CSC1100 - Chapter02 - Components of the System Unit
Chapter 2The Components of theSystem Unit
Chapter ObjectivesIdentify chips, adapter cards, and othercomponents in system unitIdentify chips, adapter cards, and othercomponents in system unitDescribe the components of a processor and howthey complete a machine cycleDescribe the components of a processor and howthey complete a machine cycleIdentify characteristics of various personalIdentify characteristics of various personalDescribe the types of expansion slots andadapter cardsDescribe the types of expansion slots andadapter cardsExplain the differences among a serial port, a parallelport, a USB port, a FireWire port, and other portsExplain the differences among a serial port, a parallelport, a USB port, a FireWire port, and other portsIdentify characteristics of various personalcomputer processors on the market todayIdentify characteristics of various personalcomputer processors on the market todayDefine a bit and describe how a series of bitsrepresents dataDefine a bit and describe how a series of bitsrepresents dataDifferentiate among the varioustypes of memoryDifferentiate among the varioustypes of memoryDescribe how buses contribute to acomputer’s processing speedDescribe how buses contribute to acomputer’s processing speedIdentify components in mobile computersand mobile devicesIdentify components in mobile computersand mobile devices
The System UnitWhat is the system unit?Case that containselectronic componentsof the computer usedto process dataAlso known asAlso known aschassis
Learning OutcomeSuccessful students will be able to:Describe the characteristics of computer hardwaredevices and explain their functionalities.
The System UnitWhat are common components inside the systemunit?MemoryAdapter cardsSound cardpower supply drive baysprocessorProcessorSound cardVideo cardPortsDrive baysPower supplyports memorysound cardvideo card
The System UnitWhat is the motherboard?Main circuitboard in systemunitContains adaptercards, processorcards, processorchips, andmemory chipsAlso calledsystem board
The System UnitWhat is a chip?Small piece of semi-conducting material on whichintegrated circuits are etchedIntegrated circuits contain many microscopic pathwayscapable of carrying electrical current – can containmillions of elements: resistors, capacitors, transistors,…p. 186millions of elements: resistors, capacitors, transistors,…Chips are packaged so they can be attached to acircuit board
ProcessorProcessorControlControlUnitUnitArithmeticArithmeticLogic Unit (ALU)Logic Unit (ALU)ArithmeticArithmeticLogic Unit (ALU)Logic Unit (ALU)ProcessorWhat is the central processing unit (CPU)?Interprets and carriesout basic instructionsthat operate a computerInstructionsInstructionsDataDataInformationInformationControlControlUnitUnitControl unit directs andcoordinates operations incomputerp. 187 Fig. 4-4InputInputDevicesDevicesStorageStorageDevicesDevicesOutputOutputDevicesDevicesMemoryMemoryDataData InformationInformationInstructionsInstructionsDataDataInformationInformationInformationInformationcomputerArithmetic logic unit(ALU) performsarithmetic, comparison,and logical operationsAlso called the processor
ProcessorWhat is a machine cycle?Step 1. FetchObtain program instructionor data item from memoryFour operations of the CPU comprise a machine cycleProcessorControl UnitMemoryALUStep 2.DecodeTranslateinstruction intocommandsStep 4. StoreWrite result to memoryStep 3. ExecuteCarry out command
ProcessorWhat is pipelining?CPU begins fetching second instruction beforecompleting machine cycle for first instructionResults in faster processing
Stores locationStores locationfrom where instructionfrom where instructionProcessorWhat is a register?Temporary high-speed storage area that holdsdata and instructionsfrom where instructionfrom where instructionwas fetchedwas fetchedStoresStoresinstruction while it isinstruction while it isbeing decodedbeing decodedStores dataStores datawhile ALUwhile ALUcomputes itcomputes itStores resultsStores resultsof calculationof calculation
ProcessorWhat is the system clock?Controls timing of all computer operationsGenerates regular electronic pulses, or ticks, that setoperating pace of components of system unitEach tickEach tickis ais aclock cycleclock cyclePace of systemPace of systemclock isclock is clock speedclock speedMost clock speeds areMost clock speeds arein the gigahertz (GHz)in the gigahertz (GHz)range (1 GHz = onerange (1 GHz = onebillion ticks of systembillion ticks of systemclock per second)clock per second)Processor speed canProcessor speed canalso be measured inalso be measured inmmillions ofillions of iinstructionsnstructionspperer ssecondecond (MIPS)(MIPS)
ProcessorComparison of some of themore widely usedprocessors
Quick Quiz1) What is the system unit?Answer:A case that contains electronic components of the computerused to process dataAnswer:Many microscopic pathways capable of carrying electrical2) What does an integrated circuit contain?Many microscopic pathways capable of carrying electricalcurrentAnswer: The control unit is the component of the processorthat directs and coordinates most computer operations; thearithmetic logic unit is the component that performsarithmetic and comparison operations.3) How is the control unit different from thearithmetic logic unit?
