# Chapter DOS (DISK OPERATING SYSTEM)

### DOS (DISK OPERATING SYSTEM)

DOS is the most popular example of single user operating system. DOS stands for Disk Operating System. Disk operating system is a ready-made program which provide various computer handling facilities through its appropriate commands.

##### BOOTING

The loading procedure of operating system into computer’s main memory or RAM to make a user able to work on the computer, is called Booting Procedure.
Booting means to start up the computer so as tom make it able to understand the instruction provided by the user and it executes them step by step. Three files are needed for booting:

(i) IO.SYS
(ii) MSDOS.SYS
(iii) COMMAND.COM

These files are called system files. After booting when computer gets ready for user, its displays a special sign on the monitor which is called the DOS Prompt. For example:

C:\>- It is called C prompt. In case a computer has been started up using the hard disk.

A:\>-It is called A prompt. In case a computer has been started up using the floppy disk.

Imediately after the prompt a small blinking line (-) appears on the screen. It is called Cursor. DOS Commands are divided into two types:
(i) Internal commands
(ii) External commands

Here we learn about only internal commands. In next class we learn about external commands.

##### INTERNAL COMMANDS

The commands which are automatically loaded in main memory while loading the DOS is known as Internal commands. Some internal commands of DOS are given below:

1. DIR COMMAND : DIR command shows the list of all the files and sub-directory existing in the current directory.

SYNTAX
C:\> DIR <ENTER>

2. CLS COMMAND : CLS Command is used to clean or clear the content on the screen.

SYNTAX
C:\> CLS <ENTER>

3. COPY COMMAND : Copy Command is used to make a duplicate copy of the existing file.

SYNTAX
C:\> COPY <file name> <drive> <ENTER>

example- C:\> COPY Droid.Bas A: [This command copy the file Droid.Bas from C drive (C:) to A drive (A:)]

4. RENAME COMMAND : This command is used to change the name of a file but without changing the contents of that file.

SYNTAX
C:\> RENAME <source file> <target file> <enter>

example- C:\> RENAME Droid.Bas Era.Bas (This command will rename file Droid.Bas as Era.Bas)

5. DELETE COMMAND : This command is used to delete or erase the file from the disk.

SYNTAX
C:\> DELETE <file name> <ENTER>

example- C:\> DELETE Era.Bas (This command delete Era.Bas file)

6. PROMPT COMMAND : This command is used to change the format of prompt.

example- C:\> Prompt WELCOME <ENTER>

You can get back your original prompt by the following command:

SYNTAX
WELCOME> $P$ G <ENTER> ($P stores the path and$ G stores the greater than sign.)