Two Operating Systems

1. 11
Computers:Computers:
Tools for an Information AgeTools for an Information Age
Chapter 3Chapter 3
Operating Systems: Software in the BackgroundOperating Systems: Software in the Background

2. 22CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
ObjectivesObjectives
Describe the functions of an operating systemDescribe the functions of an operating system
Explain the basics of a personal computer operating Explain the basics of a personal computer operating
systemsystem
Describe the advantages of a graphical operating Describe the advantages of a graphical operating
systemsystem
Differentiate among different versions of Microsoft Differentiate among different versions of Microsoft
WindowsWindows
Explain the need for network operating systemsExplain the need for network operating systems
Describe the methods of resource allocation on Describe the methods of resource allocation on
large computerslarge computers
Describe the differences among multiprocessing, Describe the differences among multiprocessing,
multiprogramming, and time-sharingmultiprogramming, and time-sharing
Explain the principles of memory managementExplain the principles of memory management
List several functions that are typically performed by List several functions that are typically performed by
utility programsutility programs

3. 33CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Operating Systems: Hidden SoftwareOperating Systems: Hidden Software
Serves as intermediary between hardware Serves as intermediary between hardware
and applications softwareand applications software
Operating SystemOperating System
Systems softwareSystems software
KernelKernel

4. 44CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Operating SystemOperating System
A set of programs that lies A set of programs that lies
between applications software between applications software
and the hardwareand the hardware

Manages computer’s resources Manages computer’s resources
(CPU, peripheral devices)(CPU, peripheral devices)

Establishes a user interfaceEstablishes a user interface
Determines how user interacts with Determines how user interacts with
operating systemoperating system

Provides and executes services Provides and executes services
for applications softwarefor applications software

5. 55CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Systems SoftwareSystems Software
All programs related to coordinating All programs related to coordinating
computer operationscomputer operations
ExamplesExamples

Operating systemsOperating systems

Language translatorsLanguage translators
Convert program code to machine-readable formConvert program code to machine-readable form

Utility programsUtility programs
Perform secondary choresPerform secondary chores

6. 66CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
KernelKernel
Manages the operating systemManages the operating system

Loaded from hard drive into memory when Loaded from hard drive into memory when
computer is bootedcomputer is booted
BootingBooting refers to starting the computer refers to starting the computer

Loads other operating system programs from Loads other operating system programs from
disk storage as neededdisk storage as needed
Other programs referred to as Other programs referred to as nonresidentnonresident

7. 77CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Operating Systems for Personal Operating Systems for Personal
ComputersComputers
Platform: combination of computer hardware and Platform: combination of computer hardware and
operating system softwareoperating system software

WintelWintel (Microsoft Windows running on an Intel-based (Microsoft Windows running on an Intel-based
PC) is one of the most commonPC) is one of the most common
Common PlatformsCommon Platforms

MS-DOSMS-DOS

WindowsWindows

MAC OSMAC OS

UnixUnix

LinuxLinux

8. 88CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Graphical User InterfaceGraphical User Interface
User clicks an icon to User clicks an icon to
perform tasksperform tasks
Start Menu in lower Start Menu in lower
left corner launches left corner launches
programsprograms
Use menus to Use menus to
activate commandsactivate commands

9. 99CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Windows XPWindows XP
Brings consumer and Brings consumer and
corporate versions of corporate versions of
Windows together into a Windows together into a
single productsingle product

Has Home and Professional Has Home and Professional
EditionsEditions

10. 1010CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Windows XP EnhancementsWindows XP Enhancements
Improved user interfaceImproved user interface

Much clearer and uncluttered desktopMuch clearer and uncluttered desktop

More icons on redesigned Start MenuMore icons on redesigned Start Menu
Improved multimedia supportImproved multimedia support
More personalizationMore personalization
Multiple user supportMultiple user support

User can log off, leaving programs running, and allow User can log off, leaving programs running, and allow
another user to log onanother user to log on

Set up limited accounts for children to use; i.e., no Set up limited accounts for children to use; i.e., no
inappropriate games or no Internet accessinappropriate games or no Internet access
Internet support and protectionInternet support and protection

11. 1111CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Operating Systems for NetworksOperating Systems for Networks
Network operating system (NOS) Network operating system (NOS)

Handles network functionsHandles network functions
Sharing resources (hard disks and printers)Sharing resources (hard disks and printers)
Data securityData security
TroubleshootingTroubleshooting
Administrative controlAdministrative control

Make resources appear as though they were Make resources appear as though they were
running from client computersrunning from client computers

12. 1212CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Operating Systems for Large Operating Systems for Large
ComputersComputers
Resource allocation: assigning computer Resource allocation: assigning computer
resources to certain programs and processes for resources to certain programs and processes for
their usetheir use
Main issues related to resource allocationMain issues related to resource allocation

