1. Unit – II
MS - DOS

2. Objective: To acquire the knowledge
about the Ms Dos O/S which is an
interface and to working with the O/S.
Ms Dos an operating system –
Introduction – operations – Internal
commands – Dir, Date, time, copy, Del
– Creating/Removing directories –
External commands –
format, label, disk
copy, backup, Restore.

3. Ms Dos an operating system
Ms-dos – disk operating system was first
released in august of 1981. Ms-dos is a
command line user interface where the key
borad is used to navigate instead of a mouse.
You actually have to type the commands at a
c: , instead of just clicking on a command.
There was a new release of dos every
year up until 1994, except for 1985. During
1993 and 1994 there was two releases of ms-
dos.

4. Introduction to the operating system
DOS, as with any operating system, controls
computer activity. It manages operations such as
data flow, display, data entry amongst other various
elements that make up a system.
The role of DOS is to interpret commands that the
user enters via the keyboard.
These commands allow the following tasks to be
executed:
file and folder management
disk upgrades
hardware configuration
memory optimisation
program execution

5. MEANING OF INTERNAL AND EXTERNAL
COMMANDS
There are two kinds of commands in MS-
DOS. The Internal command, which is a
command which is fixed into the
command.com file,
and the other one is external command,
which is not fixed into command.com and
accordingly requires a part of file to be used.

6. Internal Commands in DOS
DIR
Mkdir
RMDIR
DATE
TIME
Copy
CLS etc.,

7. INTERNAL COMMANDS
DIR
Displays directory of files and directories stored on disk.
Syntax
DIR [d:][path][filename] [/A:(attributes)] [/O:(order)]
[/B][/C][/CH][/L][/S][/P][/W]
Mkdir
Command to create a new directory. Creates a directory.
Syntax
MKDIR [drive:]path
MD [drive:]path
RMDIR
Removes an empty directory.Removes (deletes) a directory.
Syntax
RMDIR [drive:]path
RD [drive:]path

8. DATE
Displays and/or sets the system date.
Syntax
DATE mm-dd-yy
DEL (ERASE)
Deletes (erases) files from disk
syntax
DEL (ERASE) [d:][path]filename [/P]
TIME
Displays current time setting of system clock and provides a way for you
to reset the time.
Syntax
TIME hh:mm[:ss][.cc][A|P]
Copy:
Copies or appends files. Files can be copied with the same name or with
a new name.
Syntax:
COPY [/Y|-Y] [/A][/B] [d:][path]filename [/A][/B] [d:][path][filename] [/V]
or COPY [/Y|-Y] [/A][/B] [d:][path]filename+[d:][path]filename[...]
[d:][path][filename] [/V]

9. External Commands in DOS
DISKCOPY
FORMAT
LABEL
RESTORE
Backup
TREE
UNDELETE
FIND etc.,

10. External Commands
DISKCOPY
Makes an exact copy of a diskette.
Syntax
DISKCOPY [d:] [d:][/1][/V][/M]
FORMAT
Formats a disk to accept DOS files.
Syntax
FORMAT d:[/1][/4][/8][/F:(size)] [/N:(sectors)]
[/T:(tracks)][/B|/S][/C][/V:(label)] [/Q][/U][/V]
LABEL
Creates or changes or deletes a volume label for a disk.
Syntax
LABEL [d:][volume label]

11. RESTORE
Restores to standard disk storage format files previously
stored using the BACKUP command.
Syntax
RESTORE d: [d:][path]filename [/P][/S][/B:mm-dd-yy] [/A:mm-
dd-yy][/E:hh:mm:ss] [/L:hh:mm:ss] [/M][/N][/D]
Backup
Makes a backup copy of one or more files.
Syntax:
BACKUP [d:][path][filename] [d:][/S][/M][/A][/F:(size]
[/P][/D:date] [/T:time] [/L:[d:][path]filename]