ProcessorWhat are heat sinks, heat pipes,and liquid cooling?Heat sink —small ceramic or metal componentwith fins – absorbs & disperses heat producedby electrical componentsHeat pipe —smallerBesides computer’s main fan,today’s processors requireadditional coolingHeat pipe e—smallerdevice for notebookcomputersLiquid cooling —uses acontinuous flow of fluids (water,glycol,..) to transfer heat awayfrom processor to a radiator typegrill and returns the cooled fluidto the processor
ProcessorMobile computers & devices often have LowVoltage or Ultra Low Voltage (UVL) processorsHave such low power demands that they do notrequire additional cooling.
ProcessorWhat is parallel processing?Control ProcessorControl ProcessorProcessor 1Processor 1 Processor 2Processor 2 Processor 3Processor 3 Processor 4Processor 4Using multipleprocessorssimultaneously toexecute a programfaster MemoryMemory MemoryMemory MemoryMemory MemoryMemoryfasterRequires specialsoftware to divideproblem and bringresults together
Parallel ProcessingSingle problem divided into portionsMultiple processors work on their assignedportions of the problem at the same timeSome PC use dual-core or multi-core processorsOthers have two or more separate processorsOthers have two or more separate processorschips.Massively parallel processinglarge scale parallel processinginvolves hundreds or thousands of processors.Used by supercomputers – AI & weather forecastingapplications.
Data RepresentationHow do computers represent data?Recognize only two discretestates: on or offUse a binary system toMost computers are digitalUse a binary system torecognize two statesUse Number system with twounique digits: 0 and 1, calledbits (short for binary digits)
Data RepresentationComputers – electronic devices powered byelectricity – has only two states: ON and OFFThe digit 0 represents the electronic state OFF:absence of electronic chargeThe digit 1 represents the electronic state ON:presence of electronic chargeThe digit 1 represents the electronic state ON:presence of electronic chargeThe binary system is a number system that hasjust two unique digits, 0 and 1, called bit.A bit (is not very informative) is the smallest unit ofdata the computer can process.
Data RepresentationWhat is a byte?EIGHT bits grouped together as a unitProvides enough different combinations of 0s and 1sto represent 256 individual charactersNumbersUppercaseUppercaseand lowercaselettersPunctuationmarksOther
Data RepresentationWhat are three popular coding systems to represent data?ASCII - American Standard Code for Information Interchange- Used in PCs & serversEBCDIC - Extended Binary Coded Decimal Interchange Code- Used primarily on mainframe & supercomputers(both coding schemes sufficient for English & Western Europe languagesbut not for Asian, using different alphabets)Unicode - 16-bit coding scheme capable of representing allworld’s languages- implemented in Windows Vista, XP, Mac OS & LinuxASCII Symbol EBCDIC00110000 0 1111000000110001 1 1111000100110010 2 1111001000110011 3 11110011
Data RepresentationHow is a letter converted to binary form and back?Step 1.The userpresses thecapital letter D(shift+D key)on thekeyboard.Step 2.An electronic signal forthe capital letter D issent to the system unit.Step 3.The signal for the capitalletter D is converted to itsASCII binary code(01000100) and is stored inmemory for processing.Step 4.After processing, thebinary code for the capitalletter D is converted to animage, and displayed onthe output device.
Quick Quiz1) What is a dual-core processor?Answer: A single chip that contains two separate processors2) How are analog signals different from digitalsignals?Answer:Analog uses continuous (wave form) signals that vary instrength and quality; digital signals, which are used by mostcomputers, recognize only two discrete states: on and offsignals?
