1. Computer Hardware and Architecture 1

2. Objectives: By the end of this session, the student will be able to:  Name and define 5 categories of Computer Architecture  Show how these categories inter-relate  Define the function of input devices  List and describe the operation of the input devices described in the course  Define the function of output devices  List and describe the operation of the output devices described in the course  Define Primary Storage  List 2 types of primary storage  List the two parts of the CPU  Describe the function of each part of the CPU  List the factors that affect processor speed  Describe how each of these factors affects processor speed  List the 3 operating modes of the Intel processor  Describe the traits of these modes  Define Secondary Storage  List 2 types of secondary storage, give examples of each  List the 3 structures of magnetic secondary storage  List 3 PC ports that perform both input and output  Compare and contrast these ports based on maximum data transfer speed, maximum number of concurrently attached devices 2

3. Computer Systems History 1642: Pascaline was invented by Blaise Pascal in 1642. The device is able to add two decimal numbers. Using ten's complement it is also possible to subtract. Pascal had started production of his calculator (about 50 machines were produced), but there was no interest, so he had to stop. 3

4. Computer Systems History 1671: First calculator with multiplication and division 1801: Joseph-Marie Jacquard’s loom- introduction of punch cards 1822: Analytical Engine invented by Charles Babbage 4

5. Computer Systems History 1939: Atanasoff-Berry Computer. First computer built with vacuum tubes. 5

6. Computer Systems History 1940: Prototype of the Bombe developed by Alan Turing (Enigma code) 6

7. Computer Systems History 1943: Mark I. Developed in the U.S., with the help International Business Machines IBM) 7

8. Computer Systems History 1944: Colossus, designed by Tommy Flowers was operational (Lorenz code) 8

9. Computer Systems History 1946: ENIAC developed to calculate missile trajectories originally. Computers began to achieve manageable size. 9

10. Computer Systems History 1951: UNIVAC, first commercially sold computer 1954: First completely transistorized computer 1963: DEC PDP-8 1971: Intel 4004, first true CPU 1975: Altair Sphere 8800, sold as kits to hobbyists 1977: Apple II, Commodore PET 1978: Atari 400 and 800 1981: IBM PC 10

11. Computer Systems Definition A computer system is hardware that contains software to transform data into information. This transformation requires four aspects of data handling:  Input  Processing  Output  Storage 11

12. Computer Systems, Continued Structure A computer system can be though of as: Hardware Computer System Software 12

13. Computer Architecture The architecture of a computer can be broken down into 5 categories. These 5 categories interrelate with each other in a structured way. Categories The categories of the architecture of a computer system are: 13

14. Computer Architecture, Continued Interrelation of Categories The categories interrelate in the following way: 14

15. Computer Systems Diagram This is a diagram of the elements of a computer system: 15

16. Computer Systems Diagram This is a diagram of the elements of a computer system, inside the chassis: 16

17. Input Purpose The purpose of input is to take data that is external to the computer system, and transform it into data that is internal to the computer system. Some of the devices that perform this function are:  Keyboard  Mouse  Barcode scanner  Optical Mark Recognition (OMR)  Optical Character Recognition (OCR)  Hand-written characters  Voice recognition  Touch screens 17

18. Input: Keyboard Keyboard The keyboard is probably the most common way to get data into a computer system. What it does A keyboard converts the keys pressed by the user into electrical patterns that represent the letter or symbol that was pressed on the keyboard. Diagram Below is a diagram of a keyboard, with different regions labelled: 18

19. Input: Mouse Mouse The mouse has become a very popular means of providing input to a computer system. What it does The mouse is used to position a pointer over a symbol on the screen. The buttons on the mouse can then be used to perform a defined action. Diagram Below is a picture of a typical mouse: 19

20. Input: Barcode scanner Barcode scanner Barcode scanners are a means to read some data (numbers and letters) very quickly and enter them into a computer system faster and more accurately than a human. What it does A laser is reflected off of a label consisting of different width lines and into a photocell. The electronics of the barcode scanner convert the patterns of light and dark into an equivalent keyboard character. Diagram Below are pictures of typical barcode scanner applications: 20

