Conqueror

A low level Operating System designed using Linux Kernel

To develop the basic low level operating system, we need following

• Virtual Machine
• Clean Debian OS
• KDE Desktop Environment

You need to have basic knowledge on

• Programming in C
• x86_64 Assembly Programming
• Linux Basic Commands

After getting all this, lets start building the Operating System using Kernel

[$Checking and Creating Hard drive Partitions:~#]

• Open the Terminal
• Type lsblk command
• It will display sdb. Its actually a Hard Drive
• Change the user to root by typing the command sudo su
• Type cfdisk /dev/sdb
• It will open Hard drive partition table
• Click on [ New ] and hit enter
• Hit Enter again so that it will allocate default size
• Click on [ Primary ] and hit enter
• Click on [ Bootable ] and hit enter
• And then click on [ Write ] and type yes and hit enter
• Finally, click on [ Quit ] to exit
• Run lsblk command again, then we can see that new partition has been created
• This is how we can create a new Bootable hard drive partition to test our OS

[$Getting Things Ready for Operating System:~#]

• Type mkfs.ext4 /dev/sdb1
• Go to the folder /mnt by typing cd /mnt
• Create a New Folder by typing mkdir folder_name. That will be Name of your OS.
• Mount Your Folder using mount /dev/sdb1 folder_name
• Now, get into the OS by typing cd folder_name
• Remove all the things inside the folder by typing rm -rvf *
• Create following folders that will be used for OS Creation by typing the command given below
• mkdir -p ./{etc,lib,lib64,boot,bin,sbin,var,dev,proc,sys,run,tmp,src}
• After creating the folders, set mknod by typing following commands
• mknod -m 600 ./dev/console c 5 1
  mknod -m 666 ./dev/null c 1 3
• Go to boot folder by typing cd boot
• Now, let's copy the Kernel File and Initial Ram Disk from /boot folder
• cp /bootvmlinuz-4.19.0-10-amd64 .
  cp /boot/initrd.img-4.19.0-10.amd64
• Now, let's install some dependences using following command
• grub-install /dev/sdb --skip-fs-probe --boot-directory=/mnt/folder_name/boot
• It will install grub folder. Now, let's start coding part

[$Starting Coding Part for Operating System:~#]

• Make sure you are in grub directory created previously
• Create a new file grub.cfg using any editor. My suggestion is to go with VI
• The code is at [ grub.cfg ]. For Explanation, go to [ Documentation/grub/readme.md ]
• After that, Go to src folder created in folder_name or simple type cd ../../src
• Create folders [ lib ] and [ init ] using mkdir -p ./{lib,init}
• Go to lib folder and create [ start.S ]
• Get back to src folder and go to init folder and create [ init.c ]