UNIT: - 01
INTRODUCTION
TO OPERATING SYSTEM
01.01 Evaluation of
Operating Systems
01.02 Types of Operating
Systems
01.03 Different views of the
Operating Systems
Q. What is operating system?
·
An operating system is software (it is a type of software) that supports a computer’s functions, such as controlling
hardware and system applications. It also provides common services for computer
programs and acts as an intermediary between a user of a computer and the
computer hardware.
·
The operating system is essential component
of system software.
·
These are the four components in which a
computer system can be divided roughly :
1. The hardware
2. The operating system
3. The application programs, and
4. The users
·
An operating system works as a manager which
provides an environment within which other programs can do useful work.
·
The hardware functions such as the CPU (Central Processing
Unit), the memory, and the Input Output devices-provides the basic computing
resources.
·
Here,
are some examples of operating system: - UNIX-OS, MS-DOS (Micro-Soft Disk
Operating System), MS-Windows - 98/XP/Vista/8.1/10 (Versions of Windows OS),
Windows-NT/2000, OS/2 and Mac OS(IOS).
·
Purpose of an operating
system:-
1. Providing Execution Environment.
2. Proper utilization of resources.
3. Controlling programs.
Q. Objectives/goals of Operating System: -
i. The primary goal of some operating system is convenience for the
users in an efficient manner.
ii.
It allows hiding the details of the
hardware resources from the users.
iii.
It would act as an intermediary between
its hardware & users to making it
easier for the users who uses it and to access and use other resources.
iv.
It allows managing the resources of a
computer system.
v. Among users and programs, to provide
efficient and fair sharing of resources.
Q. Features of an operating system program: -
·
It acts as an interface between the software and the computer
hardware.
·
Due to the set of integrated specialized programs it used to
manage overall resources and operations of the computer.
Q. Functions of Operating System: -
· Process
management: -
a.
Control execution of applications.
b.
Create, execute and delete a process.
c.
Cancel or resume a process.
· Main-Memory
management: -
a.
Allocate memory.
b.
Keep track of free memory
c.
Keep track of memory usage.
·
File management: -
a.
Create and delete both files and
directories.
b.
Provide access to files.
c.
Keep backup of files.
d.
Secure files.
· System
management: -
a.
Open, close and write device drivers.
b.
Communicate, control and monitor the device
driver.
· Secondary
Storage management: -
a. Free-space
management
b. Storage
allocation
c. Disk
scheduling
· Protection
system: -
a.
Protects the resources of system.
b.
It provide basic protection to OS i.e. authentication,
read & write encryption.
·
Program execution and
I/O Operations: -
a.
It loads the content of the file into
memory.
· Communication
and error detection: -
a.
Deals with network devices for message
passing
b.
Also perform error detection.
01.01 Evaluation of Operating Systems: -
The evolution of
operating systems is dependent on the development of computer systems and there
uses, depend on users.
Some important
development: -
i.
In 1945 ENIAC Developed by Moore School of
Engineering, University of Pennsylvania.
ii.
In 1949 EDSAC and EDVAC were developed.
iii.
In !949 BINAC which was a successor to the ENIAC (also say
that advance version of ENIAC)
iv.
In 1951 UNIVAC developed by Remington
v.
In 1952 IBM 701 launch
into the computer industries.
vi.
Between
the years of 1954-1957 FORTRAN was
developed
vii.
In 1966 Minicomputers got cheaper, more
powerful, and really useful.
viii. Between
the years of 1967-1968 Mouse was
invented which made our work very easy.
ix. In 1969 The UNIX Time-Sharing System from Bell Telephone Laboratories which
was command based operating system also say that DOS.
x.
August 12, 1981 IBM introduces the IBM Personal
Computer commonly known as IBM PC.
xi.
In the year of 1983 Microsoft begins work on MS-Windows which we are using
now-a-days.(We use the upgrade version of windows)
xii.
In 1984 Apple Macintosh which is a family of personal computers designed,
manufactured and sold by Apple Inc. comes out.
xiii.
In 1990 Microsoft Windows 3.0
xiv.
In 1991 GNU/Linux
xv.
