Chapter 4 Computer Science

Gen 5 Wifi and wireless broadband have made computing?

mobile and pervasive

Gen 0 1642

- Pascal built a mechanical calculating machine -used mechanical gears, a hand-crank, dials and knobs -other similar machines followed

Generation 5

-1985-???? -ultra large scale integration (ULSI) -practical impact: parallel computing, artificial intelligence

Gen 5 Artificial Intelligence (AI) applications dominate the news

-Apple's Siri (2011) and Amazon's Alexa (2014) can recognize voice commands and control smart home devices -facial recognition software is used by law enforcement and businesses -credit card companies model purchasing patterns to identify fraud -retailers like Amazon use your history to predict future purchases -Self-driving cars from Google and Tesla use video processing and AI techniques to control vehicles on open roads

programming was still difficult and tedious because

-each machine had its own machine language, 0's & 1's corresponding to the settings of physical components -in 1950's, assembly languages replaced 0's & 1's with mnemonic names e.g., ADD instead of 00101110

Gen 1 COLOSSUS (1943)

-first "electronic computer", built by the British govt. (based on designs by Alan Turing) -used to decode Nazi communications during the war -the computer was top-secret, so did not influence other researchers

Gen 1 ENIAC (1946)

-first publicly-acknowledged "electronic computer", built by Eckert & Mauchly (UPenn) -18,000 vacuum tubes and 1,500 relays -weighed 30 tons, consumed 140 kwatts -"programmed" by women CS pioneers

Gen 2 Transistor

-is a piece of silicon whose conductivity can be turned on and off using an electric current -they performed the same switching function of vacuum tubes, but were smaller, faster, more reliable, and cheaper to mass produce -invented by Bardeen, Brattain, & Shockley in 1948 (earning them the 1956 Nobel Prize in physics)

Gen 5 the invention of the World Wide Web (Tim Berners-Lee, 1989) led to the rapid expansion of the Internet

-more than ½ of the world (4.021 billion) accesses the Internet [2018 Global Digital Report, We Are Social, Ltd.] -more than 1.5 billion Web sites exist, with tens of trillions of pages [2019NetCraft Web Server Survey]

Gen 5 workarounds

-multi-core processors increase the chip size by adding duplicate circuitry so that it can execute operations simultaneously -parallel processing computers have multiple independent processors that can share the load (e.g., a Web server)

Gen 2 Mid 1950's

-transistors began to replace tubes -some historians claim the transistor was the most important invention of the 20th century

Gen 1 Mid 1940s

-vacuum tubes replaced relays -a vacuum tube is a light bulb containing a partial vacuum to speed electron flow -vacuum tubes could control the flow of electricity faster than relays since they had no moving parts -invented by Lee de Forest in 1906

Gen 2 computers became commercial as

cost dropped

1980's

demand grew for networking computers together 1982: 235 computers connected to ARPANet 1989: 300,000 computers connected to Internet object-oriented programming represented a new approach to program design which views a program as a collection of interacting software objects that model real-world entities

calculating devices have been around for?

for millennia (e.g., abacus ~3,000 B.C.)

Gen 1 1940s

hybrid computers using vacuum tubes and relays were built

Gen 3 mid 1960's

integrated circuits (IC) were produced -Noyce and Kilby independently developed techniques for packaging transistors and circuitry on a silicon chip (Kilby won the 2000 Nobel Prize in physics) -this advance was made possible by miniaturization & improved manufacturing -allowed for mass-producing useful circuitry

Gen 3 1960's

saw the rise of Operating Systems recall: an operating system is a collection of programs that manage peripheral devices and other resources in the 60's, operating systems enabled time-sharing, where users share a computer by swapping jobs in and out as computers became affordable to small businesses, specialized programming languages were developed Pascal (1971, Wirth), C (1972, Ritchie)

Gen 5 1989

the Intel 486 contained 1.2 million transistors -manufacturing improvements are more difficult to achieve as components get smaller and smaller (Moore's Law in jeopardy?)

