Shahzad Bhatti Welcome to my ramblings and rants!

July 23, 2009

Day 2 at #oscon 2009

Filed under: Computing — admin @ 2:34 pm

On the second day of OSCon 2009, I started with PhoneGap tutorial. The PhoneGap is an ambitious project that provides Javascript based unified APIs to develop mobile applications for a variety of mobile platforms such as iPhone, Blackberry, Android, Windows Mobile, Nokia, Palm, etc (most of those are not yet support, but 1.0 is expected in a few months that will have support most of them). It competes with a number of other open source projects such as Joyent Smart platform, Big five, Corona, Nimblekit, Appcellerator, Rhodes, etc. The PhoneGap uses HTML, CSS and Javascript for development and relies on Webkit and HTML5 technologies and standards. Many of mobile platforms such as iphone, android, palmpre support Webkit, though Blackberry and Windows Mobile are exceptions. The PhoneGap uses a number of features of HTML5 such as caching, CSS transformation, fonts, local storage, etc. The PhoneGap uses XUI, which is a subset of jQuery as some of the platforms such as iPhone provide limited caching (25K) for Javascript. It uses selectors and CSS for animations. The session introduced Dashcode tool that comes with XCode to build web applications and then converting those web applications into native applications using PhoneGap. The presenation for this session is available from

For the second half I decided to attend “Scalable Internet Architectures” — more than 10 million consumers/day. It was interesting talk that discussed building scalable architectures from hardware and networking perspective. It empahsized awareness on end-to-end architecture including javascript, application, database, network and machines and stressed importance of including people from operations in the architecture of the system. The presenter suggested use of CDN for static contents and using peer-based HA instead of load balancers as it eliminates load balancers as point of contention or failures. The speaker also suggested use of reverse proxy cache such as Varnish or Squid. He also suggested setting up multiple DNS servers for each data center and registering local servers with local DNS so that they take advantage of shortest path routes and talk to local servers. Other suggestions included use of caching, avoiding 302 redirects, separtion of OLTP and OLAP databases, use of DHT. The speaker also pointed to a number of networking techniques such isolating network for different services to prevent starvation of bandwidth when one of the service is surging the network with high dataload by using mac based filtering.
The speaker mentioned a number of usability techniques to offload expensive operation or hinting users when something is going on in the background. He mentioned use of queuing technology for offload processing. Finally, the speaker talked about a number of lesson learned from scaling and some of big WTF moments from his consulting work. Overall, this talk summarized a lot of existing knowledge for building scalable applications (such as from Steve Souders work) with a couple of new networking techniques to tackle slashdot or denial of service attack. The slides from this talk are available at

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