Nokia Engineers on KHTML, Collaboration and aKademy

So, you have KDE on your desktop and laptop systems, you've heard that Apple uses KDE components for its web browser Safari and you've tried Konq/Embedded on your handheld. But did you know that KDE could soon be making its way into your mobile phone? At aKademy in August David Carson and Deepika Chauhan from Nokia presented the work they've done in integrating KDE components into the latest version of the company's mobile phone software. I recently caught up with them to ask about the technical side of their work, why they chose KDE components and their experiences of aKademy.

David and Deepika at their talk in Malaga

Can you describe briefly what you're working on within Nokia?

We are working on the Series 60 Browser application for the S60 platform. The Series 60 Platform is the software platform that runs Series 60 devices, which are also called smart phones. The Series 60 Platform consists of a user interface for interacting with the device's data and software, and programs (Series 60 applications) that provide advanced phone functions such as messaging, the calendar, browsing, etc. The Series 60 Platform runs on top of the open Symbian OS operating system. In addition to existing applications, users can also install additional applications.

What technical challenges do you face in that work?

Mobile devices are constrained by ROM, RAM, network latency and bandwidth, display, input mode, and less powerful CPU as compared to desktop world. We need to make some changes to take into account these constraints. The code execution behaviors which are correct in the desktop world do not always work well on mobile device.

To give an example, in browsers Javascript needs to be executed at the point that it is found in the markup, resulting in blocking the parser. External Javascript files take a much longer time to arrive at the client over GPRS. In the worst case scenario, the consecutive multiple external javascript references cause the requests to go out serially. Similar problems are encountered in CSS processing since rendering blocks on external CSS. We do not encounter these problems when the Javascript and CSS are inline.

What parts of KDE are you using to help you achieve your aims?

We are using WebCore and JavaScriptCore components from Apple's Safari Browser which are based on KHTML and KJS components respectively that were developed by the KDE community.

Why did you choose KDE over the competition?

We have been developing a proprietary browser for Series 60. We found that we have been focusing a lot of resources on dealing with issues like rendering and script execution - issues that have already been dealt with by open-source components. We decided that since browsing is a complex technology, we should not re-invent the wheel. We started investigating the available open-source solutions and decided to go with a KDE-based solution for primarily 3 reasons:

1. Series 60 devices are constrained by ROM/RAM. WebCore/KHTML and JavaScriptCore/KJS provide rendering engines that use very small RAM/ROM footprint. That was really a clincher for us.
2. WebCore/KHTML and JavaScriptCore/KJS provide a very clean architecture enabling easy ramp up of resources.
3. WebCore/KHTML and JavaScriptCore/KJS are very fast. The startup time and general performance of the browser is quite good.

How do you see the relationship between the KDE project and your team at Nokia developing?

We would like to find a model where we can collaborate with the KDE community focused towards browsing related solutions.

More generally, where do you think mobile technology is going in the near future, and what part will open source software like KDE play?

With the advent of faster networks and more capable mobile devices we expect to see a lot of development in the mobile software area. We hope that in the future the KDE community will be interested to look beyond desktop software and considers taking on projects in the mobile software space. We see Nokia's new open source browser as a good project to spark the open source community's interest in mobile software applications.

What was your experience of aKademy?

We had a great time at aKademy, and we got much more out of it than we ever anticipated. We came to aKademy since we wanted to thank the KDE community for the great components created by them that form the basis of the future Series 60 browser, meet some of the contributors in person, and share with the community our experiences of building a browser around WebCore/KHTML and JavascriptCore/KJS. The conference gave us a better understanding of the working model of KDE. We hope that we can work together with KDE on the mobile browser. We have observed a lot of excitement among developers in contributing to the mobile applications and we hope the community can bring their innovations to the mobile platform.

Many thanks to Deepika and David for taking the time to talk to me.