MemoryWhat is memory?Electronic components that store:- instructions waiting to be executed,- data needed by those instructions, and- the results of processed data (information)Consists of one or more chips on motherboard or othercircuit boardEach byte stored in memory at unique location calledan address
MemoryWhat is memory? (cont.)A byte (a character) – 8 bits - is the basic storage unit inmemoryEach byte resides temporarily in a location in memorythat has an address – a unique number that identifies thelocation of a byte in memorylocation of a byte in memoryTo access data or instruction in memory, computerreferences the addresses that contain bytes of data
MemoryHow is memory measured?Term Abbreviation Approximate SizeKilobyte KB or K 1 thousand bytesBy number of bytes available for storageKilobyte KB or K 1 thousand bytesMegabyte MB 1 million bytesGigabyte GB 1 billion bytesTerabyte TB 1 trillion bytesActually a kilobyte = 1,024 bytes
MemoryWhat is random access memory (RAM)?Also calledAlso calledMost RAM isMost RAM isMemory chips that can beMemory chips that can beread from and writtenread from and writtento by processor & other devicesto by processor & other devicesThe more RAM aThe more RAM acomputer has, thecomputer has, thefaster it respondsfaster it respondsAlso calledAlso calledmain memorymain memoryor primaryor primarystoragestoragevolatilevolatile, it is lost, it is lostwhen computer’swhen computer’spower ispower isturned offturned off
MemoryHow do program instructions transfer in and out of RAM?Step 1. When you start the computer,certain operating system files are loadedinto RAM from the hard disk. Theoperating system displays the user interfaceon the screen.Operating systemOperating systeminstructionsinstructionsWeb browserWeb browserinstructionsinstructionsOperating systemOperating systeminterfaceinterfaceWeb browserWeb browserwindowwindowRAMStep 2. When you start a Web browser, theprogram’s instructions are loaded intoRAM from the hard disk. The Web browserwindow is displayed on the screen.Word processingWord processingprogram instructionsprogram instructionsWord processingWord processingprogram windowprogram windowRAMWeb browser programWeb browser programinstructions areinstructions areremoved from RAMremoved from RAMWeb browserWeb browserwindow is no longerwindow is no longerdisplayed ondisplayed ondesktopdesktopwindow is displayed on the screen.Step 3. When you start a word processingprogram, the program’s instructions areloaded into RAM from the hard disk. Theword processing program, along with theWeb Browser and certain operating systeminstructions are in RAM. The wordprocessing program window is displayedon the screen.Step 4. When you quit a program, such asthe Web browser, its program instructionsare removed from RAM. The Web browseris no longer displayed on the screen.
Do not have toDo not have tobe rebe re--energizedenergizedas often asas often asDRAMDRAMMostMostcommoncommontypetypeMemoryWhat are two basic types of RAM chips?StaticStaticMust beMust berere--energizedenergizedconstantlyconstantlyFaster andFaster andmore reliablemore reliablethan DRAMthan DRAMchipschipsRAMRAM(SRAM)(SRAM)DynamicDynamicRAMRAM(DRAM)(DRAM)Newer Type: Magnetoresistive RAM (MRAM)
Two types ofDIMMs: a 168-pinSDRAM module(top) and a 184-pinDDR SDRAMmodule (bottom).30- (top) and 72-pin(bottom) SIMMs.Early 30-pinmodules commonlyhad either 256 KB or1 MB of memory.http://www.maplin.co.uk/images/Full/a23aj.jpghttp://www.makeitsimple.com/articles/ramguide/ramguidep2.htm
MemoryWhere does memory reside?Resides on small circuitboard called memorymoduleMemory slots onmotherboard hold memorydual inline memory modulemotherboard hold memorymodulesmemory chip memory slot
MemoryHow much RAM does an application require?Depends on the types ofsoftware you plan touseFor optimalperformance, youperformance, youneed more thanminimum specifications
MemoryHow much RAM do you need?Depends on type of applications you intend to runon your computerRAMUse256 MB to 1 GB 512 MB to 1 GB 2 GB and up• Home and businessusers managing• Users requiring more advancedmultimedia capabilities• Power users creatingprofessional Web sitespersonal finance• Using standardapplication softwaresuch as word processing• Using educationalor entertainmentCD-ROMs• Communicating withothers on the Web• Running number-intensiveaccounting, financial, orspreadsheet programs• Using voice recognition• Working with videos, music, anddigital imaging• Creating Web sites• Participating in video conferences• Playing Internet games• Running sophisticatedCAD, 3D design, orother graphics-intensivesoftware
MemoryWhat is cache?L1 cache built into processorL2 cache slower but has largerHelps speed computer processes by storing frequently usedinstructions and dataAlso called memory cacheL2 cache slower but has largercapacityL2 advanced transfer cache isfaster, built directly on processorchipL3 cache is separate from processorchip on motherboard (L3 is onlyon computers that use L2 advancedtransfer cache)
