1) Dos stands for DISK OPERATING SYSTEM.

2) It is the most popular operating system which was developed by Microsoft Corporation of USA in early 1981.

3) It provides a set of commands that enables you to access or manipulate information on your disks, as well as simply interacts with your computer.

MS-DOS is divided into three layers are:-

1) BIOS(Basic Input Output System)‏

2) Dos Kernel

3) The Command Processor (Shell)‏

This part of Dos is

supplied by the individual manufacturer of the

system. It contain a set of programs called

drivers that manage the following devices

attached to a computer system like screen,

printer, secondary storage devices, system

clock,

block device - a driver that is used for primary

bootstrap.

One part of BIOS is stored in a

read only memory(ROM).The remaining part of

BIOS is stored in a system file called IO.SYS file

resides on the boot disk.

It is a set of programs called system functions which provide the following services :

a) File Management.

b) Memory Management.

c) Character Device (INPUT/OUTPUT)‏

d) Access to real time clock.

e) Basic networking function

The shell or command processor is

an interface between the user and the dos. It is

contained processor is an interface between the

user & the dos. It contained in a file called

command.com

It provides a standard set of

commands that gives users access to file-

management, device management, configuration

& miscellaneous functions, such as maintaining

and verifying the time and miscellaneous

functions, such as maintaining and verifying the

time and date.

1) Internal commands

2) External commands

Internal commands are built into

the operating system as part of a file

called COMMAND.COM (or, on a 2000 or

XP machine CMD.EXE) . They are loaded

into memory whenever you switch on your

computer. When you type an internal

command, MS-DOS performs it

immediately.

• DIR

• TYPE

• COPY

• REN

• MD

• DEL

• CD

• RD

• DATE

• TIME

• VER

• VOL

• CLS

• PROMPT

• EXIT

• COPY CON

Files with extension COM or

EXE are external commands. Because

these commands are files, they are not

built into the operating system ( these are

the commands that alter between

versions of MS-DOS).

COPY

RESTORE

ATTRIB

LABEL

BACKUP

MODE

SORT

CHKDSK

SCANDISK

FIND

PRINT

DELTREE

XCOPY

REPLACE

DISKCOPY

SYS

FORMAT

DATE COMMAND –

This command is used to display the

current date on the screen. we can also set the

date by using this command.

Syntax :-

c:\> date

Example :-

c:\> date [ dd/mm/yy]

This command is used to see the

current time or used to set the time.

Syntax :-

c:\> Time

Example :-

c:\> Time [hh/mm/ss]

This command is used to clear the

screen.

Syntax :-

c:\> cls

Example :-

c:\> cls

This command is used to see all or

specified files on the specified drive.

Syntax :-

c:\>dir

or

c:\>dir[drive:][pathname]

or

c:\>dir[drive:][pathname][/p][/w]

Example -

c:\>dir d/p

/P - Display page wise listings of directory.

/W – Display widthwise listing of directory.

/B – Displays a bare filename listing without size,date &

time information.

/L – Displays files information in lowercase.

Type command :-

Display the contents of specified file.

Syntax :-

c:\>type <filename>

or

c:\>type[drive:]<filename>

Example -

c:\>type A: try.txt