Introduction to ComputingIntroduction to ComputingCS 101CS 101

Autumn 2004Autumn 2004

Chapter 1Chapter 1Introduction to ComputingIntroduction to Computing

Charles Babbage Charles Babbage

Life : 1791 – 1871 UK

Known as "Father of Computing" for his contributions to the basic design of the computer through his Analytical Machine

http://ei.cs.vt.edu/~history/Babbage.html

The First ProgrammerThe First Programmer

Countess of Lovelacehttp://ei.cs.vt.edu/~history/Ada.GIF

Ada Augusta KingAda Augusta King

The MillThe Analytical Engine of Charles Babbage was never completed in his lifetime, but his son Henry Provost Babbage built the "mill" portion of the machine from his father's drawings

On January 21, 1888 the Mill computed multiples of pi to prove the adequacy of the design.

First Electronic ComputerDate: February 14, 1946Place:University of PennsylvaniaName: ENIACDesigned by:J. Presper Eckert and John MauchlyPurpose:Computing firing tables for the Aberdeen Proving Ground.Programming: RewiringMemory: NilComment: ENIAC was a parallel processor well ahead of its time.

Working with ENIAC

ENIACENIAC

http://www.seas.upenn.edu/~museum/This is only 1/10th of the original. It was announced on February 14th, 1946.

How many Computers?How many Computers?

The world only needs maybe three computers.

Thomas J. Watson, Sr. (CEO IBM)

IBM System 360IBM System 360

Automatic loomAutomatic loom

Patterns controlled by a Patterns controlled by a linked sequence of linked sequence of

punched cardspunched cards

Punched cards

First TransistorFirst Transistor

Year : 1947

Inventors John Bardeen Walter Brattain William Shockley

Nobel prize in 1956

http://ei.cs.vt.edu/~history/

John Louis von NeumannJohn Louis von Neumann

Born: 1903, HungaryBorn: 1903, HungaryDied: 1957, USADied: 1957, USA

Brilliant Brilliant mathematician, mathematician, synthesizer, and synthesizer, and promoter of the stored promoter of the stored program concept,…program concept,…

The von Neumann The von Neumann ArchitectureArchitecture

Alan Turing Alan Turing

Life: 1912 – 1954 UK

Pioneer in developing modern computer logic

One of the first to approach the topic of artificial intelligence.

http://ei.cs.vt.edu/~history/Turing.html

Number SystemsNumber Systems

o Decimal SystemDecimal SystemBase 10Base 10

o Binary SystemBinary SystemBase 2Base 2

o Octal SystemOctal SystemBase 8Base 8

o Hexadecimal SystemHexadecimal SystemBase 16Base 16

Decimal Number SystemDecimal Number System

o Base 10 system (Ten digits: 0, 1, 2, …, 9)Base 10 system (Ten digits: 0, 1, 2, …, 9)

o Counting processCounting processEvery digit goes through a cycle 0 Every digit goes through a cycle 0 9 9 Higher significant digit incremented by 1 for Higher significant digit incremented by 1 for

every cycle of the immediately lower significant every cycle of the immediately lower significant digitdigit

o ExampleExample000001010202……090910101111……1919202021…21…

Decimal Number SystemDecimal Number System

o Expanded formExpanded form 5429 = 5,000 + 400 + 20 + 95429 = 5,000 + 400 + 20 + 9

OROR 5,429 = 5x105,429 = 5x1033 + 4x10 + 4x1022 + 2x10 + 2x1011 + 9x10 + 9x1000

o AdditionAdditionCarryCarry

o SubtractionSubtractionBorrowBorrowNegative numberNegative number

Decimal Number SystemDecimal Number System

o AdditionAddition

o SubtractionSubtraction

7799112211

99118877++

88773344

1111

995555

99118833--

88773344

181866131333

Decimal Number SystemDecimal Number System

o 10’s compliment10’s compliment Let N be an n digit numberLet N be an n digit numberP = 10P = 10nn – N is 10’s compliment of N – N is 10’s compliment of N

o Example 1Example 1 N = 5802N = 5802 P = 10P = 1044 – 5802 = 4198 – 5802 = 4198

o Example 2Example 2 N = 4198N = 4198 P = 10P = 1044 – 4198 = 5802 – 4198 = 5802