In 1993 Windows NT (which was 32-bit operating system that supports preemptive
multitasking.)
xvi.
In 2007 iOS is mobile operating system
created and developed by Apple Inc.
xvii.
In 2008 Android OS is
a mobile operating system based on a modified version of the Linux kernel and
other open source software
01.02 Types of Operating Systems: -
Operating
system is there form the very first computer generation. Operating systems keep
evolving over the period of time. Following are few of the important types of
operating system.
1.
Mainframe
system: -
Mainframe computer systems were the first
computers used to tackle many commercial and scientific applications
A.
Batch System: - The users of batch operating system do not
interact with the computer directly.
B.
Multi-programmed
system: - In multi programming
system, when one program is waiting for I/O transfer, there is another program
ready to utilize the CUP. So it is possible for several jobs to share for several
jobs to share the time of the CPU.
C.
Interactive system: - It provides direct communication between the user and
the system.
D.
Time-sharing System
(Multi-tasking): - Operating system
uses CPU scheduling and multi programming to provide each user with a small
portion of a time.
1.
Desktop
System: -
A.
Nowadays, the desktop systems are becoming more users
convenient.
B.
These systems can adopt technology for larger operating
systems.
C.
It can run different operating systems (Windows, MacOS,
UNIX, Linux) as per use.
2.
Multi-processor
System: -
In Multiprocessor systems communication
takes place through shared communication takes place through shared memory
parallel systems.
It has three main advantages: -
a. Increased throughput
b. Economy of scale
c. Increased reliability
3.
Distributed
System: -
A.
Distributed systems use multiple central processors to
swerve multiple real time application.
B.
Data processing jobs are distributed among the
processor accordingly to which one can perform each job most efficiently.
4.
Clustered
System: -
A.
Clustered systems are made by combining multiple
computers into a single system.
B.
The clustered computers share storage and are closely
linked via LAN networking.
C.
Clustering is usually used to provide high availability.
5.
Real Time
System: -
A.
A real time operating system is a multitasking
operating system designed for real time applications i.e. embedded system,
industrial robots, and scientific research.
B.
Real-time operating systems use specialized scheduling
algorithms in order to provide the real time applications.
C.
Real-time systems come in two ways: -
1. Hard real time
system
2. Soft real time
system
6.
Handheld
System: -
A.
Handheld system is nothing but a small computer system
performs simple tasks such as calendars, email, & web browsing.
B.
A mobile device is handheld operating system which run
small applications.
01.03 Different
views of the Operating Systems: -
1.
User’s
View: -
I.
The user view of computer depends on the
interface which is user friendly. Every computer that is to be operated by an
individual requires a user interface.
II.
The user interface views the directory
structure and requests services from the operating system that will acquire
data from input hardware devices, such a keyboard, mouse and such on output
hardware devices, such as video monitor and printer.
III.
Some computers have little or no user view.
For example, embedded computers in home devices and automobiles may have
numeric, keypads but they and their operating systems are designed primarily to
run without user intervention.
2. System View: - The operating system manages
the hardware resources of computer system.
I.
Resources include processors, memory,
disks, network interfaces, I/O devices etc..
II.
The operating system allocates resources among
running programs. It controls the sharing of resources within multiple
programs.
III.
The operating system itself uses resources,
which it must share with application programs.
3. Programming View:
-
I.
The programmers view involves application
programming environment which work as an interface between the user and operating
systems.
II.
These applications provide writing a
particular program executing, compiling and working with a developing framework
with input of a skilled programmer.
III.
In short, the operating system provides an
environment for developing programs which are used by other users at user view.
(Note:- Update available soon, comment for any type of help)
{Other links
COA : -
OS
ISP: -
https://diplomaforcse.blogspot.com/2019/08/previous-year-question-for-computer_31.html
NOTES of COA (unit-1): -
NOTES of ISP (unit-4): -
NOTES of OS (unit-1): -
https://diplomaforcse.blogspot.com/2019/11/notes-for-computer-science-and.htmlNOTES of OS (unit-2): -
https://diplomaforcse.blogspot.com/2019/11/notes-for-computer-science-and_20.htmls:Scheduling algorithm numerical click me
}
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