Dev411 Blog

I recently had a discussion on taxonomies and ontologies for formal classification. These are often used to organize websites, databases, etc. ; however I havne't run into any real world applications where these are shared across multiple projects and software platforms using a develop once, use many approach. Looking around, I found a few open standards that are listed below, but I wonder if and how these are used in the wild. If anyone knows of successful, compelling implementations (of these or other) standards, please let me know.

• SKOS - Simple Knowledge Organization System: "a family of formal languages designed for representation of thesauri, classification schemes, taxonomies, subject-heading systems, or any other type of structured controlled vocabulary. SKOS is built upon RDF and RDFS, and its main objective is to enable easy publication of controlled structured vocabularies for the Semantic Web" according to Wikipedia. This standard has been developed for some time and seems to have some traction. There is some activity at the Library of Congress and Apache Forrest project. The W3C Glossary and Dictionary Project also put together a set of SKOS formatted glossaries.
• OWL - Web Ontology Language: according to Wikipedia, "a family of knowledge representation languages for authoring ontologies, and is endorsed by the World Wide Web Consortium.[1] This family of languages is based on two (largely, but not entirely, compatible) semantics: OWL DL and OWL Lite semantics are based on Description Logics,[2] which have attractive and well-understood computational properties, while OWL Full uses a novel semantic model intended to provide compatibility with RDF Schema. OWL ontologies are most commonly serialized using RDF/XML syntax. OWL is considered one of the fundamental technologies underpinning the Semantic Web, and has attracted both academic and commercial interest."
• TCS - Taxonomic Concept Transfer Schema: This is supported by the Drupal Taxonomy project.

Given the interest in the semantic web and semantic web standards, are we getting to a point where real life classification projects have started to use the XML standards, or are people still mostly using non-standard approaches (e.g. text files and spreadsheets) to manage this information?

A few years ago I had picked Xapian after evaluating a number of solutions. More recently, the popularity surge of Lucene had me curious to learn about it. I needed to do a rip and replace of MySQL fulltext search due to scaling issues so I decided to check out clucene. I quickly found out the API was not as up to date as Lucene (a fast moving target) and that the mailing list had only had 4 posts in the last year or so. That led to a conclusion to move away from clucene. After that, I was told to check out Solr as an easy way to use Lucene without needing to implement Java. I replaced MySQL with Xapian but still had Solr in the back of my mind to check out.

Recently, an email from Jonathan Drake, Senior Developer at YouSport.com, came across the xapian-discuss mailing list that said:

We were using Solr before but it was constantly causing headaches in terms of scalability and complexity. I gave Xapian a go and so far I'm blown away by how awesome it is. Its incredibly lightweight, its scaled a 100 times better and everyone involved is happier.

I'm curious to hear what scaling and complexity problems they faced, but it's good to hear a strong endorsement of Xapian from a former Solr developer. That, and a quick check of the current users page listing del.icio.us with over 100 million documents, seems to indicate that Xapian remains a strong contender in the search space. That being said, I work with very scalable Lucene-based solutions as well, just in Java projects.

Byrne Reese, the product manager behind MT 4.0, and Aaron Stone, both formerly of Six Apart, recently discussed their project, mod_perlite, with chromatic in the article CGI is Dead; mod_perlite is Alive! mod_perlite is designed to bring some of the ease of use of mod_php to Perl. For where this can help, think of WordPress and their Famous 5-Minute Install. Now imagine having the same thing for MovableType and other Perl apps. To catch up on mod_perlite, follow the article comments and the PerlMonks thread.

Continuing the thread of useful projects for Perl, I think it would be very beneficial to enhance Perl's relatively unstructured documentation system (POD) to bring it up to par with other languages today, e.g. Java and possibly others. Structured documentation should enable many benefits to speed development that I've long been a fan of including the following:

1. ability to generate standardized docs listing params, results, exceptions, etc. like Javadoc,
2. ability to auto-generate lists of files, classes and methods like rdoc, and
3. ability to auto-display required parameters like in Visual Studio 2008.

I recently used C# and Visual Studio 2008 for the first time and the auto-display of parameters in the IDE made development much more efficient with a new and unfamiliar language / API. It's something I'd like to see integrated into a Perl IDE, e.g. Eclipse/EPIC, Padre, ActiveState Komodo, etc.

A new documentation system like this for Perl may be easier to build off of Moose which could make it attractive as a Tim Toady Bicarbonate project. Some of the benefits of Javadoc and lessons from C# XML doc can be seen in this thread: C# documentation comments: useless?

Ideally, this effort could be headed up by a TPF or EPO working group consisting of multiple people and organizations including people with interest in documentation and IDEs, e.g. developers or product managers from the various Perl IDE products.

I was recently researching home NAS solutions. Synology and QNAP, both of which are based on Linux, came up as some of the leading contenders. HP's MediaSmart which is based on Windows Home Server (a derivative of Windows Server 2003 SP2) also seems popular. A post in this thread raised some interesting issues by claiming QNAP and Synology are the closed solutions while Windows Home Server is the open one. This is especially interesting given the GPL v2 licensing of Linux and how it is used in embedded solutions.

The main thing to consider when evaluating this choice is how much flexibility you require. NAS boxes such as the QNAP or ReadyNAS are, in fact, specialized servers, built on a proprietary embedded OS. Bug fixes and increased functionality are provided, occasionally, via firmware updates; additionally a limited number of "add-ons" (essentially, applications written for the particular box) are available to provide other capabilities.

By contrast, an open server platform such as WHS should be much more extensible over time. WHS is based on Microsoft's enterprise-class server products (presently Server 2003, but future versions are rumored to be based on Server 2008), so it in fact is built on an extremely reliable and stable core.

So, in practice, the question comes down to who is actually providing their source code.

• Microsoft WHS: For the foreseeable future, we can rest assured the source will not be available for WHS.
• QNAP: QNAP offers source code but a quick check of Wikipedia's QNAP TS-101 page shows that people have been porting SqueezeBox's GPL SqueezeServer (formerly SlimServer) software to QNAP. It would be interesting to find out why people are porting SlimServer.
• Synology: Access to Synology source code was very easy to find here on their GPL page, www.synology.com/enu/gpl/, and in fact, their source code is posted to SourceForge.net.

Considering that Synology and QNAP make their source code available and HP MediaSmart / WHS does not, it's clear that the former are more open than the latter. With HP MediaSmart and Windows, it's possible to end up with a solution where you can no longer upgrade your software as with my recent discovery that VB 6 is alive and well.