Technology

Grub is boot loader used to handle loading of multiple OS on machine.  Grub get installed to MBR of boot device which bios detects having MBR.  Grub will present a menu to choose OS to boot.  Once grub gets installed to MBR making changes to grub.conf file does not need reinstall of grub to MBR.  Here is nice video on Linux Boot Process . Once OS selected if its windows then Grub will give control to windows OS loader. If its Linux then Grub loads kernel and initrd.  kernel vmlinux is small in size and its meant to start init but it does not have all modules and neither has file system setup yet.  initrd is ram file system and has modules which are then inserted into kernel.  Now kernel itself can talk to disk and load actual file system and so as it does that.  Now it unloads initrd.  grub will call head.S which sets up the stack and head.S will call decompress_kernel and then call startup_32.  it calls then start_kernel (process 0) in main.c which will then call kernel_thread

Pathogen is one of many plugin management plugin for vim.  you can setup vim as below: mkdir -p ~/.vim/autoload ~/.vim/bundle && \ curl -LSso ~/.vim/autoload/pathogen.vim https://tpo.pe/pathogen.vim Now to enable vim to use pathogen add to .vimrc: execute pathogen#infect() Now we can install plugins by just extracting pathogen based plugins to ~/.vim/bundle To install jedi-vim plugin do below: git clone --recursive https://github.com/davidhalter/jedi-vim.git ~/.vim/bundle/jedi-vim Now open python file and place cursor under keyword like "len" and SHIFT + K will open the help window.  You can also type the module . and then it will open auto complete drop down and as you use some function of it shows help.  

On Premises Software applications developers/companies used to buy hardware, OS, virtualization software (to run more OS on same hardware).  Also they would buy storage servers and networking hardware.  Then they will deploy the application managing the security, os patching, monitoring.  Here they manage on premise data center. Off Premises Now part of above tasks can be availed in various off the shelf manner called iaas, paas, saas. 1. iaas will provide virtualization ready systems.  Developer will need to install the guest OS, setup networking/security (network and storage is provided), install application servers middleware like tomcat and then install their application like web app.  They need to take care of defining load balancing (networking hardware for Load Balancer LB will be provided).  EC2 provides an IP and you can choose what OS you want. 2. paas will provide more relief where in developer will not need to worry about LB and application clustering.  The middlw

When editing html files we at times want to tidy things up. vim as such might have out of box indentation for files identified by extension like java, c. Below can help in case indentation is not setup for html. add line to .vimrc: filetype indent on Now edit file and see if html tags start to indent well as you type. if above does not work still then try adding below lines also: set smartindent If it still does not work in edit window of html file from command mode :set filetype=html Now to indent when you do from vim normal mode  gg=G  it will indent file. For javascript in style tag need to install jsbeautifier plugin (python). pip install jsbeautifier if it fails then from pypi download tar.gz and run python setup.py install https://pypi.python.org/pypi/jsbeautifier It should install without error then test from vim. Open file which has script tag and highlight it and get into command mode.  The command line already has some character.  To end of it t