Unit 1, Lesson 2Technology History and the Development of

Computers

AOITPrinciples of Information Technology

The word computer has a broad meaning

What is a computer?

A computer is a person, instrument, or machine that gathers, processes, and stores information.

Early counting methods were very basic

• The first counting tools were people’s own fingers. The word digit can refer to a finger (or toe) or to a single character in a number system.

• Bones with carved notches have been found in Europe dated between 30,000 to 20,000 B.C. One had notches in groups of five — early evidence of the tally system.

• When you use objects instead of fingers to count, you can store results for later reference.

The abacus was the first calculator

• The abacus was invented around 3,000 B.C. in Babylonia.

• Early abaci use small stones or pebbles lined up in columns in the sand.

• A modern abacus has rings or beads that slide over rods in a frame.

Early calculators used decimals

• In the 1670s, Gottfried Leibniz invented the Stepped Reckoner, a machine for multiplication, division, and square roots.

• Although Leibniz’s machine used the decimal number system (with ten values), he advocated the use of the binary number system with two values: 0 and 1.

What Counting to Ten Looks Like

Decimal: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Binary: 0, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, 1010

Punched cards stored data

In 1801, a weaver named Joseph Marie Jacquard invented a loom that used wooden or pasteboard punched cards to make complex designs in fabric.

Punched cards can hold a lot of data

A modern punched card made of thin cardstock holds data as patterns of holes made by a keypunch machine. Each of the 80 columns holds one character.

Charles Babbage is called the “father of computing”

• Charles Babbage designed a steam-powered calculator called the Difference Engine in 1821.

• His next idea was the Analytical Engine (1856), designed to perform any kind of mathematical calculation.

Ada Byron was the first computer programmer

Ada Byron, a friend of Babbage, wrote an analysis of the Analytical Engine in which she outlined computer programming basics.

More inventions made communication easier

The 1800s brought many more inventions:• In 1837, Samuel Morse developed the first American telegraph.• In 1850, the first key-driven adding machines appeared.• In 1857, punched paper tape was used to send messages.• In 1867, the first marketable typewriter was created.• In 1879, the first mechanical cash register appeared.

Tabulating machines improved data gathering

In 1890, Herman Hollerith created an electric tabulating machine for the U.S. Census Bureau, the Hollerith desk.

The desk had a device to “read”or sense the holes in punched cards,a gear-driven mechanism that could count, and a wall of dials to show results.

Hollerith formed the Tabulating Machine Company in 1896. It later became known as International Business Machines (IBM).

Konrad Zuse made the first programmable digital computers

• During World War II, Konrad Zuse, a German engineer, created a series of computers: the Z1, Z2, Z3, and Z4.

• The Z3 was the first freely programmable, digital computing machine.

The British Colossus decoded messages during WWII

• In 1943, the British built the first “Colossus” computer.• These machines were used to decipher encrypted

teleprinter messages sent by the Germans during World War II.

Integrated circuits brought “chips” to computers

• One major step in computer development was the integrated circuit, a group of tiny transistors and electric wires built on a silicon wafer, or “chip.”

• Over the years, integrated circuits have continued to get smaller in size but larger in their capacity to function.

The Altair was a computer individuals could afford

• The first computer that most individuals could afford was the Altair 8800, built in 1975 by a small company, MITS.

• Since there was no keyboard or screen, information was entered by clicking switches on the front of the machine.

Apple created the first user-friendly personal computer

• Steve Jobs and Steve Wozniak created the first user-friendly personal computer, called the Apple, with a built-in keyboard, display screen, and storage unit.

• The term personal computer refers to a computer designed to be used by one person at a time.

The IBM PC gave way to many clone “compatibles”

• In 1981, IBM introduced its version of the personal computer—the IBM PC.

• IBM made the general design available to competing companies, resulting in many clones or “compatibles.”

• Today, the term PC often refers to computers running Microsoft’s Windows operating system.

Personal computers are also called microcomputers

• Microcomputers are more commonly known as personal computers.

• Microcomputers come in many different shapes and sizes.

• The microcomputers shown at the right are “desktop” models, which are generally meant to stay in one place.

Laptops and PDAs are also microcomputers

• Notebook or laptop computers are portable microcomputers.

• An even smaller portable microcomputer is a “handheld” device, often referred to as a personal digital assistant (PDA).

Workstations are more powerful than microcomputers

• Workstations are single-user computers that are more powerful than microcomputers.

• Workstations are commonly used by professionals such as engineers, scientists, and graphic artists.

Minicomputers & mainframes process and store lots of data

• Minicomputers and mainframe computers are generally connected to many other computers, or terminals.

• A minicomputer is smaller and less powerful than a mainframe.

• Government agencies and businesses that need to process and store lots of information use these.

Supercomputers are the most powerful computers

• Supercomputers are the largest, most powerful, and most expensive computers.

• Supercomputers are not very common.

Image credits

The images on slide 7, the telegraph on slide 10, the images on slide 14, the Macintosh on slide 16, and the PC on slide 17 can be accessed on wikipedia.org and are reproduced here under the terms of the GNU Free Documentation License. Permission is granted to copy, distribute, and/or modify these images under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is available at http://commons.wikimedia.org/wiki/Commons:GNU_Free_Documentation_License.

The image on slide 8 can be accessed on wikipedia.org and is reproduced here under the terms of the Creative Commons Attribution ShareAlike 1.0 license. The original photograph was taken by Joe D. in January 2005.

The image on slide 11 can be accessed on http://www.officemuseum.com/data_processing_machines.htm. It shows the Hollerith Electric Tabulator at the US Census Bureau, Washington, DC, 1908, Photograph by Waldon Fawcett. Library of Congress, LC-USZ62-45687.

The Sun workstation on slide 20 can be accessed on http://www.sun.com/desktop/workstation/ultra40/

All other images are in the public domain.