Definition of Disk Operating System (DOS)

A disk operating system (DOS) is a type of computer software that helps

manage files and data stored on a computer's disk drive. It is like the traffic cop
for a computer's hard drive, organizing and directing the flow of information.
DOS used to be the primary operating system used on older computers, but
nowadays it is mostly used for specific tasks or for troubleshooting older
systems.

MS-DOS Operating System

MS-DOS Operating System also called the Disk Operating system was
developed by Microsoft for x86 personal computers. It works on the
phenomenon of doing less and getting more. It is a 16-bit operating system. A
closed-source model was initially released on August 12, 1981, and the final
release on September 14, 2000.
Why is it used?

It is used for many purposes:

 Education and research: It is used in the Education and research field
to know how simple MS-DOS is and how it works. The source code is
available from Microsoft in two versions.
 Legacy systems: Some organizations prefer using MS-DOS because it
has been used reliably over decades whereas others don’t have the budget
to upgrade the application since this process is costly.
 Embedded systems: Embedded systems are dependent on MS-DOS
especially new devices with x86 processor architecture. It is also used on
legacy Embedded systems which have been used for decades.
 Classic Computer Games: There are still some games that were
developed on MS-DOS and still support only MS-DOS.

Features:

1. It is a minimalist OS which means it can boot a PC and run programs.

2. Still usable for simple tasks like word processing and playing games.
3. The mouse cannot be used to give inputs instead it uses basic system
commands to perform the task.
4. It is a 16-bit, free operating system.
5. It is a single-user operating system.
6. It is very lightweight due to fewer features available and no multitasking.

Working of MS-DOS:

MS-DOS input and output occur at the command line in the form of issued
commands and system results of those commands. When booted, MS-DOS
systems display a command prompt. MS-DOS commands are then entered
using a keyboard. Commands are either one of the standard DOS commands,
implemented as part of the OS, or they are the file name of an executable
program. Although it does not natively support a GUI, MS-DOS can run
graphical programs if they are installed on a system disk or diskette. Users
enter the command for a graphical program, and the program takes control of
the input and output devices. When the program terminates, the control reverts
to MS-DOS and the command prompt reappears.
 Limitations:

1. It is not a multitasking operating system that is we cannot run too many

applications in the background.
2. Files on the system can be easily deleted or the system can also be
easily destroyed.
3. It does not provide any warning message before you delete or perform
any unwanted task like in windows or Linux.
4. It is text-based and it does not have any graphical user interface.
5. Not secure to be used in any kind of public network.
6. Encryption is not supported.
7. Difficulty in memory access.
8. Mouse cannot be used to give inputs.

Types of MS-DOS Commands:

There are mainly two types of MS-DOS commands:

1. Internal Commands: Internal commands are those commands that are
loaded automatically in the memory when DOS is loaded into memory during
the booting process. These commands are easier to learn and use. They
require no external files for their storage as in the case of external
commands. These are for performing a basic operation on files and in
directories. They do not need any external file support. These commands
are used for common jobs such as copying and erasing files.
2. External Commands: These external commands are for performing
advanced tasks and they do not need some external file support as they are
not stored in COMMAND.com. The external commands are used less
frequently and are stored in some external files which are stored in some
secondary storage devices. Whenever an external command is to be
executed then the external file in which that particular command is stored is
transferred from the secondary storage disk to the main memory (RAM).

Example Of Ms-dos Internal Command Are:

1. CLS – It is a command that allows you to clear the complete contents of
the screen and leave only a prompt.
2. BREAK – Break can be used to enable or disable the braking capability
of the computer.
3. REN – It is used to rename files and directories from the original name
to a new name.
4. CHDIR – Chdir (change directory) is a command used to switch
directories in MS-DOS.
5. EXIT – The exit command is used to withdrawal from the currently
running application and the MS-DOS session.
6. RMDIR – Removes an empty directory in MS-DOS.
7. DEL- Del is a command used to delete files from the computer.
8. COPY – Allows you to copy one or more files to an alternate location.
9. VOL – Displays the volume of information about the designated drive.
10. TYPE- Display the contents of a text file.
11. DATE – The date command can be used to look at the current date of
the computer as well as change the date to an alternate date.
12. TIME – Allows the user to view and edit the computer’s time.
13. DIR – The dir command displays information about files and directories,
and how many spaces available.
14. SET – Allows you to change one variable or string to another.
15. MKDIR/MD – Allows you to create directories in MS-DOS.
16. PATH – Path is used to specify the location where MS-DOS looks when
using a command.
17. DISKCOMP- Comparing two diskettes.
18. DISKCOPY- Copying a diskette.
19. RD- Remove a directory.

