What is DOS? You might have heard this word a lot of times, right? DOS is Disc Operation System. It is Microsoft's first operating system. The command line screen (black screen) that you see no of times from your Windows, that command line is basically an interface to work under DOS environment.
DOS was the most basic operating system. With no fancy interfaces, only a black screen and sometime blue screen you could see. All the instructions or commands are given to DOS through command prompt.
In above image you can clearly see the C prompt i.e. "C:\>". All the commands are given from such Command prompts be it C prompt C:\> or D prompt D:\> or may be E prompt E:\>. Please refer following images for few DOS commands.


