Bytes and codes. everyday life and Second World War. Mars Lycée du Bois d Amour POITIERS

Transcription

1 everyday life and Second World War Lycée du Bois d Amour POITIERS Mars 2018

2 Bytes or bits? Do you know the difference?

3 Bytes or bits? Do you know the difference? Is there a difference?

4 Bytes or bits? bit the smallest unit of storage Claude Shannon ( ) 1948 A Mathematical Theory of Communication

5 Bytes or bits? bit the smallest unit of storage binary information digit : 1 or 0 Origin John Tukey (Bell Labs) January 1947 John Tukey ( ) electric current On 1 Off 0

6 Bytes or bits? byte

7 Bytes or bits? byte a group of 8 bits, an octet

8 Bytes or bits? byte a group of 8 bits, an octet Example

9 Bytes or bits? byte a group of 8 bits, an octet Example spaces, 2 } 2 {{... 2 } = 2 8 = 256 possibilities 8 times

10 Numbers and bits How can we write every number using only 1s and 0s?

11 Numbers and bits How can we write every number using only 1s and 0s? Why? Gottfried W. Leibniz( ) by Christoph Bernhard Francke

12 Numbers and bits How can we write every number using only 1s and 0s? Why? to avoid human error Gottfried W. Leibniz( ) by Christoph Bernhard Francke

13 Numbers and bits How can we write every number using only 1s and 0s? Video from Story of one In «Explanation of Binary Arithmetic, which uses only the characters 1 and 0»

14 Numbers and bits From decimal to binary How can we write 19 using the 1s and 0s on one byte? 19 =

15 Numbers and bits From decimal to binary How can we write 19 using the 1s and 0s on one byte? 19 =

16 Numbers and bits From decimal to binary How can we write 19 using the 1s and 0s on one byte? 19 = is written using one byte or 8 bits

17 Numbers and bits From binary to decimal What is the number written with one byte?

18 Numbers and bits From binary to decimal What is the number written with one byte? = is the binary writting of the decimal number 89.

19 Numbers and bits Binary numbers and additions

20 Numbers and bits Binary numbers and additions Example from Leibniz (he forgot something... )

21 Numbers and bits Binary numbers and additions Example from Leibniz (he forgot something... ) How can you add and ?

22 Memory and bits

23 Memory and bits

24 Memory and bits IBM first drive RAMAC 1956

25 Memory and bits IBM first drive RAMAC 1956

26 Memory and bits Kilo-octet 1Ko 2 10 = Bytes Mega-octet 1Mo Bytes Giga-octet 1Go Bytes Tera-octet 1To Bytes Peta-octet 1Po Bytes Exa-octet 1Eo Bytes Zetta-octet 1Zo Bytes

27 Memory and bits o Ko Mo Go T o P o Eo

28 Memory and bits o Ko Mo Go T o P o Eo Mo a 500 page book ; color photo( poor quality) 1 Go an encyclopedia ; a 1 hour good quality video 32 Go a USB key 1 To information in the million of books published per a year ; 500 hours of video (good quality) 2 Po archive of internet in Eo all the information written on paper on Earth

29 Memory and bits Music One Petaoctet (or Go) of average MP3-encoded songs 2000 hours would require 2000 days 2000 weeks 2000 years to play.

30 Memory and bits Music One Petaoctet (or Go) of average MP3-encoded songs 2000 hours would require 2000 days 2000 weeks 2000 years to play. Photos January 2013, Facebook over 240 billion photos uploaded, with 350 million new photos every day. For each uploaded photo, Facebook generates and stores four images of different sizes, which translated to a total of 960 billion images and an 357 Go estimated 357 To 357 Po 357 Eo of storage.

31 Bits and everyday life codes Codes in everyday life?

32 Bits and everyday life codes Codes in everyday life? Universal Product Code (UPC-A) barcode for tracking trade items in stores.

33 Bits and everyday life codes Codes in everyday life? Universal Product Code (UPC-A) barcode for tracking trade items in stores. ISBN (books), QR code Credit cards...

34 Bits and everyday life codes Universal Product Code (UPC-A) or EAN

35 Bits and everyday life codes Universal Product Code (UPC-A) or EAN The last digit is a check digit

36 Bits and everyday life codes Universal Product Code (UPC-A) or EAN How to check the code a 1 a 2 a 3 a 4 a 5 a 6 a 7 a 8 a 9 a 10 a 11 a 12? S = 3 a 1 + a a 3 + a a 9 + a a 11 + a 12 The code is right if S is a multiple of 10.

37 Bits and everyday life codes QR codes (Quick Response Code)

38 Bits and everyday life codes QR codes (Quick Response Code)

39 Second World War and Codes

40 Second World War and Codes During the Second World War, German transmissions for U-Boat were encrypted with the enigma machine.

41 Second World War and Codes

42 Second World War and Codes Alan Turing created a kind of computer named Bomba that craked the Enigma code. He saved thousands of lives during the battle of the Atlantic.

43 Alan Turing

44 Alan Turing Turing machine a mathematical model of a computer.

45 Alan Turing Turing machine a mathematical model of a computer. Turing patterns patterns on animals skins

46 What you need to remember bit byte Binary numbers Decimal numbers Units and data storage (Go, To, Po... ) Everyday life codes (UPC... ), check digit Enigma, Alan Turing and its Bomba during WW2