/

From: Antoine Sanchez <ckkoshi@gmail.com>
Date: Wed, 15 Dec 2010 23:35:40 +0100
Message-ID: <AANLkTimZ7VbL1z5q4BmGjhN13_GM1WAVrRxgcn-UmXK2@mail.gmail.com>
To: Philip Gladstone <pgladstone@cisco.com>
Cc: public-device-apis@w3.org

I'll just give an answer about 4.4.

About level, I don't see the point why there's a negative value, 0 is
enough to say there's no more power, can you explain?

I think if isExternal is false, there's no way that isCharging can be
nothing else than false.
If there's a solar charging, or even micro-wave charging, power source
will be external, not from battery.


On Wed, Dec 15, 2010 at 10:58 PM, Philip Gladstone <pgladstone@cisco.com> wrote:
> Hi
> I note the the StorageUnit property does not include flash memory. Since
> this is the most common sort of memory in phones (and probably in next years
> laptops in the form of SSDs), it seems a pity to use TYPE_UNKNOWN.
> I also have a philosophical objection to TYPE_UNKNOWN as it occurs in many
> places in this document. In some cases the type may really be unknown, but
> in most cases it is really TYPE_OTHER (such as the flash example). You may
> want to consider whether to add a TYPE_OTHER to each (effective)
> enumeration, or whether to define an extension mechanism to allow new
> technology to be adequately represented.
> In section 4.4 Power, it is clear that a very simple model of power is being
> assumed. It isn't obvious how you would fit an integrated solar charger for
> a cellphone (or e-book reader) into this model. When the sun is shining, is
> 'isExternal' true or false? Since the values of isCharging and isExternal
> have specific relationships, this gets complicated very quickly. If the
> solar charger was external, would this make a difference? I have seen
> laptops with fuel cells and batteries, and even one with a hand-crank.
> I would define the terms as follows;
> level of type float, readonly, nullable Specifies how much of the internal
> energy source remains, scaled as follows. A value of 0 means that the stored
> energy level is at a point where the system will enter shutdown mode, and 1
> indicates that the system's stored energy level is maximal. Negative values
> are only likely during the system shutdown process. Any threshold parameter
> used in a watch function to monitor this property applies to this attribute.
> No exceptions.
> timeRemaining of type unsigned long, readonly, nullable Represents the
> estimated time remaining in seconds before the system enters shutdown mode,
> based on net current power consumption (which may be averaged over a short
> period of time) and how much stored energy remains. If this value is null,
> this means that there is essentially infinite time remaining.
> No exceptions.
> isExternal of type boolean, readonly If true the device is currently
> receiving any power from an external source. If false the device is not
> receiving power from an external source.
> No exceptions.
> isCharging of type boolean, readonly Indicates whether the internal stored
> energy  level is currently increasing. If isExternal is false, this value is
> likely to be false, meaning that the system is consuming net positive power,
> and the stored energy source is therefore depleting.
> No exceptions.
> In the case of the section 4.7 Network, there seems to be an assumption that
> there is only a single connection to the network. This isn't the case for
> nearly all systems today. Also, with the advent of v6, each interface will
> have multiple ip addresses (probably at least one v4 address and probably at
> least two v6 addresses). This doesn't seem obviously representable in this
> schema.  Even if the interface was changed to return multiple Network
> property objects, it isn't clear whether it will return interfaces that are
> down. For example, would it return a TYPE_IEEE802_11 object if the Wifi was
> not currently associated to an access point (or a member of an adhoc
> network)? I suggest that having a way to enumerate the down interfaces will
> be useful. Further, there are logical interfaces such as VPNs or general
> tunnels as might be used in an I-WLAN implementation. It is not clear how to
> represent these. I also note that an application cannot tell what interface
> will be used for any particular network operation as it does not have access
> to the routing table. A use case might be to delay downloading large images
> while connected over GSM (and only show thumbnails) but show the full images
> if connected over 802_11. The problem is that the app cannot tell whether
> the connection to a particular data source will use GSM or 802_11. For
> example, if the 802_11 interface is associated to a public access point,
> there probably needs to be some sort of captive portal remediation before
> connectivity is established to the Internet. If the user chooses not to pay,
> then the connection will remain up at layer 2, but not able to communicate
> with the Internet.
> Thanks for reading this far...
> Philip
> --
> Philip Gladstone
> Distinguished Engineer
> Product Development
> pgladstone@cisco.com
> Phone: +1 978-ZEN-TOAD (+1 978 936 8623)
> Google: +1 978 800 1010
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> Blog: http://wwwin-blogs.cisco.com/pgladsto/
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Received on Wednesday, 15 December 2010 22:36:33 UTC

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