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# Principles It Lesson2 Presentation 052308

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• The focus of this lesson is technology history and the development of computers. We’ll begin by exploring a few of the early technologies and tools that helped pave the way for modern computers and then look at some key milestones in computer development. Key terms in the PowerPoint slides are in boldfaced type.
• In this lesson, you will begin to broaden your vision of the word computer to include many things that process and store information, including people. In fact, the word computer , in older dictionaries, is defined as a person who makes calculations.
• The tally system is still in use today, making it one of humankind’s most enduring inventions. The number shown on the slide is 17.
• Some say that the Chinese invented the abacus. (The model shown on this slide is Chinese.) The word calculate is derived from the Latin word for pebble. A standard abacus can be used to perform addition, subtraction, division, and multiplication.
• Sometimes the process of “calculating” is referred to as “reckoning.” We are accustomed to using the decimal number system, which has ten symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. However, the binary number system, which simplifies information processing, is fundamental to how modern computers operate. In today’s computers, data is represented by the state of electrical switches: an “on” switch represents a “1” and an “off” switch represents a “0.” The topic of how computers use the binary system to represent data will be covered in more detail in Unit 3.
• The patterns of punched holes in punched cards serve as a way to store data. In a Jacquard loom, the punched holes controlled the fabric design, with one row of punches corresponding to one row of the design. Modern versions of punched cards are still in use; for example, presidential voting ballots in some states.
• This image shows an example of an 80-hole punched card. These are rarely, if ever, used today.
• Charles Babbage is often referred to as the “father of computing.” The purpose of the Difference Engine was to compile mathematical tables. Babbage received British government funding for his project, but when his attempts to build the machine failed, the project was cancelled in 1842. The photo on this slide shows a reproduction of the Difference Engine. The Analytical Engine used punched cards inspired by those used in Jacquard’s loom. Babbage died before the Analytical Engine could be completed, although part of it was built by Babbage’s son in 1910. The entire machine would have used 25,000 parts and weighed three tons.
• After she married, Ada became the Countess of Lovelace. The Analytical Engine utilized logic based on conditions or situations, a characteristic of today’s computers. This meant that while the machine was running, different results could be achieved based on the conditions the machine detected.
• The telegraph used a system of dots and dashes (Morse Code) to transmit messages over a wire. Paper tapes were introduced by Sir Charles Wheatstone. These tapes used two roles of holes to represent Morse Code and helped increase the speed of sending messages. Eventually, an additional function was found for old paper tapes—as confetti at “ticker-tape” parades. On the left is a typewriter from the late 1800s. There are two sets of keys, one for uppercase letters and one for lowercase. On the right is Samuel Morse’s electrical telegraph.
• By 1880, the American population had grown so much that the census count took over seven years to tabulate by hand. Hollerith’s device reduced the amount of time to six weeks. Odometers in cars are similar to the counting device in the Hollerith desk. Likewise, a car’s speedometer is an example of a dial indicator. The photo shows Hollerith at his tabulating machine.
• The photo on this slide shows a reconstructed model of Zuse’s Z1 machine.
• While optically reading a paper tape, the machine applied programmable logic to every character in an encrypted message and then counted how many times the logic function was determined to be “true.” The photo on this slide shows the Colossus Mark II. Notice the slanted control panel on the left and the paper tape on the right. Information about Colossus was not available to the general public until the late 1970s, after the Official Secrets Act ended in 1976.
• In 1958, Texas Instruments built the first integrated circuit. The top photo shows microchips with clear windows showing the integrated circuit inside. The bottom photo shows an old integrated circuit with thin wires going to the connection pins.
• Computers kept getting smaller and more powerful but they were not very “user-friendly.” Until the mid-1970s, computers were mostly used by the government, scientists, and large companies. The Altair’s computing results were displayed as patterns of small red lights.
• The Apple I was introduced in 1976. The Apple II was first produced in 1977 and is pictured on the far left. Since then, Apple Computer, Inc., has created many more computer models including Macintosh computers and iMac computers. The first Macintosh is shown in the center, and one of the newest versions of the iMac is shown on the right.
• Microsoft, founded by Bill Gates and Paul Allen in 1975, created the software that operated the IBM PC. We’ll learn more about that in Units 3 and 5. The photo shows an early IBM PC. Though people still refer to “IBM compatibles,” IBM does not even make computers now!
• Now that we’ve completed an overview of computer development, let’s take a look at the categories of today’s computers, starting with microcomputers.
• Portable machines, such as laptops and PDAs, are becoming increasingly popular with consumers.
• Scientists and graphics professionals are the main users of powerful workstations. A typical consumer does not need the power that these machines are capable of. The workstations shown here are made by Apple (left) and Sun Microsystems (right).
• Minicomputers and mainframes are often called multi-user computers because many people can access and share the information stored on them. The photo shows an IBM mainframe computer, the zSeries 800.
• Supercomputers are generally used in high-tech military and space programs, and for weather forecasting. The image on this slide is NASA’s Columbia Supercomputer.
• ### Principles It Lesson2 Presentation 052308

1. 1. Unit 1, Lesson 2 Technology History and the Development of Computers AOIT Principles of Information Technology
2. 2. The word computer has a broad meaning <ul><li>What is a computer? </li></ul>A computer is a person, instrument, or machine that gathers, processes, and stores information.