Examples of External Commands are:-

1. DELTREE- Short for delete tree, deltree is a command used to delete
files and directories permanently from the computer.
2. TREE- Allows the user to view a listing of files and folders in an easy to
read the listing.
3. PRINT – The print command allows users to print a text file to a line
printer, in the background.
4. FIND – Allows you to search for text within a file.
5. XCOPY – Xcopy is a powerful version of the copy command with
additional features; has the capability of moving files, directories, and even
whole drives from one location to another.
6. DISK COMP- Compares the contents of a floppy disk in the source drive
to the contents of a floppy disk in the target drive.
7. FORMAT – Format is used to erase information off of a computer
diskette or fixed drive.
8. ATTRIB – Attrib allows a user to change the attributes of a file or files.
9. SORT- Sorts the input and displays the output to the screen.
10. CHKDSK- Chkdsk is a utility that checks the computer’s hard drive
status for any cross-linked or any additional errors with the hard drive.
11. FORMAT – Format a diskette.
12. PRINT – Printing a file.
13. MOVE- Allows you to move files or directories from one folder to
another, or from one drive to another.

MS-DOS file and filetypes:

A computer file created by an application running under the DOS operating

system. is called an MS-DOS file. There are three main files of DOS. During the
Booting process, the computer loads the operating system into its memory.
DOS booting involves reading the following files into memory namely
1. IO. SYS: A hidden executable binary file that processes instructions that
tell the operating system (OS) how the computer is set up when it is booted
or started. It contains the default MS-DOS device drivers (hardware
interfacing routines) and the DOS initialization program.
2. MSDOS. SYS: The MSDOS.SYS file is a hidden, system, read-only file
created on the root of the boot drive. There are several configurations that
can be changed using this file. Most values in the MSDOS.SYS are either 0
or 1, which is off or on.
3. COMMAND.COM: COMMAND.COM is the default command-line
interpreter for MS-DOS. It is the default user interface as
well.COMMAND.COM is the command shell on MS-DOS and PC-DOS, as
well as versions of Windows that depend on DOS. Gives users a command
line interface to DOS as well as a way to run scripts called “batch files” with
the .BAT file extension.

Different Versions of MS-DOS

1. MS-DOS 1. x
2. MS-DOS 2. x
3. MS-DOS 3. x
4. MS-DOS 4.x/4.0
5. MS-DOS 5. x
6. MS-DOS 6. x
7. MS-DOS 7/8

Advantages of using Disk Operating System(DOS)

We use disk operating systems (DOS) for several reasons, including −

 File management − DOS provides a command-line interface for managing files and
directories on a disk storage device. It allows users to copy, move, rename,
delete, and view files and directories.
 Program execution − DOS allows users to execute programs or applications
directly from the command line. This was an important feature in the early days of
computing when graphical user interfaces (GUIs) were not yet widely available.
 Troubleshooting and system maintenance − DOS can be used for
troubleshooting and repairing issues on older systems, as it provides a low-level
interface to the hardware and file system.
 Learning computing basics − Learning DOS commands is a good way to
understand the basics of computing, including file systems, operating systems, and
programming.

What is a batch file commands?

A batch file is a script file that stores commands to be executed in a serial order.
It helps automate routine tasks without requiring user input or intervention. Some
common applications of batch files include loading programs, running multiple
processes or performing repetitive actions in a sequence in the system.
 How to use command in bat file?
Steps
1. Press the Windows key on your keyboard.
2. Type cmd .
3. If your batch file doesn't need administrator rights, click Command Prompt.
4. If your batch file does require administrator rights: Right-click Command Prompt.
Select Run as administrator. Click Yes.

How to code batch files?

To create a Windows batch file, follow these steps:
1. Open a text file, such as a Notepad or WordPad document.
2. Add your commands, starting with @echo [off], followed by, each in a new line,
title [title of your batch script], echo [first line], and pause.
3. Save your file with the file extension BAT, for example, test.bat.

What is a batch file called?

BAT file extension is a Windows batch file. It's a plain text file that contains various
commands used for repetitive tasks or to run groups of scripts one after another.
Software of all types use BAT files for various purposes—for example, to copy or delete
files, run applications, and shut down processes.