Augusta Ada King, Countess of Lovelace ● Charles Babbage’s patron, assistant, and chronicler ● Daughter of Lord Byron, the poet ● Wrote sets of instructions for the Analytical Engine ● World’s first computer programmer ● U.S. Department of Defense named its programming langauge Ada after her ”The Analytical Engine weaves algebraic patterns just as the Jacquard loom weaves flowers and leaves” Jacquard loom

Herman Hollerith ● Developed a tabulating machine for the U.S. census of 1890 ● Stacks of punched cards served as a permanent memory ● Cut census time from 10+ years to 6 weeks ● Not programmable ● Started a company to market his machine which merged with others to form the Computing- Tabulating-Recording Company (eventually known as... )

Herman Hollerith

John Atanasoff and Clifford Berry ● American physicists at Iowa State College ● Berry was Atanasoff’s grad student ● Built ABC machine in late 1930s ● Special-purpose calculator for finding solutions to systems of equations ● All-electronic design using vacuum tubes for switching elements ● Never completed, due to insufficient funding

The Atanasoff-Berry Computer (replica)

Konrad Zuse ● German engineer under the Third Reich ● Built Z1, Z2, Z3, and Z4 in late 1930s and early 1940s with Helmut Schreyer ● Electromechanical design with relays for switching elements ● General-purpose computing device ● Controlled by perforated celluloid strips (like punched cards) ● First machine to use binary number system ● Never completed, due to insufficient funding from the Nazi government

Howard Aiken ● American physicist and applied mathematician ● Built Mark I at Harvard in collaboration with Grace Hopper and IBM engineers in 1944 ● Inspired by Babbage’s Analytical Engine ● Electromechanical design with relays for switching elements Rear Admiral Grace Hopper

Howard Aiken ● Handled 23-digit numbers, logarithms, trigonometric functions ● Controlled by punched paper tape ● Fully automatic but slow (3-5 seconds per multiplication) ● Remained in use at Harvard until 1959 Rear Admiral Grace Hopper

The First Bug ● Grace Hopper found the first actual computer bug while working on the Mark II in 1945

Alan Turing ● English mathematician and first true computer scientist ● Invented a mathematical model of a computer called a Turing Machine ● Proved fundamental theorems about the limitations of computers ● Wrote groundbreaking papers in many different fields – Theory of computation (1936) – Artificial intelligence (1950) – Self-organizing chemical reactions (1952)

Alan Turing ● During World War II, he secretly worked for the British government to crack German Enigma codes ● Helped develop the British electronic code-breaking computer called Colossus ● Enabled Allies to read German military transmissions from 1942 on ● Persecuted by British government after the war for being homosexual ● Forced to undergo hormone “therapy” ● Committed suicide in 1954 at the age of 41

ENIAC ● Electronic Numerical Integrator And Calculator ● Developed by John Mauchly and J. Presper Eckert at the University of Pennsylvania in 1945 ● First general-purpose all-electronic digital computer ● Filled a 30 x 50 ft. room ● Weighed 30 tons ● Dissipated 150,000 watts of energy ● Performed calculations for the atomic bomb project at Los Alamos

ENIAC ● Used 19,000 vacuum tubes

ENIAC ●...which tended to burn out frequently Hmm...maybe it’s this one? Nope... How about this one? Nope...

ENIAC ● Reprogramming required physically rewiring the machine

ENIAC ●...which was a tedious and error-prone process Hold on... I think the blue one and the red one are supposed to be reversed...

ENIAC

John von Neumann ● Hungarian mathematician, computer scientist, cyberneticist, all-around genius ● Worked on atomic bomb project in WW II ● Invented game theory and developed theory of self-replicating automata ● Originated key concept of stored-program computer in 1945 ● Program instructions = data ● Easily reprogrammable ● Von Neumann architecture is still the universal standard

EDVAC ● Electronic Discrete Variable Automatic Computer ● Designed by Mauchly, Eckert, and Von Neumann ● Stored-program design ● Used binary instead of decimal to represent information ● Version called UNIVAC I was the first commercially available computer system ● Sold to the U.S. Census Bureau in 1951

First Generation Computers ● Mid 1940s to late 1950s ● Stored-program design with ~ 1000 words of RAM ● Used vacuum tubes, but required less space than ENIAC ● Punched cards for input and output ● Vacuum tube or magnetic core memory for data storage ● Programmed directly in binary machine language ● Included EDVAC and UNIVAC

First Generation Computers

Transistors ● Invented at Bell Labs in 1947 by William Shockley, John Bardeen, and Walter Brattain ● Generated far less heat than vacuum tubes ● Required far less power ● Much faster, smaller, cheaper, and more reliable

Transistors ● Incorporated into Second Generation computers in the late 1950s and early 1960s

Integrated Circuits ● Invented in the late 1950s by Jack Kilby of Texas Instruments ● Many transistors etched on a single silicon chip as a single electronic circuit ● Faster due to decreased distance between transistors Incorporated into Third Generation computers in the mid 1960s to early 1970s

VLSI Technology ● Very Large Scale Integration ● Thousands or millions of transistors per chip ● First microprocessor chip: Intel 4004 (1971) ● Designed by Ted Hoff for Japanese calculator company ● Followed by Intel 8008 and 4040 (1972) and 8080 (1974) ● Entire computer packaged as a single integrated circuit chip ● Like having an Analytical Engine the size of a shirt button

VLSI Technology ● Incorporated into Fourth Generation computers from the mid 1970s to the present VAX minicomputer from Digital Equipment Corporation (early 1980s)

MITS Altair 8800 (1975) ● First popular and affordable microcomputer ($375) ● Based on Intel 8080 chip ● 256 bytes of RAM (that’s bytes, not kilobytes or megabytes) ● Programmed by manually flipping switches on front panel ● Output in the form of blinking lights ● No software available ● MITS couldn’t sell them fast enough!

MITS Altair 8800 (1975) ● Some assembly required

MITS Altair 8800 (1975) ● Some assembly required ● Bill Gates and Paul Allen promised MITS a BASIC interpreter for the Altair, leading to the creation of Microsoft in 1975 Ha, ha, I’m richer than you!

Other Early Developments ● IMSAI 8080 microcomputer was similar to the Altair 8800 ● Doug Engelbart invented the mouse at SRI in 1964 ● Xerox PARC Alto computer (1974) used mouse, graphics, menus, and icons

Apple Computer, Inc. Steve Jobs and Steve Wozniak The original Apple I Apple II (1977) ● color graphics ● BASIC, 4K RAM ● cassette tape data storage ● $1300 ● VisiCalc released in 1979

Apple Computer, Inc. ● Sales went from $2.5 million to $583 million in six years ● Fortune 500 by 1982 ● Steve Jobs visits Xerox PARC in 1979 ● Apple Macintosh introduced in 1984 ● First widely available microcomputer with GUI

The Personal Computing Era is Born TRS-80 Model II Radio Shack TRS-80 Model I affectionately known as the “Trash 80” Commodore PET (1977) IBM PC (1981) reverse-engineered by Compaq in 1985

The Internet and the World Wide Web ● ARPANET created in 1969 by connecting together 4 computers at UCSB, UCLA, Utah, and SRI ● World Wide Web conceived at CERN in Switzerland in late 1980s by Tim Berners-Lee ● First Web browser written in 1990 by Tim Berners-Lee using a NeXT computer

The Internet and the World Wide Web ● Marc Andreesen and Eric Bina at the University of Illinois develop Mosaic Web browser ● Marc Andreesen and Jim Clark found Netscape Communications, Inc. in 1994 ● Netscape goes public on August 9, 1995 and is worth $3 billion by the end of the day Marc Andreesen

The Future... ? ● “I think there is a world market for maybe five computers” —Thomas J. Watson Chairman of IBM, 1943 ● “If automotive technology had progressed as fast as computer technology between 1960 and today, the car today would have an engine less than a tenth of an inch across, would get 120,000 miles per gallon, have a top speed of 240,000 miles per hour, and would cost $4” —Rick Decker and Stuart Hirshfield The Analytical Engine ● Other predictions, anyone?

For Further Reading One of the best available histories of the personal computer revolution is Fire in the Valley: the Making of the Personal Computer by Paul Freiberger and Michael Swaine