1. Computer Hardware Chapter 3 Copyright © 2010 by the McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin

2. 3-2 Learning Objectives Understand the history and evolution of computer hardware Identify the major types and uses of microcomputer, midrange, and mainframe computer systems Outline the major technologies and uses of computer peripherals for input, output, and storage

3. 3-3 Learning Objectives Identify and give examples of the components and functions of a computer system Identify the computer systems and peripherals you would acquire or recommend for a business of your choice, and explain the reasons for your selection

4. 3-4 Pre-Computer Calculations Counting on fingers and toes Stone or bead abacus –Calculate comes from calculus, the Latin word for small stone 1642: first mechanical adding machine –Invented by Blaise Pascal, wheels moved counters –Modified in 1674 by Von Leibnitz Age of industrialization –Mechanical loom used punch cards

5. 3-5 Early Computing 19th Century –Charles Babbage proposed the Analytical Engine, which could calculate, store values in memory, perform logical comparisons –Never built due to of lack of electronics 1880s –Hollerith’s punched cards used to record census data using On/Off patterns –The holes turned sensors On or Off when run through tabulating machine –This company became the foundation for IBM

6. 3-6 Electronic Computers 1946 - First Generation Computer –ENIAC –Programmable –5000 calculations per second –Used vacuum tubes –Drawbacks were size and processing ability 1950s –ENIAC replaced by UNIVAC 1, then IBM 704 –Calculations jumped to 100,000 per second

7. 3-7 Waves of Computing Late 1950s - Second Generation –Transistors replaced vacuum tubes –200,000 to 250,000 calculations per second Mid-1960s - Third Generation –Integrated circuitry and miniaturization 1971 - Fourth Generation –Further miniaturization, multiprogramming, virtual storage 1980s - Fifth Generation –Millions of calculations per second

8. 3-8 Microcomputers 1975 –ALTAIR, programmed by flicking switches 1977 –Commodore & Radio Shack produce PCs 1979 –Apple computer, the fastest selling PC thus far 1982 –IBM introduced the PC, which changed the market

9. 3-9 Categories of Computer Systems

10. 3-10 Microcomputer Systems Computing power now exceeds that of the mainframes of previous generations Called a personal computer or PC Relatively inexpensive Hand-held, notebook, laptop, tablet, portable, desktop, and floor-standing Networked professional workstations used by businesses

11. 3-11 Recommended PC Features

12. 3-12 Microcomputer Uses Workstations Supports heavy mathematical computer and graphics display demands CAD, investment, and portfolio analysis Network Servers More powerful than workstations Coordinates telecommunications and resource sharing Supports small networks and Internet or intranet websites

13. 3-13 Microcomputer Uses Terminals –Any device that allows access to a computer Types –Dumb –Intelligent (Windows or Internet) –Transaction

14. 3-14 Corporate PC Criteria Solid performance at a reasonable price Operating system ready Connectivity Security-equipped

15. 3-15 Information Appliances Hand-held microcomputer devices Known as personal digital assistants (PDAs) –Web-enabled PDAs use touch screens, handwriting recognition, or keypads –Mobile workers use to access email or the Web, exchange data with desktop PCs or servers –Latest entrant is the BlackBerry PDAs include –Video-game consoles –Cellular and PCS phones –Telephone-based home email appliances

16. 3-16 Midrange Systems High-end network servers that handle large-scale processing of business applications –Not as powerful as mainframes –Less expensive to buy, operate, maintain Often used to manage –Large Internet websites, intranets, extranets –Integrated, enterprise-wide applications –First became popular as minicomputers Used as front-end servers –Assists mainframes with telecommunications and networks

17. 3-17 Mainframe Computer Systems Large, fast, powerful computer systems –Large primary storage capacity –High transaction processing –Handles complex computations Widely used as superservers for… –Large client/server networks –High-volume Internet websites Becoming a popular computing platform for… –Data mining, warehousing, electronic commerce applications

18. 3-18 Supercomputer Systems Extremely powerful systems designed for… –Scientific, engineering, and business applications –Massive numeric computations Markets include… –Government research agencies –Large universities –Major corporations Uses parallel processing –Billions to trillions of operations per second (gigaflops and teraflops)

19. 3-19 The Next Wave of Computing Harnessing the infinite amount of unused computing power Desktops and laptops within an organization Distributed or grid computing Parallel computing that relies on complete computers connected to a network Harnesses the unused CPU power in all connected computers, even between organizations

20. 3-20 Computer System Concept System of hardware devices organized by function Input Processing Output Storage Control

21. 3-21 Computer System Concept

22. 3-22 Computer Processing Speeds Early computers –Milliseconds (thousandths of a second) –Microseconds (millionths of a second) Current computers –Nanoseconds (billionth of a second) –Picoseconds (trillionth of a second) Program instruction processing speeds –Megahertz (millions of cycles per second) –Gigahertz (billions of cycles per second) Commonly called “clock speed”

23. 3-23 Computer Processing Speeds Throughput –Ability to perform useful computation or data processing assignments during a given period Speed is dependant on… –Size of circuitry paths (buses) that interconnect microprocessor components –Capacity of instruction processing registers –Use of high-speed cache memory –Use of specialized microprocessors, such as math coprocessor