21. Input: OMR Optical Mark Recognition Optical Mark Recognition (OMR) is another means to get data into a computer system faster and more accurately that a person. Example Common examples of the use of OMR are:  the bubble-sheets used in tests  old style computer cards What it does The OMR reader recognizes marks on paper based on their position and converts them into data that is meaningful to the computer system. 21

22. Input: OMR, Continued Diagram Below is a picture of a computer card that reads 'WELCOME TO ICS124SB!': 22

23. Input: OCR Optical Character Recognition Optical Character Recognition (OCR) is another way to quickly and accurately input data into a computer system, yet the data itself is also readable by humans. What it does The characters used in OCR are very structured. Again a laser is reflected off a label containing the characters and into a photocell. The electronics in the OCR reader convert the patterns into equivalent keyboard characters. Diagram Below are OCR symbols: 23

24. Input: Hand-written characters Hand-written characters The complexity of computer systems and electronics has advanced to the point where hand writing can be recognized by the computer. The purpose of this is to eliminate transcribing hand-written forms into electronic format through data entry operators. What it does The hand-written word is scanned and the pattern of lines compared to 'model' characters. When a match is found, that character is sent as a keyboard character. Diagram Below are samples of hand-written characters and the rules to write them: 24

25. Input: Voice recognition Voice recognition Is means to provide some convenience when entering data into a computer system. What it does The process of voice input is: 25

26. Input: Voice recognition, Continued Diagram Below is a picture of the process: 26

27. Input: Touch-screens Touch screens Touch screens are a means to allow a user to simply choose among a list of predefined choices, and provide the selection to the computer system. What it does A grid of light beams are projected vertically and horizontally across the surface of a screen. When a finger interrupts a horizontal and vertical light beam, the position of the finger is known. This information is passed to the computer system. Diagram Below is a picture of a touch-screen installation: 27

28. Output Purpose The purpose of output is to take information that is internal to the computer system, and transform it into information that is external to the computer system, and therefore available for the user to use. Some of the devices that perform this function are:  Monitor  Dot-matrix printer  Bubble-jet printer  Laser printer  Voice 28

29. Output: Monitors Monitors Monitors are the most common means to display information to a user. When viewing information on a monitor, it is said to be in 'soft copy' format. What it does The monitor consists of a Cathode Ray Tube, or CRT, that projects a stream of electrons across the back of its screen. The electron beam sweeps back and forth from the top to the bottom of the screen. The back of the CRT has a phosphorous coating that glows when hit by the electrons. 29

30. Output: Monitors, Continued Attributes of a monitor There are various attributes of monitors that need to be considered when comparing one monitor to another: 30

31. Output: Monitors, Continued LCD Technology LCD is an acronym for Liquid Crystal Display. The crystals are sandwiched between two layers of polarizing film, set at right angles. The natural twist of the crystals causes light passing through them to reorient its plane of vibration. By passing an electric current though the crystals, the crystals will straighten out- losing their twist. If the twist of the crystals causes the light to reorient itself by 90 o, then it can get through the second polarizing film layer. If the twist has been eliminated, the light is not reoriented (maintains its original plane of vibration), and fails to get through the second polarizing film. 31

32. Output: Monitors, Continued Light entering first polarizing film layer. The right-most light wave is blocked. 32

33. Output: Monitors, Continued Light passing through first polarizing film, top wave enters crystal that has an electric current applied, the middle wave missed a crystal, the bottom wave enters a crystal with its natural twist 33

34. Output: Monitors, Continued Only the wave that was reoriented by the crystal escapes, and will be visible. 34

35. Output: Monitors, Continued LCD Panels There are three elements of a 'pixel' in an LCD screen: Red Green Blue By turning on combinations of the elements of a pixel, 256 colours are available By altering the amount of light that gets through the backlit screen or reflective screen, 256 shades per element are possible, therefore 16 million colours are available. 35 = White = Yellow = Red = Blue = Green = Magenta

