M.Sc Ist semester,
Deptt. Of Biotechnology
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.
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.
To manage disk files.
To allocate system resources according to the
To provide features essential to control hardware
devices such as Keyboard, Screen,
Disk Devices, Printers, Modems and programs.
EXAMPLES OF DISK OPERATING
DOS/360 for IBM system/360 family of Mainframe
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.
NAMING THE FILES IN DOS
DOS permits the user to assign a name
consisting of two parts to a filename - primary &
Primary can consist of 8 characters while
secondary can consist of 3 characters.
Both names are separated by a dot (.)
For eg; Bioedit.exe
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.
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
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.