 2002 Prentice Hall Computer Currents: From Calculation to Communication Chapter 1

 2002 Prentice Hall 2 Topics Living without Computers Computers in Perspective: An Evolving Idea Computers Today: A Brief Taxonomy Computer Connections: The Internet Revolution Living with Computers Topics

 2002 Prentice Hall 3 What would we do without computers in our personal and professional lives? Living Without Computers

 2002 Prentice Hall 4 Information-Processing Machine Input documents Process data Print materials

 2002 Prentice Hall 5 Howard Aiken John Atanasoff The scientists and mathematicians who designed and built the first working computers: The First Real Computers Konrad Zuse John Mauchly & J. Presper Eckert

 2002 Prentice Hall 6 In 1939, Zuse built the first programmable, general-purpose digital computer. His computer was built from electric relays to automate engineering calculations. “I was too lazy to calculate and so I invented the computer.” Konrad Zuse

 2002 Prentice Hall 7 Atanasoff-Berry Computer (ABC)— the first electronic digital computer Built in 1939, this computer used vacuum tubes and was based on binary arithmetic. It was never a fully operational product. John Atanasoff

 2002 Prentice Hall 8 Howard Aiken In 1944, he completed the Mark I, the largest electromechanical calculator ever built. It was built with electromechanical relays and followed instructions punched in paper tape.

 2002 Prentice Hall 9 John Mauchly and Presper Eckert In 1945, Mauchly and Eckert built the ENIAC (Electronic Numerical Integrator and Computer). The ENIAC was built with 18,000 vacuum tubes that failed on an average of once every seven minutes. After the war, they created the Univac I - the first general-purpose commercial computer.

 2002 Prentice Hall 10 Evolution and Acceleration Hardware changes are defined by generations. First Generation Vacuum tubes Second Generation Transistors Third Generation Integrated circuits Fourth Generation Microprocessor

 2002 Prentice Hall 11 First-Generation Computers 1930s – 1940s Vacuum tubes used as switches Large computers Extremely slow by today’s standards Prone to frequent failure Includes the ABC, Mark I, ENIAC, UNIVAC, and others of similar design

 2002 Prentice Hall 12 Second-Generation Computers 1950s – mid-1960s Transistors used as switches Smaller than vacuum-tube-built computers As much as a thousand times faster than first-generation computers More reliable and less expensive

 2002 Prentice Hall 13 Third-Generation Computers Late 1960s Hundreds of transistors packed into a single integrated circuit on a silicon chip Dramatic reduction in size and cost Significant increases in reliability, speed, and efficiency Mass production techniques to manufacture chips inexpensively

 2002 Prentice Hall 14 Fourth-Generation Computers 1970s to present Complete computer on a chip Radical change in the appearance, capability and availability of computers

 2002 Prentice Hall 15 A Brief Taxonomy Mainframes Supercomputers Workstations Personal Computers Portable Computers Embedded Computers Special-Purpose Computers

 2002 Prentice Hall 16 Multi-User Computers Supercomputers… the fastest, most powerful computers

 2002 Prentice Hall 17 Multi-User Computers Mainframes many users can access computer resources simultaneously Minicomputers smaller and less expensive than mainframes

 2002 Prentice Hall 18 Single-User Computers Workstations  High-end desktop computer Servers provide software and other resources to computers over a network

 2002 Prentice Hall 19 Single-User Computers Personal Computers (PC)  Dedicated to serving one user  Computing power for word processing, accounting and other common applications

 2002 Prentice Hall 20 Portable Computers Laptop  lightweight, battery-operated computers with flat screens, Hand-held or Palmtop  computers designed for communications and computing

 2002 Prentice Hall 21 Special-Purpose Computers Special-Purpose  often attached to sensors to measure and/or control the environment  programs etched in silicon so they can’t be altered (firmware) Embedded  e nhance consumer goods  control a variety of hardware devices, including robots

 2002 Prentice Hall 22 Computer Connections: The Network Revolution Local Area Networks (LAN) –resource sharing allow communication between users (in the same building or cluster of buildings) Wide Area Networks (WAN) –resource sharing allow communication between users (across the country or the world) “There are three kinds of death…there’s heart death, there’s brain death, and there’s being off the network.”

 2002 Prentice Hall 23 The Internet Explosion A network of networks World Wide Web for usability Electronic mail Multimedia content Self-publishing On-line transactions Intranets Network computers

 2002 Prentice Hall 24 World Wide Web Web browsers are portals into the Web Web pages are interlinked documents Web sites are web pages grouped together

 2002 Prentice Hall 25 Electronic Mail ( ) The primary use of the Internet today is for communications:  is easy to use  Messaging is quick “The great success of the Internet is not technical, but its human impact” Dave Clark

 2002 Prentice Hall 26 Explosive Internet Growth 1994? 3 million people connected Today? Hundreds of millions The United States leads the world in Internet activity Approximately 1/3 of U.S. households connected in 1999 By 2003, twice that number is expected to be connected

 2002 Prentice Hall 27 Impact of the Internet Companies are replacing mainframe and PC systems with Intranets  Private intra-organizational networks that allow people to transmit, share and store information Computers may be used mostly as gateways to intranets and the Internet  These network computers cost less than typical PCs because they contain less hardware and are easier to maintain (software stored on a central server)

 2002 Prentice Hall 28 Internet Connections Direct connection  One that’s hard wired through a business, school or government Indirect connection  Telephone system Cable TV connection Wireless connection

 2002 Prentice Hall 29 Living with Computers What do you really need to know about computers?  Understand the basic computer concepts  Learn how to use software applications  Be aware of the social and ethical issues

 2002 Prentice Hall 30 Concepts of hardware and software

 2002 Prentice Hall 31 Software Applications  Word processing and desktop publishing  Spreadsheets and databases  Computer graphics, multimedia and hypermedia  Telecommunication and networking  Artificial intelligence  General problem-solving  Programming languages

 2002 Prentice Hall 32  Threat to personal privacy  Hazards of high-tech crime & keeping data secure  Risks of computer system failures Social and Ethical Issues  Threat of automation and dehumanization of work  Abuse of information  Over dependence on complex technology “True computer literacy is not just knowing how to make use of computers and computational ideas. It is knowing when it is appropriate to do so.” Seymour Papert

 2002 Prentice Hall 33