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

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 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

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 Blasé Pascal, wheels moved counters –Modified in 1674 by Von Leibnitz

3-5 Pre-Computer Calculations

3-6 Pre-Computer Calculations Age of industrialization –Mechanical loom used punch cards Above left: Punch card reader. Above right: Punch card writer

3-7 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 – representing digits and letters. –The holes turned sensors On or Off when run through tabulating machine –This company became the foundation for IBM

3-8 Electronic Computers First Generation Computer –ENIAC (Electronic Numerical Integrator and Computer ) –Programmable –5000 calculations per second –Used vacuum tubes –Drawbacks were size and processing ability (140 square meters)

3-9 ENIAC

3-10 Electronic Computers 1950s –ENIAC replaced by UNIVAC 1, then IBM 704 –Calculations jumped to 100,000 per second

3-11 Waves of Computing Late 1950s - Second Generation –Transistors replaced vacuum tubes –200,000 to 250,000 calculations per second

3-12 Waves of Computing Mid-1960s - Third Generation –Integrated circuitry and miniaturization Fourth Generation –Further miniaturization, multiprogramming, virtual storage 1980s - Fifth Generation –Millions of calculations per second

3-13 Microcomputers 1975 –ALTAIR, programmed by flicking switches 1977 –Commodore & Radio Shack produce PCs

3-14 Microcomputers 1979 –Apple computer, the fastest selling PC –IBM introduced the PC, which changed the market

3-15 Categories of Computer Systems

3-16 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

3-17 Microcomputer Systems

3-18 Microcomputer Systems Apollo 11 spacecraft Today's computersApollo 11 spacecraft 4 GHz2.048 MHz CPU 1 Pound70 Pounds

3-19 Recommended PC Features

3-20 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 (LAN)and Internet or intranet websites

3-21 Workstations

3-22 Microcomputer Uses Terminals –Any device that allows access to a computer Types –Dumb –Network (Windows or Internet) –Intelligent –Transaction

3-23 Terminals

3-24 Network Computers Solid performance at a reasonable price Operating system ready, from the network servers No or minimal disk storage linked to network Connectivity Security-equipped Low TCO Ease of software distribution and licensing Corporate PC Criteria:

3-25 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 or the Web, exchange data(appointments, to do list) with desktop PCs or servers –Latest entrant is the BlackBerry, iPhone PDAs include –Video-games

3-26 Information Appliances

3-27 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 as a powerful network server used to manage –Large Internet websites, intranets, extranets –Integrated, enterprise-wide applications –First became popular as minicomputers –E.g. used in manufacturing plants. Used as front-end servers –Assists mainframes with telecommunications and networks

3-28 Mainframe Computer Systems Large, fast, powerful computer systems –Large primary storage capacity –Reduction in acquisition and operating cost (coolers) –High transaction processing –Handles complex computations –E.g. international banks, oil companies Widely used as superservers for… –Large client/server networks –High-volume Internet websites for large companies Becoming a popular computing platform for… –Data mining, warehousing, electronic commerce applications

3-29 Mainframes

3-30 Super-server

3-31 Supercomputer Systems Extremely powerful systems designed for… –Scientific, engineering, and business applications –Massive numeric computations Markets include… –Government research agencies –Large universities –Major corporations –E.g. global weather forecasting Uses parallel processing or (MPP) –Billions to trillions of operations per second (gigaflops and teraflops) –Price range

3-32 Minisupercomputers Use (SMP) symmetric multiprocessing (DSM) distributed shared memory, smaller number of interconnected microprocessors Price range: hundreds of thousands

3-33 The Next Wave of Computing Harnessing the infinite amount of unused computing power Desktops and laptops within an organization Distributed or grid computing (opposite to traditional supercomputers) Parallel computing that relies on complete computers connected to a network Harnesses the unused CPU power in all connected computers, even between organizations

3-34 Distributed (grid) Computing Advantage: computers can be purchased as a hardware and when combined, produces similar computer resources to a multiprocessor supercomputer Significantly cheaper Can be formed from computing resources belonging to multiple individuals or organizations e.g. SETI

3-35 Grid Computing

3-36 Distributed (grid) Computing Disadvantage: Computers might not be trustworthy Solution: Assign same work to different nodes Disadvantage: Lack of central control over the hardware, computers might drop out of the network. Solution: Assign work and reduce the need for continuous connectivity. Reassign work when no result is reported.

