computer architecture computer generations first generation (1945 – 1955) second generation...

Computer Architecture

Computer GenerationsComputer Generations

First Generation (1945 – 1955)First Generation (1945 – 1955) Second Generation (1955 – 1965)Second Generation (1955 – 1965) Third Generation (1965 – 1975)Third Generation (1965 – 1975) Fourth Generation (1975 – Present)Fourth Generation (1975 – Present)


Before the Computer GenerationsBefore the Computer Generations

Born in England in 1791, Born in England in 1791, Charles BabbageCharles Babbage conceptualizes a conceptualizes a difference enginedifference engine. In . In 1830 he enthusiastically began to build a 1830 he enthusiastically began to build a full-scale working version, using a grant full-scale working version, using a grant from the British government – from the British government – He failsHe fails



He conceived another He conceived another machine, called the machine, called the analytical engineanalytical engine and and receive the support of receive the support of AdaAda, the countess of , the countess of Lovelace, which is Lovelace, which is considered the first considered the first computer programmer in computer programmer in history. Ada developed history. Ada developed the instructions for doing the instructions for doing computations on the computations on the analytical engine. analytical engine. The The machine was never machine was never completed.completed.

In 1991, London Science Museum constructs the Analytical Engine in memory of Charles Babbage



Herman HollerithHerman Hollerith builds the builds the Tabulating Tabulating MachineMachine and won the and won the 1890 census contest1890 census contest In 1880 United States In 1880 United States

census took 7.5 years census took 7.5 years to complete the to complete the calculationcalculation

With Hollerith With Hollerith machine, the 1890 machine, the 1890 census calculation census calculation took 6 weekstook 6 weeks



In 1896, Hollerith established the In 1896, Hollerith established the Tabulating Machine Company to market Tabulating Machine Company to market the productthe product

In 1924, the company merges with two In 1924, the company merges with two other companies and form the other companies and form the International Business Machines International Business Machines Corporation - Corporation - IBMIBM



Thomas J Watson SrThomas J Watson Sr. rules IBM for more . rules IBM for more than 30 years (1924 – 1956) and finances than 30 years (1924 – 1956) and finances a project conducted by young Harvard a project conducted by young Harvard professor of mathematics, professor of mathematics, Howard AikenHoward Aiken

In 1936 Howard reads the notes of Lady In 1936 Howard reads the notes of Lady Lovelace and proposes the construction of Lovelace and proposes the construction of a machine, for which Watson gave him $1 a machine, for which Watson gave him $1 million. million. Harvard Mark 1Harvard Mark 1 was born was born



Harvard Mark 1 is 8 feet high and 55 feet Harvard Mark 1 is 8 feet high and 55 feet long of steel and glass. It was released in long of steel and glass. It was released in 1944.1944.

In early 1940s, the American military In early 1940s, the American military approaches approaches Dr. John MauchlyDr. John Mauchly at at University of Pennsylvania to calculate University of Pennsylvania to calculate trajectories for military missiles & artillerytrajectories for military missiles & artillery



Dr. Mauchly builds the Dr. Mauchly builds the ENIAC (Electrical ENIAC (Electrical Numerical Integrator and CalculatorNumerical Integrator and Calculator) ) based on the previous work of based on the previous work of Dr. John V Dr. John V AtanasoffAtanasoff (professor of physics at Iowa (professor of physics at Iowa State University) called State University) called ABC (Atanasoff-ABC (Atanasoff-Berry Computer)Berry Computer) in the late 1930s in the late 1930s


First GenerationFirst Generation

The ENIAC later evolved into The ENIAC later evolved into UNIVACUNIVAC (Universal Automatic Computer) 1, which (Universal Automatic Computer) 1, which was the first commercial general purpose was the first commercial general purpose computer sold in June 14, 1951 to the US computer sold in June 14, 1951 to the US Bureau of the CensusBureau of the Census

Key concept of Key concept of stored programstored program introduced introduced by by John von NeumannJohn von Neumann



Introduction of Introduction of Assembly LanguageAssembly Language

Vacuum tubeVacuum tube technology was used technology was used to implement logic to implement logic functionsfunctions

The I/O uses The I/O uses typewriter-like input typewriter-like input and output devicesand output devices

The Vacuum tubes The Vacuum tubes produce great deal of heat produce great deal of heat and causing many and causing many problems in temperature problems in temperature regulation and climate regulation and climate controlcontrol



The UNIVAC uses The UNIVAC uses Magnetic coreMagnetic core memories. memories. It consisted of small It consisted of small doughnut-shape rings doughnut-shape rings about the size of about the size of pinheads strung like a pinheads strung like a beads on intersecting beads on intersecting wireswires

Magnetic tapeMagnetic tape device device were also developed in were also developed in 19571957


Second GenerationSecond Generation

In late 1940s, In late 1940s, AT&T Bell LaboratoriesAT&T Bell Laboratories scientists (J. Bardeen, H. W. Brattain and scientists (J. Bardeen, H. W. Brattain and W. Shockley) invent the W. Shockley) invent the Transistor,Transistor, replacing vacuum tubes. They get Nobel replacing vacuum tubes. They get Nobel Prize for their invention.Prize for their invention. They need no warm-up time, consumed less They need no warm-up time, consumed less

energy, were faster and more reliableenergy, were faster and more reliable



Magnetic core memories and magnetic Magnetic core memories and magnetic drum storage are widely useddrum storage are widely used

