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Software - 2 Software - 2 OperatingOperatingSystemsSystems

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ObjectivesObjectives

The The objectivesobjectives of this session are to: of this session are to: Describe what an operating system is;Describe what an operating system is; Define the main Define the main functionsfunctions of operating systems; of operating systems; Describe the leading operating systems in use Describe the leading operating systems in use

today;today; Outline current trends in operating system Outline current trends in operating system

technology.technology.

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Operating Systems Operating Systems

The operating system ‘runs’ the computer. The operating system ‘runs’ the computer. It is It is the program used to control the hardware of the the program used to control the hardware of the computer directly. computer directly.

Without such programs the hardware would be Without such programs the hardware would be useless. useless.

Systems software is often said to form the Systems software is often said to form the bridge between the applications’ software and bridge between the applications’ software and the hardware.the hardware.

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Operating SystemsOperating Systems Operating systems may be:Operating systems may be:

• Proprietary.Proprietary.• Open Open

There is a shrinking range of operating systems in use There is a shrinking range of operating systems in use today.today.

It is important to be aware of:It is important to be aware of:• the different types of operating system;the different types of operating system;• what the leading products are;what the leading products are;• the business implications of selecting different operating the business implications of selecting different operating

systems;systems;• current trends.current trends.

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Operating System ServicesOperating System Services

Key services include:Key services include:

• File/disk management;File/disk management;

• Screen management;Screen management;

• Recovery;Recovery;

• Peripheral management;Peripheral management;

• Resource management;Resource management;

• Access and security controlAccess and security control..

We will look at each of these.We will look at each of these.

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OS Services: File/Disk File/Disk ManagementManagement

Physical location management;Physical location management; Housekeeping;Housekeeping; File names;File names; Directories and directory structures;Directories and directory structures; Underpinning of other data management Underpinning of other data management

systems.systems. Maximum number of files supported.Maximum number of files supported. Compression and fragmentation managementCompression and fragmentation management

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OS Services: File/Disk File/Disk ManagementManagement

Disk FragmentationDisk Fragmentation

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Text;Text;

Graphical User Interface (GUI);Graphical User Interface (GUI);• Icons;Icons;• Pull down menus;Pull down menus;• Action buttons;Action buttons;• Scroll bars;Scroll bars;• Drag and drop.Drag and drop.

OS Services: Screen ManagementScreen Management

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OS Services: Screen ManagementScreen Management

Browser.Browser.• Hypertext linking;Hypertext linking;• Action buttons;Action buttons;• Forms;.Forms;.

The GUI is not necessarily part of the O/SThe GUI is not necessarily part of the O/S

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The operating system must manage devices such The operating system must manage devices such as:as:• Printers;Printers;• Modems;Modems;• Scanners;Scanners;• External disk drives;External disk drives;• CD drives;CD drives;• Tape drives;Tape drives;• Plug and play technology.Plug and play technology.

OS Services: PeripheralsPeripherals

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OS Services: RecoveryRecovery It must handle problems such asIt must handle problems such as

• Crash management; Crash management; • File recovery;File recovery;• Rollback;Rollback;

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It must handle a variety of security issues:It must handle a variety of security issues:• Authorised user lists;Authorised user lists;• Logon ids;Logon ids;• Passwords;Passwords;• Directory permissions;Directory permissions;• File access permissions:File access permissions:

Read;Read; Write;Write; Append;Append; Execute.Execute.

• EncryptionEncryption• Auditing logsAuditing logs• Accounting logsAccounting logs

OS Services: Access and Security Access and Security ControlControl

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OS Services: Resource Resource ManagementManagement

The Operating System must manage the The Operating System must manage the machine resources includingmachine resources including::•Job management and scheduling;Job management and scheduling;•Resource allocation;Resource allocation;•Conflict resolution;Conflict resolution;•Managing the flows of data throughout the Managing the flows of data throughout the systemsystem•Start up and shut down;Start up and shut down;

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Operating Systems EvolutionOperating Systems Evolution SystemSystem DeveloperDeveloper Approx. Approx.

YearYear OS/360OS/360 IBMIBM 19641964 Unix Unix Bell LabsBell Labs 1969 1969 VMS VMS DigitalDigital 19781978 DOSDOS MicrosoftMicrosoft 19811981 MacOS MacOS AppleApple 19841984 OS/400 OS/400 IBMIBM Mid 1980sMid 1980s OS/2 1.0 OS/2 1.0 Microsoft/IBMMicrosoft/IBM 19871987 Windows 3 Windows 3 MicrosoftMicrosoft 19901990 LinuxLinux Open SourceOpen Source 19911991 Windows NTWindows NT Microsoft Microsoft 1993 1993 Windows 95Windows 95 MicrosoftMicrosoft 19951995

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Operating Systems EvolutionOperating Systems Evolution SystemSystem DeveloperDeveloper Approx. Approx.