Memory CacheCache speeds up processing timeIt stores frequently used instruction & data.When the processors needs them, it searches thememory in an order with greater delay inprocessing for each level of memory it must searchas the following order:as the following order:L1 cache, thenL2 cache, thenL3 cache if it exists, thenRAMIf the instruction or data is not found in memory,then it must search a slower speed storage medium(h/disk, CD, or DVD)
MemoryWhat is read-only memory (ROM)?Memory chips that storeMemory chips that storepermanent datapermanent dataand instructionsand instructionsNonvolatile memoryNonvolatile memory, it is not, it is notlost when computer’slost when computer’spower is turned offpower is turned offThree types:Three types:EEPROMEEPROM((eelectricallylectricallyeerasablerasable pprogrammablerogrammableFirmwareFirmware——ROM chips manufacturedROM chips manufacturedwith permanently writtenwith permanently writtendata, instructions,data, instructions,or informationor informationeerasablerasable pprogrammablerogrammablerreadead--oonlynly mmemory)emory)——Type of PROMType of PROMcontaining microcodecontaining microcodeprogrammerprogrammercan erasecan erasePROMPROM((pprogrammablerogrammablerreadead--oonlynlymmemory)emory)——Blank ROMBlank ROMchip onto whichchip onto whicha programmera programmercan write permanentlycan write permanentlyUse Microcodeinstructions to programa PROM chipErase microcode with anelectrical signal
MemoryWhat is flash memory?Nonvolatile memory that can be erased electronically and rewrittenUsed with PDAs, digital cameras, smart phones, music players, digitalvoice recorders, printers, Internet receivers, and pagersflash memoryflash memorychipsUSBportfrom thecomputerPortable media playerearphonescable
MemoryWhat is CMOS?Complementarymetal-oxidesemiconductormemoryUsed in someRAM chips, flashmemory chips, andother types ofmemory chipsUses batterypower to retaininformation whenother power isturned offStores date,time, andcomputer’sstartupinformationmemory chipsThe flash memorychips that storecomputer’s startupinformationoften use CMOStechnology
MemoryWhat is access time?Amount of time it takes processorto read data from memoryMeasured in nanoseconds (ns),one billionth of a secondIt takes 1/10 of a second to blink10 million operations = 1 blinkIt takes 1/10 of a second to blinkyour eye; a computer can performup to 10 million operations in same amount oftimeTerm SpeedMillisecond One-thousandth of a secondMicrosecond One-millionth of a secondNanosecond One-billionth of a secondPicosecond One-trillionth of a second
Memory Access TimeThe access time (speed) of memory contributes tothe overall performance of the computer.Accessing data in memory – 200,000 times fasterthan h/disk, because of h/disk’s mechanical motion.Access time also stated in MHz667 MHz DDR2 SDRAM667 MHz DDR2 SDRAMDivide 1 billion ns by the megahertz number667 MHz = (1,000,000,000/667,000,000)ns ≈ 1.5nsManufacturers & retailers list a computer’smemory in terms of its size, not its access time.512 MB of SDRAM upgradeable to 4 GB
Expansion Slots and Adapter CardsWhat is an adapter card?A circuit board thatenhances system unit orprovides connections toexternal devices calledperipherals – devicesperipherals – devicesconnected to system unit &controlled by processor:modems, disk drives,printers, scanners,keyboards,…Also called anexpansion card
Expansion Slots and Adapter CardsWhat is an expansion slot?An opening, or socket,on the motherboardthat can hold anadapter cardWith Plug and Play,With Plug and Play,the computerautomaticallyconfigures cardsand other devicesas you install them
Expansion Slots and Adapter CardsWhat are PC cards, and flash memory cards?PC cardthin removable flash memory device toenable wireless Internet access tonotebook computersExpressCard moduleExpressCard moduleNext generation of PC Cards.Removable flash memory device, to addmemory, storage, sound, fax/modem,communications, and other capabilitiesto computers
Expansion Slots and Adapter CardsWhat are PC cards, and flash memory cards?Flash memory cardallows users to transfer data frommobile devices to desktop computersstorage capacity range: 32 MB – 8 GBhot plugging – feature allows user tohot plugging – feature allows user toinsert & remove the removable flashmemory & other devices whilecomputer is runningUSB Flash driveflash memory storage that plugs in aUSB port on a computer32 MB – 64 GB
Ports and ConnectorsWhat are ports and connectors?Port connects external devices to system unitConnector joins cable to peripheralMale connector: have 1 or more pinsFemale connector: have matching hollows to accept the pins on a maleconnector
Ports and ConnectorsWhat are different types of connectors?
