DOS stands for Disk Operating System. It is used to manage secondary storage devices like hard disks and floppy disks by organizing files in a hierarchical directory structure and allocating system resources. Some examples of early DOS systems include DOS/360 for IBM mainframes and DOS for DEC PDP-11 minicomputers. The most well-known DOS was MS-DOS, developed by Microsoft for the IBM PC. DOS allows naming files with a primary eight-character name and secondary three-character extension separated by a period. It provides commands to manage files and directories, hardware devices, and system resources.

1. Submitted by-
Hasnahana Chetia
M.Sc Ist semester,
Deptt. Of Biotechnology

2. What is DOS???
DOS stands for Disk operating system.
It is used for abstraction and management of
secondary storage devices of the computers and the
information stored there.

3. HISTORY
In early days of computers, there
were no disk drives; instead magnetic tapes,
punched cards etc. were used.
After creation of hard disks and
floppy disks, the need of a software for
managing rapid access to block storage of
sequential and other data became inevitable.
So, DOS was developed.

4. FUNCTIONS
To manage disk files.
To allocate system resources according to the
requirement.
To provide features essential to control hardware
devices such as Keyboard, Screen,
Disk Devices, Printers, Modems and programs.

5. EXAMPLES OF DISK OPERATING
SYSTEMS
DOS/360 for IBM system/360 family of Mainframe
computers.
DOS for DEC PDP-II Minicomputers.
The best known family of operating systems
named DOS was that running on IBM PC’s type
hardware using the INTEL CPU’s or alike. The original
was 86-DOS, which later became MS-DOS when
Microsoft bought the license and rights.

6. NAMING THE FILES IN DOS
DOS permits the user to assign a name
consisting of two parts to a filename - primary &
secondary names.
Primary can consist of 8 characters while
secondary can consist of 3 characters.
Both names are separated by a dot (.)
For eg; Bioedit.exe

7. DIRECTORY STRUCTURE IN DOS
DOS files are organized in a hierarchical
or inverted tree-like structure. The general analogy is
with a file cabinet having a no. of drawers, which in
turn may contain folders that may contain info.
The file cabinet in DOS is the ROOT
DIRECTORY, the drawer is INDIVIDUAL DIRECTORY,
the folders are SUB-DIRECTORY and the info
contained in these files may be termed as FILES.

8. COMMANDS IN DOS
1.cd-command used to switch directories.
2.dir-allows you to see the available files in the current and/or parent directories.
3.copy-allows the user to copy one or more files to an alternate location.
4.del- command used to delete files from the computer.
5.edit-allows a user to view, create, and/or modify their computer files.
6.move-Allows you to move files or directories from one folder to another, or
from one drive to another.
7.ren (rename)-Used to rename files and directories from the original name to a
new name.
8.deltree-Short for delete tree, deltree is a command used to delete files and
directories permanently from the computer.
9.cls-Cls is a command that allows a user to clear the complete contents of the
screen and leave only a prompt.
10.format-Format is used to erase all of the information off of a computer
diskette or fixed drive.

9. THANK
YOU