36. Output: Monitors, Continued Diagram Below is a picture of a monitor: 36

37. Output: Dot-Matrix printers Dot-Matrix printers The dot-matrix printer is one of the early types of printers. They tend not to be used today as they are too noisy for an office environment. They do have uses when multiple copies need to be printed simultaneously. They typically do not print in colour. When sending output to a printer, it is referred to as a 'hard copy'. What is does The dot-matrix printer contains a 'print head' that passes between a ribbon and the paper. Contained in the print head is a matrix of pins that strike the ribbon against the paper in a pattern of a character. The pins in the print head can be arranged as 5x7, 9x9 or better. Diagram An example of how the character 'A' would be displayed on a 5x7 dot-matrix printer: 37

38. Output: Ink jet printers Ink jet printers The ink jet printer is very popular due to its:  lost cost  high resolution (300dpi)  reasonable print speed  use of colour  low noise What is does The ink jet printer sprays ink onto the paper to form the images of characters or graphics. 38

39. Output: Ink jet printers, Continued Diagram Below is a picture of an ink jet printer: 39

40. Output: Laser printers Laser printers The laser printer is a high end printer that provides:  superior resolution (600dpi - 1200dpi)  fast print speed  Is capable of colour, if you are willing to pay the price What it does A laser is used to neutralize points on a positively charged drum inside the printer. As the drum passes by a toner cartridge, toner sticks to the neutral spots on the drum. The toner is then transferred to paper and heated to fuse it in place. 40

41. Output: Laser printers, Continued Diagram Below is a picture of a laser printer: 41

42. Output: Audio Audio The output of audio information can take two forms:  Speech synthesis  Music Speech synthesis There are two methods of speech synthesis:  synthesis by analysis  synthesis by rules Synthesis by analysis uses pre-recorded words stored and retrieved when needed. This method is limited by the number of words that were pre-recorded. Synthesis by rules uses a device that applies linguistic rules to create artificial speech. This method is not as natural sounding as using pre-recorded words, however it is not as restricted. 42

43. Output: Audio, Continued Music MIDI (Musical Instrument Digital Interface) is a set of rules designed for recording and playing back music on digital synthesizers. 43

44. Primary Storage Purpose The purpose of primary storage is to store data for a short period of time while it is being manipulated. The term 'memory' is also used when referring to Primary Storage, however this term also includes forms of memory that are not Primary Storage.

45. Primary Storage, Continued Types of memory The types of memory are listed below:  RAM (Primary Storage)  DRAM  SRAM  External cache  ROM (not Primary Storage)  PROM  EPROM  EEPROM 45

46. Primary Storage, Continued Measuring memory The smallest unit of memory is the byte. A byte can used to represent a single character or symbol. When evaluating memory size the following aggregates are also used:  KB - kilobyte = 1,024 bytes  MB - megabyte = 1,048,576 bytes  GB -gigabyte = 1,073,741,824 bytes A typical modern home computer will have 512MB or more 46

47. Primary Storage, Continued RAM RAM is an acronym for Random Access Memory. RAM is volatile, in that when power is removed from the circuit, the contents of RAM are lost. SRAM SRAM is Static RAM. When data is written to SRAM, it is retained by the memory without any further intervention by the computer system. DRAM DRAM is Dynamic RAM. When data is written to DRAM, it must be periodically refreshed or it will loose its contents. DRAM may be slower than SRAM, however due to its size and cost, it is used in most PCs. 47

48. Primary Storage, Continued DRAM, Continued This is a picture of DRAM: 48

49. Primary Storage, Continued External cache Cache is a a small amount of memory, typically 512KB, that is very fast. By keeping instructions or data that is frequently used or most recently used in cache memory, there is a chance that the processor will not need to access the slower RAM memory to process the next instruction. 49

