• OSistheinterfacebetweenhardwareanduser• AllcomputersneedanOS• OSes areusedtorunapplicationsandcontrolhardware• PopularOSes includeWindows,Linux,MacOSX• LinuxisOpensource

WhatisLinux- OperatingSystem

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TheHistoricalDevelopmentofLinux

• Intheearly1990s,Torvalds becameinterestedinafreewareproductcalledMinixwerewrittenbyAndrewS.Tanenbaum.DevelopedbyAndrewS.Tanenbaum,MinixwasacloneofthecommercialUNIXoperatingsystem.

• Linuxversion0.02,releasedonOctober5,1991,consistedofonlytheLinuxkernelandthreeutilities:■ bash:acommand-lineinterface■ update:autilityforflushingfilesystembuffers■ gcc:aC++compiler

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WhatisGNU?

• GNUProject:RichardStallman onSeptember27th1983.• TheGNUProjectwaslaunchedin1984todevelopa

completeUnix-likeoperatingsystemwhichisfreesoftware:theGNUsystem.

• GNU'skernelisn'tfinished,soGNUisusedwiththekernelLinux.ThecombinationofGNUandLinuxistheGNU/Linuxoperatingsystem,nowusedbymillions.

• www.gnu.org

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RichardStallman,fatheroftheGNUProject

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LinuxDistributions• Todaytherearehundredsofdifferentdistributions

availablepopularLinuxdistributionsinclude

■ SUSELinux ■ TurboLinux■ FedoraLinux ■MandrakeLinux■ RedHatEnterpriseLinux ■ LycorisLinux■ DebianLinux■ CentOS ■ Linspire■ ALTLinux■ GentooLinux ■ Ubuntu

■SlackwareLinux

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Distributions..

– SoftwarePackages– Installer– Re-configure– Update/Patch– CommercialSoftware– UserGuide

WhereLinuxisused

WhereLinuxisused

Linuxinthe“wild”

Linuxinthe“wild”

Linuxinthe“wild”

Linuxinthe“wild”

RedHatLinux

• A2001studyof RedHatLinux 7.1foundthatthisdistributioncontained30million sourcelinesofcode.[101] Usingthe ConstructiveCostModel,thestudyestimatedthatthisdistributionrequiredabouteightthousandhuman-yearsofdevelopmenttime.Accordingtothestudy,ifallthissoftwarehadbeendevelopedbyconventional proprietary means,itwouldhavecostabout$1.38 billion(2011USdollars)todevelopintheUnitedStates.

CentOS

• CommunityEnterpriseOperatingsystem• “Free”versionofRedHatEnterpriseLinux• Version6• Centos.org

Ubuntu