3-37 Computer System Concept System of hardware devices organized by function Input Processing Output Storage Control

3-38 Computer System Concept

3-39 Computer Processing Speeds Early computers –Milliseconds (thousandths of a second) –Microseconds (millionths of a second) Current computers –Nanoseconds (billionth of a second) –E.g. person –Picoseconds (trillionth of a second) Program instruction processing speeds –Million instructions per second (MIPS) –Megahertz (millions of cycles per second) –Gigahertz (billions of cycles per second) Commonly called “clock speed”

3-40 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

3-41 Moore’s Law Doubling of the number of transistors per integrated circuit every 18 to 24 months

3-42 Moore’s Law Can computers get any faster? Can we afford the computers of the future? The price of a given level of computing power will be cut in half approximately every 18 to 24 months It is useful in understanding where we have been and where are we going This caused marketing and engineering departments of semiconductor manufacturers to focus on the increase in processing power. The improvement in hardware does not mean improvement in the software.

3-43 Computer Peripherals: Input, output, and storage technology

3-44 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

3-45 Peripherals Advice

3-46 Input Technologies Common input devices –Keyboard –Graphical User Interface (GUI) –Electronic mouse and trackball –Pointing stick –Touchpad –Touch screen

3-47 Input technologies Keyboard: most widely-used Graphical user interface (GUI) –Icons, menus, windows, buttons, bars –Used for selection

3-48 Pointing Devices Electronic Mouse Trackball – Stationary device like a mouse – Roller ball used to move cursor on screen. Pointing Stick – Small eraser head-like device in keypad –Moves cursor in direction of pressure placed on stick.

3-49 Pointing Devices Touchpad – Small rectangular touch-sensitive surface –Moves the cursor in the direction of finger moves on the pad Touch Screen – use computer by touching screen –Video display screen that emits a grid of infrared beams, sound waves, or a slight electric current –Grid is broken when the screen is touched.

3-50 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

3-51 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

3-52 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

3-53 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

3-54 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

3-55 Other Input Technologies Magnetic Stripe Magnetic Ink Character Recognition (MICR) Digital Cameras Smart Cards

3-56

3-57 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)

3-58 Storage Tradeoffs

3-59 Computer Storage Fundamentals On (1) or Off (0) 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

3-60 Representing Characters in Bytes

3-61 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

3-62 Direct (Random) and Sequential Access

3-63 Direct Access Direct or Random Access –Also called random access. –Directly store and retrieve data –Each storage position has: a unique address can be accessed in the same length of time –Represent primary storage devices such as: Semiconductor memory chips, magnetic disks.

3-64 Sequential Access –Data is stored and retrieved sequentially –Must be accessed in sequence by searching through prior data –Media such as: Magnetic tape known as sequential access devices.

3-65 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

3-66 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 “nonvolatile” 2. Can be read, but not overwritten 3. Frequently used programs burnt into chips during manufacturing 4. Called firmware

3-67 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

3-68 Magnetic Disks Used for secondary storage –Fast access and high capacity –Reasonable cost Hard Disk Drives & Floppy Disks (diskettes)

3-69 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

3-70 Magnetic Tape Secondary storage –Tape reels, cassettes, and cartridges –Used in robotic, automated drive assemblies –Archival and backup storage –Lower-cost storage solution

3-71 Optical Disks

3-72 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

3-73 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

3-74 RFID Versus Bar Coding Invisible nature of the system Capacity to transmit fairly sophisticated messages Privacy Concerns Scans from greater distance Can store data RFID