The IT journey across industries

Back in the days, in the absence of handy automation tool, I used to install 40+ servers all manually, following exact same sequence of steps 40 times. I did not neglect the existence of automation tools. At the get-go, I estimated the efforts between sorting out automation and just plowing through the install manually. The … Read moreThe IT journey across industries

Overview of vSphere

This post is a summary of VMware’s white paper Introduction to VMware vSphere. ESXi is the hypervisor (virtualization layer) on bare metal servers that abstracts processor, memory, storage and networking resources into multiple virtual machines. It was previously known as ESX and VMware discontinued ESX at version 4.1 so only ESXi is provided at and … Read moreOverview of vSphere

DICOM data encoding

DICOM is a standard for medical imaging exchanges, originally in radiology, but later expanded into other departments where mass imaging data are acquired, such as cardiology. One part of the DICOM standard defines how to lay out the data without providing any official code implementation. It is up to each vendor to implement their application … Read moreDICOM data encoding

Linux Admin Basics 3 of 3 – text processing, regex, sed & awk

Most of the text processing can be processed by awk and sed. Sed is non-interactive stream editor that allows you to specify all editing instructions in one place and execute them on a single pass through the file. Awk is a pattern-matching programming language. Using sed and awk requires some understanding of regular expressions. Here’s … Read moreLinux Admin Basics 3 of 3 – text processing, regex, sed & awk

cron and anacron in RedHat Linux (How logrotate works)

Cron and anacron We all know cron is a job scheduler. Many admin uses crontab to manage scheduled task. It is also important to know that crontab works at different levels as well, as well as the distinction between cron and anacron. They are similar, but different, managed by different sets of files. Below is … Read morecron and anacron in RedHat Linux (How logrotate works)

Basics of Linux OS

These are the things quite confusing or abstract while I was at school but now makes lots of sense after many years working with different flavours of OS. GPL and BSD as software license types The main difference is that BSD (Berkeley Software Distribution) is a permissive (non-protective) license, while GPL(GNU General Public License) is … Read moreBasics of Linux OS