- From: Antoine Sanchez <ckkoshi@gmail.com>
- Date: Wed, 15 Dec 2010 23:35:40 +0100
- To: Philip Gladstone <pgladstone@cisco.com>
- Cc: public-device-apis@w3.org
Hello, 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. Thanks, /toni 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 > Ham radio: N1DQ > Blog: http://wwwin-blogs.cisco.com/pgladsto/ > > Cisco.com - http://www.cisco.com > > This email may contain confidential and privileged material for the sole use > of the intended recipient. Any review, use, distribution or disclosure by > others is strictly prohibited. If you are not the intended recipient (or > authorized to receive for the recipient), please contact the sender by reply > email and delete all copies of this message. > > For corporate legal information go to: > http://www.cisco.com/web/about/doing_business/legal/cri/index.html >
Received on Wednesday, 15 December 2010 22:36:33 UTC