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Computer Currents: From Calculation to

Communication

Chapter 1

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Topics

Living without Computers

Computers in Perspective: An Evolving Idea

Computers Today: A Brief Taxonomy

Computer Connections: The Internet Revolution

Living with Computers

Topics

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What would we do without

computers in our personal

and professional

lives?

Living Without Computers

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Information-Processing Machine

Input documents

Processdata

Print materials

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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

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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

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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

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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 GenerationVacuum tubes

Second GenerationTransistors

Third GenerationIntegrated circuits

Fourth GenerationMicroprocessor

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First-Generation Computers

1930s – 1940sVacuum tubes used as switchesLarge computersExtremely slow by today’s standardsProne to frequent failureIncludes 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

Minicomputerssmaller 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 can’t 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 death…there’s heart death, there’s brain death, and there’s 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

“The great success of the Internet is not technical, but its human impact”

Dave Clark

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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 that’s 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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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

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