Chapter 4 The Components of the System Unit

1. Chapter 4The Components of the System Unit

2. Chapter 4 Objectives Next Differentiate among various stylesof system units Differentiate among the varioustypes of memory Identify chips, adapter cards, and other components of a motherboard Describe the types of expansion slots and adapter cards Describe the components of a processor and how they complete a machine cycle Explain the difference among a serial port, a parallel port, a USB port, and other ports Identify characteristics of various personal computer processors on the market today Describe how buses contribute to acomputer’s processing speed Define a bit and describe how a series of bits represents data Identify components in mobile computersand mobile devices Explain how programs transfer inand out of memory

3. The System Unit Next • What is thesystem unit? • Case that contains electronic components of the computer used to process data • Sometimes called thechassis p. 180 Fig. 4-1

4. The System Unit power supply drive bays processor memory ports sound card video card modem card network card Next • What are common components inside the system unit? • Processor • Memory • Adaptercards • Sound card • Modem card • Video card • Network card • Ports • Drive bays • Powersupply p. 181 Fig. 4-2

5. The System Unit adapter cards processor chip memory chips memory slots Expansionslots for adapter cards Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click Clock Motherboards below Chapter 4 motherboard Next • What is themotherboard? • Main circuit board in system unit • Contains adapter cards, processor chips, andmemory chips • Also calledsystem board p. 182 Fig. 4-3

6. The System Unit Click to view animation Next dual inline packages (DIP) holds memory chips • What is achip? • Small piece of semi-conducting material on which integrated circuits are etched • Integrated circuits contain many microscopic pathways capable of carrying electrical current • Chips are packaged so they can be attached to a circuit board pin grid array (PGA) package holds processor chips p. 182 Fig. 4-4

7. Processor Processor Control Unit Arithmetic Logic Unit (ALU) InstructionsDataInformation InstructionsDataInformation Next • What is thecentral processing unit (CPU)? • Interprets and carries out basic instructions that operate a computer ControlUnit ArithmeticLogic Unit (ALU) • Control unit directs and coordinates operations in computer • Arithmetic logic unit (ALU) performs arithmetic, comparison, and logical operations Memory InputDevices OutputDevices Data Information • Also called theprocessor StorageDevices p. 183 Fig. 4-5

8. Processor Memory Processor ALU Control Unit Next • What is amachine cycle? • Four operations of the CPU comprise a machine cycle Step 1. FetchObtain program instruction or data item from memory Step 2. DecodeTranslate instruction into commands Step 4. StoreWrite result to memory Step 3. ExecuteCarry out command p. 184 Fig. 4-6

9. Processor Next • What ispipelining? • CPU begins fetching second instruction before completing machine cycle for first instruction • Results in faster processing p. 185 Fig. 4-7

10. Processor Next • What is aregister? • Temporary high-speed storage area that holds data and instructions Stores location from where instruction was fetched Stores instruction while it is being decoded Stores data while ALU computes it Stores results of calculation p. 185

11. Processor Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click Clock Speed below Chapter 4 Next • What is thesystem clock? • Controls timing of all computer operations • Generates regular electronic pulses, or ticks, that set operating pace of components of system unit Each tick is a clockcycle Pace of system clock is clock speed Most clock speeds are in the gigahertz (GHz) range (1 GHz = one billion ticks of system clock per second) Processor speed can also be measured in millions of instructions per second (MIPS) p. 185

12. Processor Comparison of Widely UsedPersonal Computer Processors Name Date Clock Introduced Speed Itanium 2 2002 1.3–1.5 GHZ Xeon 2001 1.4–3.06 GHZ Itanium 2001 733–800 MHZ Pentium 4 2000 1.4–3.2 GHZ Pentium III Xeon 1999 500–900 MHZ Pentium III 1999 400 MHZ–1.4 GHZ Celeron 1998 266 MHZ–2.6 GHZ Operon 2003 2–2.4 GHZ Athlon MP 2002 1.53–2.25 GHZ Athlon XP 2001 1.33–2.26 GHZ Athlon 1999 500 MHZ–1.4 GHZ ™ Click to view video Next • How do personal computer processors compare? p. 186 Fig. 4-8

13. Processor Intel Processor Desired Clock Speed Itanium or Xeon 1.3 GHz and up 3.0 GHz and up 2.4 GHz to 3.0 GHz Up to 2.4 GHz 2.2 GHz and up Pentium family Celeron Click to view video Next • Which processor should you select? • The faster the processor, the more expensive the computer p. 188 Fig. 4-9

14. Processor Chip-for chip upgradereplace the chip Piggyback upgradestack new chip on top of old one Daughterboard upgradechip is on adapter card that plugs into motherboard Next • What are the types of processor upgrades? p. 188

15. Processor lever lever Step 1.Lift the lever on the socket. Step 2.Insert the chip. Step 3.Push the lever down. Next • What is azero-insertion force (ZIF)socket? • Allows you to install and remove chips with no force p. 189 Fig. 4-10

