THIS IS A TOPIC OF COMPUTER BASICS FROM SCRATCH

What you will learn in OS and MS-DOS
Index for operating
System
Questions on OS and
MS-DOS

Index for operating System
 What is Operating System
 Functions
 Components
 Types
 MS-DOS
 MS-DOS architecture
 MS-DOS commands and utilities
 MS-DOS file System

What is Operating System
An operating system is an interface between computer user and computer
hardware.

An operating system is software which performs the entire basic task like
file
management, process management, memory management and controlling
peripheral device such as disk drive and printers.
“An operating system is a collection of software that manages
computer hardware resources and provide common service to
computer programs.

Examples of Operating System
 Some of the following are examples of
operating system
1. Windows
2. MacOS
3. Linux
4. Android
5. iOS

Windows
This is the most popular operating system of a graphical user
interface developed by Microsoft. Microsoft introduced the first
version as 1.0 on 10 November 1983. Later, it was released on
many versions ofWindows as well as the current version,
Windows 10.

MacOS
 Mac os is an operating system developed by Apple Inc. in 2001. It is built
on unix based architecture.

Linux
Linux is an open source unix-like operating system based on Linux kernel
or OS kernel, first published on 17 September 1991 by Linux Torvalds.

Android
Android is a mobile operating system based on a modified version of the
Linux kernel and other open-source software, designed primarily for
touchscreen mobile devices such as smartphones and tablets.

Android is developed by partnership of developers known as the open
handset alliance and commercially sponsored by Google. It was disclosed
in November 2007, with the first commercial android device, the HTC
Dreams, launched in September 2008.

iOS
iOS operating system was originally developed for use on Apple devices.
It is the second popular operating system for mobile devices, supports
iPhone, iPad, iPodtouch.

Functions of Operating System
 There are various functions of operating
system but most important are:-
 Memory Management
 Process Management
 File Management
 Security
 Error detecting aids

Memory Management
 In multiprogramming the OS devices the order in which processes are
granted access to memory, and for how long. It allocates the memory to
a process that has terminated or is performing an i/o operation.
Process Management
 A process is a program in execution. Process management involves
various tasks like creation scheduling, termination of processes, and a
deadlock.The os must allocate resources that enable processes to share
and exchange information.
File Management
 A file system is organized into directories for efficient or easy navigation
and usage.These directories may contain other directories and other
files. It keeps track of where information is stored, user access settings
and status of every file.
Security
 The operating system uses password protection to protect user data and
similar other techniques. It also prevents unauthorized access to
programs and user data.
Error detecting aids
 Operating system constantly monitors the system to detect errors and

Types of Operating System:
1. Batch Operating System
2. Time Sharing Operating
System
3. Distributed Operating
System
4. Real Time operating System
5. Network Operating System

Batch Operating System
This type of operating system does not interact
with the computer directly.There is an operator
which takes similar jobs having the same
requirements and groups them into batches. It
is the responsibility of the operator to sort jobs
with similar needs. Batch Operating System is
designed to manage and execute a large number
of jobs efficiently by processing them in groups.

THIS IS A TOPIC OF COMPUTER BASICS FROM SCRATCH

Time Sharing Operating System
Each task is given some time to execute so
that all the tasks work smoothly. Each user
gets the time of the CPU as they use a single
system.These systems are also known as
Multitasking Systems.The task can be from a
single user or different users also.The time
that each task gets to execute is called
quantum.After this time interval is over OS
switches over to the next task.

Distributed Operating System
These types of operating systems are a recent advancement in
the world of computer technology and are being widely
accepted all over the world and, that too, at a great pace.
Various autonomous interconnected computers communicate
with each other using a shared communication network.
Independent systems possess their own memory unit and CPU.
These are referred to as loosely coupled systems or distributed
systems.These systems’ processors differ in size and function.
The major benefit of working with these types of the operating
system is that it is always possible that one user can access the
files or software which are not actually present on his system
but some other system connected within this network i.e.,
remote access is enabled within the devices connected in that
network.

Real Time operating System
 These types of OS serve real-time
systems.The time interval required to
process and respond to inputs is very
small.This time interval is called
response time. Real-time systems
are used when there are time
requirements that are very strict like
missile systems, air traffic control systems,
robots, etc.

Network Operating System
These systems run on a server and provide the
capability to manage data, users, groups, security,
applications, and other networking functions.These
types of operating systems allow shared access to files,
printers, security, applications, and other networking
functions over a small private network. One more
important aspect of Network Operating Systems is
that all the users are well aware of the underlying
configuration, of all other users within the network,
their individual connections, etc. and that’s why these
computers are popularly known as tightly coupled
systems.

MS-DOS
 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.

Features of MS-DOS Operating System
 It is a minimalist OS which means it can boot a
computer and run programs.
 Still usable for simple tasks like word processing
and playing games.
 The mouse cannot be used to give inputs instead it
uses basic system commands to perform the task.
 It is a 16-bit, free operating system.
 It is a single-user operating system.
 It is very lightweight due to fewer features available
and no multitasking.

