this presnted by Rizwan Federal Board IN PAKISTAN

1. Disk Operating System
PRESENTED
BY
RIZWAN AKRAM

2. What is Dos?
DOS stands for Disk Operating System.
DOS (Disk Operating System) was the first widely-installed
operating system for personal computers.
 DOS controls the computer’s hardware and provides
an environment for programs to run.
 This system program must always be present when
working with your computer.

3. Dos is a single user operating system. Single user
operating system is most popular in microcomputer
upto mid of 1990s.It is also called DOS because it is
store on a disk of a computer.

4. Major Task Of a DOS
The major tasks the DOS must carry out are:-
 To control input and output devices.
 To enable user to load and execute program.
 To maintain an orderly system of data on the disk.

5. DOS Files
DOS has three important or special files are :-
BAT (batch files)
COM (command files)
EXE (executable files)

6. DOS Commands
DOS consist of a series of a program designed to
control the computer resources.
DOS commands have three parts: File name,
parameters, switches.
Mostly these commands consist of regular English
word like words.
 For example ERASE,COPY,DEL,PRINT etc.

7. Types of DOS Commands
 There are two types of DOS commands.
DOS Internal Commands.
DOS External Commands.

8. DOS Internal Commands
DOS internal commands are stored in the
COMMAND.COM file.
DOS internal command are loaded automatically
into the memory (RAM) when you start your
systems.
These includes the simpler and common commands
that are needed on regular basis.
 Internal commands are the part of COMMAND.COM

9. Some DOS Internal Commands
 Some DOS internal command are:-
 CLS – CLS command is use for clear the screen.
 VER – Display the DOS version number.
 VOL –Displays the volume label and serial
 TYPE –Display the contents of a text.
 Exit –Exit the command processor
(COMMAND.COM Program).

10. DOS External Commands
 Second type of DOS Commands is External
command.
DOS External Command required less frequently.
 These are reside on disk.
 Loaded automatically into memory (RAM) only
when needed.

11. Some DOS External Commands
 Some DOS External Commands are:-
CHKDSK – Check the validity of disk and reports
the total space, number of files and
amount of free space.
COMP – Compare the content of two sets of
files.
COMMAND – Starts the command processor.
SYS –Creates a bootable drive.

12. THANK YOU