Transcript Operating Systems

Computer Skills For
Preparatory Programs
"Applied1 Track"
CS 051
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. Provides means for software to work with the CPU
4. Responsible for management, scheduling, and
interaction of tasks
5. Provides user interface
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What the OS Does?
1.
2.
3.
4.
Provides user interface
Manages the CPU
Manages memory and storage
Manages hardware and peripheral
devices
5. Coordinates application software with
the CPU
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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 a specific purpose and a certain
result.
• Real-time operating systems 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 more
than one user
• 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.
– Microsoft Windows/Intel
– Apple Macintosh/Motorola
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Desktop and Notebook
Operating Systems (Conti.)
• Desktop and notebook operating systems
include:
–
–
–
–
Microsoft Windows
MAC OS
Linux
UNIX
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Windows
• Microsoft Windows began with MS-DOS.
• In 1995, they incorporated a user-friendly Interface and
Multi-tasking capabilities that was released as Windows
95.
• Windows XP
• was a major update that provided Networking
capabilities.
• Windows 7
• is the newest release featuring Security and userinterface upgrades.
• Windows improvements have concentrated on:
– increasing user functionality and friendliness
– Improving internet capabilities and enhancing file
privacy and security.
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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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Linux
• Open-source operating
system
• Based on UNIX
• Stable system
• Free to developers
• May be downloaded
through the Internet
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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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UNIX
• Multiuser, multitask operating system
• Used primarily with mainframes
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The User Interface
• Enables you to interact
with the computer
• Types of interfaces:
1. Command-driven
interface:
-The user had to type very
specific commands to
get the computer to load
a program.
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The User Interface (Conti.)
2. Menu-driven interface:
• by incorporating a menu-driven interface in
which you choose a command from
menus displayed on the screen.
• Eliminated the need to know every
command because you could select most
of the commonly used commands from a
menu.
3. Graphical user interface (GUI):
•
GUIs display graphics and use the point-andclick technology of the mouse and cursor,
making them much more user friendly.
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Processor Management
• Controls the timing
processor works on.
of
events
the
– 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
– Preemptive multitasking:
• The OS processes the task assigned a higher
priority before processing
• A task that has been assigned a lower priority.
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Processor Management (Conti.)
– 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
• Virtual Memory :
– The process of optimizing RAM storage by
borrowing hard drive space.
– Swap File:
• When more RAM space is needed, the OS moves
from RAM the data or instructions that have not
been recently used to a temporary storage area on
the hard drive.
– Paging :
• If the data and/or instructions in the swap file are
needed later, the OS swaps them back into RAM.
– Thrashing:
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Virtual Memory
• Instructions and data are stored on the
hard drive when RAM is full.
Data & instruction needed
now
Operating
System
Hard Disk
RAM
Data & instruction not
recently Used
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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
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Software Application
Coordination (Conti.)
• Software programmers need only refer to the
API code blocks in their individual application
programs rather than including the entire code in
the application itself.
– APIs avoid redundancies in software code.
– Make it easier for software developers to
respond to changes in the OS.
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Software Application
Coordination (Conti.)
• An example of API:
– Microsoft DirectX:
• is a group of multimedia APIs built into the
Windows operating system
• Improves graphics and sounds when you ’ re
playing games or watching video on your PC.
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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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The End
Next :
Chapter The Internet and World Wide Web
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