Isuru's Blog

Recently, I encrypted my disks using LUKS (The Linux Unified Key Setup) specification and installed Ubuntu 19.04 on encrypted partitions. In my experience, I think that LUKS is currently the best and stable way to encrypt your data on Ubuntu. Read my medium story on how I enabled LUKS full disk encryption on selected partitions with step by step instructions (including screenshots) .

I wanted to find out the processor details in my laptop and I found out that there are several ways to check. For example, see The RedHat community discussion on  Figuring out CPUs and Sockets . In this blog post, I'm listing few commands to find out details about CPUs. I'm using Ubuntu in my Lenovo ThinkPad T530 laptop and following commands should be working any Linux system. Display information about CPU architecture $ lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 4 On-line CPU(s) list: 0-3 Thread(s) per core: 2 Core(s) per socket: 2 Socket(s): 1 NUMA node(s): 1 Vendor ID: GenuineIntel CPU family: 6 Model: 58 Model name: Intel(R) Core(TM) i7-3520M CPU @ 2.90GHz Stepping: 9 CPU MHz: 1199.988 CPU max MHz: 3600.0000 CPU min MHz: 1200.0000 BogoMIPS: ...

I am learning about Linux Performance Tools and I found Brendan Gregg 's talks on Linux Performance  are very interesting. There are so many performance tools for Linux. Brendan recommends to follow a performance analysis methodology  to analyze system or application performance. These methodologies can guide us to choose and use these performance tools effectively. Linux Performance Observability Tools There are different types of command line tools available in Linux. In this blog post, I'm going to focus on Linux Performance Observability Tools . I highly recommend to watch Brendan's talk at Velocity 2015 on Linux Performance Tools and I took details about following tools from his presentation and his website. Linux Performance Observability Tools Taken from Brendan Gregg's Website:  http://www.brendangregg.com/Perf/linux_observability_tools.png Here are some examples of using Linux Performance Observability Tools in Ubuntu.  I tested each of th...

Few months ago, I wrote a blog post on Installing Oracle JDK 7 (Java Development Kit) on Ubuntu . It has several steps to install the JDK on Ubuntu. Every time when there is a new version, I upgrade the Java version in my laptop. Since I do few repetitive steps for every Java installation, I wrote a simple installation script for Java. The installation script is available at GitHub:  https://github.com/chrishantha/install-java You just have to run "install-java.sh" with root privileges once you download the JDK from Oracle. It also supports the installation of JDK Demos and "Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files" Please refer the install-java.sh README at GitHub.  The script supports JDK 7 and JDK 8. Please try the installation scripts and let me know any feedback! :)

In this year I started following the Master of Computer Science ( MCS ) at University of Colombo School of Computing and these days I'm following a module named "Advanced Concepts in Data Communication Networks" The lecturer asked us to install a program called NS-2 and to play around with it as we will get an assignment on it soon! As usual when I hear a new name, I just  googled for it and found the official website:  http://www.isi.edu/nsnam/ns/ What is NS-2? NS-2 is a Network Simulator. According to Wikipedia, NS-2  is a "discrete event network simulator" and the latest available version as of now is NS-3, which is available at  http://www.nsnam.org/ The difference between NS-2 and NS-3 The FAQ at www.nsnam.org clearly mentions the difference between NS-2 and NS-3. NS-3 is a new software development effort and uses C++ programs or python scripts to define simulations. However NS-2 uses OTcl for scripts.  So the most i...