The document discusses operating systems and their functions. It describes how operating systems control computer systems by managing programs, files and directories, system devices, and allowing multitasking. It also discusses the different types of user interfaces that operating systems use including command line interfaces, menu driven interfaces, and graphical user interfaces.

1. Chapter 2
OPERATING
SYSTEM
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2. • The operating system is very important system
software .it consists of set of programs and data
for performing general task on a computer .these
are the tasks that have to be performed by all
computers .
• It is a collection of system software that controls
the working of computer systems .it acts as an
interface between the computer user and
computer .
• It facilitates program execution and helps in
developing application programs .
INTRODUCTION
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3. 1. Booting up and providing a user
interface
2. Managing programs
3. Managing files and directories
4. Controlling system devices
5. Multitasking
FUNCTIONS OF OPERATING SYSTEM
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4. • Helps in booting up process .
• An interface is the way in which two people
communicate.
• The term booting refers to the process of
loading an operating system into a computer’s
main memory from hard disk or diskette.
• This loading is accomplished by a program
called a boot routine or the bootstrap loader.
BOOTING UP AND PROVIDING USER INTERFACE
BOOTING UP
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5. • Programs that start working as computer is
switched on .It locates the Operating System
from Backing Storage and loads it into Main
Memory.
• It starts up the Peripheral Devices and Disk
Drivers.
• Once the Operating System and system
devices have been activated the BIOS transfer
control of the computer to operating system .
• Transfer control of the computer to the
operating system.
BIOS (BASIC INPUT OUTPUT
OPERATIONS)
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6. Stored in
ROM CHIP
Consist of
BOOT
SEQUENCE
BOOT LOADER
BIOS (BASIC INPUT OUTPUT
OPERATIONS)
A boot sequence
includes the first few
operations needed to
boot the computer
The bootloader loads
the operating system
from the memory
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7. A user interface is a program that allows a
user to communicate with the computer .
USER INTERFACE
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8. • The operating system runs all the system
software and application software store
on the computer . Any problem in
operating system means that neither
system nor application software can run
properly .
MANAGING PROGRAMS
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9. The Operating System maintains files and
folders by storing each file at a unique
location in its memory .The operating
system can also change the location of
file if required by user .It also allows the
same file to be used by two different
application programs
MANAGING FILES AND
DIRECTORIES
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10. • Controls system devices such as
peripheral devices and drives
• Makes sure device perform exact
function as needed by user
CONTROLLING SYSTEM DEVICES
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11. • Doing two or more things at a
same time.
• The operating system lets users
use several devices and work on
several application program at
the same time
MULTITASKING
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12. MULTITASKING
User
Application
Operating System
Hardware
During multitasking
,the operating system
divides processing
time and memory
among the devices and
programs
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13. COMMON TYPES OF
OPERATING SYSTEM
a. Command Line Interface (CLI)
b. Menu Driven Interface (MDI)
c. Graphical User Interface (GUI)
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14. A. Command Line Interface (CLI):
DOS (disk operating system) is based on
command line interface. It follows typed
commands to perform required tasks.
B. Menu Driven Interface (MDI)
It allows you to choose a command from
a menu .menus are easy to use as
compare to Command Line Interface
especially fob beginners
Disadvantage : they are slower to use.
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15. C. Graphical User Interface (GUI)
Easiest interface to use ,the Graphical
User Interface (GUI),uses images to
represent options . Some of these images
take the form of icons .Icons are small
pictorial figures that represents tasks
,functions or programs .
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