Linear and non linear editing (Edited for resubmission)

Linear editing - Linear editing is a post production editing process.  This process includes selecting, arranging and modifying images and sound into an ordered sequence. 

Non linear editing - Non linear editing is an editing system using video and audio.  It is a digital audio workstation system.  The system performs non destructive editing on source material. 
  

In the beginning of electronic video production, linear editing (tape to tape) was the only way to edit video tapes.  As the industry progressed, in the 1990s, non linear editing computers became available to use.  This enabled flexibility while editing.  
In the 21st century non linear editing became very popular and gained huge acceptance in the industry.  Almost all editing was then digital.  People within this field of work are still encouraged to learn the method of linear editing as the knowledge behind it improves the technique of the editor.