IBComputerScience

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ComputerScienceDepartment

Resource Management

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1:Systemdesign 2:ComputerOrganisation

3:Networks 4:Computationalthinking

5:Abstractdatastructures

6:Resourcemanagement

7:Control D:OOP

HL Topics 1-7, D1-4

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1:Systemdesign

2:ComputerOrganisation

3:Networks

4:Computationalthinking

5:Abstractdatastructures

6:Resourcemanagement

7:Control

D:OOP

HL only 6 OverviewSystemresources6.1.1Identifytheresourcesthatneedtobemanagedwithinacomputersystem

6.1.2Evaluatetheresourcesavailableinavarietyofcomputersystems

6.1.3Identifythelimitationsofarangeofresourcesinaspecifiedcomputersystem

6.1.4Describethepossibleproblemsresultingfromthelimitationsintheresourcesinacomputersystem

Roleoftheoperatingsystem

6.1.5Explaintheroleoftheoperatingsystemintermsofmanagingmemory,peripheralsandhardwareinterfaces

6.1.7OutlineOSresourcemanagementtechniques:scheduling,policies,multitasking,virtualmemory,paging,interrupt,polling

6.1.8Discusstheadvantagesofproducingadedicatedoperatingsystemforadevice

6.1.9Outlinehowanoperatingsystemhidesthecomplexityofthehardwarefromusersandapplications

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Topic 6.1.1Identifytheresources thatneedtobemanaged withinacomputersystem

Content developed by Dartford Grammar School Computer Science Department

Content developed by Dartford Grammar School Computer Science Department

Important resources to manage• Primarymemory(RAM)• Secondarystorage(HDD/SSD/opticaldrives)• Processorspeed• Bandwidth• Screenresolution• Soundprocessor• Graphicsprocessor• Cache• Networkconnectivity

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It’s all about the moneyUltimately,mostcomputersarecommodities – itemstobesold.Ifprofit isafactor,sowillbereducingthecostsofmanufacturing.Togiveusersthebestpossibleexperience,itisessentialtotailoreachsystem’sconfigurationtoitsintendedpurpose.Eachcomponentinacomputeraffectsitsfunctioninaparticularway.

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Primary Memory (RAM)Whatitdoes:• Placewherealldata/programscurrentlybeing

processedarekeptCommoncapacities:• Gigabytes(GB):1/2/4/8/16Effectonsystemiftoolimited:• Iftoolittlephysicalmemoryexists,thesystemwill

needtousesecondarystorage,whichismuchslower,bymeansofvirtualmemory.

• Ifvirtualmemorycannotbecreatedorisinsufficient,theprogram/datasimplycannotbeloaded.

• Itinfluenceshowmanyprocessescanbedonesilmulataneously.

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Secondary Storage (HDD/SSD/Optical)

Whatitdoes:• Placeweredata/programcanbestoredif

poweredislost(RAMisvolatile).Commoncapacities:• Gigabytes(GB)/Terabyte(TB):

– HDD:500GB/1TB/2TB– SDD:256GB/512GB– Optical:CD650MB/DVD4.7GB

Effectonsystemiftoolimited:• Noplaceto‘save’work– sodatamightbelost• CanalsopreventtheOSfromusingstorageas

virtualmemoryifRAMfillsup• Limitshowmuchdatacanbekept

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Processor: SpeedWhatitdoes:• Processordoesallcalculationsina

computersystem.• Speedismeasurementofhowmany

calculationscanbedonepersecond(1Ghz=1billioncalculationspersecond)

Commonspeeds:• Gigahertz(GHz):1/1.2/2/2.4/3.2Effectonsystemiftoolimited:• Processorwilltakelongertoperform

tasks

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Content developed by Dartford Grammar School Computer Science Department

Processor: CoresWhatitdoes:• Eachprocessorhasatleast1ALUorcore.If

youhave2ALUsyoucandotwooperationsatonce,etc.

Commoncapacities:• 2core=dualcore,4=quad,8=octa,etc.Effectonsystemiftoolimited:• Ifyouhaveonlyonecore,youcanonly

performonesetofoperations/calculationsatatime.Ifyouhavetwoormoreyoucandomorecalculationinthesametimeframe.

• Itaffectshowmanytasksasystemcancopewithsimulataneously.

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Bandwidth (network transmissions)Whatitdoes:• Measurementofhowmuchdatacanbesent

atsametimeinacertaintimeframe(alsocalledbitrate)

Commoncapacities:• Measuredinbitspersecond(bps):

Broadband=16-100Mbps;LAN=upto1Gbps(note:1Gbps =1/8GBps)

Effectonsystemiftoolimited:• Limitingthebandwidthmeansdatawilltake

longertomovebetweentwopoints.• Itaffectshowlongittakesbeforedatacan

beprocessedinitsentirety.

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Low vs High bandwidth

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Screen resolutionWhatitis:• Measurementofnumberofpixelsinheightxwidthof

displayCommoncapacities:• 1024×768(XGA)• 1366×768(HD720p)• 1920x1080 (HD1080p)• 4096x2304(4K)Effectonsystemiftoolimited:• Ifresolutionistoolimited,thenumberofpixles thatcan

bedisplayedisless– displaymightbepixelated(blocky)• Lowerresolutions=smallerfilesizebutpoorerquality

imageshttps://en.wikipedia.org/wiki/List_of_common_resolutions

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Sound processorWhatitdoes:• Soundreproductionisdonebyaseparateprocessor,

freeinguptheCPUtodoothercalculations.• Canalsocontainabankof‘sampled’soundsto

reproducebetterqualitymusic/audioCommonlyseenin:• Hometheatresystems• CinemasEffectonsystemiftoolimited:• CPUistaxedwithhavingtoprocessessounds,slows

downsystemoverall.• Overallqualityisnotashighasinasystemwitha

dedicatedsoundprocessor.

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Graphics processor (GPU)Whatitdoes:• Doescomplexgraphic

processing(like3Drendering)Commonlyseenas:• Nvidia graphicscard• ATIgraphicscardEffectonsystemiftoolimited:• IfCPUhastodographics

processing,itwilltakelongerorbelimited.

Note:SoC vs ‘onboard’vs GPUvs Graphicscard

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Cache (physical cache)Whatitdoes:• Containstheinstruction/datatheCPUis

likelytorequestnextfromRAM– itmassivelyspeedsupprocessingastheCPUdoesnothaveto‘wait’forinstructionstoarrivefromRAM.

Commoncapacities:• Megabytes(MB):1to128Effectonsystemiftoolimited:• CPUwillhaveto‘wait’for

instructions/datatobefetchedfromRAM– slowingdownsystem.Userexperiences‘sluggish’system.

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Network connectivity (NIC/WNIC/Bluetooth)

Whatitis:• Eachnetworkcardconnectstoa

particulartypeofnetworkmedia(cable/wirelesssignal)

Commonlyfoundas:• NIC=LAN/ethernet cables• WNIC=WiFi signals• Bluetooth=Bluetoothsignals• 3Gradio=cellularsignalsEffectonsystemiflimited:• Limitedconnectiontypeslimitstheway

datacanbesentorreceivedinasystem.• Speedcanalsobeafactor.

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Connectivity (in general)