Computer Currents: From Calculation to Communication

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Chapter 1

• Computer Currents From Calculation to
  Communication

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Topics
Topics

• Living without Computers
• Computers in Perspective An Evolving Idea
• Computers Today A Brief Taxonomy
• Computer Connections The Internet Revolution
• Living with Computers

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Living Without Computers
What would we do without computers in our
personal and professional lives?
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Information-Processing Machine
Input documents
Process data
Print materials
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The First Real Computers
The scientists and mathematicians who designed
and built the first working computers
Konrad Zuse
John Atanasoff
Howard Aiken
John Mauchly J. Presper Eckert
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Konrad Zuse
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.
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John Atanasoff
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.
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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.
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John Mauchlyand 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.
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Evolution and Acceleration

• Hardware changes are defined by generations.
• First Generation
• Vacuum tubes
• Second Generation
• Transistors
• Third Generation
• Integrated circuits
• Fourth Generation
• Microprocessor

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First-Generation Computers

• 1930s 1940s
• Vacuum tubes used as switches
• Large computers
• Extremely slow by todays standards
• Prone to frequent failure
• Includes the ABC, Mark I, ENIAC, UNIVAC,and
  others of similar design

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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

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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

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Fourth-Generation Computers

• 1970s to present
• Complete computer on a chip
• Radical change in the appearance, capability and
  availability of computers

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A Brief Taxonomy

• Mainframes
• Supercomputers
• Workstations
• Personal Computers
• Portable Computers
• Embedded Computers
• Special-Purpose Computers

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Multi-User Computers

• Supercomputers
• the fastest, most powerful computers

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Multi-User Computers

• Mainframes
• many users can access computer resources
  simultaneously
• Minicomputers
• smaller and less expensive than mainframes

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Single-User Computers

• Workstations
• High-end desktop computer Servers provide
  software and other resources to computers
  over a network

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Single-User Computers

• Personal Computers (PC)
• Dedicated to serving one user
• Computing power for word processing,
  accounting and other common applications

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Portable Computers

• Laptop
• lightweight, battery-operated computers with flat
  screens,

• Hand-held or Palmtop
• computers designed for communications and
  computing

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Special-Purpose Computers

• Special-Purpose
• often attached to sensors to measure
  and/or control the environment
• programs etched in silicon so they cant
  be altered (firmware)
• Embedded
• enhance consumer goods
• control a variety of hardware devices,
  including robots

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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 deaththeres heart
  death, theres brain death, and theres being
  off the network.

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The Internet Explosion

• A network of networks
• World Wide Web for usability
• Electronic mail
• Multimedia content
• Self-publishing
• On-line transactions
• Intranets
• Network computers

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World Wide Web

• Web browsers are portals into the Web

• Web pages are interlinked documents

• Web sites are web pages grouped together

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Electronic Mail (e-mail)

• The primary use of the Internet today is for
  communications
• E-mail is easy to use
• Messaging is quick

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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

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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)

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Internet Connections

• Direct connection
• One thats hard wired through a business, school
  or government
• Indirect connection
• Telephone system
• Cable TV connection
• Wireless connection

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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

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Concepts of hardware and software
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Software Applications

• Word processing anddesktop publishing
• Spreadsheets anddatabases
• Computer graphics,multimedia and hypermedia

• Telecommunication and networking
• Artificial intelligence
• General problem-solving
• Programming languages

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Social and Ethical Issues

• Threat to personal privacy
• Hazards of high-tech crime keeping data secure
• Risks of computer system failures

• Threat of automation and dehumanization of work
• Abuse of information
• Over dependence on complex technology

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