16. Processor Next • What areheat sinksandheat pipes? • Heat sink—componentwith fans that cools processor heat sink fan • Heat pipee—smallerdevice for notebook computers heat sink p. 190 Fig. 4-11

17. Processor Next • What is acoprocessor? Chip that assists processor in performing specific tasks One type is a floating-point coprocessor, also known as a math or numeric coprocessor p. 190

18. Processor Processor 1 Processor 2 Processor 3 Processor 4 Memory Memory Memory Memory Next • What isparallel processing? • Using multiple processors simultaneously to execute a program faster • Requires special software to divide problem and bring results together Control Processor Results combined p. 190 Fig. 4-12

19. Data Representation Next • How do computers represent data? • Most computers aredigital • Recognize only two discrete states: on or off • Use a binary system to recognize two states • Use Number system with two unique digits: 0 and 1, called bits (short for binary digits) p. 191 Fig. 4-13

20. Data Representation Next • What is abyte? • Eight bits grouped together as a unit • Provides enough different combinations of 0s and 1s to represent 256 individual characters • Numbers • Uppercase and lowercase letters • Punctuation marks p. 191 Fig. 4-14

21. Data Representation ASCII Symbol EBCDIC 00110000 0 11110000 00110001 1 11110001 00110010 2 11110010 00110011 3 11110011 Next • What are three popular coding systems to represent data? • ASCII—AmericanStandardCodeforInformationInterchange • EBCDIC—ExtendedBinaryCoded DecimalInterchangeCode • Unicode—coding scheme capable of representing allworld’s languages p. 192 Fig. 4-15

22. Data Representation Step 1.The user presses the capital letter D (shift+D key) on the keyboard. Step 4.After processing, the binary code for the capital letter D is converted to an image, and displayed on the output device. Next • How is a letter converted to binary from and back? 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. p. 193 Fig. 4-16

23. Memory Next Seat #2B4 Seat #2B3 • What ismemory? • Electronic components that store instructions, data, and results • Consists of one or more chips on motherboard orother circuit board • Each byte stored in unique location called anaddress, similar to seats on a passenger train p. 193 Fig. 4-17

24. Memory Term Abbreviation Approximate Size Kilobyte KB or K 1 thousand bytes Megabyte MB 1 million bytes Gigabyte GB 1 billion bytes Terabyte TB 1 trillion bytes Next • How is memory measured? • By number of bytes available for storage p. 194 Fig. 4-18

25. Memory Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click RAM below Chapter 4 Next • What israndom access memory (RAM)? Memory chips that can be read from and written to by processor Also called main memory or primary storage Most RAM is volatile, it is lost when computer’s power is turned off The more RAM a computer has, the faster it responds p. 195

26. Memory RAM RAM Next • 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 system interface Operating system instructions 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. Web browser instructions Web browser window 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. Word processing program instructions Word processing program window Step 4.When you quit a program, such as the Web browser, its program instructions are removed from RAM. The Web browser no longer is displayed on the screen. Web browser program instructions are removed from RAM Web browser window no longer is displayed on desktop p. 195 Fig. 4-19

27. Memory Most common type Used for special applications such as cache Faster variations of DRAM are SDRAM and RDRAM Faster and more reliable than DRAM chips Next • What are two basic types of RAM chips? Static RAM (SRAM) Dynamic RAM (DRAM) • Future: Magnetoresistive RAM (MRAM) p. 196

28. Memory Next dual inline memory module • Where does memory reside? • Resides on small circuit board calledmemory module • Memory slotson motherboard hold memory modules memory chip memory slot p. 196 Fig. 4-20

29. Memory • System Requirements • Windows® XP Home Edition/Professional • Intel Pentium processor at 233MHZ or higher • AMD K6 (Athlon Duron Family processor at 233MHZ or higher • 64 MB of RAM Next • How much RAM does an application require? • Software package typically indicates RAM requirements • For optimal performance, you need more than minimum specifications p. 197 Fig. 4-21

30. Memory RAM 128 to 256 MB 256 to 1 GB 1 GB and up Use • Home and businessusers managingpersonal finance • Using standardapplication softwaresuch as word processing • Using educational or entertainmentCD-ROMs • Communicating with others on the Web • Users requiring more advanced multimedia capabilities • 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 • Power users creating professional Web sites • Running sophisticatedCAD, 3D design, orother graphics-intensive software Next • How much RAM do you need? • Depends on type of applications you intend to runon your computer p. 197 Fig. 4-22

31. Memory Click to view Web Link,click Chapter 4, Click Web Link from left navigation, then click Cache below Chapter 4 Next • What iscache? • Helps speed computer processes by storing frequently used instructions and data • Also calledmemory cache • L1 cache built into processor • 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) p. 198 Fig. 4-23

