Computing in the Modern World

Mr. Van NusColquitt County High School

The History of ComputersGenerations 1, 2, & 3

Mr. Van NusColquitt County High School

Generation 1 (1945-1954)

• Electro. Relays required open/closing of switches…so…computing speed was limited by the inertia of moving parts

• Often jammed– “a bug”

• 1940’s Electo. Relays were replaced with “Vacuum tubes”.– Small glass tube with all gases removed

allowing electrons to move with minimal interference

Timeline

• Although vacuum tubes had been invented in 1906, they were not cost effective until the 1940’s

• Without moving parts the Vacuum tubes could perform 1000 times faster

Timeline

• Computing during World War II• 1943– British govt. built the first electronic

computer to decode NAZI messages• It was called COLOSSUS

– Contained 230 vacuum tubes– Remained classified for 30 yrs• No one knew about it

Timeline

• Roughly the same time John Mauchly and J. Presper Eckert were building ENIAC, an electric computer– Designed to compute ballistic tables for

the U.S. Army– 18000 vacuum tubes and 1500 relays–Weighed 30 tons– Required 140 kilowatts of power– Less memory and 500 times faster than

Mark I– It was also programmable, reconfigured

Timeline

• John von Neumann– Recognized that programming with

switches and cables was tedious and error prone

– Created a computer architecture where programs along with data could be stored in memory.

– Also created the binary (base2) memory– First used in vacuum tube computers

such as the EDVAC, and IAS

Timeline

• Because of the “stored program” architecture, computer programming became more important than computer design– First language used was “machine

language”• 0’s and 1’s correspond to instructions

– Faster than rewiring, but still slow and tedious

– 1950’s programmers began to use “assembly languages”• Used mnemonic names for binary #

Timeline

• 1950 – Commercial computer industry began

• Echert, Mauchly left Univ. of Penn. to form own company– 1951 – began selling UNIVAC I– First purchased by the US Census Bureau– CBS used it to predict the Presidential

Elec.

Generation 2…Timeline• The weaknesses of Vacuum tubes became

known:– Relatively large– Produces large amounts of heat• Required lots of space for cooling

– Burnt out frequently

• Replacement of vacuum tubes with transistors began– A piece of silicon whose conductivity can be

turned on and off with electric current– Smaller, cheaper, more reliable, and more

efficient• = smaller, faster machines that were cheaper

Timeline• Transistors led to many small, affordable

electronic devices, including: radios, televisions, phones, computers, etc…

• The scientific community recognized the potential impact immediately awarding Bardeen, Brattain, and Shockley the 1956 Nobel Prize in physics

• First transistorized computers were Sperry-Rand’s, “LARC” and IBM’s, “STRETCH”

• 1960 – transistor-based comp. marketed to private business

Timeline• High-level Programming languages–With more affordable computers being

produced, a larger emphasis began to be placed on programming

–Why?...if non “geniuses” or common people were going to have computers, they would have to be more simple

– 1957, John Backus produced FORTRAN• FORmula TRANslator• a very high level programming language

– Followed by: LISP (John McCarthy, 59), BASIC (John

Kemey, 59), and COBOL (Grace Murray-Hopper, 60)

Generation 3…Timeline

• Integrated Circuits (1963-1973)– Before I.C. chips, transistors would be

produced individually and connected via wire• Tedious, often included 100’s & 1000’s of

transistors• This also limited the size of transistors

– To small and could not be connected by hand

– 1958 – Jack Kilby (Texas Instruments) began developing techniques to mass produce much smaller, already-connected transistors on a silicon disk• Silicon disc not electrically conductive• Metal wires connecting transistors were conductive

Timeline

• This allowed transistor’s to be created much smaller and placed much closer together– Hundreds could be placed on a disc– Packaged in metal or plastic and conne

cted by external pins

• This capability allowed computers to once again be produced quicker, cheaper, and perform faster

• Jack Kilby was awarded the Nobel Prize in physics in 2000

Timeline

• Large Scale Integration• As manufacturing improved the # of

transistors that could be mounted increased.

• 1965, Gordon Moore noticed that about every 12-18 months the # of transistors that could be fit on 1 chip doubled– This became known as “Moore’s Law”

Timeline

• 1970’s – Large Scale Integration (LSI), where thousands of transistors could be loaded on a single chips became possible

• 1971 – Intel combined all the control circuitry for a calculator on 1 chip– Called a “microprocessor”– It was called the Intel 4004– It contained 2300+ transistors

• 1974 – Intel released 8080– 6000+ transistors

Timeline

• The 8080 and it’s successors (8086, 8088) served as the Central Processing Units (CPU’s) for many personal computers in the 70’s

• Tex. Instru., National Semiconductors, Fairchild Semiconductors, and Motorola began producing microprocessors at this time also

Timeline• Computing for Business– Again this led to development of

smaller, faster, and cheaper computers–Which allowed business other than the

very large corporations to purchase and integrate them into daily business

• What comes next?– Education• For non-technical users

– Simplification• Operating sys, master control programs, peripheral

(keyboards, mice, monitors) device managers, etc…

Timeline

• New programming languages were developed to meet the needs of the computers new, broader base of users– 1971, Niklaus Wirth developed “Pascal”• Simple language for teaching programming

skills

– 1972, Dennis Ritchie developed “C”• Used in the development of “UNIX” and

other operating systems of the 70’s and 80’s

Electro-magnetic Relay Tube

When an electrical current is applied to the wire at the bottom, the metal coil to the left generates a magnetic field. The magnetic attraction pulls the armature on the right, closing the switch and allowing electricity to flow through the relay.

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Vacuum Tube

Vacuum tube - A filament inside the tube controls the flow of electricity –when a current is applied to the filament, electrons are released to bridge the vacuum and allow electrical current to flow through the tube.

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The COLOSSUS

The COLOSSUS at Bletchley Park, England. The messages to be decoded were fed into the machine on paper tape, as shown on the right. The panels show some of the more than 2,300 vacuum tubes that comprised the logic for breaking German codes. back

ENIAC

ENIAC, with some of its 18,000 vacuum tubes visible (U.S. Army photo).

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IAS computer

John von Neumann with the IAS computer (Princeton University).

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TransistorsMany experts

consider transistors to be the most important technological development of the 20th century.

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Electronic Circuitry

• Microscopic photograph of electronic circuitry. Transistors (seen as small rectangles) and connecting wires (seen as lines) are constructed out of layers of metal on a silicon chip.

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Integrated Circuits

Early integrated circuits, packaged in plastic with metal pins as connectors.

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Intel 4004Microscopic image of

the Intel 4044 microprocessor, with the connections between transistors dyed to appear white. The blue rectangles around the outside represent the pins, which connected the circuitry of the chip to the other computer components.

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