Limitations of MS DOS Operating System
 It is not a multitasking operating system that is we cannot
run too many applications in the background.
 Files on the system can be easily deleted or the system can
also be easily destroyed.
 It does not provide any warning message before you delete
or perform any unwanted task like in windows or Linux.
 It is text-based and it does not have any graphical user
interface.
 Not secure to be used in any kind of public network.
 Encryption is not supported.
 Difficulty in memory access.
 Mouse cannot be used to give inputs.

How to open MS-DOS in windows?
 Step 1: Click on Windows.
 Step 2: Search for ‘Run’ or directly use
(Windows key+R) to open.
 Step 3: Type ‘cmd’ in run and press
‘Enter’.
 Step 4: MS-DOS will open in many cases
with default command prompt i.e. c:>

MS-DOS Architecture
The architecture of MS-DOS (Microsoft
Disk Operating System) was designed to be
efficient, lightweight, and closely integrated
with the underlying hardware.At its core,
MS-DOS was a single-tasking, command-
line-driven operating system that provided
a direct interface between the user and the
computer's resources.
The key components of the MS-DOS
architecture included the following:

Kernel and Device Drivers:
The MS-DOS kernel was responsible for managing the system's memory,
handling interrupts, and providing low-level access to the computer's hardware.
This included device drivers for various components, such as the keyboard,
display, and storage devices, allowing MS-DOS to communicate with and
control these peripherals.
File System:
MS-DOS utilized a relatively simple file system, known as the File Allocation
Table (FAT), which allowed for the organization and management of files and
directories on the computer's storage media.The FAT file system provided a
hierarchical structure, enabling users to navigate and manipulate files and
folders through the command-line interface.
Command Interpreter:
The MS-DOS command interpreter, often referred to as the "shell," was the
primary user interface.This text-based environment allowed users to execute
commands, run programs, and manage the system's resources using a set of
built-in commands and external utilities.The command interpreter also
facilitated the loading and execution of application programs.
Hardware Abstraction
MS-DOS provided a layer of hardware abstraction, allowing applications to
interact with the computer's hardware components without the need for
direct, low-level programming.This abstraction enabled the development of
software that could run on a variety of hardware configurations, contributing to
the widespread adoption and flexibility of MS-DOS-based systems.

MS-DOS Commands and Utilities
MS-DOS, the Microsoft Disk Operating System,
was renowned for its powerful command-line
interface that allowed users to interact with the
computer and manage its resources through a
series of text-based commands and utilities.
These commands and tools provided users with
granular control over the system, enabling them
to perform a wide range of tasks, from file and
directory management to system configuration
and troubleshooting.

File Management Commands:
MS-DOS offered a suite of commands for managing files
and directories, including DIR (list directory contents),
COPY (copy files), DEL (delete files), and MKDIR/RMDIR
(create and remove directories).
System Navigation Commands:
Users could navigate the file system and change
directories using commands like CD (change directory)
and CHDIR (change directory).The PROMPT command
allowed them to customize the command prompt display.
Task Automation Commands:
MS-DOS provided the ability to automate tasks through
batch files, which were text files containing a sequence of
commands.The BATCH and ECHO commands were
used to create and execute these batch files.

Disk and Memory Management Commands:
Commands like FORMAT, DISK, and MEM allowed
users to manage disk partitions, format storage media,
and monitor system memory usage.
Network and Communication Commands:
While MS-DOS had limited networking capabilities,
commands like NET and IPCONFIG provided basic
network management and configuration options.
Utility Programs:
MS-DOS also included a range of utility programs,
such as EDIT (text editor), DEBUG (debugger), and
COMP (file comparator), which expanded the
operating system's functionality and enabled advanced
system management tasks.

MS-DOS File System
The MS-DOS (Microsoft Disk Operating
System) file system was a key component
of the overall architecture, responsible for
the organization and management of files
and directories on the computer's storage
media. MS-DOS utilized a relatively simple
file system known as the File Allocation
Table (FAT), which provided a hierarchical
structure for organizing data.

Types of MS-DOS Commands
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.
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).

Command Description Type
mem Display memory on the system. External
mkdir Command to create a new directory. Internal
mklink Creates a symbolic link. Internal
md Command to create a new directory. Internal

chdir Changes directories. Internal
chkdsk
Check the hard drive running FAT for
errors.
External
chkntfs
Check the hard drive running NTFS for
errors.
External
choice
Specify a listing of multiple options
within a batch file.
External
append
It Causes MS-DOS to look in other
directories when editing a file or
running a command.
External
arp
Displays, adds and removes arp
information from network devices.
External

Questions on OS and MS-DOS
1. Windows is the operating System of
which Company?
i.) Apple
ii.)Microsoft
iii.)Meta
iv.)Adobe

THIS IS A TOPIC OF COMPUTER BASICS FROM SCRATCH

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