2 Ch 3 Section B Operating Systems

Chapter 3
Computer Software
Section B: Personal Computer
Operating Systems

Computer Concepts 7th Edition
Parsons/Oja

Operating System Overview:
What does an operating system
do?
• An operating system (OS) is the
master controller for all of the activities
that take place within a computer.
– Microsoft Windows XP, Mac OS, Linux,
UNIX

• The operating system also interacts
with application software, device
drivers and hardware to manage a
computer’s resources

Chapter 3: Computer Software

2

What does an operating system
do?

Chapter 3: Computer Software

3

Why does an operating system
need to manage memory?
• When you want to run more than
one program at a time, the OS
has to divide up memory and set
aside RAM for each program
• The OS must ensure that
instructions and data from one
area of memory don’t “leak” into

an area allocated to another
program
• If it fails, data can get corrupted,
programs can “crash” and your
computer will display error
messages such as “General
Protection Fault”
Chapter 3: Computer Software

4

How does the OS keep track of
storage resources?
• The OS acts as a filing clerk that stores
and retrieves files from your disks and
CDs
– It remembers the names and locations of
all your files
– It keeps track of empty spaces where new
files can be stored

Chapter 3: Computer Software

5

Why does the operating system
get involved with peripheral
devices?
• To ensure that they function correctly
• OS communicates with the device
driver software so that the data can
travel smoothly between the computer
and the peripheral device
• OS controls peripherals to ensure input
and output proceeds in an orderly
fashion
Chapter 3: Computer Software

6

How does the operating system
affect the user interface?
• A user interface can be defined as the
combination of hardware and software
that helps people and computers
communicate with each other
• Two types of user interfaces
– Graphical user interface (GUI) provides
a way to point and click a mouse to select
menu options and manipulate graphical
objects that are displayed on the screen
Chapter 3: Computer Software

7

How does the operating system
affect the user interface?
– Command-line user interface requires
users to type various memorized
commands to run programs and

accomplish tasks

Chapter 3: Computer Software

8

Where is the operating system?
• Stored on the hard disk on most computers
• The OS’s small bootstrap program resides on the
Master Boot Record (MBR) and provides the
instructions to load the core parts into memory when
system boots
– These core components are called the kernel, and
provides the most essential OS services, such as memory
management and file access

• The kernel stays in memory all the time your
computer is on
• Other parts of the OS, such as customization
utilities, are loaded into memory as they are needed

Chapter 3: Computer Software

9

Do I ever interact directly with
the OS?
• Yes, typically through helpful tools
called utilities, which are used to
– Launch programs
– Manage files
– Get help
– Customize the user interface
– Configures equipment

Chapter 3: Computer Software

10

What are the most popular
operating systems?

• Microsoft Windows
– Installed on over 80% of the world’s PCs
– Since its introduction in 1985, it has evolved
through several versions, such as Windows 3.1,
NT, 95, 98, Me, 2000 and XP

• Mac OS
– Used with Macintosh computers, manufactured
by Apple Computer. Inc.
– PC and Mac platforms are not compatible
• Platform refers to the combination of a computer’s
microprocessor and OS
Chapter 3: Computer Software

11

What are the most popular
operating systems?
• UNIX
– Developed in 1969

– Command-line interface
– Many versions became available for mainframes
and microcomputers

• Linux
– Developed in 1991 by Linus Torvald as a school
project, based on UNIX
– Linux is free
– Popular OS for e-mail and Web servers
– Most Linux versions have a GUI interface
• Red Hat Linux, Caldera OpenLinux, Debian, SuSE
Chapter 3: Computer Software

12

Is Mac OS similar to windows?
• Developed several years before
windows, it still has a GUI interface
• Both have windows, icons, menus and
pointers

Chapter 3: Computer Software

13

The Mac OS

Chapter 3: Computer Software

14

Linux

Chapter 3: Computer Software

15

Why do I keep hearing about
DOS?
• First operating system that most people

have used
• DOS (Disk Operating System) was
developed by Microsoft
• Is part of the operating system kernel of
Windows 3.1, 95, 98 and ME
– DOS is well hidden behind the Windows GUI
– Found in the MS-DOS Prompt in the Start menu

Chapter 3: Computer Software

16

Why do I keep hearing about
DOS?

“DOS Command-Line Interface”
Classic Course Labs
Found in your
Computer Concepts BookOnCD

Chapter 3: Computer Software

17

What are the options for PDA
operating systems?
Palm OS

Chapter 3: Computer Software

Windows Mobile OS

18

Self Quiz Questions
1.
2.
3.
4.
5.
6.

To run more than one program at a time, the OS
must allocate specific areas of _______ for each
program.
A _______ is the combination of hardware and
software that helps people and computers
communicate.
The core part of an OS is called its _______.
List 3 popular operating systems: _______,
_______, _______
Windows uses a _______ interface.
DOS uses a _______ interface.

Chapter 3: Computer Software

19

Self Quiz Questions
1.
2.
3.
4.
5.
6.

To run more than one program at a time, the OS
must allocate specific areas of RAM for each
program.
A user interface is the combination of hardware
and software that helps people and computers
communicate.
The core part of an OS is called its kernel .
List 3 popular operating systems: Windows ,
Mac OS , Linux
Windows uses a graphical user interface.
DOS uses a command-line interface.

Chapter 3: Computer Software

20

Why do I keep hearing about
DOS?

“Using the Windows Interface”
New Perspectives Labs
Found in your
Computer Concepts BookOnCD

Chapter 3: Computer Software

21