50. ROM ROM is an acronym for Read Only Memory. ROM is non-volatile, in that when power is removed from the circuit, the contents of ROM are retained. The data on ROM is written once, or the ROM is manufactured with the data already present. PROM PROM is Programmable ROM. This is a memory chip that is manufactured with no data, however it can be written to once. EPROM EPROM is Erasable PROM. The contents of the ROM can be erased by exposing the circuit to UV radiation for 20 minutes. The EPROM is now ready to have new data written to it. 50

51. ROM, Continued EEPROM EEPROM is Electrically Erasable PROM. The contents of the ROM can be erased by sending an erase signal to the EEPROM circuit. The EEPROM is now ready to have new data written to it. 51

52. Processor Purpose The processor, or Central Processing Unit (CPU) is where the computer system performs the manipulation of data. Every computer must have at least one CPU to function. A processor is composed of:  control unit  Arithmetic / logic unit (ALU) Control unit The control unit oversees the operation of the CPU by performing:  Fetch - get an instruction from memory  Decode - decide what the instruction means and direct the necessary data be moved from memory to the ALU The combination of Fetch and Decode is called, Instruction Time or I-Time 52

53. Processor, Continued Arithmetic / Logic Unit The ALU performs two classes of operations:  Arithmetic operations  Logical operations The ALU is responsible for:  Execute  Store The combination of Execute and Store is call Execution-Time, or E-Time 53

54. Processor, Continued Arithmetic operations The arithmetic operations performed by the ALU are:  Addition  Subtraction  Multiplication  Division Older ALUs could only perform addition and subtraction. The multiplication and division operations were performed through a set of instructions. 54

55. Processor, Continued Logic operations The logic operations, or tests, performed by the ALU are:  Equal-to  Greater than  Less than These can be combined to create an additional three tests:  Greater than or equal  Less than or equal  Greater than or Less than (not equal) 55

56. Processor, Continued Machine cycle A machine cycle is the combination of I-Time and E-Time. The I-Time and E-Time differs from instruction to instruction, therefore the machine cycle will also be different. Diagram of a machine cycle This a diagram of the steps in a machine cycle: 56

57. Processor, Continued Processor speed The speed of a processor is based on different factors:  Clock speed  Number of instructions  Internal cache Clock speed The operations that are taking place in a CPU need to be organized to prevent chaos. For example, an addition operation cannot be executed until the data has finished being read from RAM. To control the timing within the CPU, a clock is used to synchronize the operations. The clock simply supplies a stream of pulses at a very fast fixed rate. 57

58. Processor: Clock speed, Continued Clock speed, continued The speed of the processor might be measure based on:  the speed of the clock:  Megahertz - millions of cycles per second, abbreviated MHz  Gigahertz - billions of cycles per second, abbreviated GHz  the number of machine cycles per second  MIPS - million instructions per second  BIPS - billion instructions per second 58

59. Processor, Continued Number of instructions Within a conventional processor there are many instructions that are rarely used. By eliminating the rarely instructions, processor speed can be increased. Processors are now also classed based on their instruction set:  CISC - Complex Instruction Set Computer  RISC - Reduced Instruction Set Computer RISC processors can outperform CISC processors by a factor of 4 to 10. Internal cache Internal cache is a small block of very fast memory manufactured into the processor. It behaves the same way as external cache memory 59

60. Processor, Continued Operating modes of the Intel processor An Intel processor has several operating modes:  Protected mode  Real mode  Virtual mode Protected mode This is the native operating mode of the processor, and provides facilities for multitasking. Real mode The processor emulates an 8086 or 8088 processor, but at a higher speed. Virtual mode Emulates 8086 / 8088 processor in a protected, multitasking environment. 60

61. Processor, Continued The Intel evolution The following history and commentary is taken from Intel's web site: http://www.intel.com/intel/museum/25anniv/hof/hof_main.htm11 1978 - 8086 / 8088 Microprocessor A pivotal sale to IBM's new personal computer division made the 8088 the brains of IBM's new hit product--the IBM PC. The 8088's success propelled Intel into the ranks of the Fortune 500, and Fortune magazine named the company one of the "Business Triumphs of the Seventies." 1982 - 80286 Microprocessor The 286, also known as the 80286, was the first Intel processor that could run all the software written for its predecessor. This software compatibility remains a hallmark of Intel's family of microprocessors. Within 6 years of it release, there were an estimated 15 million 286-based personal computers installed around the world. 61

