[opendtv] Re: Apple dashes hopes of Flash on iPhone
- From: Kilroy Hughes <Kilroy.Hughes@xxxxxxxxxxxxx>
- To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
- Date: Wed, 21 Apr 2010 23:20:44 +0000
HTML is a markup language. It is Declarative. It asks the browser/user agent
to please place a picture here or fill a <DIV> with text there, or play a video
source using the new <VIDEO> tag in HTML5. The browser accomplishes those
author requests as best it can using whatever magic it chooses. If it crashes,
it's the browser's fault, or the virtual machine, OS, vitualization layer,
hardware abstraction layer, and hardware pile it runs on.
In practice, HTML depends on ECMAScript 98% of the time to create the web pages
we see. ECMAScript is a Procedural language, an interpreted one ("script
language"). That is what adds logic, data and string manipulation, event
handling, "behaviors", animation, etc. to HTML.
There's a state machine in between called the Document Object Model (DOM) that
links the two, and Cascading Style Sheets, which determine the scene rendered
from the DOM at any point in time. Languages like SMIL and SVG allow declaring
animation, etc. behaviors that modify styles and objects over time.
The APIs provided to ECMAScript, etc. only allow a limited reach outside the
DOM controlled by the browser. They can bake and eat cookies, but not rinse
your hard drive or open of sockets (other than to ask an HTTP stack to run a
protocol) to turn your machine into a spambot.
What is a whole nother kettle of fish is binary plugins like Flash, ActiveX,
Java, Silverlight/.Net, etc. that are compiled for a particular OS and/or
hardware, installed on the machine (not IN the browser), and have APIs that let
programs potentially reach all the way to your hardware registers and disk
sectors. If an author writes bad code, you may have a crashed or evil machine
on your hands, not just a web page that came out looking stupid.
In the case of declarative code, the browser and system are mostly in control
of performance, power drain, adaptation to the particular display and user
interface, stability, security.
When you run an application on a VM with powerful APIs, you hand those keys to
the app writer (unless you "sandbox" apps with lower trust by shutting off the
powerful APIs). The term is "Write once, destroy many". It is very hard to
write apps with low level APIs that don't have ugly results on some of the many
varied hardware and software environments they were never tested on but will be
run on. MHP and Blu-ray have demonstrated the cross platform mayhem that can
be accomplished with ten thousand APIs (methods). Flash kept the problem more
tractable by basically limiting to two platforms (Mac/PC) that were strongly
managed, constantly updated, etc. to contain the surprises.
You can look at the whole debate in terms of "who is going to control the
application APIs". It isn't a new one.
PS. It's a big deal that HTML5 makes video codecs the responsibility and cost
of the browser for the first time. If HTML5 browser makers threw in MPEG-2
decoders, it would cost them around a billion dollars for the first year of
free upgrades, so lots of people working on plan B. One theory, close to PC
market reality, is that a browser isn't a browser without Flash and its
decoders installed on the machine and linked to the browser as a plugin.
However, what sorta worked for PCs doesn't work so well for TVs and cell phones
and their progeny.
Kilroy Hughes
-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On
Behalf Of Bob England
Sent: Wednesday, April 21, 2010 10:20 AM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: Apple dashes hopes of Flash on iPhone
On Wed, Apr 21, 2010 at 9:49 AM, <dan.grimes@xxxxxxxx> wrote:
>
> dan.grimes wrote:"...will actually be programmed within the HTML5 language."
>
> Kon Wilms wrote: "HTML5 is not a language."
>
> Could you explain this a little further? I thought the "L" in "HTML" was for
> language, so I called it one.
From Wikepedia:
"HTML5 is being developed as the next major revision of HTML (HyperText Markup
Language), the core markup language of the World Wide Web."
(http://en.wikipedia.org/wiki/HTML5)
Or perhaps more officially, from html5.org:
"HTML5 is a new version of HTML and XHTML. The HTML5 draft specification
defines a single language that can be written in HTML and XML."
(http://html5.org/)
Or maybe even more officially, from W3C:
See the document "HTML5: A vocabulary and associated APIs for HTML and XHTML,
W3C Working Draft 4 March 2010" at http://www.w3.org/TR/html5/
It's probably safe to call it a language, regardless of what Kon may have meant.
Bob England
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