YOUR LESSON

Introduction

In the first three modules, you learned a little bit about some of the pioneers of computer history and how an ancient calculating device, the abacus, works. You have also interviewed someone whose perspective about computers may be very different than yours.

Having grown up with computers, you may actually take them for granted; however, personal computers have only been around since the mid 1970s. During this relatively short span of history, tremendous changes have occurred. The size of computers has decreased while the speed, storage capacity, and capabilities have all increased. Fortunately, the cost of computers has also decreased during this time. These trends will continue and new ones will emerge.

Today, we generally recognize that there have been five generations of computers, but the great-great-granddaddy of the computer you use today is only about 60 years old!

Five Generations of Modern Computers

How do the five generations of modern computers differ? Each generation of computers differ in:

• Size
• Speed
• Cost
• Capability

To help you understand how computers have changed over the years, let's take a quick look at some of the features of each generation of computers. To help you remember the important points of what you are about to read, please download the following worksheet first.

Download the following worksheet now: Assignment 4.02

First Generation Computers: 1945 - 1956

The first generation of computers was developed during World War II. Germany, England, and the United States all had active research and development projects to build computers to design missiles, airplanes, and bombs. One of the most significant computers developed by the British in 1943 to decode Germany's secret messages was called the Colossus. Although very good at breaking codes, that's all it could do, so it is referred to as a "special purpose" computer.

In 1944, engineers in the United States developed an electro-mechanical calculator called the Mark I to create ballistic charts for the U.S. Navy. The Mark I was huge! It was half the length of a football field and contained 500 miles of wire. It could perform basic arithmetic and complex calculations, but each calculation took 3-5 seconds because even though it was electronic, electricity was used to move mechanical switches which were slow.

Shortly after the Mark I, the first truly electronic computer was developed by the University of Pennsylvania and the U.S. government. Known as the Electronic Numerical Integrator and Computer (or, more commonly by the acronym ENIAC), it consisted of 18,000 vacuum tubes, was as big as a school gymnasium, and could compute 1,000 times faster than the Mark I.

Most high school students have never encountered a vacuum tube! (No, it is not the tube on the vacuum cleaner at your house that sucks dirt out of the carpet.) However, all of the earliest electronic devices (radios, TVs, and computers) were built with vacuum tubes and they generated a lot of heat. How hot was it? Well, the heat generated by 18,000 vacuum tubes was so intense, that one of the very first uses of air conditioning was to keep the ENIAC from destroying itself!

The ENIAC was the first "general purpose" computer because it could do more than one specific task. However, actually programming such a computer was quite a task. Programs were developed directly in the binary number system and consisted of long, long lists of instructions written only with 0s and 1s. Only highly trained engineers, scientists, and mathematicians understood how to make computers like the ENIAC work.

In 1945, two breakthroughs were made with the invention of the EDVAC (Electronic Discrete Variable Automatic Computer) that eventually gave rise to computers as we know them today. The EDVAC was the first "general purpose" computer with a memory that could hold a stored program and data. In addition, the EDVAC had a central processing unit which allowed the computer's operation to be controlled more efficiently and effectively. The EDVAC launched the first generation of modern computers. By 1951, the UNIVAC (Universal Automatic Computer) became the first computer available to businesses.

First generation computers were large (due to the use of vacuum tubes), expensive, slow, and could only do a limited number of things. Most were designed to do specific tasks and only one job at a time. Each first generation computer had a different binary-coded program called a machine language. Yet, it did not take long to begin improving these amazing machines.

Second Generation Computers: 1956 - 1963

In 1948, the invention of the transistor soon led to a major change in computer design. Transistors eventually replaced the large, hot, cumbersome vacuum tubes in radios, TVs, and computers and gave rise to second generation computers which were smaller, faster, more reliable, and used less electricity than first generation computers. Another breakthrough occurred that allowed second generation computers to replace machine language (the difficult binary codes) with assembly language which required much shorter programming codes. Programs were still impossible for the average person to write or understand, but the trend away from machine language was set in motion.

Second generation computers were similar in design to computers of today in that they had memory, operating systems, stored programs and could use tape or disks for storage. By 1965, most large businesses processed financial information with second generation computers. The concept of the stored program and a programming language gave computers the flexibility to be cost effective and productive in the business setting. Stored programs retained inside the computer's memory allowed instructions to run a computer for a specific function and then change functions by replacing the previous instructions with a new set. And, more sophisticated high-level languages such as COBOL and FORTRAN were developed for business and scientific applications. BASIC (Beginner's All-purpose Symbolic Instruction Code) was also developed as an easy beginning computer programming language for people who were not scientists, engineers, or mathematicians. Such high-level languages replaced the old cryptic binary machine code with more easily understood words, sentences, and mathematical formulas which made it easier to program computers. This also led to new careers such as programmers, analysts, and systems experts and the launched the entire software industry.

Second generation computers were smaller in size (due to the use of transistors), less expensive, faster, and could do more than one task...if the right program was available.