32. Memory Next • What isread-only memory (ROM)? Memory chips that store permanent data and instructions Nonvolatile memory, it is not lost when computer’s power is turned off Three types: EEPROM (electrically erasable programmable read-only memory)—Type of PROM containing microcode programmer can erase Firmware—Manufactured with permanently written data, instructions, or information PROM (programmable read-only memory)—Blank ROM chip onto which a programmer can write permanently p. 198

33. Memory To headphones Flash memory chip From computer Flash memory card Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click Flash Memory below Chapter 4 MP3 Player Next • What isflash memory? • Nonvolatile memory that can be erased electronically and reprogrammed • Used with PDAs, digital cameras, digital cellular phones, music players, digital voice recorders, printers, Internet receivers, and pagers Step 3.Plug the headphones into the MP3 player, push a button on the MP3 player, and listen to the music through the headphones. Step 1.Purchase and download MP3 music tracks from a Web site. With one end of a special cable connected to the system unit, connect the other end into the MP3 player. Step 2.Instruct the computer to copy the MP3 music track to the flash memory chip in the MP3 player. p. 199 Fig. 4-24

34. Memory Used in some RAM chips, flash memory chips, and other types of memory chips Complementary metal-oxide semiconductor memory Uses battery power to retain information when other power is turned off Stores date, time, and computer’s startup information Next • What isCMOS? p. 200

35. Memory 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 Next • What isaccess 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 your eye; a computer can perform up to 10 million operations in same amount of time p. 200 Figs. 4-25-4-26

36. Expansion Slots and Adapter Cards Types of Adapter Cards Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click Adapter Cards below Chapter 4 Next • What is anadapter card? • Enhances system unit or provides connections to external devices calledperipherals • Also called anexpansion card p. 201 Fig. 4-27

37. Expansion Slots and Adapter Cards Next • What is anexpansion slot? • An opening, or socket, on the motherboard that can hold an adapter card • WithPlug and Play, the computer automatically configures cardsand other devices as you install them p. 201 Fig. 4-28

38. Expansion Slots and Adapter Cards Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click PC Cardsbelow Chapter 4 Next • What arePC cards andflash memory cards? • APC cardadds memory, storage, sound, fax/modem, communications, and other capabilities to notebook computers • Aflash memory cardallows users to transfer data from mobile devices to desktop computers • Hot plugging allows you to insert and remove cards while computer is running p. 202 Fig. 4-29–4-30

39. Ports and Connectors Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click Ports and Connectors below Chapter 4 Next • What areportsandconnectors? • Portconnects external devices to system unit • Connector joins cable to peripheral • Available in one of two genders: male and female p. 203 Fig. 4-31–4.32

40. Ports and Connectors Next • What are different types of connectors? p. 204 Fig. 4-33

41. Ports and Connectors Next • What is aserial port? • Transmits one bit of data at a time • Connects slow-speed devices, such as mouse, keyboard, modem p. 205 Fig. 4-34

42. Ports and Connectors Next • What is aparallel port? • Connects devices that can transfer more than one bit at a time, such as a printer p. 205 Fig. 4-35

43. Ports and Connectors Single USB port can be used to attach multiple peripherals in a daisy chain Third USB device connects to second USB device, and so on PCs typically have four to eight USB ports on front or back of the system unit Second USB device connects to first USB device First USB device connects to USB port on computer Next • What areUSB ports? USB (universal serial bus) port can connect up to 127 different peripherals together with a single connector type p. 206

44. Ports and Connectors Next • What arespecial-purpose ports? • Allow users to attach specialized peripherals (digital video cameras, color printers, scanners, and disk drives) or transmit data to wireless devices • FireWire port • MIDI (Musical Instrument Digital Interface) port • SCSI (small computer system interface) port • IrDA (Infrared Data Association) port • Bluetooth port p. 206 Fig. 4-36

45. Buses Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click Buses below Chapter 4 Next • What is abus? • Channel that allows devices inside computer to communicate with each other • Bus width determines number of bits transmitted at one time • Word size is the number of bits processor can interpret and execute at a given time • On motherboard p. 208 Fig. 4-38

46. Buses • Two types of buses: • System bus: is part of the motherboard and connects the processor to main memory. • Expansion bus

47. Buses Next • What is anexpansion bus? • Allows processor to communicate with peripherals p. 209 Fig. 4-39

48. Buses • PCI bus: Peripheral Component Interconnect bus, is a high speed expansion bus that connects higher speed devices. Such as video card, sound cards, network card. • AGP bus: Accelerated Graphics Port, to improve the speed with which 3D graphics and video transmit. • ISA bus: Industry Standard Architecture, the standard slow I/O bus.

49. Bays Next • What is abay? • Open area inside system unit used to install additional equipment • Drive baystypically hold disk drives p. 210 Fig. 4-40

50. Power Supply External peripherals might use an AC adapter, which is an external power supply ConvertsAC PowerintoDC Power Fan keepssystem unit components cool Next • What is a power supply? p. 211