Friday, March 20, 2009
Sunday, March 8, 2009
Common Object Request Broker Architecture
So I need to find out what are the reason for it.
- enables software components written in multiple computer languages and running on multiple computers to work together.
- CORBA uses an interface definition language (IDL) to specify the interfaces that objects will present to the outside world.
- CORBA then specifies a “mapping” from IDL to a specific implementation language like C++ or Java. Standard mappings exist for Ada, C, C++, Lisp, Ruby, Smalltalk, Java, COBOL, PL/I and Python.
Benefits :
- Language Independence
- OS Independence
- Freedom from Technologies
- Freedom From Data Transfer Details
Corba Location (CorbaLoc)
Corba Location (CorbaLoc) refers to a stringified object reference for a CORBA object that looks similar to a URL.
eg:
corbaloc::160.45.110.41:38693/StandardNS/NameServer-POA/_root
So this is the END.
Sunday, February 1, 2009
Web Crawler
RBSE [3] was the first published web crawler. It was based on two programs: the first program, "spider" maintains a queue in a relational database, and the second program "mite", is a modified www ASCII browser that downloads the pages from the Web.
Tuesday, November 11, 2008
Tuesday, October 28, 2008
How do I set my java classpath?
How do I set my java classpath?
Problem
Linux uses Red Hats java package instead of the Sun jdk.
Reason
The java interpreter from the standard Red Hat installation is placed in /usr/bin, which is in the path where Linux search for executables. This will be used be default if you don't specify otherwise.
To find the java classes, you also have to set the java classpath to point to the java kit you want to use.
Solution
Set your PATH and CLASSPATH environment variables to reflect which java kit you want to use.
In the ITU Linux machines in 2003, the following java kits are installed: jdk1.3.1 and j2sdk1.4.1. They are placed in /usr/java.
To use jdk1.3.1, add the following lines to the file ".bashrc" in your home directory:
export PATH=/usr/java/jdk1.3.1/bin:$PATH
export JAVA_HOME="/usr/java/jdk1.3.1"
export CLASSPATH=.:/usr/java/jdk1.3.1
If you want to use the j2sdk1.4.1, replace jdk1.3.1 with j2sdk1.4.1 and it should work.
netstat
netstat
Displays generic net statistics of the host you are currently connected to.
netstat -an
Shows all connections to the server including the source and destination ips and ports if you have proper permissions.
netstat -rn
Displays routing table for all ips bound to the server.
netstat -an |grep :80 |wc -l
Display the amount of active connections on port 80. Removing the pipe and wc command would display each connection.
netstat -natp
Display active Internet connections. See document CH001079 for an example of output.