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Transcript of 1 COMS 161 Introduction to Computing Title: Computer Organization Date: March 25, 2005 Lecture...
1
COMS 161Introduction to Computing
Title: Computer Organization
Date: March 25, 2005
Lecture Number: 27
4
Outline
• Computer Systems– Mechanical computers
• Pascal• Babbage• Hollerith
– Mechanical and electrical
– Electromechanical• Harvard Mark I
– Electronic• ABC, ENIAC, EDVAC
5
Computer Systems
• A dime a dozen!!– They are everywhere and their uses
continue to expand• Microwaves• Clocks• Cars• Watches• What’s next
– Shoes??– My Drawers??
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Computer System
• Electronic digital data processing machines– Data: symbolic representation of
information
– Digital: numeric codes
– Computers are discrete state machines• Finite number of states
– All are distinct and different
• Always in a state
7
Computer System
• Process– Set of actions
– Traversing certain states• Sequence of distinct states
– Fast to go from one state to another• Billionths of a second
– So fast, a process appears continuous• As do light bulbs• Your TV screen
8
Computer System
• Mechanical computers– Blaise Pascal (1623-1662)
– Develops a mechanism to calculate with 8 figures and carrying of 10's , 100's, and 1000's etc.
– Could add two decimal numbers
– Could also subtract using 10’s complement
– The machine is called the 'Pascaline'
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Mechanical computers
• Charles Babbage (1791-1871)– Tables of logarithmic and trigonometric functions,
were generated by teams of mathematicians working day and night on primitive calculators
– Since people performed computations they were referred to as computers
– He proposed building a machine called the Difference Engine to automatically calculate these tables
12
Mechanical computers
• Charles Babbage (1791-1871)– The Difference Engine was partially completed
when Babbage conceived the idea of another, more sophisticated machine called an Analytical Engine
– The Analytical Engine was to use loops of punched cards to control an automatic calculator
– Decisions could be based on the results of previous computations
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Mechanical computers
• Charles Babbage (1791-1871)– The Analytical Engine employed several features
found in modern computers• Sequential control• Branching• Looping
– He worked on the Analytical Engine from 1930 until he died
14
Mechanical computers
• Charles Babbage (1791-1871)– Ada Lovelace, the daughter of the English poet
Lord Byron wrote a program for the Analytical Engine
– Ada was a mathematician and fully understood Babbage's vision
– Ada’s program would have computed Bernoulli numbers
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Mechanical computers
• Charles Babbage (1791-1871) – Often referred to as the "Father of Computing"
for his contributions to the development of the computer
– He produced a prototype of this "difference engine" by 1822
– It was intended to be steam-powered– Fully automatic, even to the printing of the
resulting tables– Commanded by a fixed instruction program
17
Mechanical Computers
• Herman Hollerith– Estimated that compiling the data for the 1890
census would take until after the 1900 census– Idea was to use punched cards to represent the
census data– The data could be read and collates using an
automatic machine– He built a mechanism that could read the
presence or absence of holes in the cards• Using spring-mounted nails that passed through the
holes to make electrical connections
18
Mechanical Computers
• Herman Hollerith– The system included an automatic electrical
tabulating machine with a large number of clock-like counters that accumulated results
– Widely regarded as the father of modern automatic computation
– He founded the company that was to become IBM
– Hollerith's designs dominated the computing landscape for almost 100 years
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Computer System
• Electromechanical computer– During the late 1930s punched-card machine
techniques had become so well established and reliable
– Howard Aiken, in collaboration with engineers at IBM, undertook construction of a large automatic digital computer based on standard IBM electromechanical parts
– Handled 23-decimal-place numbers
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Computer System
• Electromechanical computer– IBM called the machine
• automatic sequence controlled calculator (ASCC)
– It is better known• Harvard Mark I,
26
Computer System
• Electronic Computer
– Fastest, but still performs simple steps
– One of the great illusion of the computer: • Lots of simple steps performed quickly enough
make the computer appear complicated
27
Computer System
• Electronic computer– John Vincent Atanasoff (1903 - 1995)– Clifford Berry (1918 - 1963)
• Built the world's first electronic-digital computer at Iowa State University between 1939 and 1942
• The Atanasoff-Berry Computer (ABC) represented several innovations in computing
– a binary system of arithmetic– parallel processing– regenerative memory– separation of memory and computing functions
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Electronic Computer
• Atanasoff performed intensive computing while working on his doctorate in theoretical physics (late 1920’s – 1930)– The forgotten father of computing– Faculty member at Iowa State College in
mathematics and physics– In 1937 worked out the design– In 1939 he hired a student Clifford Berry to help
him construct the machine– By 1941 they had a working machine
31
Electronic Computer
• In 1946, John Eckert and John Mauchley built Electronic Integrator and Computer (ENIAC)– Specific task was compiling tables for the
trajectories of bombs and shells– It contained roughly 18,000 vacuum tubes– Measured about 2.5 meters in height and 24
meters in length– The machine was more than 1000 times faster
than its electromechanical predecessors– It could execute up to 5000 additions per second
33
Electronic Computer
– The ENIAC machine occupied a room thirty by fifty feet
– The controls are at the left– A small part of the output device is at the right
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Electronic Computer
• Improvement ideas developed as ENIAC was built– The stored program concept among them
• John von Neumann
– EDVAC• A new machine with improvements over
ENIAC• The first stored program computer
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Enter the Sharks
• Mauchley filed and received patents for the first general computer
• However– Mauchly visited Atanasoff in 1941 and was
inspired by Atanasoff's work– In 1941 Atanasoff knew more about basic
elements of electronic computation than Mauchly and openly shared this knowledge
– Enter the lawyers• Early 1967
37
Sharks
• October 19, 1973– Judge Larson had ruled that John Vincent
Atanasoff and Clifford Berry had constructed the first electronic digital computer at Iowa State College in the 1939 - 1942 period
– He had also ruled that Mauchly and Eckert, who had for more than twenty-five years been feted, trumpeted, and honored as the co-inventors of the first electronic digital computer, were not entitled to the patent upon which that honor was based
38
Sharks
• October 19, 1973– Judge Larson had ruled that John Vincent
Atanasoff and Clifford Berry had constructed the first electronic digital computer at Iowa State College in the 1939 - 1942 period
– He had also ruled that Mauchly and Eckert, who had for more than twenty-five years been feted, trumpeted, and honored as the co-inventors of the first electronic digital computer
• Were not entitled to the patent upon which that honor was based