introduction to computing. computer history charles babbage born december 26, 1791 in teignmouth,...

Introduction to Computing

Computer History

Charles Babbage

Born December 26, 1791 in Teignmouth, Devonshire UK, Died 1871, London; Known to some as the "Father of Computing" for his contributions to the basic design of the computer through his Analytical machine. His previous Difference Engine was a special purpose device intended for the production of tables.

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

Ada Augusta King

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

The first programmer

The 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, and on January 21, 1888 computed multiples of pi to prove the adequacy of the design. Perhaps this represents the first successful test of a portion of a "modern" computer. Recently a portion of his earlier machine, the Difference Engine, was sold at auction by Christies of London to the Powerhouse Museum in Sydney, Australia.

… on February 14, 1946 the University of Pennsylvania unveiled the ENIAC, designed by J. Presper Eckert and John Mauchly, for the purpose of computing firing tables for the Aberdeen Proving Ground. Though arguably not the first "computer“… ENIAC was the first fully operational electronic, general purpose, machine. … programming was essentially completed by rewiring and the stored memory was not yet implemented, ENIAC was a parallel processor well ahead of its time.

Thomas J. Watson, Sr. ...he is often credited with the statement that "the world only needs three computers"

IBM System 360

Automatic loom which wove patterns controlled by a linked sequence of punched

cards

First Transistor

Year : 1947

InventorsJohn Bardeen Walter Brattain William Shockley

They all won Nobel prize in 1956

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

ENIAC

http://www.seas.upenn.edu/~museum/

This is only 1/10th of the original. It was announced on February 14th, 1946.

John Louis von Neumann

• Born 28 December 1903, Budapest, Hungary; Died 8 February 1957, Washington DC; Brilliant mathematician, synthesizer, and promoter of the stored program concept, …

• … - the von Neumann Architecture

Alan Turing

Born 23 June 1912, London; Died 7 June 1954, Manchester England; Pioneer in developing computer logic as we know it

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

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

Number Systems

• Decimal System• Base 10

• Binary System• Base 2

• Octal System• Base 8

• Hexadecimal System• Base 16

Decimal Number System

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

• Counting process– Every digit goes through a cycle 0 9

• After a complete cycle of a lower significant digit (0 through 9) immediately higher digit is incremented by 1, while the lower significant digit is reset to 0.

• 012…91011…192021 and so on

Decimal Number System

• Expanded form– 5429 = 5,000 + 400 + 20 + 9

OR– 5,429 = 5x103 + 4x102 + 2x101 + 9x100

• Addition– Carry

• Subtraction– Borrow– Negative number

Binary Number System

• Base 2 system (2 digits; 0, 1)• Counting

0,1,10,11,100,101,110,111,1000,…

2 10

2 10

2 10

2 10

2 10

(0) (0)

(1) (1)

(10) (2)

(11) (3)

(100) (4)


Expanded form– (110010)2 = 1x25 + 1x24 + 1x21

= 32 + 16 + 2 = (50)10

– Addition1 1 1 1 1 <-- Carry

1 1 1 1 1+ 1 0 1 1 1

1 1 0 1 1 0

32 16 0 4 2 0 54


• Subtraction (M-N)– M ≥ N– M < N

• Compute N-M• Multiply the answer by -1

0 10 10

1 1 0 1 13

- 0 1 1 0 - 6

0 1 1 1 7


010 2

110 2

210 2

310 2

2

2 (1) (1)

2 (2) (10)

2 (4) (100)

2 (8) (1000)

2 (100 0)n

N zeros


• Radix Diminished Complement – (r-1)’s complement 1’s complement

• If N is n digit number• 1’s complement of N is (2n-1)-N

– Example• N=1010 n=4• 24 – 1 = 10000 – 1 = 1111• 1111 – 1010 = 0101 is 1’s complement of 1010


• Radix complement – r’s complement 2’s complement

• If N is n digit number• 2’s complement of N is 2n - N

– Example• N=1010 n=4• 24 = 10000• 10000 – 1010 = 0110 is 2’s complement of 1010

– 2’s complement of N = 1’s complement of N + 1


• Using 2’s complement in subtraction– To evaluate M – N

• Let P = 2’s complement of N• Calculate S = M + P• If there is an “end carry”, discard it. Subtraction is

complete• If there is no “end carry”, take 2’s complement of S

and associate a negative sign with the result.


