[whatwg] RWD Heaven: if browsers reported device capabilities in a request header (Boris Zbarsky)

[Matthew Wilcox]

On 6 February 2012 19:24, Irakli Nadareishvili <irakli at gmail.com> wrote:
> Boris,
>
> if you don't mind me saying it, I am afraid you may be missing the point of this request. In Responsive Web Design, device capabilities are used in a high-level fashion to determine a class of the device: smartphone, tablet, desktop.

I'm afraid you have missed the point, not Boris. We do not care about
device classes at all, those are a temporary and limited idea. We care
about device capability. Right now we have to use screen-size as a
clunky proxy for processor speed, gpu acceleration capabilties,
bandwidth, latency, etc. The device class idea is no better than this
already demonstrably ridiculous and inaccurate assumption that screen
size correlates conclusivly with any of those values.

There is *nothing* that states that a small screen means a mobile
device. Or that a large screen means a desktop device. A phone today
is much more powerful than a 8yr old desktop. A tiny screen device can
be attached to a fast WIFI and a 27" iMac could be out in the sticks
on a rubbish ISDN connection. This situation does not chance when a
device reports some marketing-made-up "class" name. What's to stop a
"mobile" class device having a quad core CPU and 100Mbps WIFI and a
retina screen some 900px wide? What's to stop a "desktop" class device
being hooked up to a 800x600 projector in farm country with poor
connectivity? If you based your supplied assets on device class then
you'd be doing both those users the wrong way around.

Device class tells us *nothing* for certain. We are not interested in
some temporary and imagined "classing" system; what we want are the
device capabilities. Not assumptions of them based on other aspects
(like screen size or this class idea).

Such ideas do not hold up.