representing information digitally. digitization initially transforming data for computer use...

Representing Information Representing Information DigitallyDigitally

DigitizationDigitization

Initially transforming data for computer use

• Assigning people social security numbers

• The creation of telephone numbers

Encoding information became the way to transform the real world into a context that the computer could understand

Information MetamorphosisInformation Metamorphosis

Fitting the real world into the Fitting the real world into the computercomputer

Computer’s worldComputer’s world– ElectronicElectronic– FastFast– BinaryBinary

Real WorldReal World– Multiple forms of data / informationMultiple forms of data / information– Imprecise / vagueImprecise / vague– Non uniform speedsNon uniform speeds

Information MetamorphosisInformation Metamorphosis

Real World Data FormsReal World Data Forms– Numeric DataNumeric Data– Character DataCharacter Data– Graphical / Visual DataGraphical / Visual Data– Audio DataAudio Data– Instructional DataInstructional Data

Methodology needed to transform Methodology needed to transform real world data into computer real world data into computer world (binary)world (binary)

Binary Number SystemBinary Number System

A decimal number:A decimal number:

1,648,3191,648,319

A binary number:A binary number:1001 11011001 1101

10,0

00,0

001,

000,

000

100,

000

10,0

001,

000

100

10 1

0 1 6 4 8 3 1 9

1 0 0 1 1 1 0 1

Binary Number SystemBinary Number System

Binary for numeric dataBinary for numeric data Binary digit = BitBinary digit = Bit 8 Bits = Byte8 Bits = Byte

– Smallest addressable Smallest addressable unit within the computerunit within the computer

4 Bytes = Word4 Bytes = Word– Basic unit for arithmeticBasic unit for arithmetic– Contains 32 bitsContains 32 bits

Converting from binaryConverting from binary

1 0 0 1 1 1 0 1

1 X 128 = 1280 X 64 = 00 X 32 = 01 X 16 = 161 X 8 = 81 X 4 = 40 X 2 = 01 X 1 = 1

157

Numeric DataNumeric Data

0 0000 0000 16 0001 0000 32 0010 0000 48 0011 00001 0000 0001 17 0001 0001 33 0010 0001 49 0011 00012 0000 0010 18 0001 0010 34 0010 0010 50 0011 00103 0000 0011 19 0001 0011 35 0010 0011 51 0011 00114 0000 0100 20 0001 0100 36 0010 0100 52 0011 01005 0000 0101 21 0001 0101 37 0010 0101 53 0011 01016 0000 0110 22 0001 0110 38 0010 0110 54 0011 01107 0000 0111 23 0001 0111 39 0010 0111 55 0011 01118 0000 1000 24 0001 1000 40 0010 1000 56 0011 10009 0000 1001 25 0001 1001 41 0010 1001 57 0011 100110 0000 1010 26 0001 1010 42 0010 1010 58 0011 101011 0000 1011 27 0001 1011 43 0010 1011 59 0011 101112 0000 1100 28 0001 1100 44 0010 1100 60 0011 110013 0000 1101 29 0001 1101 45 0010 1101 61 0011 110114 0000 1110 30 0001 1110 46 0010 1110 62 0011 111015 0000 1111 31 0001 1111 47 0010 1111 63 0011 1111

Numeric DataNumeric Data

Converting to binaryConverting to binary– Repeated division by Repeated division by

22– Remainders are the Remainders are the

important partimportant part– Read from bottom Read from bottom

up as if left to rightup as if left to right

Character DataCharacter Data

Binary for Character DataBinary for Character Data– 8 bit combinations assigned to a symbol8 bit combinations assigned to a symbol– Name for mapping process is ASCII tableName for mapping process is ASCII table