62. Processor, Continued The Intel evolution, continued 1985 - Intel386 The Intel386(TM) microprocessor featured 275,000 transistors--more than 100 times as many as the original 4004. It was a 32-bit chip and was "multi-tasking," meaning it could run multiple programs at the same time. 1989 - Intel486 The 486(TM) processor generation really meant you go from a command-level computer into point-and-click computing. "I could have a color computer for the first time and do desktop publishing at a significant speed," recalls technology historian David K. Allison of the Smithsonian's National Museum of American History. The Intel 486(TM) processor was the first to offer a built-in math coprocessor, which speeds up computing because it offloads complex math functions from the central processor. 62

63. Processor, Continued The Intel evolution, continued 1993 - Pentium The Pentium® processor allowed computers to more easily incorporate "real world" data such as speech, sound, handwriting and photographic images. The Pentium brand, mentioned in the comics and on television talk shows, became a household word soon after introduction. These are pictures of a Pentium microprocessor: 63

64. Processor, Continued The Intel evolution, continued 1997 - Pentium II The 7.5 million-transistor Pentium® II processor incorporates Intel MMXTM technology, which is designed specifically to process video, audio and graphics data efficiently. It was introduced in innovative Single Edge Contact (S.E.C) Cartridge that also incorporated a high-speed cache memory chip. With this chip, PC users can capture, edit and share digital photos with friends and family via the Internet; edit and add text, music or between-scene transitions to home movies; and, with a video phone, send video over standard phone lines and the Internet. 1999 - Pentium III The Pentium® III processor features 70 new instructions--Internet Streaming SIMD extensions-- that dramatically enhance the performance of advanced imaging, 3-D, streaming audio, video and speech recognition applications. It was designed to significantly enhance Internet experiences, allowing users to do such things as browse through realistic online museums and stores and download high- quality video. The processor incorporates 9.5 million transistors, and was introduced using 0.25-micron technology. 64

65. Processor, Continued The Intel evolution, continued 2001 - Pentium 4 The Intel® Pentium® 4 processor, Intel's most advanced, most powerful processor, is based on the new Intel® NetBurst[tm] micro-architecture. The Pentium 4 processor is designed to deliver performance across applications and usages where end users can truly appreciate and experience the performance. These applications include Internet audio and streaming video, image processing, video content creation, speech, 3D, CAD, games, multi-media, and multi-tasking user environments. The Intel Pentium 4 processor delivers this world-class performance for consumer enthusiast and business professional desktop users as well as for entry level workstation users 65

66. Secondary Storage Purpose The purpose of secondary storage is to:  retain data and programs while the computer system is turned off  hold data and programs that cannot fit into primary storage Types of secondary storage Secondary storage is composed of two main groups of media, within each group are many types of secondary storage. The most common are:  Magnetic media  floppy diskette  hard disk  Optical media  CD-ROM 66

67. Secondary Storage, Continued Measuring storage capacity Secondary storage devices use the same units of measurement as primary storage. How magnetic media works Although there are other magnetic media-based secondary storage devices, the most common are disks. This is a description of how a disk works. The data is stored on the disk as magnetized spots, and is read or written using a 'read/write head'.  To read the data, the spots are converted into electrical impulses to represent the data.  To write data, electrical pulses are converted into magnetized spots on the disk to represent the data. 67

68. Secondary Storage, Continued Disk layout Disks are flat, round platters housed in a case that protects their surface from contamination. Tracks The logical structure of disk consists of a series of concentric rings, called tracks. Sectors These tracks are subdivided into sectors. The Sectors contain the data. 68

69. Secondary Storage, Continued Sectors, continued This is a diagrammatic representation of tracks and sectors: Note that the outer sectors are bigger than the inner sectors. The track layout is optimized by assigning more sectors to outer tracks than inner tracks. This is called Zone Recording. 69