Evolution from Machine Language to Evolution from Machine Language to Assembly Language (which were also Assembly Language (which were also called Symbolic Languages) and then called Symbolic Languages) and then evolve to evolve to High-level languagesHigh-level languages ( (FortranFortran - - 1954 and 1954 and COBOLCOBOL - 1959) - 1959)



System programsSystem programs called compilers were called compilers were developed to translate these high-level language developed to translate these high-level language programs into corresponding assembly programs into corresponding assembly language programlanguage program

Separate I/O processors were developed and in Separate I/O processors were developed and in 1962 the first 1962 the first removable disk packremovable disk pack was was marketedmarketed

IBM became major computer manufacturer and IBM became major computer manufacturer and most computer systems are used by most computer systems are used by government, business and universitiesgovernment, business and universities


Third GenerationThird Generation

The development of The development of silicon chipsilicon chip, called the , called the integrated circuit technologyintegrated circuit technology SiliconSilicon is the most abundant element in is the most abundant element in

earth’s crust. In the beach sands, rocks and earth’s crust. In the beach sands, rocks and clay.clay.

In 1965, the principal site for manufacturing In 1965, the principal site for manufacturing the silicon chip is Santa Clara County, 30 the silicon chip is Santa Clara County, 30 miles south San Francisco. Later nicknamed miles south San Francisco. Later nicknamed Silicon ValleySilicon Valley



IC memories replace magnetic core memories IC memories replace magnetic core memories and IC technology replaces discrete transistor and IC technology replaces discrete transistor technologytechnology

In 1964, IBM 360 series mainframe, called In 1964, IBM 360 series mainframe, called System/360 dominates the market. The System/360 dominates the market. The equipment is housed inside blue cabinets and equipment is housed inside blue cabinets and IBM begins to be known as “IBM begins to be known as “Big Blue”Big Blue”

PDP minicomputer from Digital Equipment PDP minicomputer from Digital Equipment Corporation also widely used by businesses in Corporation also widely used by businesses in this period.this period.



IBM also unbundled the software in its IBM also unbundled the software in its System/360, sSystem/360, selling the software separatelyelling the software separately from from the hardware and beginning the creation of the hardware and beginning the creation of today’s software industrytoday’s software industry

Operating systemOperating system software allows efficient software allows efficient sharing of computer systemsharing of computer system

Introduction of microprogramming, parallelism, Introduction of microprogramming, parallelism, and pipeliningand pipelining

Cache and virtual memories were developedCache and virtual memories were developed



Bill Gates, went off to Bill Gates, went off to Harvard in 1974 and Harvard in 1974 and hooks up with Paul Allen. hooks up with Paul Allen. When the When the MITS AltairMITS Altair was for sale (January was for sale (January 1975), both Bill and Paul 1975), both Bill and Paul moved to Albuquerque, moved to Albuquerque, wrote software for MITS wrote software for MITS and formed their own and formed their own company called company called MicrosoftMicrosoft


Fourth GenerationFourth Generation

Early 1970s, IC Early 1970s, IC fabrication techniques fabrication techniques evolved into evolved into VLSIVLSI ( (Very Very Large Scale IntegrationLarge Scale Integration) ) and enable the fabrication and enable the fabrication of the of the microprocessormicroprocessor

Apple ComputerApple Computer founded founded in 1977 by Steve Jobs in 1977 by Steve Jobs and Steve Wozniak to and Steve Wozniak to market their Apple 1 (and market their Apple 1 (and fails) and Apple 2fails) and Apple 2



When MITS failed, When MITS failed, Microsoft moved their Microsoft moved their operation to their operation to their native Bellevue, native Bellevue, Washington with their Washington with their 32 employees (1980).32 employees (1980).

IBM came and offered IBM came and offered a a chance to develop chance to develop the operating systemthe operating system for IBM's soon-to-be for IBM's soon-to-be personal computerpersonal computer



Placing the whole Placing the whole company at risk, company at risk, Gates purchased an Gates purchased an existing operating existing operating system, which was system, which was reworked to produce reworked to produce MS-DOSMS-DOS ( (Microsoft Microsoft Disk Operating Disk Operating SystemSystem))

IBM PCIBM PC launched in launched in 1981 and rose to the 1981 and rose to the top of best seller list top of best seller list in 18 monthsin 18 months



IntelIntel, , National SemiconductorNational Semiconductor, , MotorolaMotorola, , Texas InstrumentsTexas Instruments, , Advanced Micro Advanced Micro Device Device ((AMDAMD).).

Computer organizational concepts Computer organizational concepts developed such as developed such as concurrencyconcurrency, , pipeliningpipelining, , cachecache, , virtual memoriesvirtual memories..

PortablePortable notebook, notebook, desktopdesktop, , workstationworkstation, , local area networks (local area networks (LANLAN), wide area ), wide area networks (networks (WANWAN), ), InternetInternet..

computer architecture computer generations first generation (1945 – 1955) second generation...

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