@ 0100 0000 P 0101 0000 0110 0000A 0100 0001 Q 0101 0001 a 0110 0001B 0100 0010 R 0101 0010 b 0110 0010C 0100 0011 S 0101 0011 c 0110 0011D 0100 0100 T 0101 0100 d 0110 0100E 0100 0101 U 0101 0101 e 0110 0101F 0100 0110 V 0101 0110 f 0110 0110G 0100 0111 W 0101 0111 g 0110 0111H 0100 1000 X 0101 1000 h 0110 1000I 0100 1001 Y 0101 1001 i 0110 1001J 0100 1010 Z 0101 1010 j 0110 1010K 0100 1011 [ 0101 1011 k 0110 1011L 0100 1100 \ 0101 1100 l 0110 1100M 0100 1101 ] 0101 1101 m 0110 1101N 0100 1110 ^ 0101 1110 n 0110 1110O 0100 1111 _ 0101 1111 o 0110 1111

ASCII, The ASCII, The American American Standard Code Standard Code for Information for Information

InterchangeInterchange

Graphical DataGraphical Data

Binary for Graphical DataBinary for Graphical Data


Binary for Graphical DataBinary for Graphical Data Each black pixel is Each black pixel is

represented as a “1”represented as a “1” Each white pixel is Each white pixel is

represented as a “0”represented as a “0” Pixels are grouped in Pixels are grouped in

units of 8 so they can be units of 8 so they can be stored in 1 bytestored in 1 byte


A 1” picture scanned at 150 DPI A 1” picture scanned at 150 DPI (dots per inch)(dots per inch)

Total size = 150 X 150 Total size = 150 X 150 22,500 dots 22,500 dots

Memory required = 22,500 / 8 Memory required = 22,500 / 8 2,813 bytes 2,813 bytes

Color requires more bits to represent each Color requires more bits to represent each dotdotUsing 8 bits for each dot allows for 256 Using 8 bits for each dot allows for 256 different colors different colors

The 1” picture now requires 22,500 bytesThe 1” picture now requires 22,500 bytes


Printers are rated in DPI for print Printers are rated in DPI for print qualityquality

Scanners are rated in DPI for image Scanners are rated in DPI for image resolutionresolution

Monitors / displays have display Monitors / displays have display settings for display resolution settings for display resolution –800 X 600800 X 600–1024 X 7681024 X 768–1280 X 10241280 X 1024–1400 X 10501400 X 1050

Audio DataAudio Data

Binary for audio dataBinary for audio data Sound as a waveformSound as a waveform

–Y-axis represents Y-axis represents voltagevoltage–X-axis represents timeX-axis represents time

Suppose the wave Suppose the wave form shown form shown represents 1 second represents 1 second of soundof sound


Divide Sample into segmentsDivide Sample into segments


Divide Sample into more segmentsDivide Sample into more segments


Divide Sample into even more Divide Sample into even more segmentssegments


The more segments the The more segments the better the re-created better the re-created wave formwave form

The given sample was The given sample was divided into 34 divided into 34 segments (approx)segments (approx)

An Audio CD utilizes An Audio CD utilizes 44,000 samples per 44,000 samples per second of soundsecond of sound

Instructional DataInstructional Data

Binary for Instructional DataBinary for Instructional Data Instructional Data has not only Instructional Data has not only

content but sequencecontent but sequence Driving directions to NJ AquariumDriving directions to NJ Aquarium

–Designated number of stepsDesignated number of steps–Sequence of steps is critical to successSequence of steps is critical to success–Rearranging sequence will not get you Rearranging sequence will not get you to the NJ Acquariumto the NJ Acquarium

Recipe / Directions / ProgramRecipe / Directions / Program


Word Hunt Instruction SetWord Hunt Instruction Set–Similar to “decoder ring”Similar to “decoder ring”

Six instructionsSix instructions–GOTO #GOTO #–SELECT #SELECT #–FORWARD #FORWARD #–BACKUP #BACKUP #–WRITEWRITE–STOPSTOP


A program is a collection of instructionsA program is a collection of instructions Executing the program means to “carry Executing the program means to “carry

out” the listed instructionsout” the listed instructions GOTO# - turn to designated pageGOTO# - turn to designated page SELECT# - count down this many linesSELECT# - count down this many lines FORWARD# - count in this many wordsFORWARD# - count in this many words


Real computers have different Real computers have different types of instructionstypes of instructions–ArithmeticArithmetic–Data MovementData Movement–Logical / ComparisonLogical / Comparison–Control Control –Input / OutputInput / Output

representing information digitally. digitization initially transforming data for computer use...

Documents