CSC1100 - Chapter02 - Components of the System Unit
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This document discusses the components of the system unit. It describes the central processing unit (CPU) which includes the control unit that directs operations and the arithmetic logic unit (ALU) that performs calculations. The CPU fetches instructions from memory and follows a machine cycle of fetch, decode, execute, and store. Caching and pipelining help improve processor speed. Memory temporarily stores instructions and data and comes in types like RAM, ROM, and flash memory. Expansion slots hold adapter cards to add functionality. Various ports allow connection to other devices.
CSC1100 - Chapter02 - Components of the System Unit
- 1. Chapter 2 The Components of the System Unit
- 2. Chapter Objectives Identify chips, adapter cards, and other components in system unit Identify chips, adapter cards, and other components in system unit Describe the components of a processor and how they complete a machine cycle Describe the components of a processor and how they complete a machine cycle Identify characteristics of various personalIdentify characteristics of various personal Describe the types of expansion slots and adapter cards Describe the types of expansion slots and adapter cards Explain the differences among a serial port, a parallel port, a USB port, a FireWire port, and other ports Explain the differences among a serial port, a parallel port, a USB port, a FireWire port, and other portsIdentify characteristics of various personal computer processors on the market today Identify characteristics of various personal computer processors on the market today Define a bit and describe how a series of bits represents data Define a bit and describe how a series of bits represents data Differentiate among the various types of memory Differentiate among the various types of memory Describe how buses contribute to a computer’s processing speed Describe how buses contribute to a computer’s processing speed Identify components in mobile computers and mobile devices Identify components in mobile computers and mobile devices
- 3. The System Unit What is the system unit? Case that contains electronic components of the computer used to process data Also known asAlso known as chassis
- 4. Learning Outcome Successful students will be able to: Describe the characteristics of computer hardware devices and explain their functionalities.
- 5. The System Unit What are common components inside the system unit? Memory Adapter cards Sound card power supply drive bays processor Processor Sound card Video card Ports Drive bays Power supply ports memory sound card video card
- 6. The System Unit What is the motherboard? Main circuit board in system unit Contains adapter cards, processorcards, processor chips, and memory chips Also called system board
- 7. The System Unit What is a chip? Small piece of semi-conducting material on which integrated circuits are etched Integrated circuits contain many microscopic pathways capable of carrying electrical current – can contain millions of elements: resistors, capacitors, transistors,… p. 186 millions of elements: resistors, capacitors, transistors,… Chips are packaged so they can be attached to a circuit board
- 8. ProcessorProcessor ControlControl UnitUnit ArithmeticArithmetic Logic Unit (ALU)Logic Unit (ALU) ArithmeticArithmetic Logic Unit (ALU)Logic Unit (ALU) Processor What is the central processing unit (CPU)? Interprets and carries out basic instructions that operate a computer InstructionsInstructions DataData InformationInformation ControlControl UnitUnit Control unit directs and coordinates operations in computer p. 187 Fig. 4-4 InputInput DevicesDevices StorageStorage DevicesDevices OutputOutput DevicesDevicesMemoryMemoryDataData InformationInformation InstructionsInstructions DataData InformationInformation InformationInformationcomputer Arithmetic logic unit (ALU) performs arithmetic, comparison, and logical operations Also called the processor
- 9. Processor What is a machine cycle? Step 1. Fetch Obtain program instruction or data item from memory Four operations of the CPU comprise a machine cycle Processor Control Unit Memory ALU Step 2. Decode Translate instruction into commands Step 4. Store Write result to memory Step 3. Execute Carry out command
- 10. Processor What is pipelining? CPU begins fetching second instruction before completing machine cycle for first instruction Results in faster processing
- 11. Stores locationStores location from where instructionfrom where instruction Processor What is a register? Temporary high-speed storage area that holds data and instructions from where instructionfrom where instruction was fetchedwas fetched StoresStores instruction while it isinstruction while it is being decodedbeing decoded Stores dataStores data while ALUwhile ALU computes itcomputes it Stores resultsStores results of calculationof calculation
- 12. Processor What is the system clock? Controls timing of all computer operations Generates regular electronic pulses, or ticks, that set operating pace of components of system unit Each tickEach tick is ais a clock cycleclock cycle Pace of systemPace of system clock isclock is clock speedclock speed Most clock speeds areMost clock speeds are in the gigahertz (GHz)in the gigahertz (GHz) range (1 GHz = onerange (1 GHz = one billion ticks of systembillion ticks of system clock per second)clock per second) Processor speed canProcessor speed can also be measured inalso be measured in mmillions ofillions of iinstructionsnstructions pperer ssecondecond (MIPS)(MIPS)
- 13. Processor Comparison of some of the more widely used processors
- 14. Quick Quiz 1) What is the system unit? Answer: A case that contains electronic components of the computer used to process data Answer: Many microscopic pathways capable of carrying electrical 2) What does an integrated circuit contain? Many microscopic pathways capable of carrying electrical current Answer: The control unit is the component of the processor that directs and coordinates most computer operations; the arithmetic logic unit is the component that performs arithmetic and comparison operations. 3) How is the control unit different from the arithmetic logic unit?
