Coffee & Gems

Lately, I had a lot of conversations about multi-tenancy (MT). So I finally wrote up my thoughts on that term. In this post I will argue that MT is a value that depends on a continuous variable. Therefore, any statement about a system being “MT” can only be made in the context of the given requirements. It is not a property of the system itself . I will also show that perfect multi-tenancy is indistinguishable from single-tenancy (ST). MT is a value that depends on a continuous variable Imagine a step-function "ST-MT" (values are either 0 or 1) that determines if a given system is MT (1) or ST (0). That function will look like this: ST-MT = function (system, business requirements) Look at  the function’s arguments: the first one is obvious – the result will depend on the system itself. The second one is more interesting: it is the cumulative set of business requirements . Typically, these requirements will include: Resource sharing: systems typically declare

At this week's IKS meeting at Paderborn the second FISE Hackathon took place. FISE is an open source semantic engine that provides semantic annotation algorithms like semantic lifting. The actual annotation algorithms are pluggable through OSGi. Existing CMSs can integrate the engine through an HTTP interface (inspired from Solr ). Last week, Bertrand gave an introductory talk about FISE that is available online . There was no explicitly set goal for the second Hackathon. Rather, the existing code base was extended in various different directions. Some examples: a language detection enhancement engine (I am particularly glad to see this - automatic language detection in CMSs is a pet passion of mine) a UI for FISE users that allows humans to resolve ambiguities myself, I coded a JCR-based storage engine for the content and annotations There was also a good amount of work done on the annotation structure used by FISE and documented on the IKS wiki . A complete report of the Hack

Three days ago I had to chance to talk about NoSQL at the Internet Briefing's Developer Summit . On top of general ideas and concepts like the CAP theorem I chose to talk about Apache Jackrabbit , CouchDB and Cassandra . My slides are embedded below. It was a really good event with interesting speakers and a knowledgeable audience. I was especially pleased that when I talked about CouchDB's HTTP API someone from the audience mentioned that Apache Sling does something very similar for Jackrabbit. Special kudos to Christian Stocker of Liip for daring to do a live demo of the "real-time web" - he took a picture from his phone and had it pop up on Jabber and Twitter in about 5 secs. Vlad Trifa has posted a good summary of the whole event ( part 1 , part 2 ) - he also gave a great presentation about the application of the REST architectural style to the "Web of Things". No Sql View more presentations from mmarth .

CMS analyst Janus Boye has just published a post on CMS vendors that discontinue their products (because they get bought out or similar) During the past 10 years, a number of software products used by online professionals have been discontinued That sentence reminded me that I had given a talk almost 10 years ago (it was in 2001 exactly) that contained a slide on the CMS market at that time: The circles denote vendors that were part of CMS market overview articles by popular German IT magazines in that year (I wanted to show how differently the market place could be perceived). A vendor placed in any of the circles had enough attention to be part of at least one evaluation. The vendors outside of the circles were not part of any of these overview articles, but somehow present in the market place - at least I knew their names back then. It is interesting to look at the landscape from that time. Of course there are a number of well-known vendors that got bought (Vignette, Obtree, Gauss

On the mp3 tagger post I have received quite a bit of feedback and feature requests. Therefore, I thought it might be a good idea to do "social coding" and put the code on GitHub where it can easily be forked (and the forks can be watched). Other than that, the latest version of the tagger contains these improvements: the Last.fm keys and secret are not stored in the code anymore, but entered on the first run and stored in ~/.mp3tagger.cfg you can run the script in two additional modes: simulation and ask. In simulation mode no changes to mp3s will be saved, in ask mode you will be asked to save each change. Start the script with flags "-m simulation" or "-m ask", respectively. It is now possible to specify a list of genre tags that will be considered (additionally to the mp3 default genre tags). The list needs to be stored in a config file at ~/.mp3tagger_genres.cfg (in the "generic" section of the file). The full format this file needs to hav

Due to public demand here's a little recipe how to run last post's mp3 tagger without using the command line on OS X: Open Automator Start a new "Application" project Drag the "Run Shell Script" action into the right workflow panel, set the "pass input" drop-down to "as arguments" and edit the script to (see screenshot below): for f in "$@" do /opt/local/bin/python /Users/michaelmarth/Development/Code/mp3tagger/tag_groupings.py -d "$f" done (you will have to adapt the paths to your local setup) Save the application and happily start dropping mp3 folders onto the application's icon.