Ports and ConnectorsWhat is a serial port?Transmits one bit of data at atimeConnects slow-speed devices,such as mouse, keyboard,modemmodemE.g. COM port
Ports and ConnectorsWhat is a parallel port?Connects devices that cantransfer more than one bit ata time, such as a printerCan transfer 8 bits of data(one byte) simultaneously(one byte) simultaneouslythrough 8 separate lines in asingle cable
Ports and ConnectorsWhat are USB ports?USB (universal serial bus) port can connectup to 127 different peripherals togetherwith a single connector typeUSB (universal serial bus) port can connectup to 127 different peripherals togetherwith a single connector typeThird USBdevice connectsto second USBdevice, and so onThird USBdevice connectsto second USBdevice, and so onSecond USBdevice connectsto first USBdeviceSecond USBdevice connectsto first USBdeviceFirst USBdevice connectsto USB porton computerFirst USBdevice connectsto USB porton computerSingle USB port canbe used to attachmultiple peripheralsin a daisy chainSingle USB port canbe used to attachmultiple peripheralsin a daisy chainPCs typically havesix to eight USB portson front or back ofthe system unitPCs typically havesix to eight USB portson front or back ofthe system unit
Ports and ConnectorsWhat are FireWire ports?Similar to a USB portConnects multiple types of devices that requirefaster data transmission speeds: digital videocamera, color printer, scanners, digital cameras,camera, color printer, scanners, digital cameras,DVD drives,…Allows you to connect up to 63 devices togetherCan use FireWire hub to attach multiple devicesto a single FireWire port
Ports and ConnectorsWhat are special-purpose ports?MIDI (Musical Instrument Digital Interface) porteSata (external SATA – Serial Advances TechnologyAttachment) port – connect SATA h/disk to computerNot included in typical computerAllow users to attach specialized peripherals or transmit datato wireless devicesAttachment) port – connect SATA h/disk to computerSCSI (small computer system interface) portIrDA (Infrared Data Association) port – data transmission viainfrared light waves; need to align the IrDA port on thedevice with IrDA port on the computer (like televisionremote control)Bluetooth port – Bluetooth technology uses radio waves totransmit data between two devices; do not need to bealigned with each other)
Ports and ConnectorsUSB & FireWire ports are replacingtraditional ports completely
BusesWhat is a bus?Channel that allows devicesinside computer to communicatewith each otherData bus – transfers actual dataAddress bus – transfers the info. wherethe data should reside in memorythe data should reside in memorySystem bus connects processor and RAMBus width determines number of bitstransmitted at one time (32-bit, 64-bit bus)Word size is the number of bits processorcan interpret and execute at a given time;in most computers, the word size is thesame as the bus widthBus clock speed: 1066 MHzMemorychips
BusesSystem Bus/Front Side Bus (FSB)Part of motherboardConnects processor to main memoryExpansion BusAllows processor to communicate with peripheralsPCI bus (Peripheral Component Interconnect bus)PCI bus (Peripheral Component Interconnect bus)PCI Express busAccelerated Graphics Port (AGP) busUSB & FireWire busPC Card busFireWireBusPCIBusAGPBusUSBBus
BaysWhat is a bay?Open area inside systemunit used to installadditional equipmentDrive bays typically holddisk drivesdisk drivesExternal drive bay – allowuser to access the drive fromoutside the system unit: CD& DVD drivesInternal drive bay – withinsystem unit: h/disk
Power SupplyWhat is a power supply?ConvertsAC PowerintoFan keepssystem unitcomponentsExternal peripheralsmight use an ACadapter, which is anexternal power supplyDC Power coolOne end of AC adapter plugs in the wall outlet& the other end attached to the peripheral.The AC adapter converts the AC power into DCpower that the peripheral requires.
Mobile Computers and DevicesWhat is a mobile computer?Notebook, weighing between 2.5 and 8 pounds, ormobile device such as a PDA
Mobile Computers and DevicesWhat ports are on a notebook computer?
Mobile Computers and DevicesWhat ports and slots are on a tablet PC?
Putting It All TogetherWhat are suggested processor, clock speed, and RAMrequirements based on the needs of various types ofusers?
Keeping Your Computer CleanOver time, the system unit collects dust – even in aclean environmentPreventative maintenance requires a few basicproducts: