1 COMS 161 Introduction to Computing Title: Computer Organization Date: March 25, 2005 Lecture Number: 27

2 Announcements Research paper rough draft –Due Monday 3/28/2005

3 Review HTML –Document structure Tables

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??

6 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 ( ) –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'

9 Pascaline

10 Pascaline

11 Mechanical computers Charles Babbage ( ) –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 ( ) –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

13 Mechanical computers Charles Babbage ( ) –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 ( ) –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

15 Mechanical computers Charles Babbage ( ) –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

16 Difference and Analytical Engine

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

19 Hollerith 1890 Census Tabulator

20 Hollerith Punch Card

21 IBM Punch Card

22 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

23 Computer System Electromechanical computer –IBM called the machine automatic sequence controlled calculator (ASCC) –It is better known Harvard Mark I,

24 Harvard Mark I feet long weighs 5 tons incorporates 750,000 parts

25 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 ( )John Vincent Atanasoff –Clifford Berry ( )Clifford Berry 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

28 Electronic Computer Atanasoff performed intensive computing while working on his doctorate in theoretical physics (late 1920’s – 1930) –The forgotten father of computingforgotten 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

29 Electronic Computer Clifford Berry with ABC in 1942

30 Electronic Computer Replica of ABC

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

32 Electronic Computer ENIAC –The first general purpose computer

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

34 Electronic Computer

35 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

36 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 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 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

39 Sharks October 19, 1973 –Judge Larson also ruled Mauchly had pirated Atanasoff's ideas For more than thirty years had palmed those ideas off on the world as the product of his own genius