70. Secondary Storage, Continued Clusters Depending on the operating system of the computer that is managing the disk, sectors may be placed into 'Clusters' of sectors (2 to 8 sectors per cluster). The operating system treats the cluster as a unit of storage. Cylinders When a hard disk has multiple platters stacked one over another, the tracks that are directly above or below each other are considered part of the same cylinder. 70

71. Secondary Storage, Continued Contamination of disk surfaces The read/write head that is responsible for placing the magnetized spots on the disk, is very close to the surface of the disk. Any slight contamination will cause disk failures, sometimes referred to as head crashes. This is a diagram showing relative sizes of contaminants on a disk surface: 71

72. Secondary Storage, Continued Floppy diskette A floppy diskette derives its name from the nature of the platter that data is stored on; it is flexible Mylar Typical capacity The typical floppy diskette can hold 1.44MB Diagram This is a diagram of the parts of a floppy diskette: 72

73. Secondary Storage, Continued Hard disk A hard disk derives its name from the nature of the platter that data is stored on; it is non-flexible metal platter. Typical capacity Capacity ranges based on how much you are willing to spend. 40GB to 250 GB hard disks are not uncommon. Diagram This is a diagram of a hard disk that has had its cover removed. Caution: do not do this with a functional hard disk. 73

74. Secondary Storage, Continued How optical media works Unlike magnetic media, the write technology is different than the read technology for optical media. When writing optical media, laser heat produces tiny spots on the metallic surface of the disk. When reading optical media, a laser reflected off the surface picks up the spots. Disk layout The layout of optical disks is the same as for magnetic disks. CD-ROM CD-ROM derives its name from 'Compact Disk- Read Only Memory'. The significance of 'ROM' in its name means that once written (usually during manufacture), the contents of the disk cannot be altered. 74

75. Secondary Storage, Continued Typical capacity The contemporary CD-ROM can store up to 700MB. Access speed terms There are common terms used when defining the speed of operation of a disk: Seek Time: The time it takes the Read/Write head to be positioned over a track Rotational Delay: The time it takes for a sector to rotate under the read/write head 75

76. Computer Systems Input / output Although there are elements of computer systems that can be easily categorized as either input or output, there are other devices that can be used for either:  Serial port  Parallel port  USB port  SCSI port Serial port A serial port is used to send/receive data one bit at a time.  Typical speed: 14.4KB/second  Maximum number of devices concurrently attached: 1 76

77. Input / Output, Continued Parallel port A parallel port was originally for output only.  Typical speed: 50KB/second - 150KB/second  Maximum number of devices concurrently attached: 1 New versions allow for input and output of data. USB port USB is an acronym for Universal Serial Bus. This is a relatively new technology. The intent is to be able to attach devices without having special interface cards for each device.  Typical speed: 1.5MB/second  Maximum number of devices concurrently attached: 127 77

78. Input / Output, Continued SCSI port SCSI is an acronym for Small Computer System Interface. This was the original high speed interface for computers.  Typical speed: 320MB/second (new technology)  Maximum number of devices concurrently attached: 16 (new technology) 78

79. Your PC - Turned Off Power Supply CPU BIOS Hard Disk Floppy Disk RAM 79

80. Power Supply Press the Power Button Power Supply CPU BIOS Hard Disk Floppy Disk RAM 80

81. Power Supply Signal the CPU to Start Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 81

82. Power Supply CPU Gets Initial Instructions Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 82

83. Power Supply Self Test Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 83

84. Power Supply Check for Boot Sector Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 84

85. Power Supply Check for Boot Sector - Found it Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 85

86. Power Supply Boot Sector Leads to Loading of O/S Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 86

87. Power Supply O/S Loaded - PC Operational Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 87

88. Power Supply Additional O/S & Programs Loaded as Req'd Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 88

89. Power Supply Cast of Characters Power Supply CPU BIOS Hard Disk Floppy Disk RAM CPU 89