HISTORY of COMPUTERS

History of Computers

Who invented the computer? is not a question with a simple answer. The real answer is that many inventors contributed to the history of computers and that a computer is a complex piece of machinery made up of many parts, each of which can be considered a separate invention.

-Mary Bellis

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What was it before computers?

Manual calculators

abacus

Napier bones

slide rule

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What was it before computers?

Mechanical calculators

Schickards calculator (1623)

series of interlocking geard

Pascaline (1642)

performed basic arithmetic operations

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What was it before computers?

Mechanical calculators

Leibniz calculator (1673)

similar with pascaline

de Colmars Arithmometer (1820)

first mass produced mechanical calculator

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What was it before computers?

Difference engine (1822)

device proposed by Charles Babbage that would operate using steam engine

too complicated to work until 1853

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What was it before computers?

Analytical engine (1834)

new device designed by Babbage

never completed

design embodies many concepts that define modern computers

memory

programmable processor

output device

user-definable input

data

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Computer Prototypes

Prototype

experimental device that must be further developed and perfected before going into production and becoming widely available.

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ABC (circa 1942)

Atanasoff-Berry Computer

John Atanasoff and Clifford Berry (Iowa State University)

Represented several innovations in computing

binary system of arithmetic

parallel processing

regenerative memory

separation of memory and computing functions.

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Atanasoff-Berry Computer

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Z1 (1936)

Mechanical calculator, first binary computer

Invented by Konrad Zuse

Z2 invented in 1939

first fully functioning electro-mechanical computer

Z3 invented in 1941

digital computer based on a binary floating-point number and switching system

used old movie film instead of paper and punch card to store data

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Z1

Z2

Z3

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MARK Series (1944)

Designed by Howard Aiken and Grace Hopper at Harvard University

MARK I in 1944

Giant roomful of noisy, clicking metal parts, 55ft X 8ft

Used by US Navy for gunnery and ballistic calculations

In operation until 1959

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Harvard MARK Computer

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ENIAC (1945)

Electronic Numerical Integrator and Computer

Developed by John Mauchly and J. Presper Eckert

Sponsored by the US military

for writing artillery-firing tables

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ENIAC

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First Generation Computers

Characterized by their use of vacuum tubes to store individual bits of data

Vacuum tube

An electronic device that controls the flow of electrons in a vacuum

Respond more quickly than mechanical relays, resulting in faster computations, but they also have several disadvantages

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UNIVAC (1951)

Universal Automatic Computer

Developed by John Mauchly and J. Presper Eckert

Considered by most historians to be the first commercially successful digital computer

Could read data at the rate of 7,200 characters per second, and complete 2.25 million instruction cycles per second

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UNIVAC 1

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Second Generation Computers

Generations of computers that used transistors instead of vacuum tubes

Transistors

regulate current or voltage flow and act as a switch for electronic signals

performed functions similar to vacuum tubes, but they were much smaller, cheaper, less power hungry, and more reliable

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Third Generation Computers

Based on integrated circuits

Became possible in 1958, when Jack Kilby at Texas Instruments and Robert Noyce at Fairchild Semiconductor independently developed integrated circuits

Integrated circuit

Packed the equivalent of thousands of vacuum tubes or transistors onto a single miniature chip, vastly reducing the physical size, weight, and power requirements for devices such as computers

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First Integrated Circuit

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Third Generation Computers

First computers to incorporate ICs

RCA Spectra 70

IBM 360

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Third Generation Computers

DEC PDP-8

The first commercially successful minicomputer

IBM AS/400

One of the few remaining devices that could be classified as a minicomputer

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Fourth Generation Computers

Microprocessor-based computer systems that were faster, smaller, and even less expensive than third-generation computers

Microprocessor

developed by Ted Hoff in 1971

Intel 4004

equivalent to 2,300 transistors

4 bit data path

ran at 108 KHz

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Home Computers (early 1970s)

Based on microprocessors

Utilize LSI (large scale integration) and VLSI (very large scale integration)

Smaller, faster and more complex than computers built on ICs

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Scelbi

Scientific Electronic Biological Computer

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MARK 8

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Altair 8800

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IBM 5100

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Personal Computer (1981)

IBM PC

Introduced by IBM

MS-DOS 1.0 operating system

Intel 8088 processor

Success lead many other companies to develop their products IBM compatible

IBM PC XT

The IBM PC was soon followed by the IBM PC XT, which featured RAM upgradable to 640 KB, and a 10 MB hard disk drive.

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First IBM PCs

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Personal Computers by Apple

Apple I

a kit containing a system board with 4 KB of RAM that sold for $666.66.

released during 1976 by Apple Computer Corporation founded by Steve Jobs and Steve Wozniak.

Apple II

preassembled computer which featured color graphics, expansion slots, a disk drive, a 1.07 MHz 6502 processor, and 16 KB of RAM for $1,195.

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Personal Computers by Apple

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Apple Lisa

Computer developed by Apple Computer, Inc.

Developed starting 1978, released 1983

Features:

protected memory, cooperative multitasking

hard disk based OS, built-in screensaver

advanced calculator, numeric keypad

support for up to 2MB RAM

Motorola 68000 CPU running at 5 MHz

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Apple Lisa

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Apple Macintosh

Featured a graphical user interface that made programs easier to use than those on the command-line-based IBM PC.

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Microsoft Windows 1.0 (1983)

Announced this new OS in 1983 but was released in 1985

Originally called Interface Manager but Windows prevailed because it best describes the boxes or computing windows that are fundamental to the new system

Provides graphical user interface (GUI)

Multitasking environment for IBM computers

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Windows 1.0 Screenshot

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Trends

Desktop computers were very famous and still are available

Trend goes to portable devices

Portable computers became smaller, lighter and popular

outsold desktop computers in 2005

Apple iPhone ushered in the era of handheld computing devices

Smartphones outsold desktop and notebook computers in 2011

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