Binary Representation of Information

bit: 0

byte: 0110 11000 "word": 01011100 11101111

00010000 11110000

chapter8

Slide 8-2

Digital Information (Binary)

There are 10 different kinds of people in the world: those who know binary and those who don't. --Anon

Slide 8-3

Digital Information (Binary)

Von Neumann ArchitectureA. CPU; B. RAM; C. I/O; D. Bus

What Can Computers Do?1. I/O operations2. Storage ops. (RAM, disk, disc, ...)3. Arithmetic ops. (+, -, *, /, %, ^, ...) 4. Logic ops. (<, <=, ==, !=, >=, >, AND,

OR, ...)

==> Computers are technologically complex but conceptually simple

Slide 8-4

Digital Information (Binary)

Pictures of the Tinker Toy computer.

How the Tinker Toy computer works.

Slide 8-5

Digital Information Processing Performance Speeds

How Fast Are Computers?

Two measures of throughput

MIPS: 2 ^ 3 ==> 8FLOPS: 3.14159 ^ 2.718 =

22.45186162

Supercomputers: MFLOPS; GFLOPS; TFLOPS; PFLOPS.

The Prefixes of the S.I.

Slide 8-6

Digital Information Processing Performance Speeds

Q: If a supercomputer can execute 1 GFLOPS, one instruction requires how much time to execute?A: 1 nanosecond.

Q: If a supercomputer can execute 1 PFLOPS, one instruction requires how much time to execute?A: ???

Slide 8-7

Information Processing Speeds

People

MFLOPS: recite 1..1M; 2 sec/recitation; 2Msec = 33,333 min. == 23 days

GFLOPS: recite 1..1G; 3 sec/recitation; 3Gsec = 50M min. == 34K days = 100 yrs

TFLOPS: recite 1..1T; 6 sec/recitation; 6Tsec = 200K yrs

Slide 8-8

Neurobiology

1011 neurons, each connected to 104 others

Switching Speed: 10-3 sec.vs.computer: 10-10 sec.

Yet humans are able to make surprisingly complex decisions, surprisingly quickly.

(eg) 10-1 sec. for infant to visually recognize its mother

Slide 8-9

Neurobiology

the information-processing abilities of biological systems must follow from highly parallel processes distributed over many neurons

Artificial Neural Networks

Slide 8-10

Artificial Intelligence Research:

Basic Premise

Genus:Information Processing System(IPS)

/ \Species: Biological Computers

Systems

Both species governed by same principles

Slide 8-11

AI Research

Scientific Metaphors

The heart is a pump

The brain is a computer (IPS)

Metaphor “The heart has its reasons of which reason knows nothing.”

-- Blaise Pascal

Slide 8-12

Digeratus: Alan Turing

During WWII Turing worked at Bletchley Park, Britain's codebreaking centre, & was responsible for German naval cryptanalysis. He devised a number of techniques for breaking German ciphers, including the method of the bombe, an electromechanical machine that could find settings for the Enigma machine.

Slide 8-13

The Turing Test for Intelligence: "Computing machinery and intelligence." (1950)

The Turing test is a proposal for a test of a machine's capability to demonstrate intelligence:

A human judge engages in a natural language conversation with one human and one machine, each of which try to appear human; if the judge cannot reliably tell which is which, then the machine is said to pass the test.

Slide 8-14

Slide 8-15

Five Categories of Information

1. Rover photos of Mars. Category: ? 2. 100 Kdigits of PI. Category: ?3. Clerk's Prolog, Canterbury Tales.

Category: ?4. Prelude & Fugue in C, J.S. Bach.

Category: ?5. A statement in a computer program.

Category: ?

Slide 8-16

Five Categories of Information

Q: Which of the 5 categories is this?    01011100 11101111 00010000 11110000

A: It could be any one of the 5(eg) How bit maps are used to represent images in

computers.

Slide 8-17

Why Do Computers Use Binary?

Nine Rungs of the Computer Inferno

1. Physics level.2. Device Level: Transistors3. Gate Level: AND, OR

PandA = TandF (p. 212)

“Logic is the foundation of reasoning, and the foundation of computing.

By associating true with presence & False with Absence, we can use the physical world to implement the logical world. This produces Information Technology.”

Slide 8-18

Why Do Computers Use Binary?

4. Machine Level:

full adder

a water adder

flip-flop (stores one bit)