Third Generation Computers: 1964 - 1971

Heat is harmful to electronic circuitry. So, even though transistors produced less heat than vacuum tubes, heat was still a problem because sensitive internal components were placed closer together; however, the invention of the integrated circuit in 1958 eventually solved this problem. Over time, more and more smaller components were included on a single chip (called a semiconductor) which allowed computers to become even smaller. Computer capability also increased in third generation computers as operating systems were developed that allowed many programs to run at once directed by a central program that coordinated and monitored the memory of the computer.

So, the successful trend continued during the third generation of computers: smaller size, faster speed, lower cost, great capability.

Fourth Generation Computers: 1971 - Present

As improvements were made in the design and production of integrated circuits, more and more components could be placed on smaller and smaller chips. Large-scale integration (LSI) allowed one chip to hold hundreds of components. In the 1980s, very large-scale integration (VLSI) put hundreds of thousands of components on a single chip. Eventually, ultra-large-scale (ULSI) enabled manufacturers to place millions of components on one chip. With each new level of integration, the size and cost of computers decreased while increasing their power, reliability, and efficiency.

In 1971, Intel Corporation developed the 4004 chip which allowed, for the first time, all of a computer's main functions (central processing, memory, input and output controls) to be placed on a single chip. Earlier computers were built to perform a special purpose (to do only one thing), but the Intel 4004 microprocessor could be programmed to do many different tasks. As a result, computers started becoming accessible to everyday people in the 1980s. These "microcomputers" led to the development of word processors and spreadsheets that were useful to the general public, including students. Apple, Commodore, and Radio Shack were some of the early pioneer companies to produce microcomputers.

By 1981, IBM developed its personal computer (PC) for use in homes, offices, and schools. Clones of the IBM made personal computers even more affordable. The trend of decreasing size continued as computers shrunk from desktop models to portable laptops and eventually to hand held computers (or "palmtop" computers that can fit in your pocket). A major development during this period was Apple's Macintosh computer which had an operating system that allowed the user to move and select screen icons with a mouse instead of only typing commands on the keyboard.

Soon, computers were linked together in networks to share memory, software, information, and communication. The most popular use for computer networks such as the Internet is electronic mail. By the 1990s, the World Wide Web had been created and computer use continued to expand at an ever increasing rate. The small, cheap, fast, versatile computers you use today owe their heritage to those huge, expensive, slow, and very limited machines developed in the late 1940s. Makes you wonder where the next generation of computers will take us, right?

Fifth Generation Computers: The Future

Dating the fifth generation of computers is difficult. While we may have fictional images ranging from a computer like the HAL 9000 in the film 2001: A Space Odyssey to run away cyber control as seen in the film The Matrix, the fact is that the earliest versions of fifth generation computers are already here.

A fifth generation computer will have artificial intelligence, use visual input, and learn from its own experience. In addition, fifth generation computers will be capable of voice recognition and will be able to "imitate" human reasoning.

A classic example of the ability to "imitate" human reasoning is Big Blue, the computer that finally won the world championship chess match against a human. Big Blue does not "know" chess, but it can analyze so many alternative moves and calculate their probability of success that it appears to be thinking. In reality, Big Blue is no more powerful than the man behind the curtain in the Wizard of Oz! Big Blue can "play" chess, but it is no more capable than the people who programmed it.

Can you think of any "real" examples of fifth generation computers around today? Some of the most amazing devices which might be considered early fifth generation computers can be found in high-tech industries that use robots or in use by doctors performing complicated surgeries; however, a computer that can truly think for itself and learn from experience is not here...yet.

Two advances that will permit further development of fifth generation computers are parallel processing and superconductivity. Parallel processing harnesses the power of many central processing units (CPUs) to work as one. Superconductivity is a technology that allows the flow of electricity with little or no resistance. Both of these developments greatly improve the speed of information flow required to handle fifth generation computing tasks.

In Summary

Since the mid-1940s, amazing breakthroughs have led to the personal computers routinely used in homes, schools, and businesses. Today, we generally recognize that there have been five generations of computers. Over time, computers have gotten smaller, faster, cheaper, and more capable. This trend will continue, and eventually there will be computers that "imitate" human reasoning.

Part A: Five Generations of Modern Computers

YOUR ASSIGNMENT

After learning about the five generations of computers, you should easily be able to answer the following:

Now, to complete Part A of this lesson you need to take the Quiz for Assignment 4.02 History.

Part B - Discussion

As you have just learned, computers have changed tremendously from one generation to the next. These changes have had impacts on many products and services that we sometimes take for granted such as communication, transportation, entertainment, etc.

In your own family, there may be several generations of relatives (e.g. you and your brothers or sisters, your parents, your grandparents). Find out what changes each generation in your family has seen in at least two of the categories shown below.

News - How it is gathered and distributed?
Music - How it is created, listened to, and distributed?
Movies - How are they produced, viewed, and distributed?
Transportation - What has disappeared or been developed? What features have changed?
Television - How is it distributed and viewed?
Telephones - How has communication changed?

Go to the Discussion topic for Module 4 and describe the changes you and your family members have observed in at least two of the categories shown above. Then look for those who have vastly different responses than yours and respond to the postings of at least two other students.

This assignment is worth 5 points.

Participate in the 04.02 Products and Services (Discussion) in the Discussions area.

When you have completed the Quiz for Assignment 4.02, please continue to the next assignment.