CONF@JMILUG The day started with setting-up of Linux Adda. While we were still setting it up, for around an hour everyone was sharing laughter with Kumar Vishwas - a poet of IIT fame. As soon as his humorous poems were over, crowd rushed to the stalls, one of which was Linux Adda. It takes only a glace for someone to get attracted to the Fedora DVDs and Fedora Badges spread over a white-cloth-covered table i.e.
I have been thinking about this question: Is NoSQL database an alternative for a search engine? I think I just found an answer here. Lets talk about some terms and definitions first. NoSQL - Not only SQL means that a NoSQL database differs from a RDBMS in some way. IR - Information Retieval is the science of searching documents, their metadata, and retrieval. Here we compare a NoSQL storage engine MongoDB, and Information Retrieval library Apache Lucene.
I couldn’t install pylucene simply by following command: yum install pylucene Nor did following work: easy_install pylucene Nor the following :-( pip-python install pylucene So. I had to build it myself. Here, I list those steps: Install JCC $ JCC_JDK=/usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64 pip-python install jcc Download pylucene pylucene wget -c http://apache.mirrors.pair.com//lucene/pylucene/pylucene-2.4.1-1-src.tar.gz tar zxf pylucene-2.4.1-1-src.tar.gz cd pylucene-2.4.1-1 Build and install http://lucene.apache.org/pylucene/documentation/install.html pushd jcc # edit setup.py to match your environment JCC_JDK=/usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64 python setup.py build` sudo python setup.py install popd # edit Makefile to match your environment I had to update the Makefile for Fedora 14: # Linux (Fedora 14, Python 2.7, OpenJDK 1.6, setuptools 0.6.14) PREFIX_PYTHON=/usr ANT=ant PYTHON=$(PREFIX_PYTHON)/bin/python JCC=$(PYTHON) -m jcc --shared NUM_FILES=2 Continue building make sudo make install make test # (look for failures) The last step make test gave some failures.
http://foss.in/ I was looking at content faces. They all had made it. Some laughing, some teasing, some pondering and recollecting the past - greeting each other with a hearty welcome «Hi!». And there some were observing tenderly the atmosphere which was animate instantly, as everyone from far off places finally arrived at FOSS.IN 2010 service apartment. Rahul had reached the airport earlier than us and we met him there. We - I, Shreyank, Siddhesh, Amit, Rahul, Neependra and Anand - were at the airport three hours ago.
I just configured feeds aggregator on JMILUG.ORG. Right now this link shows feeds aggregated from various sites related to FOSS or Development blogs. I noticed issues with Drupal ( version 6 ) that it doesn’t work well with ATOM feeds ( specially with blogger.com ). I am not clear if its a bug in Drupal itself, although RSS feeds work perfectly fine. Any pointers to fix this will be highly appreciated.
While building {OpenGrok from source I came across a common error. {OpenGrok also needs JFlex to be present on the classpath as mentioned in the README.TXT file. $ sudo yum install jflex $ hg clone ssh://anon@hg.opensolaris.org/hg/opengrok/trunk/ opengrok-dev $ cd opengrok-dev $ CLASSPATH=$CLASSPATH:/usr/share/java/JFlex.jar Compilation failed giving the following error. BUILD FAILED java.lang.NoClassDefFoundError: java_cup/runtime/lr_parser at JFlex.anttask.JFlexTask.execute(JFlexTask.java:71) at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288) at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106) at org.apache.tools.ant.Task.perform(Task.java:348) at org.apache.tools.ant.Target.execute(Target.java:357) I couldn’t locate the cause of this error and after struggling a lot, the solution was pretty simple.
I was surprized to find that following command reboots my Fedora 13 x86_64 system: cat /dev/watchdog Wait for around 30-50 seconds and Linux reboots! This happens even with a non-root user. Then I googled it I found this is a pretty interesting thread on the subject. Bottom line is It’s a watchdog device, it’s meant to reboot the machine if whatever task is poking the watchdog dies. So consider that in any installation if /dev/watchdog support is present in the default Linux kernel and the file has read permission to all users.
Debugging Everyone knows that debugging is twice as hard as writing a program in the first place. So if you're as clever as you can be when you write it, how will you ever debug it? - Brian Kernighan
Here is a simple looking C++ program, which has two classes A and B ( which derives from A ). A has a function fun() which B tries to overload as fun(int). Sounds simple and the program looks correct but it doesn’t compile. Have a look at http://codepad.org/NQ3JNuRr . Its hard to digest for it is an obvious code to compile in C++. The code listing is as below: #include<iostream> using namespace std; class A{ public: void fun(){cout<<"fun\n";} }; class B: public A{ void fun(int i){cout<<"funB\n";} }; int main() { B b; b.fun(); } This typical case has two work-arounds: One is using A::fun inside class B : http://codepad.org/RnCIBBuO Other is calling as b.A::fun() inside function main() It looked like to puzzle to me, but its clearly mentioned in section «13.2 - Declaration matching» from the C++ International Standard ( which can be found here http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1905.pdf ) and I quote: Two function declarations of the same name refer to the same function if they are in the same scope and have equivalent parameter declarations (13.1).
FAD - Fedora Activity Day I was excited to know what it would be like but I had no clue as it was one of my first such gathering in Fedora Community. Day 1 I reached there at 10:00am feeling that I would be just on time but to my surprise I was an hour late. I snapped into the room and took a seat quietly. What a beginning! Autotools workshop was in progress.