1. Computers in Society History of Computing

2. Homework Assignment #3 is ready to go – let’s have a look. Questions about HW1? More people to schedule for HW2? Start thinking about a term paper topic!

3. Futurism Can we understand the future of computing? What sort of predictions have been made?

4. Looking Back to Look Ahead Perhaps the best way to look into the future of computing is to look back. Many predictions have been made – in books, in movies, by academics, by entertainers, by companies. Most of these predictions have been very wrong! What are some examples of “serious” predictions about the future of computing?

5. Dubious Quotes "Everything that can be invented has been invented." — Charles H. Duell, Commissioner, U.S. Office of Patents, 1899. "Computers in the future may weigh no more than 1.5 tons." — Popular Mechanics, 1949 "I have traveled the length and breadth of this country and talked with the best people, and I can assure you that data processing is a fad that won't last out the year." — The editor in charge of business books for Prentice Hall, 1957. "There is no reason anyone would want a computer in their home." — Ken Olson, president of Digital Equipment Corp., 1977. "640K (of memory) ought to be enough for anybody." — Bill Gates, 1981. "If the automobile had followed the same development cycle as the computer, a Rolls-Royce would today cost $100, get a million miles per gallon, and explode once a year, killing everyone inside." — Robert X. Cringely, InfoWorld

6. A Tour of The Computer * Processing * Memory * Transmission * Interfacing with the real world It is important to understand how we assess these things! What makes one device better than another?

7. The Computing Element John Von Neumann, one of the pioneers of computing, used the word “Organ” to describe these elements. The biological metaphors started from day 1 … The original computing element was the human brain. But eventually mechanical devices were created to speed up the calculation process. The apex of mechanical computing was Babbage’s “analytical engine”, a device too complex to ever work. This early computing was mathematical – building tables of numbers for navigation and engineering purposes.

8. Historical Computing Devices

9. Electronic Computing The big innovation in computing was the replacement of mechanical computing devices by purely electronic ones. A gear or relay is too big / slow / unreliable to use in large quantities. An electronic switch has no moving parts – it operates by pushing electrons around. The original electronic computers used vacuum tubes – later transistors took over.

10. Electronic Gates A gate is a device in which one signal controls another. In a vacuum tube, the grid could block or allow flow from input to output. So this is just like a relay. Transistors are very similar – just a lot smaller.

11. Silicon The “computer revolution” came about when VLSI technology allowed a single chip to contain LOTS of transistors. A Pentium has about 50 million transistors. That would have been a lot of vacuum tubes. Manufacturing cost is something like $0.000001 per transistor. Note that computers are built from a single part!

12. Timeline 2500BC – 300BC: Abacus 1617: Napier’s Bones 1820: First mass-produced mechanical calculators 1822: Babbage’s difference engine 1930: motorized mechanical calculators able to quickly add, subtract, multiply, divide 1940s: digital computers (vacuum tubes)

13. Timeline 1950s: computers are mass produced and become common in the business world 1960s: transistors give way to integrated circuits 1980s: personal computing arrives Now: a typical computer can do 5 – 10 million numeric calculations per second (MFLOP)

14. Assessing Computation How can we assess a computational technology? This turns out to be REALLY HARD! Knowing how fast a device can do one task doesn’t tell us a lot about other tasks. Approaches: Clock rate (not very accurate) MFLOP (only helps for numeric calculations) Specific benchmarks Units: tasks / second