Sharing the Central Processing UnitSharing the Central Processing Unit
MultiprocessingMultiprocessing
MultiprogrammingMultiprogramming
Time-SharingTime-Sharing

Sharing memorySharing memory

Sharing storage resourcesSharing storage resources

Sharing printing resourcesSharing printing resources

13. 1313CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Sharing the CPUSharing the CPU
MultiprocessingMultiprocessing

The use of a powerful computer with multiple CPUsThe use of a powerful computer with multiple CPUs

Multiple programs run simultaneously (each runs on Multiple programs run simultaneously (each runs on
its own processor)its own processor)
MultiprogrammingMultiprogramming

Two or more programs executed concurrentlyTwo or more programs executed concurrently
Programs take turns using the CPUPrograms take turns using the CPU
Event-drivenEvent-driven
Time-SharingTime-Sharing

Programs take turns using the CPUPrograms take turns using the CPU

Time-drivenTime-driven

Typically used in applications with many usersTypically used in applications with many users

14. 1414CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Sharing MemorySharing Memory
Memory managementMemory management
Divides memory into foreground and backgroundDivides memory into foreground and background
Uses virtual storage (also called virtual memory)Uses virtual storage (also called virtual memory)

Programs currently executed are stored on disk Programs currently executed are stored on disk
Portions of program brought into memory as neededPortions of program brought into memory as needed
Minimizes the amount of memory neededMinimizes the amount of memory needed

Can be implemented by Can be implemented by pagingpaging
Divide memory into small, fixed-size pagesDivide memory into small, fixed-size pages
Page table keeps track of memory locationsPage table keeps track of memory locations

15. 1515CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Sharing Storage ResourcesSharing Storage Resources
Keeps track of location of filesKeeps track of location of files
Responds to commands to manipulate Responds to commands to manipulate
filesfiles
Keeps track of input and output requests Keeps track of input and output requests
for filesfor files

Processes them in the order receivedProcesses them in the order received

16. 1616CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Sharing Printing ResourcesSharing Printing Resources
Spooling: program writes a line to a disk Spooling: program writes a line to a disk
file rather than sending directly to a printerfile rather than sending directly to a printer

When file is completed, placed in queueWhen file is completed, placed in queue

File printed when printer becomes availableFile printed when printer becomes available
Allows program to complete execution Allows program to complete execution
much more quicklymuch more quickly

Writing to disk much quicker than writing to Writing to disk much quicker than writing to
printerprinter

17. 1717CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Utility ProgramsUtility Programs
Perform secondary chores – some examples:Perform secondary chores – some examples:

File managerFile manager
Stores files in a hierarchical Stores files in a hierarchical
directory structuredirectory structure
Windows uses Windows ExplorerWindows uses Windows Explorer

File compressionFile compression
Reduces amount of space a file requiresReduces amount of space a file requires

Makes file take up less space on diskMakes file take up less space on disk

Takes less time to transmit across Takes less time to transmit across
communication linescommunication lines
Others
Backup and Restore
Backup: make copies of
disks and store in a safe
place
Restore: restore files
from backups
Disk defragmenter:
reorganizes disk so all files
are stored in contiguous
locations
Device driver:
handles commands for
devices, such as printers
and storage devices

18. 1818CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Types of System Software? Functions?
Utility Programs? Operating Systems?

19. 1919CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Graphical user interface (GUI)Graphical user interface (GUI)
KernelKernel
Memory managementMemory management
MultiprocessingMultiprocessing
MultiprogrammingMultiprogramming
Operating systemOperating system
PartitionsPartitions
PlatformPlatform
Terms to Know:
Chapter 3
Resource Allocation
Response time
Spooling
Time share
Utility programs
Virtual Memory/Storage

20. 2020CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
Can You Explain If Asked?Can You Explain If Asked?
Describe the functions of an operating systemDescribe the functions of an operating system
Explain the basics of a personal computer operating Explain the basics of a personal computer operating
systemsystem
Describe the advantages of a graphical operating Describe the advantages of a graphical operating
systemsystem
Differentiate among different versions of Microsoft Differentiate among different versions of Microsoft
WindowsWindows
Explain the need for network operating systemsExplain the need for network operating systems
Describe the methods of resource allocation on Describe the methods of resource allocation on
large computerslarge computers
Describe the differences among multiprocessing, Describe the differences among multiprocessing,
multiprogramming, and time-sharingmultiprogramming, and time-sharing
Explain the principles of memory managementExplain the principles of memory management
List several functions that are typically performed by List several functions that are typically performed by
utility programsutility programs

21. 2121CIS 105 – Mesa Community CollegeCIS 105 – Mesa Community College
SourcesSources
Capron; Computers: Tools for An Capron; Computers: Tools for An
Information Age, 8Information Age, 8
thth
Ed. 2003 Ed. 2003
Pfaffenberger; Computers in Your Future Pfaffenberger; Computers in Your Future
20032003
Microsoft ClipartMicrosoft Clipart
WebopediaWebopedia