An operating system is an integrated set of
programs that controls the resources (cpu, memory,
input/output devices etc. ) of a computer system and
provides its users with an interface.
3. The OS is the computers master control
program. The Os provides us with commands that
enables us to interact with the pc. When we issue
a command, the OS translate it into code that the
machine can use.
4. Some popular operating system are-
Unix, Ms-Dos, Microsoft Windows, Microsoft
Windows NT, Linux.
5. Functions of the operating
1. It displays the on-screen elements
which we interact.
2. It loads programs into the computers memory
so that we can use them.
3. It coordinates how programs work with the
computers hardware and other software.
4. OS manages the way how information is stored
on and retrieved from disk.
6. Types of operating system;
1. Real time operating system,
2. Single user Single tasking OS,
3. Single user MultitaskingOS,
4. Multi user Multitasking OS.
7. Real time operating system
A real time operating system is a very fast, relatively
It is needed to run real-time applications.
It may support multiple simultaneous tasks or it may
support only single tasking.
Real time applications are needed to run medical
diagnostics equipment, life-support system, scientific
instruments & industrial system.
8. Single user/single tasking operating
An operating system that allows a single user to perform
just one task at a time is a Single user-single tasking
To a user a task is a function such as printing a document
, writing a file to disk, editing a file or downloading a
file from a network server.
MS-DOS is an example of a single-tasking OS
9. Single user/multitasking Operating
A single user-multitasking operating system is one that
allows a single user to perform two or more functions
The most commonly used personal computers usually
run such Oss, including Microsoft Windows and
Macintosh operating system.
10. Multi user/ Multi tasking Operating
A multi user-multi tasking operating system is an
operating system that allows multiple users to use
programs that are simultaneously running on a single
network server called terminal server.
In a multi user-multi tasking operating system
environment all or most of the computing occurs at
Examples of multi user- multi tasking Oss include
11. User Interface
When we work on a computer we see and use a set of
items on the screen
Taken together, these items are called the user interface.
12. The two most common types of user interface are:
Graphical user interface and
Command line user interfaces.
13. Prepared by:
Md. Aziz ullah
Dept. of CSE
Manarat International University
Gulshan-2, Dhaka-1212, Bangladesh.