I really like developing with Rails but for some types of web applications Merb is a very good fit. The Merb framework is much smaller than Rails and you have a lot of choices for ORM, template engines, etc. My DevX Merb article was just published this evening and provides a simple example: rewriting my RubyPlanet.net Ruby news filtering web application. I find Merb to be complementary to Rails so if you like developing with Rails I think that you will like Merb also.

I live in a remote area (2 1/2 hours from the nearest large airport) so I am always on the lookout for great online conference videos to watch - avoid travel and expense when possible. So far, my favorite online video from the European Web2Expo is the conversation with Yossi Vardi who was the founder of ITC and as O'Reilly says is "the godfather of Israeli venture capitalists." Vardi's business model seems to be choose people who he likes and have a passion for something, and invest in them, treating them fairly. I liked his comment that "business plans are a sub-genera of science fiction", meaning that although you need a long term goal and basic business ideas, you need to be adaptive in how you reach your goals. O'Reilly and Vardi also had good thoughts on the cultural stigma of failure and how that can affect entrepreneurship. A question from the audience addressed when a web 2.0 company might want to transition from free to paid-for use. Their advi...

Why would I care? If you read my blog you know that I mostly enjoy developing in Ruby, Lisp, and Java. That said, I tend to get small consulting jobs using a wide range of programming languages and this is one thing that I like so much about OS X: good support for Python, Perl, PHP, Prolog, and yes, now C# . So we all have our favorite programming languages but computer science is mostly about algorithms, understanding operating systems, infrastructure software, etc.

As I mentioned in my last post, I am making the rewrite of my Java-based RubyPlanet.net web site in Ruby and Merb the subject of a DevX article. I just pushed the code to my server that I use for Ruby and Common Lisp web deployments. By default the site shows recent Ruby news but the more interesting way to use it is to filter the results (for example just show web blog entries containing "JRuby", etc.) An interesting thing was that both the Java + JSP (which I did about 3 years ago) and the Ruby + Merb versions took about the same amount of time to implement and deploy (about 3 to 4 hours).

I am re-writing a quick one or two evening hack from 3 years ago ( RubyPlanet.net ) in Ruby + Merb. I originally wrote this web site in Java - humorous since it is a Ruby blog feed aggregator :-) I am also using this as the example program for a DevX article on Merb that I am working on. I just did a very quick first cut at the example program for the article (i.e., what soon will be the new RubyPlanet.net) and without doing any caching and hitting a database a lot, I was surprised to see that ab -n 5 http://localhost:4000/ showed 44 page requests per second. My goal is to get 100 to 200 page requests handled per second (depending on the number of blog entries on the main page) using a single process on my MacBook, and that looks like it may be easy. Deployed on a very low cost VPS with a bunch of other applications, this web app may not be all that fast "out in the field" but I want that to be a limitation of the server, not the code.

I am back home after attending MerbCamp in San Diego last weekend. Merb is sort of like a micro-kernel architecture version of Rails: a small core with many plugins (and also complete "slice" mini-apps) that (hopefully) do not depend on each other. The idea is that you only add in what you need. Right now is probably not the time to try Merb for the first time: the developers are working right now to release version 1.0 RC1 (with version 1.0 to follow as quickly as possible). I am currently using Merb 0.9.9 and I am not going to update until I can do a "gem update merb" to move up to the 1.0 APIs. As announced at MerbCamp, the developers want to stabilize the APIs for version 1.0 and then continually work with minor 1.x releases for about one year, then release 2.0 that is likely to not be very backwards compatible with 1.0. Also, 1.x releases will be backwards compatible with 1.0 but not necessarily other 1.y releases. I think that this is a good plan, and matches ...

I am at MerbCamp - so far an enjoyable conference. Merb is a more modular and more efficient version of Rails. As you might expect, Merb does not yet have the easy 'out of the box' experience that Rails provides. That said, I will probably start to use Merb instead of Rails on some new projects because of performance (run time and much less memory required) reasons.

A long time ago, my first useful experiments with using RDF were based on (after trying other tools) using Swi-Prolog 's semantic web libraries. Since then, I have also been using other tools (mostly Sesame, some Jena, and some Franz's commercial AllegroGraph product - which I am planning on writing a short 'applications' book on, BTW, after I finish my Java AI book). I noticed (see linked PDF paper) this morning that the RDFizing and Interlinking the EuroStat Data Set Effort (riese) architecture (diagram) uses Swi-Prolog on the back end. Very cool. The riese web site itself is interesting: human readable web pages with embedded RDFa for semantic web software agents. (Make sure you view page source on your browser.)

While I like using Rails for many types of web applications I still look to the Java platform for applications requiring higher run time efficiency and to take advantage of deployment tools and environments. The problem I am having is that I would very much like to settle on a single framework in order to reduce the effort of staying on top of too many tools and frameworks. In the past I have used JSP, my own custom JSP tag libraries, other people's JSP tag libraries, struts, various ORMs, some work with GWT, some work with Spring, and some with Wicket. I used to use the full J2EE stack, but largely gave that up about 5 years ago. I would like to be able to invest at most 100 hours of study time, and get back up to speed on a single framework, but I am not sure which to choose. GWT is very tempting but GWT does not cover all of the types of web applications and services that I am likely to be contracted to build. Seam looks good as an integrated framework, but I need to set aside a...

About a year ago a customer asked me to do a quick demo avatar for their Rails-based web site. We decided to use a trial license of OddCast.com 's avatar toolkit. The demo was a lot of fun and very simple to implement (a few hours) but my customer decided to not buy the service. Anyway, I just received an OddCast newsletter that contained this link - make sure that you try uploading a picture of a face to animate; also move the mouse cursor around: OddCast avatars act like the old "X eyes" program, looking at the cursor. I used to do development work for both Disney and Nintendo, and the lesson I took away was to make things fun - entertainment is an end to itself. While browser based entertainment has a hard time right now competing with rich clients like World of Warcraft, browser entertainment experiences will keep getting better with JIT compiled Javascript, FLEX, Silverlight, etc.