24. 3-24 Moore’s Law Doubling of the number of transistors per integrated circuit every 18 to 24 months

25. 3-25 Peripherals Separate from, and not under the control of, the CPU Offline Devices Separate from the CPU, but electronically connected to (and controlled by) it Online Devices Generic name for all input, output, and secondary storage devices Peripheral Parts of the computer system (not the CPU) All online devices

26. 3-26 Peripherals Advice

27. 3-27 Input Technologies Common input devices –Keyboard –Graphical User Interface (GUI) –Electronic mouse and trackball –Pointing stick –Touchpad –Touchscreen

28. 3-28 Pen-Based Computing Used in Tablet PCs and PDAs –Pressure-sensitive layer, similar to touch screen, under liquid crystal display screen –Software digitizes handwriting, hand printing, and hand drawing

29. 3-29 Speech Recognition Systems Speech may be the future of data entry –Easiest, most natural means of human communication Recognizing speech patterns –Discrete, requires pauses between each word –Continuous speech recognition software (CSR) recognizes continuous, conversationally paced speech

30. 3-30 Speech Recognition Software Speech recognition systems digitize, analyze, and classify speech and sound patterns –Compares to a database of sound patterns –Passes recognized words to software –Typically requires voice recognition training Speaker-independent systems –Allow computers to recognize words from a voice never heard before –Typically used in voice-messaging computers

31. 3-31 Optical Scanning Devices read text or graphics and convert them into digital computer input –Enables direct entry of data from source documents Document management library system –Scans documents, then organizes and stores them for easy reference or retrieval

32. 3-32 Optical Scanning Scanners Optical Character Recognition (OCR) Compact desktop models are popular for low cost and ease of use Larger, more expensive flatbed scanners are faster, offer high-resolution color scanning Software that reads characters and codes Used to read merchandise tags, sort mail, score tests, read bar codes

33. 3-33 Other Input Technologies Magnetic Stripe Magnetic Ink Character Recognition (MICR) Digital Cameras Smart Cards

34. 3-34 Output Technologies Voice Response Increasingly found along with video displays in business applications Video Displays Cathode-ray tube (CRT) Printed Output Inkjet and laser Liquid crystal display (LCD) Plasma displays (TVs, flat-panel monitors)

35. 3-35 Storage Tradeoffs

36. 3-36 Computer Storage Fundamentals On (1) or Off (2) Data processed & stored in computer systems through On/Off signals Uses two-state (binary) data representation Smallest element of data Either zero or one Bit Group of eight bits, which operate as a single unit Represents one character or number Byte

37. 3-37 Representing Characters in Bytes

38. 3-38 Using Binary Code to Calculate

39. 3-39 Storage Capacity Measurement Kilobyte (KB) One thousand bytes Megabyte (MB) One million bytes Gigabyte (GB) One billion bytes Terabyte (TB) One trillion bytes Petabyte (PB) One quadrillion bytes

40. 3-40 Direct (Random) and Sequential Access

41. 3-41 Semiconductor Memory Microelectronic semiconductor memory chips are used for primary storage –Advantages: small size, fast, shock and temperature resistance –Disadvantages: volatility; must have uninterrupted electric power or loses memory

42. 3-42 Types of Semiconductor Memory Random Access Memory (RAM) Read-Only Memory (ROM) 1. Most widely used primary storage medium 2. Volatile memory 3. Read/write memory 1. Permanent storage 2. Can be read, but not overwritten 3. Frequently used programs burnt into chips during manufacturing 4. Called firmware

43. 3-43 Flash Drives Sometimes called a jump drive –Uses a small chip containing thousands of transistors –Can store data for virtually unlimited periods without power –Easily transported –Highly durable –Storage capacity of up to 20 GB –Plugs into any USB port

44. 3-44 Magnetic Disks Used for secondary storage –Fast access and high capacity –Reasonable cost Hard Disk Drives & Floppy Disks (diskettes)

45. 3-45 RAID Storage Redundant Arrays of Independent Disks –Provides virtually unlimited online storage –6 to more than 100 hard disk drives are combined into a single unit –Data is accessed in parallel, over multiple paths, from many disks –Redundant storage of data on several disks provides fault-tolerant capacity Storage area networks can interconnect many RAID units

46. 3-46 Magnetic Tape Secondary storage –Tape reels, cassettes, and cartridges –Used in robotic, automated drive assemblies –Archival and backup storage –Lower-cost storage solution

47. 3-47 Optical Disks

48. 3-48 Uses of Optical Disks Image Processing Long-term storage of historical image files Storage of scanned documents Publishing Medium Allows fast access to reference materials Catalogs, directories, and so on Interactive Multimedia Applications Video games, educational videos, and so on

49. 3-49 Radio Frequency Identification (RFID) One of the newest, fastest growing storage technologies –System for tagging and identifying mobile objects –Used with store merchandise, postal packages, casino chips, pets –Special reader allows objects to be tracked as they move from place to place –Chips half the size of a grain of sand Passive chips derive power from reader signal –Active chips are self-powered

50. 3-50 RFID Versus Bar Coding Invisible nature of the system Capacity to transmit fairly sophisticated messages Privacy Concerns Scans from greater distance Can store data More information can be tracked RFID