4th Generation Computer (1971-Today) – The Microprocessor

This generation can be characterized by both the jump to monolithic integrated circuits (millions of transistors put onto one integrated circuit chip) and the invention of the microprocessor (a single chip that could do all the processing of a full-scale computer).  By putting millions of transistors onto one single chip more calculation and faster speeds could be reached by computers.  Because electricity travels about a foot in a billionth of a second, the smaller the distance the greater the speed of computers.

However what really triggered the tremendous growth of computers and its significant impact on our lives is the invention of the microprocessor.  Ted Hoff, employed by Intel (Robert Noyce’s new company) invented a chip the size of a pencil eraser that could do all the computing and logic work of a computer.  The microprocessor was made to be used in calculators, not computers.  It led, however, to the invention of personal computers, or microcomputers.

Intel 4004

The first advertisement for a microprocessor, the Intel 4004, appeared in Electronic News.  Developed for Busicom, a Japanese calculator maker, the 4004 had 2250 transistors and could perform up to 90,000 operations per second in four-bit chunks.  Federico Faggin led the design and Ted Hoff led the architecture.

It wasn’t until the 1970’s that people began buying computer for personal use.  One of the earliest personal computers was the Altair 8800 computer kit.  In 1975 you could purchase this kit and put it together to make your own personal computer.  In 1977 the Apple II was sold to the public and in1981 IBM entered the PC (personal computer) market.

Advertisement for Atari 400 and 800
Both sold well, though they had technical and marketing problems, and faced strong competition from the Apple II, Commodore PET, and TRS-80 computers.

Original Atari Pong Game
Pong is released. In 1966, Ralph Baer designed a ping-pong game for his Odyssey gaming console. Ralph Baer designed a ping-pong game for his Odyssey gaming console. Nolan Bushnell played this game at a Magnavox product show in Burlingame, California.Pong would revolutionize the arcade industry and launch the modern video game era.

Today we have all heard of Intel and its Pentium^® Processors and now we know how it all got started.  The computers of the next generation will have millions upon millions of transistors on one chip and will perform over a billion calculations in a single second.  There is no end in sight for the computer movement

3rd Generation Computer (1965-1970) – Integrated Circuits and Miniaturizing the Computer

Transistors were a tremendous breakthrough in advancing the computer.  However no one could predict that thousands even now millions of transistors (circuits) could be compacted in such a small space.  The integrated circuit, or as it is sometimes referred to as semiconductor chip, packs a huge number of transistors onto a single wafer ofsilicon. Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the amazing attributes of integrated circuits.  Placing such large numbers of transistors on a single chip vastly increased the power of a single computer and lowered its cost considerably.

Since the invention of integrated circuits, the number of transistors that can be placed on a single chip has doubled every two years, shrinking both the size and cost of computers even further and further enhancing its power.  Most electronic devices today use some form of integrated circuits placed on printed circuit boards– thin pieces of bakelite or fiberglassthat have electrical connections etched onto them — sometimes called a mother board.

These third generation computers could carry out instructions in billionths of a second.  The size of these machines dropped to the size of small file cabinets. Yet, the single biggest advancement in the computer era was yet to be discovered.

DEC PDP-8

Digital Equipment Corp. introduced the PDP-8, the first commercially successful minicomputer.  The PDP-8 sold for $18,000, one-fifth the price of a small IBM 360 mainframe.  The speed, small size, and reasonable cost enabled the PDP-8 to go into thousands of manufacturing plants, small businesses, and scientific laboratories.

2nd Generation Computer (1959-1964) – The Era of the Transistor

The transistor computer did not last as long as the vacuum tube computer lasted, but it was no less important in the advancement of computer technology.  In 1947 three scientists, John Bardeen,William Shockley, and Walter Brattain working at AT&T’s Bell Labs invented what would replace the vacuum tube forever.  This invention was the transistor which functions like a vacuum tube in that it can be used to relay and switch electronic signals.