- 15. Processor What are heat sinks, heat pipes, and liquid cooling? Heat sink —small ceramic or metal component with fins – absorbs & disperses heat produced by electrical components Heat pipe —smaller Besides computer’s main fan, today’s processors require additional cooling Heat pipe e—smaller device for notebook computers Liquid cooling —uses a continuous flow of fluids (water, glycol,..) to transfer heat away from processor to a radiator type grill and returns the cooled fluid to the processor
- 16. Processor Mobile computers & devices often have Low Voltage or Ultra Low Voltage (UVL) processors Have such low power demands that they do not require additional cooling.
- 17. Processor What is parallel processing? Control ProcessorControl Processor Processor 1Processor 1 Processor 2Processor 2 Processor 3Processor 3 Processor 4Processor 4 Using multiple processors simultaneously to execute a program faster MemoryMemory MemoryMemory MemoryMemory MemoryMemoryfaster Requires special software to divide problem and bring results together
- 18. Parallel Processing Single problem divided into portions Multiple processors work on their assigned portions of the problem at the same time Some PC use dual-core or multi-core processors Others have two or more separate processorsOthers have two or more separate processors chips. Massively parallel processing large scale parallel processing involves hundreds or thousands of processors. Used by supercomputers – AI & weather forecasting applications.
- 19. Data Representation How do computers represent data? Recognize only two discrete states: on or off Use a binary system to Most computers are digital Use a binary system to recognize two states Use Number system with two unique digits: 0 and 1, called bits (short for binary digits)
- 20. Data Representation Computers – electronic devices powered by electricity – has only two states: ON and OFF The digit 0 represents the electronic state OFF: absence of electronic charge The digit 1 represents the electronic state ON: presence of electronic charge The digit 1 represents the electronic state ON: presence of electronic charge The binary system is a number system that has just two unique digits, 0 and 1, called bit. A bit (is not very informative) is the smallest unit of data the computer can process.
- 21. Data Representation What is a byte? EIGHT bits grouped together as a unit Provides enough different combinations of 0s and 1s to represent 256 individual characters Numbers UppercaseUppercase and lowercase letters Punctuation marks Other
- 22. Data Representation What are three popular coding systems to represent data? ASCII - American Standard Code for Information Interchange - Used in PCs & servers EBCDIC - Extended Binary Coded Decimal Interchange Code - Used primarily on mainframe & supercomputers (both coding schemes sufficient for English & Western Europe languages but not for Asian, using different alphabets) Unicode - 16-bit coding scheme capable of representing all world’s languages - implemented in Windows Vista, XP, Mac OS & Linux ASCII Symbol EBCDIC 00110000 0 11110000 00110001 1 11110001 00110010 2 11110010 00110011 3 11110011
- 23. Data Representation How is a letter converted to binary form and back? Step 1. The user presses the capital letter D (shift+D key) on the keyboard. Step 2. An electronic signal for the capital letter D is sent to the system unit. Step 3. The signal for the capital letter D is converted to its ASCII binary code (01000100) and is stored in memory for processing. Step 4. After processing, the binary code for the capital letter D is converted to an image, and displayed on the output device.
- 24. Quick Quiz 1) What is a dual-core processor? Answer: A single chip that contains two separate processors 2) How are analog signals different from digital signals? Answer: Analog uses continuous (wave form) signals that vary in strength and quality; digital signals, which are used by most computers, recognize only two discrete states: on and off signals?
