Transcript Operating Systems

Computer Skills For
Preparatory Programs
CS 017
Chapter 4
Using System Software:
The Operating System, Utility Programs, and File
Management
© 2009 Prentice-Hall, Inc.
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Chapter Objectives
After reading this chapter, you should be able to answer the
following questions:
1. What software is included in system software?
2. What are the different kinds of operating systems?
3. What are the most common operating systems?
4. How does the operating system provide a means for users to interact
with the computer?
5. How does the operating system help manage resources such as the
processor, memory, storage, hardware, and peripheral devices?
6. How does the operating system interact with application software?
7. How does the operating system help the computer start up?
8. What are the main desktop and window features?
9. How does the operating system help me keep my computer
organized?
10.What utility programs are included in system software, and what do
they
do?
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© 2009
Prentice-Hall,
Inc.
Chapter Topics
• System software
• Kinds of operating systems
• OS role in:
– Providing user interaction
– Managing the processor
– Managing memory
– Managing hardware
– Interacting with application software
– Starting the computer
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Chapter Topics (cont.)
• Desktop and windows features
• OS role in keeping desktop organized
• Utility programs
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System software
• consists of two primary types of programs:
– Operating system (OS):
• the main program that controls how your
computer system functions
– Utility programs:
• Is a small program that performs general housekeeping tasks for the computer
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System Software: The OS
1. Controls computer functions
2. The OS manages the Computer’s:
• Hardware
• Processor
• Memory
• Devices
3. Enable software to work with the CPU
4.
Responsible for management, scheduling,
and interaction of tasks
5. Provides user interface
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System Software: Utilities
• Utilities:
Programs that perform computer
housekeeping tasks
–
–
–
–
–
Manage system resources
system maintenance
file compression.
Improve efficiency
Virus prevention
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Operating System Categories
• Operating systems are classified into four
categories, depending on:
1.
2.
the number of users they serve
the tasks they perform.
• Categories:
1.
2.
3.
4.
Real-Time (RTOS)
Single-User, Single-Task OS
Single-User, Multitask OS
Multiuser OS
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Real-Time Operating Systems
(RTOS)
Systems with :
1. specific purpose
2. certain result.
• RTO don’t require the intervention of any users at all.
• Uses include:
–
–
–
–
–
Industrial machines
Robotic equipment
Automobiles
Video game consoles
Home appliances
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Single-User Operating
Systems
Single-task systems
– Perform one task at a time
• Examples:
1. PDAs:
•
they require single-user, singletask operating system software
such as:
Multitask systems
•
•
•
•
Perform simultaneous tasks
Windows
MAC OS
Linux
• Palm OS
• Windows Mobile
2. Microsoft Disk Operating
System (MS-DOS)
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Multiuser Operating Systems
• Known as network operating systems
• Allow access to the computer system by
multiple users.
• Manage user requests.
• Systems include:
–
–
–
–
–
–
Linux
UNIX
Novell Netware
Windows Server 2003
Windows XP
Windows Vista
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Desktop and Notebook
Operating Systems
• Platform
Operating system combined with the processor
EX:
– Microsoft Windows/Intel
– Apple Macintosh/Motorola
Desktop and notebook operating systems include:
–
–
–
–
Microsoft Windows
MAC OS
Linux
UNIX
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Windows OS family
Windows Release Capabilities
Windows 95
-user-friendly Interface
-Multi-tasking capabilities
Windows XP
-major update
- Networking capabilities
Windows 7
-Security
-user-interface upgrades
UNIX
• Multiuser, multitask operating system
• Used primarily with mainframes
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Linux
• Open-source operating
system
• Based on UNIX
• Stable system
• Free to developers
• May be downloaded
through the Internet
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MAC OS
• First commercially available OS with point-and-click
technology (graphical user interface)
• Mac OS X, is based on the UNIX operating system.
• Excellent in:
– Graphics display
– Processing capabilities
– System reliability
– Document recovery
• Fewer software applications available
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Operating Systems for
Servers and Mainframes
• Servers
– Computers on a network that manage
network resources.
• Mainframes
– Handle requests from hundreds or thousands
of users simultaneously
• Operating Systems:
– Windows Server
– Unix
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The User Interface
• Enables users to interact with the computer
• Types of interfaces:
1. Command-driven interface:
- specific commands
2. Menu-driven interface:
• choose a command from menus .
3. Graphical user interface (GUI):
• display graphics
• use the point-and-click technology
• user friendly interface.
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The user interface cont
Command driven
Menu driven
Graphical
Processor Management
– Interrupts:
•Is a signal that tells the OS it is in need of attention
to perform a task
– Interrupt handler:
•special numerical code that prioritizes the requests.
– Interrupt table:
•A special place in RAM that the requests are
placed in.
– Stack :
•Is a special location in RAM that the CPU puts a
“memo” so it can know where he was before the
interrupt.
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Memory and Storage
Management
• The operating system allocates space in RAM for
instructions and data.
OS gets
ready
data to
RAM
process
OS ensure there are free
space to allocate data
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Operating
System
OS clears items from RAM
when the processor no
longer needs
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Virtual Memory
FULL
Operating
System
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Virtual Memory
• Virtual Memory :
– The process of optimizing RAM storage by borrowing
hard drive space.
– Swap File:
• OS moves from RAM the data or instructions that
have not been recently used to a temporary
storage area on the hard drive.
– Paging :
• OS swaps the needed data or instructions back
from the hard drive into RAM.
– Thrashing:
• The condition of excessive paging .
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Virtual Memory
Data & instruction needed
now
Operating
System
Hard Disk
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Data & instruction not
recently Used
RAM
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Hardware and Peripheral Device
Management
• Device drivers
– Programs that enable the operating system to
communicate with peripheral devices
– Provided by the manufacturer of the device
• Plug and Play (PnP)
– Driver preinstalled in Windows
– PnP is Hardware and software standard
– PnP facilitates the installation of new hardware
(immediately use the device, when it plugged to the
port)
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Software Application Coordination
• Application programming interfaces (APIs)
– Blocks of code contained in the operating system, so
that the software programs can work with the CPU.
– API code must recognize by CPU.
– Coordinates the operating system (OS) with software
applications
• Similar toolbars and menus
API Ex:
Microsoft DirectX
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Starting the Computer
The Boot Process
• Step 1: The basic input/output system (BIOS) is activated
• Step 2: A power-on self-test (POST) checks attached hardware
• Step 3: The operating system loads into RAM
• Step 4: Configuration and customization settings are checked
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Handling Errors in the
Boot Process
• Safe mode
– Windows
does not
boot properly
– Try rebooting
– Uninstall any
new devices
or software
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Chapter 4 Summary
•
•
•
•
What software is included in system software?
What are the different kinds of operating systems?
What are the most common desktop operating systems?
How does the operating system provide a means for
users to interact with the computer?
• How does the operating system help manage:
– the processor?
– memory and storage?
– hardware and peripheral devices?
• How does the operating system interact with application
software?
© 2009 Prentice-Hall, Inc.
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Chapter 4 Summary
• How does the operating system help the computer start
up?
• What are the main desktop and windows features?
• How does the operating system help me keep my
computer organized?
• What utility programs are included in system software,
and what do they do?
© 2009 Prentice-Hall, Inc.
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