3. 3. Early counting methods were very basic <ul><li>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. </li></ul><ul><li>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 . </li></ul><ul><li>When you use objects instead of fingers to count, you can store results for later reference. </li></ul>
4. 4. The abacus was the first calculator <ul><li>The abacus was invented around 3,000 B.C. in Babylonia. </li></ul><ul><li>Early abaci use small stones or pebbles lined up in columns in the sand. </li></ul><ul><li>A modern abacus has rings or beads that slide over rods in a frame. </li></ul>
5. 5. Early calculators used decimals <ul><li>In the 1670s, Gottfried Leibniz invented the Stepped Reckoner, a machine for multiplication, division, and square roots. </li></ul><ul><li>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. </li></ul><ul><li>What Counting to Ten Looks Like </li></ul><ul><li>Decimal : 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 </li></ul><ul><li>Binary : 0, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, 1010 </li></ul>
6. 6. Punched cards stored data <ul><li>In 1801, a weaver named Joseph Marie Jacquard invented a loom that used wooden or pasteboard punched cards to make complex designs in fabric. </li></ul>
7. 7. Punched cards can hold a lot of data <ul><li>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. </li></ul>
8. 8. Charles Babbage is called the “father of computing” <ul><li>Charles Babbage designed a steam-powered calculator called the Difference Engine in 1821. </li></ul><ul><li>His next idea was the Analytical Engine (1856), designed to perform any kind of mathematical calculation. </li></ul>
9. 9. Ada Byron was the first computer programmer <ul><li>Ada Byron, a friend of Babbage, wrote an analysis of the Analytical Engine in which she outlined computer programming basics. </li></ul>
10. 10. More inventions made communication easier <ul><li>The 1800s brought many more inventions: </li></ul><ul><ul><li>In 1837, Samuel Morse developed the first American telegraph. </li></ul></ul><ul><ul><li>In 1850, the first key-driven adding machines appeared. </li></ul></ul><ul><ul><li>In 1857, punched paper tape was used to send messages. </li></ul></ul><ul><ul><li>In 1867, the first marketable typewriter was created. </li></ul></ul><ul><ul><li>In 1879, the first mechanical cash register appeared. </li></ul></ul>
11. 11. Tabulating machines improved data gathering <ul><li>In 1890, Herman Hollerith created </li></ul><ul><li>an electric tabulating machine for the </li></ul><ul><li>U.S. Census Bureau, the Hollerith desk . </li></ul><ul><li>The desk had a device to “read” </li></ul><ul><li>or sense the holes in punched cards, </li></ul><ul><li>a gear-driven mechanism that could </li></ul><ul><li>count, and a wall of dials to show results. </li></ul><ul><li>Hollerith formed the Tabulating </li></ul><ul><li>Machine Company in 1896. It later </li></ul><ul><li>became known as International </li></ul><ul><li>Business Machines (IBM). </li></ul>
12. 12. Konrad Zuse made the first programmable digital computers <ul><li>During World War II, Konrad Zuse, a German engineer, created a series of computers: the Z1, Z2, Z3, and Z4. </li></ul><ul><li>The Z3 was the first freely programmable, digital computing machine. </li></ul>
13. 13. The British Colossus decoded messages during WWII <ul><li>In 1943, the British built the first “Colossus” computer. </li></ul><ul><li>These machines were used to decipher encrypted teleprinter messages sent by the Germans during World War II. </li></ul>
14. 14. Integrated circuits brought “chips” to computers <ul><li>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 .” </li></ul><ul><li>Over the years, integrated circuits have continued to get smaller in size but larger in their capacity to function. </li></ul>
15. 15. The Altair was a computer individuals could afford <ul><li>The first computer that most individuals could afford was the Altair 8800, built in 1975 by a small company, MITS. </li></ul><ul><li>Since there was no keyboard or screen, information was entered by clicking switches on the front of the machine. </li></ul>
16. 16. Apple created the first user-friendly personal computer <ul><li>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. </li></ul><ul><li>The term personal computer refers to a computer designed to be used by one person at a time. </li></ul>
17. 17. The IBM PC gave way to many clone “compatibles” <ul><li>In 1981, IBM introduced its version of the personal computer—the IBM PC. </li></ul><ul><li>IBM made the general design available to competing companies, resulting in many clones or “compatibles.” </li></ul><ul><li>Today, the term PC often refers to computers running Microsoft’s Windows operating system. </li></ul>
18. 18. Personal computers are also called microcomputers <ul><li>Microcomputers are more commonly known as personal computers. </li></ul><ul><li>Microcomputers come in many different shapes and sizes. </li></ul><ul><li>The microcomputers shown at the right are “desktop” models, which are generally meant to stay in one place. </li></ul>
19. 19. Laptops and PDAs are also microcomputers <ul><li>Notebook or laptop computers are portable microcomputers. </li></ul><ul><li>An even smaller portable microcomputer is a “handheld” device, often referred to as a personal digital assistant (PDA). </li></ul>
20. 20. Workstations are more powerful than microcomputers <ul><li>Workstations are single-user computers that are more powerful than microcomputers. </li></ul><ul><li>Workstations are commonly used by professionals such as engineers, scientists, and graphic artists. </li></ul>
21. 21. Minicomputers & mainframes process and store lots of data <ul><li>Minicomputers and mainframe computers are generally connected to many other computers, or terminals . </li></ul><ul><li>A minicomputer is smaller and less powerful than a mainframe. </li></ul><ul><li>Government agencies and businesses that need to process and store lots of information use these. </li></ul>
22. 22. Supercomputers are the most powerful computers <ul><li>Supercomputers are the largest, most powerful, and most expensive computers. </li></ul><ul><li>Supercomputers are not very common. </li></ul>
23. 23. Image credits <ul><li>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 . </li></ul><ul><li>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. </li></ul><ul><li>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. </li></ul><ul><li>The Sun workstation on slide 20 can be accessed on http://www.sun.com/desktop/workstation/ultra40/ </li></ul><ul><li>All other images are in the public domain. </li></ul>