- 25. Memory What 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 other circuit board Each byte stored in memory at unique location called an address
- 26. Memory What is memory? (cont.) A byte (a character) – 8 bits - is the basic storage unit in memory Each byte resides temporarily in a location in memory that has an address – a unique number that identifies the location of a byte in memorylocation of a byte in memory To access data or instruction in memory, computer references the addresses that contain bytes of data
- 27. Memory How is memory measured? Term Abbreviation Approximate Size Kilobyte KB or K 1 thousand bytes By number of bytes available for storage Kilobyte KB or K 1 thousand bytes Megabyte MB 1 million bytes Gigabyte GB 1 billion bytes Terabyte TB 1 trillion bytes Actually a kilobyte = 1,024 bytes
- 28. Memory What is random access memory (RAM)? Also calledAlso called Most RAM isMost RAM is Memory chips that can beMemory chips that can be read from and writtenread from and written to by processor & other devicesto by processor & other devices The more RAM aThe more RAM a computer has, thecomputer has, the faster it respondsfaster it responds Also calledAlso called main memorymain memory or primaryor primary storagestorage volatilevolatile, it is lost, it is lost when computer’swhen computer’s power ispower is turned offturned off
- 29. Memory How do program instructions transfer in and out of RAM? Step 1. When you start the computer, certain operating system files are loaded into RAM from the hard disk. The operating system displays the user interface on the screen. Operating systemOperating system instructionsinstructions Web browserWeb browser instructionsinstructions Operating systemOperating system interfaceinterface Web browserWeb browser windowwindow RAM Step 2. When you start a Web browser, the program’s instructions are loaded into RAM from the hard disk. The Web browser window is displayed on the screen. Word processingWord processing program instructionsprogram instructions Word processingWord processing program windowprogram window RAM Web browser programWeb browser program instructions areinstructions are removed from RAMremoved from RAM Web browserWeb browser window is no longerwindow is no longer displayed ondisplayed on desktopdesktop window is displayed on the screen. Step 3. When you start a word processing program, the program’s instructions are loaded into RAM from the hard disk. The word processing program, along with the Web Browser and certain operating system instructions are in RAM. The word processing program window is displayed on the screen. Step 4. When you quit a program, such as the Web browser, its program instructions are removed from RAM. The Web browser is no longer displayed on the screen.
- 30. Do not have toDo not have to be rebe re--energizedenergized as often asas often as DRAMDRAM MostMost commoncommon typetype Memory What are two basic types of RAM chips? StaticStatic Must beMust be rere--energizedenergized constantlyconstantly Faster andFaster and more reliablemore reliable than DRAMthan DRAM chipschips RAMRAM (SRAM)(SRAM) DynamicDynamic RAMRAM (DRAM)(DRAM) Newer Type: Magnetoresistive RAM (MRAM)
- 31. 1 Gb SDRAM Dual-in-line Memory Module
- 32. Two types of DIMMs: a 168-pin SDRAM module (top) and a 184-pin DDR SDRAM module (bottom). 30- (top) and 72-pin (bottom) SIMMs. Early 30-pin modules commonly had either 256 KB or 1 MB of memory. http://www.maplin.co.uk/images/Full/a23aj.jpg http://www.makeitsimple.com/articles/ramguide/ramguidep2.htm
- 33. Memory Where does memory reside? Resides on small circuit board called memory module Memory slots on motherboard hold memory dual inline memory module motherboard hold memory modules memory chip memory slot
- 34. Memory How much RAM does an application require? Depends on the types of software you plan to use For optimal performance, youperformance, you need more than minimum specifications
- 35. Memory How much RAM do you need? Depends on type of applications you intend to run on your computer RAM Use 256 MB to 1 GB 512 MB to 1 GB 2 GB and up • Home and business users managing • Users requiring more advanced multimedia capabilities • Power users creating professional Web sites personal finance • Using standard application software such as word processing • Using educational or entertainment CD-ROMs • Communicating with others on the Web • Running number-intensive accounting, financial, or spreadsheet programs • Using voice recognition • Working with videos, music, and digital imaging • Creating Web sites • Participating in video conferences • Playing Internet games • Running sophisticated CAD, 3D design, or other graphics-intensive software
- 36. Memory What is cache? L1 cache built into processor L2 cache slower but has larger Helps speed computer processes by storing frequently used instructions and data Also called memory cache L2 cache slower but has larger capacity L2 advanced transfer cache is faster, built directly on processor chip L3 cache is separate from processor chip on motherboard (L3 is only on computers that use L2 advanced transfer cache)
