DOS:
DOS stands for disk Operating System. It is a single user, single tasking, CUI and Command based Operating system. It was first design by Tim peterson that name was Q.DOS (Quick and Dirty Operating System). P.C DOS (Personal Computer Disk Operating System) was design by IBM Company. MS DOS (Microsoft Disk Operating System) was design by Microsoft Company in the year 1981 and started with the version 1.0. 8.0 is the latest version of DOS.

 How to open MS DOS:
  • Click on Start button
  • Click on Program
  • Click on Accessories
  • Click on Command Prompt
Basic Commands:
  • CLS: This Command is use to clear the screen
  • EXIT: This command is use to close the Command Prompt.
  • DATE: Date Command is use to display Current System date. (MM/DD/YY) or (MM-DD-YY)
  • TIME: This command is use to display current system time. (H:M:S.MS)
  • VER: This command is use to display current DOS version which is loaded in the system.
  • VOL: This command is use to display the volume of current drive.
FILE:
File is the container of data and instruction. In computer any data can be store in the form of file that data may be text, may be audio, may be graphic or may be video. In DOS a file has two parts one is primary name and second is extension name.
E.X:- ok.txt
ok - primary name           .txt-extension name

 FILE NAMING RULES/CONVERSION:
  1. In DOS a file name has two part one is Primary part and Second is extension part.
  2. DOT(.) is the media between primary name and extension name.
  3. Without extension name that file is not valid.
  4. According to DOS rule primary name length should not be more than 8 character and extension name length should not be more than 3 character.
  5. We can't use some symbol in our file name this symbols are >, <, /, \, ?, *, :, ", !
  6. We can't use some reserve word as our file name these are: prn (printer), con (conference), (COM1 (Communication Ports), COM2, LPT1 (Printer Port), LPT2, LPT3
DIRECTORY / FOLDER:
Directory is a container where we can store both file and Directoris. Generally Directory is use to find or locate particular file easily.

 HOW TO MAKE A NEW FILE:
In DOS we can make a new file by using two Command

 1) Copy con: It is one internal command by using copy con command we can make a new file. But file name must follow file naming rule.

 Syntax: copy con (file name)
             type something
             to save press F6 or ctrl+z
             to check the file type dir

 2) edit: Edit is one external command by which we can make new file as well as modifying the existing file. In DOS edit command is only one command where mouse is functioning.

 Syntax: edit (file name)
             type something
             click on file menu -> save -> file menu -> exit

HOW TO MODIFY AND EXISTING FILE:
we can modify an existing file in 2 different ways

 1) overwrite (>)
 In overwrite mode old content will be replace by new content.

 Syntax: type con > (file name)
             type something
              to save press F6 or ctrl+z

 2) append mode (>>)
 In append mode we can add new data at end of the existing file. As a result both old data and new data will be store in that file.

Syntax: type con >> (file name)
             type something
             to save press F6 or ctrl+z

HOW TO MAKE DIRECTORY IN DOS:


  1. to change the drive type d: press enter
  2. md songs
  3. cd songs
  4. md french
  5. cd french
  6. md audio
  7. md movie
  8. then go to songs type cd.. to go to the parent directory.
  9. type similarly like french