There were obvious differences between the transistor and the vacuum tube.  The transistor was faster, more reliable, smaller, and much cheaper to build than a vacuum tube.  One transistor replaced the equivalent of 40 vacuum tubes.  These transistors were made of solid material, some of which is silicon, an abundant element (second only to oxygen) found in beach sand and glass.  Therefore they were very cheap to produce.  Transistors were found to conduct electricity faster and better than vacuum tubes.  They were also much smaller and gave off virtually no heat compared to vacuum tubes.  Their use marked a new beginning for the computer.  Without this invention, space travel in the 1960’s would not have been possible.  However, a new invention would even further advance our ability to use computers.

IBM’s 7000 Series

IBM´s 7000 series mainframes were the company´s first transistorized computers. At the top of the line of computers — all of which emerged significantly faster and more dependable than vacuum tube machines — sat the 7030, also known as the “Stretch.”  Nine of the computers, which featured a 64-bit word and other innovations, were sold to national laboratories and other scientific users.  L. R. Johnson first used the term “architecture” in describing the Stretch.

1st generation computer (1940s-1956) – The Vacuum Tubes years

Simply put, the first generation computer is like the UNIVAC and computers, which were considered first- generation computers and were the last use vacuum tubes to store data.

The first generation computers were huge, slow, expensive, and often undependable.  In 1946, two Americans, Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.  The ENIAC used thousands of vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do.  The ENIAC led to other vacuum tube type computers like the EDVAC (Electronic Discrete Variable Automatic Computer) and the UNIVAC I (UNIVersal Automatic Computer). Wilkes, a physicist, was inspired to build a computer by reading von Neumann’s description of EDVAC and attending the Moore School lectures in 1946. For over 50 years he made pioneering contributions in microprogramming, timesharing, operating systems, and more.

The vacuum tube was an extremely important step in the advancement of computers.  Vacuum tubes were invented the same time the light bulb was invented by Thomas Edison and worked very similar to light bulbs.  It’s purpose was to act like an amplifier and a switch.  Without any moving parts, vacuum tubes could take very weak signals and make the signal stronger (amplify it).  Vacuum tubes could also stop and start the flow of electricity instantly (switch).  These two properties made the ENIAC computer possible.

The ENIAC gave off so much heat that they had to be cooled by gigantic air conditioners.  However even with these huge coolers, vacuum tubes still overheated regularly.  It was time for something new.

John von Neumann

John von Neumann wrote “First Draft of a Report on the EDVAC” in which he outlined the architecture of a stored-program computer.  Electronic storage of programming information and data eliminated the need for the more clumsy methods of programming, such as punched paper tape — a concept that has characterized mainstream computer development since 1945.  Hungarian-born von Neumann demonstrated prodigious expertise in hydrodynamics, ballistics, meteorology, game theory, statistics, and the use of mechanical devices for computation.  After the war, he concentrated on the development of Princeton´s Institute for Advanced Studies computer and its copies around the world.

ENIAC

In February, the public got its first glimpse of the ENIAC, a machine built by John Mauchly and J. Presper Eckert that improved by 1,000 times on the speed of its contemporaries. (Start of project: 1943  / Completed: 1946 / Programmed: plug board and switches / Speed: 5,000 operations per second / Input/output: cards, lights, switches, plugs / Floor space: 1,000 square feet / Project leaders: John Mauchly and J. Presper Eckert.)

UNIVAC

On election night, November 4, CBS News borrowed a UNIVAC to make a scientific prediction of the outcome of the race for the presidency between Dwight D. Eisenhower and Adlai Stevenson.  The opinion polls predicted a landslide in favor of Stevenson, but the UNIVAC´s analysis of early returns showed a clear victory for Eisenhower.  Its sharp divergence from public opinion made newscasters Walter Cronkite and Charles Collingwood question the validity of the computer´s forecast, so they postponed announcing UNIVAC´s prediction until very late.

 

http://www.crews.org/curriculum/ex/compsci/articles/generations.htm

http://www.computerhistory.org/