Pimp my Nepomuk

Being both a really old KDE user and a semantic desktop partisan at the same time, I am, of course, keeping my eye on the progress in Nepomuk project.  It was apparently close to my old dream of a tagging framework supported natively and consistently across the whole desktop environment, so I highly appreciated this effort and it was nice to hear that Nepomuk would be officially included into KDE – my desktop of choice for many years.

Unfortunately, the experience was rather disappointing. It’s turned out to be painfully slow, not only slow by itself, but being a brake for overall desktop navigation. Even hovering the cursor over files and folders in Dolphin made Nepomuk process to eat above 50% of CPU time and caused annoying delays. The simple operations like assigning a tag to a file took seconds, the responsiveness which is obviously inappropriate for a real-world desktop system. It thus was turned off in a hope that the things would be improved in future versions (I was confused a bit by how it might appear in the production release, but, frankly, early KDE 4 was full of much more disastrous things). Since then, I checked it after every KDE version upgrade, but there was no visible progress in performance, alas.

It was really good news – the author of the post above argues that the performance issues are in fact, caused by a storage backend which Soprano, an RDF framework underlying to Nepomuk, uses to keep RDF data. By default, it’s shipped with Redland (aka librdf), an RDF database library written in C. Luckily, the backend is easily replaceable and it’s worth to try to install a faster alternative seeking for a better performance. The author recommends Sesame2 – a 100% pure Java RDF framework which works (surprisingly for many, I think – but not for me!) much faster than it’s native code counterpart.

I tested Nepomuk with Sesame and convinced that now it works really faster – as it should, in fact. There is of course, a room for improvements in Nepomuk to be a real end-user tool – e.g. a tag navigation interface without which the tags are rather useless, but its another story. At least, the performance is not a blocker anymore, so Nepomuk now is enabled in my KDE all the time.

For Kubuntu users: How-to

I tested the Sesame2 backend for Nepomuk on Kubuntu 9.04 Jaunty Jackalope, KDE 4.3.0 and Sun JRE 6 (I have no idea if it works with GNU Java, but you can give it a try).

1. Install soprano-backend-sesame package (sudo apt-get install soprano-backend-sesame)
2. Make a symlink from $JAVA_HOME/jre/lib/i386/client/libjvm.so in the /usr/lib directory
3. Restart Nepomuk server

Check if Sesame2 backend is used now:

qdbus org.kde.NepomukStorage /nepomukstorage usedSopranoBackend

It should answer “sesame2“. If it still answers “redland“, something was wrong. You may need also to replace the value “redland” to “sesame2” in ~/.kde/share/config/nepomukserverrc file manually and restart Nepomuk again.

• Technorati now tracks over 37.3 Million blogs
• The blogosphere is doubling in size every 6 months
• It is now over 60 times bigger than it was 3 years ago
• On average, a new weblog is created every second of every day
• 19.4 million bloggers (55%) are still posting 3 months after their blogs are created
• Technorati tracks about 1.2 Million new blog posts each day, about 50,000 per hour
• English, while being the language of the majority of early bloggers, has fallen to less than a third of all blog posts in April 2006.
• Japanese and Chinese language blogging has grown significantly.
• Technorati now tracks more than 100 Million author-created tags and categories on blog posts.

45% of new bloggers give up during first 3 months after they started! Fortunately, the “Chronicles” is five months old, so it passed that critical point.

I was surprised to discover that English is not a primary language of the blogosphere and that its Japanese and Chinese parts are nearly so large as the English one.

• System Requirements
• Security
• Support
• Ease of Use
• Management
• Interoperability
• Flexibility
• Performance
• Built-in Applications
• Commerce

Just select the products of your interest and click “Compare”. You will get a matrix of comparing the selected alternatives to evaluate their strengths and weaks. You can also read the detailed description of each product, vote for them, see the best rated software and discuss it on the forum.

We at Rusmeco now are in development of requirements for a collaboration platform for SME’s and are looking for platform alternatives, so it makes a lot of help for us.

If you are developer of CMS which is still not listed there, do add your project ASAP!

[other Things That Just Work, Links]