Amazon's Silk browser one-ups Opera's approach to the Web

The Kindle Fire tablet's browser uses intelligent caching and pre-rendering to speed page delivery -- and does away with HTTP on the client side

Although the Kindle Fire tablet consumed much of the focus at's launch event today in New York, the company also showed off a bit of radical software technology as well, namely the new browser for the Fire, called Silk.

Silk is different from most other browsers in that it can be configured to let Amazon's cloud service do much of the work assembling complex Web pages. The result is that users may experience much faster load times for Web pages, compared to other mobile devices, according to the company. Opera's mobile browser does the same thing to reduce bandwidth usage, sending just the final rendered Web page to the browser.

[ While InfoWorld's Galen Gruman says that the Kindle Fire can't hold a candle to the iPad, Robert X. Cringely says the Amazon Store is the real iPad killer. |Keep up on key mobile developments and insights via Twitter and with the and . ]

Amazon CEO Jeff Bezos noted that most modern Web pages are complex creations, with multiple photos, animations, and complex scripts and mark-up code. The CNN home page, for instance, is built by the browser from 53 static images, 39 dynamic images, three Flash files, 30 JavaScript files from seven different domains, 29 HTML files, and seven CSS files. ... The modern Web has become a complicated place. It is difficult -- challenging -- for mobile devices to display modern Web pages rapidly."

Silk's split-browser approach
To speed page rendering on the Kindle Fire, Silk uses a "split browser" approach, Bezos said. "It partially lives in EC2, and it partially lives on Kindle Fire." All the user's Web page requests will be sent through a service in the Amazon EC2 (Elastic Compute Cloud) for processing. The service acts as a caching service, as well as a staging area where the more complex bits of Web pages can be preprocessed before being redirected to the user's browser.

Silk is also fully functional as a stand-alone browser, said Jon Jenkins, director of platform analysis at, at a demonstration booth after the event. It supports HTML5, JavaScript, CSS, and associated next-generation Web standards. It also supports Flash. Amazon built the software from the ground up using the WebKit open-source browser engine. That standa-alone nature is essential to be able to handle interactive websites that use technologies such as AJAX and Flash, where the user has to interact with the Web page components individually, not just look at a rendered whole.

All the user's requests are directed to the EC2 service, which then fetches the pages from the source and optimizes the content for the platform. Complex parts of JavaScript may be preprocessed and images may be downsized to a more manageable size. Many common but rarely updated elements of a popular Web page are served directly from the EC2 cache, such as the logo. "EC2 knows that logo hasn't changed for months, so it doesn't wait until getting the HTML file back before pushing that logo back to you," Jenkins said.

The site's original content, as well as content personalized for each user, will be requested from the content provider.

The service uses content compression techniques, such as re-encoding video and images before sending them to a device. The service also keeps connections constantly open to popular websites, which reduces the time needed to negotiate connections on a one-to-one basis.

The browser will determine whether to download the mobile or the static version of any given website, based on the capabilities of the hardware, as well as the richness of the site itself. "It learns effectively as you're browsing to get the best possible version of the content to you," Jenkins said. This works particularly well on popular sites, where many of the common elements can be cached.

HTTP is replaced with SPDY
Amazon also sped operations by doing away with the HTTP protocol, which is normally used to convey Web pages from the server to the user. The HTTP protocol "is not the most efficient protocol of the modern Web," Jenkins said. "It doesn't multiplex content well -- it is hard to get a bidirectional flow of content." As an alternative, Silk uses a variant of the Google SPDY protocol. HTTP is still used between the content provider and EC2.

Amazon dismisses privacy fears
Of course, the fact that all the user's Web browsing is being directed through Amazon will raise the interest of privacy advocates, who might see the technology as invasive. Jenkins denied that Amazon would be doing any personal traffic analysis, though. "There is no personal information stored on the EC2 at all," Jenkins said. He also noted that it is possible for users to turn off the EC2 service altogether and use the browser in a standard way.

The company also spent a lot of time making sure that one user would not accidentally be served another user's content when checking popular sites such as Facebook. "Some of the earlier efforts that other companies made at this did result in that. So we thought very very carefully about that. That was just unacceptable as an outcome."

Amazon's approach to the tablet is an "interesting spin" in a cluttered market, one analyst said. "While the split browser architecture is not new, Opera having been a player for a couple of years, I find the overall strategy to be an interesting spin on the me-too Android software we have seen so far, and possibly a game changer," noted Al Hilwa, IDC analyst for applications development software. "In one fell swoop Amazon harnesses its commanding lead in cloud services, the content richness of a leading online retailer and its successful Kindle business strategy to deliver what might become one of the most effective antidotes to the mobile bandwidth crunch."

The Kindle Fire uses smartphone-oriented Android 2.3 "Gingerbread" OS with a heavily customized interface. Amazon had no immediate plans to port Silk for other platforms, Jenkins said.

Joab Jackson covers enterprise software and general technology breaking news for the IDG News Service. Follow Joab on Twitter at @Joab_Jackson. Joab's e-mail address is

Copyright © 2011 IDG Communications, Inc.

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