YearYear Windows 98 Windows 98 MicrosoftMicrosoft 19981998 Windows 2000Windows 2000 MicrosoftMicrosoft 19991999 MacOSX MacOSX AppleApple 19991999 Windows XPWindows XP Microsoft Microsoft 20012001 Windows Vista Windows Vista MicrosoftMicrosoft 20072007

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The Major Operating SystemsThe Major Operating Systems Outside of the IBM world, there are four key operating Outside of the IBM world, there are four key operating

systems in use today:systems in use today:

Microsoft Microsoft Windows 95/98Windows 95/98, NT, 2000, XP or , NT, 2000, XP or VistaVista

Dominant desktop technology todayDominant desktop technology todayRising fast in the server market.Rising fast in the server market.

MacOS/MacOS/XXHas about 7-8% of market world-wide. Strong in Has about 7-8% of market world-wide. Strong in education, publishing and graphics.education, publishing and graphics.

UnixUnixDominates large server and scientific/engineering Dominates large server and scientific/engineering worldworld

LinuxLinux..Open-sourceOpen-source alternative to other more expensive alternative to other more expensive operating systems. operating systems. Gaining popularity.Gaining popularity.

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Microsoft Windows NT/2000/XPMicrosoft Windows NT/2000/XP ProprietaryProprietary Low end server and desktop operating systems.Low end server and desktop operating systems. Primarily 32 bit systemPrimarily 32 bit system Supports preemptive multitasking.Supports preemptive multitasking. Supports multiprocessing up to a point.Supports multiprocessing up to a point. Memory hungry Memory hungry Large storage requirementsLarge storage requirements GUI front endGUI front end NT not Plug and Play, 2000/XP is Plug and PlayNT not Plug and Play, 2000/XP is Plug and Play

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Microsoft Windows VistaMicrosoft Windows Vista ProprietaryProprietary Released January 2007Released January 2007 Biggest upgrade since Windows XPBiggest upgrade since Windows XP Hardware ImplicationsHardware Implications

• At least 1.5 GHz processorAt least 1.5 GHz processor• 512 Mb RAM512 Mb RAM• Good graphics card (64Mb)Good graphics card (64Mb)• HD MonitorHD Monitor

• http://www.microsoft.com/windowsvista/http://www.microsoft.com/windowsvista/default.mspxdefault.mspx

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Apple MacOSApple MacOS ProprietaryProprietary Currently at version - 10.5 (Leopard)Currently at version - 10.5 (Leopard) 64 bit system 64 bit system Runs on PowerPC.Runs on PowerPC. Preemptive multitasking;Preemptive multitasking; Generally recognised as having the best GUI;Generally recognised as having the best GUI; Windows emulators are available (e.g. Connectix);Windows emulators are available (e.g. Connectix); Now limited to a niche market.Now limited to a niche market.

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UnixUnix Vintage (1969) operating system with many Vintage (1969) operating system with many

derivatives.derivatives. Both proprietary and open systems availableBoth proprietary and open systems available Written in the C programming languageWritten in the C programming language Both 32 and 64 bit versions Both 32 and 64 bit versions Runs on a vast range of platforms.Runs on a vast range of platforms. Supports preemptive multitasking.Supports preemptive multitasking. Supports multiprocessing. Supports multiprocessing. StableStable Free versions such as Linux available and spreading Free versions such as Linux available and spreading

rapidly. rapidly. Problem with standardisationProblem with standardisation X WindowsX Windows

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LinuxLinux Developed in early 1990s as an alternative for MS WindowsDeveloped in early 1990s as an alternative for MS Windows Open systemOpen system Runs on a vast range of platforms.Runs on a vast range of platforms. Both 32 and 64 bit versions.Both 32 and 64 bit versions. Supports up to 4 processors. Supports up to 4 processors. Stability, security and remote managementStability, security and remote management Applications becoming availableApplications becoming available Not as user friendly as MS Windows or Mac.Not as user friendly as MS Windows or Mac.

http://www.ubergeek.tv/article.php?pid=54http://www.ubergeek.tv/article.php?pid=54

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Operating System HierarchyOperating System Hierarchy

MainframeESAUnixOthers

LargeServerUnix

Smaller ServerWindows NT/2000UnixOS/2Linux

DesktopWindows 95/98Windows 2000Mac OS LinuxUnix

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Mobile Device Operating SystemsMobile Device Operating Systems

Windows CEWindows CE Pocket PCPocket PC Palm OSPalm OS Embedded Linux – Google’s AndroidEmbedded Linux – Google’s Android

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Operating SystemsOperating Systems Provide an interface between application programs Provide an interface between application programs

and the hardware.and the hardware. Steady move away from mainframes.Steady move away from mainframes. Increasing standardisation.Increasing standardisation. Consolidation is occurring:Consolidation is occurring:

• Proprietary systems disappearingProprietary systems disappearing• Microsoft building long term dominance.Microsoft building long term dominance.• IBM dominate mainframe world.IBM dominate mainframe world.• Apple very much at a cross-roadsApple very much at a cross-roads• UNIX for high end serversUNIX for high end servers• Linux serious contender for Microsoft?Linux serious contender for Microsoft?