- 37. Memory Cache Cache speeds up processing time It stores frequently used instruction & data. When the processors needs them, it searches the memory in an order with greater delay in processing for each level of memory it must search as the following order:as the following order: L1 cache, then L2 cache, then L3 cache if it exists, then RAM If the instruction or data is not found in memory, then it must search a slower speed storage medium (h/disk, CD, or DVD)
- 38. Memory What is read-only memory (ROM)? Memory chips that storeMemory chips that store permanent datapermanent data and instructionsand instructions Nonvolatile memoryNonvolatile memory, it is not, it is not lost when computer’slost when computer’s power is turned offpower is turned off Three types:Three types: EEPROMEEPROM ((eelectricallylectrically eerasablerasable pprogrammablerogrammable FirmwareFirmware—— ROM chips manufacturedROM chips manufactured with permanently writtenwith permanently written data, instructions,data, instructions, or informationor information eerasablerasable pprogrammablerogrammable rreadead--oonlynly mmemory)emory)—— Type of PROMType of PROM containing microcodecontaining microcode programmerprogrammer can erasecan erase PROMPROM ((pprogrammablerogrammable rreadead--oonlynly mmemory)emory)—— Blank ROMBlank ROM chip onto whichchip onto which a programmera programmer can write permanentlycan write permanentlyUse Microcode instructions to program a PROM chip Erase microcode with an electrical signal
- 39. Memory What is flash memory? Nonvolatile memory that can be erased electronically and rewritten Used with PDAs, digital cameras, smart phones, music players, digital voice recorders, printers, Internet receivers, and pagers flash memoryflash memory chips USB port from the computer Portable media player earphones cable
- 40. Memory What is CMOS? Complementary metal-oxide semiconductor memory Used in some RAM chips, flash memory chips, and other types of memory chips Uses battery power to retain information when other power is turned off Stores date, time, and computer’s startup information memory chips The flash memory chips that store computer’s startup information often use CMOS technology
- 41. Memory What is access time? Amount of time it takes processor to read data from memory Measured in nanoseconds (ns), one billionth of a second It takes 1/10 of a second to blink 10 million operations = 1 blink It takes 1/10 of a second to blink your eye; a computer can perform up to 10 million operations in same amount of time Term Speed Millisecond One-thousandth of a second Microsecond One-millionth of a second Nanosecond One-billionth of a second Picosecond One-trillionth of a second
- 42. Memory Access Time The access time (speed) of memory contributes to the overall performance of the computer. Accessing data in memory – 200,000 times faster than h/disk, because of h/disk’s mechanical motion. Access time also stated in MHz 667 MHz DDR2 SDRAM667 MHz DDR2 SDRAM Divide 1 billion ns by the megahertz number 667 MHz = (1,000,000,000/667,000,000)ns ≈ 1.5ns Manufacturers & retailers list a computer’s memory in terms of its size, not its access time. 512 MB of SDRAM upgradeable to 4 GB
- 43. Expansion Slots and Adapter Cards What is an adapter card? A circuit board that enhances system unit or provides connections to external devices called peripherals – devicesperipherals – devices connected to system unit & controlled by processor: modems, disk drives, printers, scanners, keyboards,… Also called an expansion card
- 44. Expansion Slots and Adapter Cards What is an expansion slot? An opening, or socket, on the motherboard that can hold an adapter card With Plug and Play,With Plug and Play, the computer automatically configures cards and other devices as you install them
- 45. Expansion Slots and Adapter Cards
- 46. Expansion Slots and Adapter Cards What are PC cards, and flash memory cards? PC card thin removable flash memory device to enable wireless Internet access to notebook computers ExpressCard moduleExpressCard module Next generation of PC Cards. Removable flash memory device, to add memory, storage, sound, fax/modem, communications, and other capabilities to computers
- 47. Expansion Slots and Adapter Cards What are PC cards, and flash memory cards? Flash memory card allows users to transfer data from mobile devices to desktop computers storage capacity range: 32 MB – 8 GB hot plugging – feature allows user tohot plugging – feature allows user to insert & remove the removable flash memory & other devices while computer is running USB Flash drive flash memory storage that plugs in a USB port on a computer 32 MB – 64 GB
- 48. Ports and Connectors What are ports and connectors? Port connects external devices to system unit Connector joins cable to peripheral Male connector: have 1 or more pins Female connector: have matching hollows to accept the pins on a male connector
- 49. Ports and Connectors What are different types of connectors?