• Example– Evaluate the following using 2’s complement.

Verify in decimal system.

• 1010100 – 1000011 84 – 67 = 17• 1000011 – 1010100 67 – 84 = -17

Decimal & Binary conversion

• Convert (289)10 into binary

• Convert (10111010)2 into decimal

• Convert (0.289)10 into binary

• Convert (0.10111010)2 into decimal

Hexadecimal Number System

• Base 16 system (0,1,…,9,A,B,…F digits)– A (10) 10

– F (15)10

• Counting– 0,1,2,…,A,B,…,E,F,10,11,…1E,1F,20,…

• Decimal Equivalents– (10)16 = (1 x 161) + (0 x 160) = (16)10

– (F2)16 = (15 x 161) + (2 x 160) = (242)10


– Hexadecimal & decimal conversions• (462)10 (?)16

• (462)16 (?)10

• (0.462)10 (?)16

• (0.462)16 (?)10


• Binary & Hexadecimal Conversions

– Combine 4 binary digits into a hexadecimal number

– Break each hexadecimal digit into 4 binary digits

Hexadecimal& Binary Conversion

16 2

16 2

16 2

16 2

16 2

16 2

16 2

16 2

(0) (0000)

(1) (0001)

(2) (0010)

(3) (0011)

(9) (1001)

( ) (1010)

( ) (1110)

( ) (1111)

A

E

F

8 4 2 1

Hexadecimal& Binary Conversion

16 2

16 2

(3 5) (0011 1011 0101)

( 2 ) (1110 0010 1100)

B

E C

2 16

2 16

(1011 1011 0101) ( 5)

(10 0000 1001) (2 0 9)

B B

Power of 2

• Inventor of chess• All that he asked was to place one grain of rice on

the first box and keep on doubling

• Money Game• I will give you Rs 100,000 everyday for 30 days.

You will give me 1 paisa on the 1st day but will double the amount every day for 30 days.

– 230-1 ~ 10.7 x 108

Computer Architecture

Arithmetic Logic UnitALU

Control UnitCU

Datapath

Memory

Input/Output

CPU

Memory Organization

Address Data/Instructions

012

65536

6553465535

0 0 01 1 1 1 1

8 bits = 1 byte

64 Kilo byte RAM = 65,536 bytes of RAMNeeds 16 address lines

Memory Addresses

=4 M419430422=2 M209715221=1 M104857620

=512 K52428819=256 K26214418=128 K13107217

=64 K6553616=32 K3276815=16 K1638414

=8 K819213=4 K409612=2 K204811=1 K102410

5129 2568 1287 646 325

164 83 42 21 Memory LocationsAddress Lines

Address & Data Bus

CPU

AddressBus

Memory

Data Bus

Signed Numbers

• 0 +ive sign

• 1 -ive sign0000 0 1000 0

0001 1 1001 -1

0101 5 1101 -5

0111 8 1111 -8

Software

• Set of instructions for the computer.A=5

B=3

C=A+B

Print C on the terminal

Computer Languages

• URDU, FRENCH, SPANISH, ENGLISH

• MACHINE CODE

• ASSEMBLY

• ADA, FORTRAN, BASIC

• PASCAL, LISP

• C, C++ Must for CS/CE/EE

• Visual BASIC

Operating System

• Software that– efficiently utilizes computer resources– resolves issues among various computer

processes• Competing processes• Cooperating processes

• Windows95 is what Macintosh was in 85

introduction to computing. computer history charles babbage born december 26, 1791 in teignmouth,...

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