Gen 5

the latest generation of computers is still hotly debated nno new switching technologies, ultra large scale integration (ULSI) has changed how computers are used

Gen 4 Moore's Law

the number of transistors that could fit on a chip doubled every 1-2 years

Gen 0 1930s

- several engineers independently built "computers" using electromagnetic relays an electromagnetic relay is physical switch, which can be opened/closed via electrical current relays were used extensively in early telephone exchanges Zuse (Nazi Germany) - his machines were destroyed in WWII Atanasoff (Iowa State) - built a partially-working machine with his grad student Stibitz (Bell Labs) - built the MARK I computer that followed the designs of Babbage olimited capabilities by modern standards: could store only 72 numbers, required 1/10 sec to add, 6 sec to multiply ostill, 100 times faster than previous technology

Gen 0 1805

- the first programmable device was Jacquard's loom the loom wove tapestries with elaborate, programmable patterns a pattern was represented by metal punch-cards, fed into the loom using the loom, it became possible to mass-produce tapestries, and even reprogram it to produce different patterns simply by changing the cards

Generation 0

-1642-1943 -mechanical devices(gears, relays) -practical impact: calculators, looms, relay-based computers

Generation 1

-1943-1954 -vacuum tubes -practical impact: practical computers, military applications

Generation 2

-1954-1963 -transistors -practical impact: cheaper/faster computers, commercial applications

Generation 3

-1963-1973 -integrated circuits -practical impact: cheaper/faster computers, computing industry

Generation 4

-1973-1985 -microprocessors -practical impact: personal computers, networking

Gen 1 "stored program" computer

-von Neumann popularized the idea -Memory stores both data and programs -Central Processing Unit (CPU) executes by loading program instructions from memory and executing them in sequence -Input/Output devices allow for interaction with the user -virtually all modern machines follow this von Neumann Architecture (note: same basic design as Babbage)

Gen 1 COLOSSUS and ENIAC

-were not general purpose computers -could enter input using dials & knobs, paper tape -but to perform a different computation, needed to reconfigure

modern "computing technology" traces its roots to the?

16-17th centuries -as part of the "Scientific Revolution", people like Kepler, Galileo, and Newton viewed the natural world as mechanistic and understandable this led to technological advances & innovation

Gen 4 with microprocessors came personal computing

1975 - Bill Gates & Paul Allen founded Microsoft Gates wrote a BASIC interpreter for the first PC (Altair) 1977 - Steve Wozniak & Steve Jobs founded Apple went from Jobs' garage to $120 million in sales by 1980 1980 - IBM introduced PC Microsoft licensed the DOS operating system to IBM 1984 - Apple countered with Macintosh introduced the modern GUI-based OS (which was mostly developed at Xerox) 1985 - Microsoft countered with Windows

Gen 0 Mid 1800s

Babbage designed his "analytical engine" its design expanded upon mechanical calculators, but was programmable via punch-cards (similar to Jacquard's loom) Babbage's vision described the general layout of modern computers Ada Lovelace developed instructions for the never-quite-finished Analytical Engine - is considered the world's first programmer

Gen 2 high-level languages were designed to make programming more natural

FORTRAN (1957, Backus at IBM) LISP (1959, McCarthy at MIT) BASIC (1959, Kemeny at Dartmouth) COBOL (1960, Hopper at DOD) -the computer industry grew as businesses could afford to buy and use computers Eckert-Mauchly (1951), DEC (1957) IBM became market force in 1960's

Gen 4 1971

Intel marketed the first microprocessor, the 4004, a chip with all the circuitry for a calculator nby the late 1970's, manufacturing advances allowed for the very large scaleintegration (VLSI) of hundreds of thousands of transistors w/ circuitry on a chip -this "very large scale integration" resulted in mass-produced microprocessors and other useful IC's -since computers could be constructed by simply connecting powerful IC's and peripheral devices, they were easier to make and more affordable