Linux History basics

Linux is a Operating System.
Linux is open source,freeware(conditions apply)

OS is a collection of  system programs.
Operating System is interface between user and  computer(hardware device)

Founder- Linus Torvalds (1991) when he was  21 years old.
Market share-
Server side - Linux
General      - windows(laptop,pc,general using )

Unix- is a flavor of all the server OS.
1.monolithic 2.modular
1.monolithic - it's won't change or con't remove
2.Modular - it can be add/remove/modify/ any thing we do.

Ex;-  cool drinks different flavor like Pepsi,coco cola,thumps up
in all cool drinks liquid is different but common is water(monolithic).

Unix flavors OS types

Linux
Solaris
Unix 
HP-UX
AIX
Ubuntu
zenix
Irix and many more

kernal-   core of the operating systems,all system drivers can't be change like system(config) file
same like kernal.

Windows                                                                                    

user                                                                                              
  /                                                                                                  
kernel                                                                                                                                                         /
hardware

Linux                                                                                  

User
  /
SHELL
  /
Kernal
   /
hardware                                                                                                    
                                                                                                     
OS Kernels -
Linux    - unliu
Solaris  -  unix
Hp-ux-   un unix

SHELL- command interpreter or interface between user and kernal.

Windows- Every 45days or 3 months once need to reboot the server or bouncing the server.

Linux-   No down time for linux it run for years.