- 50. Ports and Connectors What is a serial port? Transmits one bit of data at a time Connects slow-speed devices, such as mouse, keyboard, modemmodem E.g. COM port
- 51. Ports and Connectors What is a parallel port? Connects devices that can transfer more than one bit at a time, such as a printer Can transfer 8 bits of data (one byte) simultaneously(one byte) simultaneously through 8 separate lines in a single cable
- 52. Ports and Connectors What are USB ports? USB (universal serial bus) port can connect up to 127 different peripherals together with a single connector type USB (universal serial bus) port can connect up to 127 different peripherals together with a single connector type Third USB device connects to second USB device, and so on Third USB device connects to second USB device, and so on Second USB device connects to first USB device Second USB device connects to first USB deviceFirst USB device connects to USB port on computer First USB device connects to USB port on computer Single USB port can be used to attach multiple peripherals in a daisy chain Single USB port can be used to attach multiple peripherals in a daisy chain PCs typically have six to eight USB ports on front or back of the system unit PCs typically have six to eight USB ports on front or back of the system unit
- 53. Ports and Connectors What are FireWire ports? Similar to a USB port Connects multiple types of devices that require faster data transmission speeds: digital video camera, color printer, scanners, digital cameras,camera, color printer, scanners, digital cameras, DVD drives,… Allows you to connect up to 63 devices together Can use FireWire hub to attach multiple devices to a single FireWire port
- 54. Ports and Connectors What are special-purpose ports? MIDI (Musical Instrument Digital Interface) port eSata (external SATA – Serial Advances Technology Attachment) port – connect SATA h/disk to computer Not included in typical computer Allow users to attach specialized peripherals or transmit data to wireless devices Attachment) port – connect SATA h/disk to computer SCSI (small computer system interface) port IrDA (Infrared Data Association) port – data transmission via infrared light waves; need to align the IrDA port on the device with IrDA port on the computer (like television remote control) Bluetooth port – Bluetooth technology uses radio waves to transmit data between two devices; do not need to be aligned with each other)
- 56. Ports and Connectors USB & FireWire ports are replacing traditional ports completely
- 57. Buses What is a bus? Channel that allows devices inside computer to communicate with each other Data bus – transfers actual data Address bus – transfers the info. where the data should reside in memorythe data should reside in memory System bus connects processor and RAM Bus width determines number of bits transmitted at one time (32-bit, 64-bit bus) Word size is the number of bits processor can interpret and execute at a given time; in most computers, the word size is the same as the bus width Bus clock speed: 1066 MHz Memory chips
- 58. Buses System Bus/Front Side Bus (FSB) Part of motherboard Connects processor to main memory Expansion Bus Allows processor to communicate with peripherals PCI bus (Peripheral Component Interconnect bus)PCI bus (Peripheral Component Interconnect bus) PCI Express bus Accelerated Graphics Port (AGP) bus USB & FireWire bus PC Card bus FireWire Bus PCI Bus AGP Bus USB Bus
- 59. Bays What is a bay? Open area inside system unit used to install additional equipment Drive bays typically hold disk drivesdisk drives External drive bay – allow user to access the drive from outside the system unit: CD & DVD drives Internal drive bay – within system unit: h/disk
- 60. Power Supply What is a power supply? Converts AC Power into Fan keeps system unit components External peripherals might use an AC adapter, which is an external power supply DC Power cool One end of AC adapter plugs in the wall outlet & the other end attached to the peripheral. The AC adapter converts the AC power into DC power that the peripheral requires.
- 61. Mobile Computers and Devices What is a mobile computer? Notebook, weighing between 2.5 and 8 pounds, or mobile device such as a PDA
- 62. Mobile Computers and Devices What ports are on a notebook computer?
- 63. Mobile Computers and Devices What ports and slots are on a tablet PC?
- 64. Putting It All Together What are suggested processor, clock speed, and RAM requirements based on the needs of various types of users?
- 65. Keeping Your Computer Clean Over time, the system unit collects dust – even in a clean environment Preventative maintenance requires a few basic products: